Obsidian and Ancient Manufactured Glasses
Author: Ioannis Liritzis; Christopher M. Stevenson
Date: 2012-04-15 00:00:00+00:00
Keywords: Archaeology; Social Science
Description: This edited volume offers archaeologists and archaeometrists the latest technical information, the fundamentals of provenance studies, instrumentation used in these investigations, and strategies for the dating and interpretation of archaeological materials in glass studies. The contributors discuss recent advances in obsidian hydration dating, secondary ion mass spectrometry, and infrared photoacoustic spectroscopy, focusing on the application of these technologies to a variety of glass forms and incorporating studies that look at the social and economic strategies of past cultures. With exam
Publisher: University of New Mexico Press

Obsidian and
ancient

Manufactured

Glasses

X

Edited by

Ioannis Liritzis
and

Christopher M. Stevenson

OBSIDIAN AND ANCIENT

MANUFACTURED GLASSES

Aspects of Secondary Ion Mass Spectrometry (SIMS) | iii OBSIDIAN AND

ANCIENT

MANUFACTURED

GLASSES

Edited by

Ioannis Liritzis
and

Christopher M. Stevenson

UNIVERSITY OF NEW MEXICO PRESS

Albuquerque

© 2012 by the University of New Mexico Press All rights reserved. Published 2012

Printed in the United States of America

17 16 15 14 13 12 1 2 3 4 5 6

Library of Congress Cataloging-in-Publication Data

Obsidian and ancient manufactured glasses / edited by Ioannis Liritzis and Christopher M. Stevenson.

p. cm.

Includes bibliographical references and index.

ISBN 978-0-8263-5159-3 (cloth: alk. paper)

ISBN 978-0-8263-5161-6 (electronic)

1. Hydration rind dating.

2. Obsidian.

3. Glassware, Ancient.

I. Liritzis, Ioannis.

II. Stevenson, Christopher M. (Christopher Moore), 1952–

CC78.7.O37 2012

748.20937—dc23

2011048531

The editors dedicate this book to their parents, whose love and emphasis on education have given us most interesting lives: Marthas and Georgios Liritzis

Joyce and William T. Stevenson

Contents

Figures and Tables ............................................ ix Part II Obsidian Glass Provenance

Preface .................................................................. xv Chapter 6

Editors’ Introduction

Provenance of Peruvian Wari Obsidian:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii Comparing INAA, LA-ICP-MS, and

Portable XRF by Patrick Ryan Williams,

Part I Obsidian Hydration Dating

Laure Dussubieux, and Donna J. Nash .......... 75

Chapter 1

Aspects of Secondary Ion Mass Spectrometry

Chapter 7

(SIMS) Depth Profiling for Obsidian

New Perspectives on Obsidian Procurement

Hydration Dating by Steven W. Novak
and Exchange at Tiwanaku, Bolivia by
and Christopher M. Stevenson

Michael D. Glascock and Martin Giesso ....... 86

. . . . . . . . . . . . . . . . . . . . . . . . . 3

Chapter 2

Chapter 8

Obsidian Hydration Chronometrics

Volcanic Glass Procurement and Use

Using SIMS and Optical Methods from
in the Late Paleolithic, Central Primorye,

26-year Temperature-controlled

Far East Russia by Trudy Doelman, Robin

Exposures by Wallace Ambrose and

Torrence, Vladimir Popov, Nikolai

Steven W. Novak

Kluyev, and Igor Sleptsov ............................... 97

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Chapter 3

Chapter 9

The SIMS-SS Obsidian Hydration

Obsidian Provenance at Several Italian

Dating Method by Ioannis Liritzis and
and Corsican Archaeological Sites Using

Nikolaos Laskaris
the Non-destructive X-ray Fluorescence

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Method by Anna Maria De Francesco,

Chapter 4

Marco Bocci, Gino Mirocle Crisci, and

Temperature Correction for

Vincenzo Francaviglia .................................... 115

Obsidian Hydration Dating by

Alexander K. Rogers

Chapter 10

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Polynesian Volcanic Glass: Uses, Sourcing,

Chapter 5
and Distribution by Marshall Weisler .......... 130

Obsidian Dating and Source Exploitation

Studies in Africa: Implications for the

Chapter 11

Evolution of Human Behavior by

Glass Vessels in Sub-Saharan Africa:

Stanley H. Ambrose

A Compositional Study of Samples from

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Mtwapa, Kenya by Laure Dussubieux and

Chapurukha M. Kusimba .............................. 143

Chapter 12

On the Provenance of Roman Glasses
by Caroline M. Jackson .................................. 157
vii
viii |

Chapter 13

Chapter 15

Characterization and Provenance of

Thoughts on Natural and Manufactured

Archaeological Glass Artifacts from

Glass Studies in a 21st-Century

Mainland and Aegean Greece by

Archaeology by M. Steven Shackley ........... 202

Konstantinos G. Beltsios, Artemios

Oikonomou, Nikolaos Zacharias,

Contributors ................................................... 211
and Pavlos Triantafyllidis ............................ 166

About the Editors .......................................... 213

Chapter 14

Index .................................................................... 215

The Provenance of Ancient Man-made

Glass: Raw Materials and the Use of

Chemical and Isotopic Analytical

Techniques by Julian Henderson ................. 185

Figures and Tables

Figures

Figure 1.1. Diagram of a magnetic sector

(CAMECA) SIMS instrument

Figure 3.1. A SIMS hydrogen profile ............. 28

. . . . . . . . . . . . . . . . . . . . . 5

Figure 1.2. Diagram of a quadrupole-

Figure 3.2. A nondimensional profile
based SIMS instrument (Phi)

with Crank’s theoretical curves ................. 30

. . . . . . . . . . . . . . . . . . . . . 5

Figure 1.3. Photomicrograph of SIMS

Figure 3.3. A Polarised Light Microscope
craters on an oriented obsidian

(PLM) image of a Melian obsidian
surface
surface ........................................................... 31

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 1.4. Quadrupole SIMS depth profile

Figure 3.4. SEM backscattering image
measurements of hydrated obsidians
of Youra Island (Cyclop’s Cave)

. . . . . . . . . 8

Melian obsidian ........................................... 31

Figure 1.5. SIMS profiles of laboratory
hydrated obsidian samples

Figure 3.5. AFM topographic image ............ 31

. . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 1.6. Correlation of hydration layer

Figure 3.6. Linear fit to the hydration
thickness
region for the calculation of R

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
std . . . . . . . . . . . . . . . . 32

Figure 1.7. AFM image of a conchoidal

Figure 3.7. Savitziky-Golay fit and the
fractured obsidian surface
first derivative of the Savitziky-Golay ........ 33

. . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 1.8. AFM image of an obsidian

Figure 3.8. (a) Fitting until the
artifact showing roughness due to
inflection depth; (b) First derivative
pitting
of the 3rd-order polynomial .......................34

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 1.9. Comparison of two SIMS

Figure 3.9. Results from the linear
profiles
regression ..................................................... 35

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 2.1. Map showing the three main

Figure 3.10. An ideal SIMS profile ................ 35
obsidian source areas in Papua New

Figure 3.11. Repeated polynomial

Guinea .......................................................... 16
fittings ...........................................................36

Figure 2.2a. The reproducibility of the

Figure 3.12. Hyperbola bell shape,

SIMS analysis (Igwageta source) ................ 18
normal and reversed.................................... 37

Figure 2.2b. Confirmation of the

Figure 3.13. Screen image of the
reproducibility of two SIMS runs ............... 19

SIMS-SS software ......................................... 38

Figure 2.3. The major element chemistry

Figure 3.14. Fitting with the “fit coef”

of the four obsidian sources as shown
button of the SIMS-SS software..................39
in this Arrhenius regression diagram ........ 21

Figure 3.15. Ages calculated with

Figure 2.4. Average curve of 5 scans (A–B)

SIMS-SS method versus expected
across an external hydration band and
archaeological ages ..................................... 40
average curve of 3 scans (A–D) across

Figure 3.16. Sensitivity of age for four
an internal fissure ........................................22
parameters: ek, C , X , and D
s
s
s,eff . . . . . . . . . . . . . . . . . 42
ix
x | FIGURES AND TABLES

Figure 3.17. Samples without a developed

Figure 6.4b. Graph reporting the concen-
hydration layer compared to a normal
tration of manganese and strontium
diffusion profile (Lamo-5)

43
measured for the samples from Cerro

Figure 3.18. Disturbed SIMS profile:

Mejia and Mejia Ladera

81

Sample YR-3 from Youra Island, Greece 43

Figure 6.5. Examples of projectile point

Figure 4.1. Relationship between site altitude types from Cerro Baúl

83
and average temperature variation,

Figure 7.1. Map of Tiwanaku and
northern Mojave Desert sample

51
other archaeological sites in the Lake

Figure 4.2. Relationship between site

Titicaca basin

88
altitude and annual temperature variation,

Figure 7.2. Topographic map of archaeo-
northern Mojave Desert sample

51
logical sites within the boundaries

Figure 4.3. Relationship between site altitude of Tiwanaku

88
and mean diurnal temperature variation,

Figure 7.3. Map showing the locations
northern Mojave Desert sample

51
of obsidian sources mentioned in

Figure 4.4. Relationship between
this study

89
average annual temperature and annual

Figure 7.4. Bivariate plot of the elements
temperature variation, northern Mojave

Cs and Hf measured by NAA on

Desert sample

51
obsidian artifacts

91

Figure 5.1. Map of East Africa, showing

Figure 7.5. Bivariate plot of the elements
obsidian sources and archaeological

Sc and Eu measured by NAA on
sites

58
obsidian artifacts

91

Figure 5.2. Map of the Lake Naivasha basin in Figure 7.6. Bivariate plot of the
the central Rift Valley of Kenya

59
elements Rb and Sr measured by XRF

Figure 5.3. Distance-decay curves for
on obsidian artifacts

91
percentages of obsidian in archaeo-

Figure 8.1. Location of the surveyed
logical sites

66
primary and secondary sources in the

Figure 6.1a and 1b. Relative deviations

Shkotovo Plateau

99
between the LA-ICP-MS and the p-XRF

Figure 8.2. Location of sites showing the
measurements for strontium and
zones of secondary volcanic glass
manganese

78
distribution in waterways of the

Figure 6.2a and 2b. Relative errors on

Shkotovo Plateau

99
the p-XRF measurements for strontium

Figure 8.3. (a) Example of hyaloclastic and manganese

79
formation profile in the Shkotovo

Figure 6.3a. Graph reporting the

Plateau; (b) Core of volcanic glass;
concentration of rubidium and strontium

(c) Tongue of volcanic glass; (d) Blocky measured for the samples from
fragments of volcanic glass; (e) Rinds

Cerro Baúl
of volcanic glass

101

80

Figure 6.3b. Graph reporting the concentra-

Figure 8.4. Types of cortex found on the
tion of manganese and strontium measured
primary and secondary sources in the
for the samples from Cerro Baúl
study area

103

80

Figure 6.4a. Graph reporting the

Figure 8.5. Examples of microblade
concen tration of rubidium and
preforms found at Tigrovy-8

105
strontium measured for the samples

Figure 8.6. Principal components
from Cerro Mejia and Mejia Lareda

81
analysis of PIXE-PIGE results

107

Figures and Tables | xi

Figure 9.1. Distribution of obsidian

Figure 13.3a. K O versus MgO for glass

2
sources in the Mediterranean area
artifacts from Rhodes (seventh, fourth,
exploitable in the Neolithic period .......... 116
third–second centuries BC) and from

Figure 9.2. Comparison between the

Thebes (Archaic to Hellenistic times) ...... 171
destructive and non-destructive

Figure 13.3b. K O versus MgO

2

. . . . . . . . . . . . . . . . . . . 171

XRF methodologies ................................... 118

Figure 13.4. MgO versus CaO for seventh-

Figure 9.3. Provenance of archaeological
century BC Rhodian artifacts and
fragments from the Catignano site and

Thebian artifacts ........................................ 173

Torre Foghe compared to the obsidian

Figure 13.5. Al O versus MgO for
sources

2 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
glass artifacts from Rhodes and

Figure 9.4. Location of Neolithic
from Thebes ............................................... 173
archaeological sites .................................... 120

Figure 13.6. Fe O versus Al O for the

2 3

2 3

Figure 9.5. Archaeological obsidian

Rhodian artifacts ....................................... 174
provenance according to geographical

Figure 13.7. Fe O versus Al O for the
area

2 3

2 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
samples from Thebes ................................. 175

Figure 9.6. A pie diagram of the

Figure 13.8. Al O versus K O for the
provenances for 1398 analyzed

2 3

2
glass artifacts from Thebes........................ 178
archaeological samples .............................. 126

Figure 14.1. Variations in the concen tra -

Figure 10.1. A volcanic glass dike at
tions of element oxides (log weight %

Waiahewahewa, west Moloka‘i,
oxide) of ashed plants of the genus

Hawaiian Islands ......................................... 131

Salsola growing in the Balikh valley,

Figure 10.2. A map of West and East
northern Syria ............................................190

Polynesia ..................................................... 133

Figure 14.2. Relative levels of Na and K

Figure 11.1. Map of Kenya with Mtwapa .... 144
in 3 samples of Salsola jordanicola from Figure 11.2. Fragments of glass from
three geologically contrasting areas of

Mtwapa
northern Syria ............................................ 191

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Figure 11.3. Na O-MgO concentrations

Figure 14.3. The location of al-Raqqa,

2
bi-plot for the dominant type of glass

Syria ............................................................ 193
at Mtwapa and for some beads from

Figure 14.4. Relative concentrations of

Madagascar ................................................. 151
weight % MgO and K O in 9th- and

2

Figure 12.1. Iron oxide and manganese

11th-century AD glass samples from
oxide concentrations for purple and blue
al-Raqqa, Syria ........................................... 195
glasses from first-century contexts ..........160

Figure 14.5. Relative concentrations of

Figure 12.2. Major element concentrations
weight % MgO and Al O in 9th- and

2 3
for amber, purple, and green glasses

11th-century AD glass samples from
from first-century contexts
al-Raqqa, Syria ........................................... 196

. . . . . . . . . . . . . . . . . . . . . . . 161

Figure 13.1. Six samples from the Rhodes

Figure 14.6. Relative concentrations of
collection
weight % P O and CaO in 9th- and

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

2 5

11th-century AD glass samples from

Figure 13.2. Six samples from the
al-Raqqa, Syria

Thebes collection

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
xii | FIGURES AND TABLES

Figure 14.7. A plot of neodymium isotope
in 9th- and 11th-century AD glass from
values against neodymium concentration
al-Raqqa by artifact type ........................... 197
in 9th- and 11th-century AD glass from

Figure 14.9. A plot of neodymium isotope
al-Raqqa by chemical type ........................ 197
values against strontium isotope values

Figure 14.8. A plot of neodymium isotope
in 9th- and 11th-century AD glass from
values against neodymium concentration
al-Raqqa by artifact type ........................... 198

Tables

Table 1.1. SIMS sputtering rates on

Table 6.2. Deviations between the
obsidians of different structural

LA-ICP-MS and p-XRF results with the
water content ................................................. 9
range of concentrations in the samples

Table 2.1. SEM EDX analysis of the
tested for each element ............................... 78
experimentally hydrated obsidians ............ 17

Table 6.3. Number of samples tested by

Table 2.2. SIMS profile depths and regression LA-ICP-MS and p-XRF.............................. 79
results for hydrated obsidians .................... 20

Table 6.4. Number of samples from each

Table 2.3. Hydration layer thicknesses on
site attributed to each source according
flake internal fissures from the Sasi site
to the analytical technique used

. . . . . 22

(LA-ICP-MS or p-XRF)

Table 2.4. Calculated age in years for

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
the Sasi obsidian flakes at different

Table 6.5. For the site of Cerro Baúl,
temperatures
proportions of samples attributed to

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
different sources using different

Table 2.5. Sasi site hydration readings
analytical techniques
partitioned by group

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Table 7.1. For the site of Tiwanaku,

Table 3.1. Samples, locations, SIMS-SS
proportions of samples attributed to
dates, and archaeological ages .................... 41
different souces ........................................... 92

Table 4.1. Temperature data summary

Table 7.2. Provenance of obsidian artifacts
in degrees Centigrade for years
from sites external to Tiwanaku

2000–2005, Amargosa Desert Research

. . . . . . . . . . . . . . . . 92

Site, 845 m altitude

Table 8.1. Counts of artifacts from sites in

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
the study area that were geochemically

Table 4.2. Weather data from 13 stations
and technologically analyzed
in the southwestern Great Basin and

. . . . . . . . . . . . . . . . . . . 100

Northern Mojave Desert

Table 8.2. Description of the primary

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
volcanic glass sources assessed in the

Table 4.3. Paleoclimatic correction factors

Shkotovo Plateau
for age computation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Table 8.3. Decrease in mean size of

Table 5.1. Age ranges of major Stone Age
nodules within secondary deposits with
industrial complexes in Sub-Saharan
increasing distance from outcrops

Africa

. . . . . . . . . . . 103

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 8.4. Types of cortex (representing

Table 6.1. Comparison of the results on
different sources types) in sites from
two obsidian samples from Sierra Pachuca,
the different zones

State of Hidalgo, Mexico, and from the

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Little Glass Buttes source, Lake County,

Table 8.5. Relationship between cross-section Oregon, USA
and size of microblade core preforms at

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Tigrovy-8 .................................................... 105

Figures and Tables | xiii

Table 8.6. Results of the specific gravity
on the geological fragments using the
tests (g/cm3)................................................ 106
non-destructive XRF methodology .......... 119

Table 8.7. Composition of elements

Table 9.2. Obsidian provenance from
found in the PIXE-PIGE samples from
archaeological sites of Central Italy .......... 121
outcrops in the Shkotovo Plateau ............. 106

Table 9.3. Obsidian provenance from

Table 8.8. The characteristics of the
archaeological sites of Northern Italy ...... 124
basaltic glass and rhyolitic glass artifacts

Table 9.4. Obsidian provenance from
obtained from Paektusan Volcano as
archaeological sites of Southern Italy ...... 124
distance increases from outcrops of
basaltic volcanic glass

Table 9.5. Obsidian provenance from

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
archaeological sites in Sardinia and

Table 8.9. The size and weight of the

Corsica ......................................................... 125
complete flakes, tools, and cores made
from basaltic glass and rhyolitic glass

Table 10.1. Volcanic glass artifacts
obtained from Paektusan Volcano
in Polynesia .................................................138

. . . . . . . . . . . 109

Table 8.10. The elongation of complete

Table 11.1. Description of the samples
flakes made from basaltic glass as
analyzed ...................................................... 146
distance increases from outcrops of

Table 11.2. Compositions for oxides
basaltic volcanic glass .................................110

(weight percent) and elements (ppm)

Table 8.11. Types of tools made from
for the 31 samples from Mtwapa............... 147
basaltic glass as distance increases

Table 11.3. Average concentrations of
from the primary sources of basaltic
the major elements (weight percent)

volcanic glass ...............................................110
in 30 Mtwapa glass samples with the

Table 8.12. Fragmentation of the tools
same composition ....................................... 151
made from basaltic glass as distance

Table 11.4. Comparison of the composition
increases from the primary sources of
found at Mtwapa with similar
basaltic volcanic glass ................................. 111
compositions from different areas ............ 153

Table 9.1a. Concentrations in ppm

Table 13.1. Synopsis of EDS compositional
obtained on the powdered geological
analysis of key oxides in glass beads from
obsidians for five selected trace
seventh-century BC Rhodes ..................... 169
elements ....................................................... 118

Table 13.2. Synopsis of EDS compositional

Table 9.1b. Secondary X-ray intensities
analysis of key oxides in glass beads
for five selected trace elements obtained
from Thebes ............................................... 169

Preface

The impetus for this book came from our the workshop but had recently published new and desire to produce an up-to-date and infor-rele vant contributions. In addition, we are especially mative volume on current obsidian and
grateful to Dr. Masao Suzuki, whose “Obsidian Sum-
man-made glass studies that will encourage further
mit” meeting held during 2004 in Tokyo provided a
work in this field. To generate a wider appreciation
venue and generous support from Rikkyo University
of the project’s aim, the editors hosted a specialized for all those contributors who presented papers. The
international workshop at the European Cultural
international “Obsidian Summit” provided a very

Cen ter in the ancient Greek town of Delphi, Greece,
useful stimulus for continuing research in obsid-
in Feb ruary 2008. At this venue, the invited authors
ian studies leading to the Delphi meeting and the
presented first drafts of their manuscripts to an
proceedings reported in this volume. Some of the
audience of their peers for comment and evaluation.

summit’s unpublished studies now appear in this

Several additional contributions were also solicited
volume after the authors revised and updated their
directly from individuals who were unable to attend
contributions.

xv

Editors’ Introduction

About every 10 years it becomes necessary of archaeological investigations into past social sys-to prepare an edited volume by experts in
tems. In this volume, the papers concerned with
the field of glass studies that reflects new
chronology look at recent advances pertinent to
developments and applications in absolute dating
the method of obsidian hydration dating (OHD).

and provenance. The pace of analytical advances and

Traditional approaches to this dating method using
instrument development is rapid, and now more
optical microscopy have become less favored and are
than ever they are applied within the historical sci-
being replaced by precise surface characterization
ences. Dating and provenance are two topics often
techniques such as secondary ion mass spectrom-
combined within a single publication since prov-
etry (SIMS) and infrared photoacoustic spectros-
enance studies are highly dependant upon age esti-
copy (IR-PAS). Archaeologists may be unaware of
mates if diachronic models of human behavior are
these developments, or intimidated by a presumed
desired. For this reason, we have again placed them
complexity of the science, such that applications
together under the conventional format.

of the new techniques are limited. In this volume

This effort continues the tradition of book publi-
we will detail the approaches and their application
cation that periodically updates archaeologists inter-
in a manner understandable and interesting to the
ested in glass studies. This tradition started in 1976
archaeologist.

with the publication of Advances in Obsidian Glass In the same vein, we look at the technology behind

Studies (R.E. Taylor, editor, Noyes Press) and was fol-artifact provenance studies that includes instru mental lowed in 1998 by the most recent publication, entitled neutron activation analysis (INAA), laser ablation–

Archaeological Obsidian Studies: Method and Theory inductively coupled plasma–mass spectrometry (LA-

(M.S. Shackley, editor, Plenum Press). These books

ICP-MS), and X-ray fluorescence (XRF). All of these
have been, and continue to be, highly referenced even
techniques are well-established technologies, and we

30 years later. This fact is supported by an important will generally focus not on the instrumentation but
point made by M.S. Shackley in his volume, that “in
on methods of application to a variety of glass forms.

the last twenty years, the use of obsidian archaeome-

We have included papers that go well beyond descrip-
try has witnessed almost boundless expansion, partly
tive applications of glass composition and provenance
due to the concomitant advances in computer tech-
and incorporate studies that look at the social and eco-nology and instrumental chemistry, and partly due
nomic strategies of past cultures.

to the recognition by archaeologists that archaeome-

This book contains 15 individual chapters by
trists provide much more than mere measurement”

scholars from many parts of the globe. The areas

(1998:2). As a result, we believe that the volume will of study include case examples from Greece, the
continue to be of interest to a wide number of schol-

Middle East, Italy, Peru, Bolivia, Russia, Africa, and ars in the years to come.

the Pacific region. The book has been subdivided

Archaeometric studies of natural and ancient
into two major sections. Part 1 discusses the ana-
manufactured glasses are conducted throughout the
lytical methods associated with current applications
world as a means of looking at chronometric age
of OHD. It begins with a close look at the instru-
and provenance and are widely applied more than
mentation used for SIMS analysis of glass surfaces.

ever before. Both of these topics are central aspects

This technology has become the favored technique
xvii
xviii | EDITOR’S INTRODUCTION
for acquiring hydrogen depth profiles on glass sur-

(mainland Greece) glass fragments (seventh–fourth
faces since it avoids the problematic issue of opera-
century BC), the latter tackling the issue of unusual
tor judgment during optical measurement at high
raw materials.

magnification. Yet there are a number of instru-

Provenance studies on manufactured glasses are
ment configurations, each with its own advantages
no less complex than the characterization of regional
and drawbacks. Sample surface conditions can also
obsidian or basalt source distributions. Human exper-
impact the shape of the profile and are thus prob-
imentation and raw materials have been combined
lematic in application to archaeological specimens.

into a single compositional product, and the task is

SIMS is a central aspect of one especially important
to distinguish not only how the glasses were made
contribution that includes the results of a 26-year-
but where they came from as well. In such cases addi-
long weathering experiment at ambient tempera-
tional tools are brought to bear on these situations
ture. It is currently unique to the discipline and will and include the use of isotopic studies. The impact of likely not be repeated for many years. The results of
regional source material selection on glass composi-
long-term weathering experiments have contrib-
tion can provide clues about geographic location as
uted to our understanding of how water diffuses
can the elements imparted by the use of specific types into glass at ambient temperature. The observations
of plants specific to areas or regions.

acquired here support the development of a new

As the methods of glass characterization be-
dating method known as SIMS-SS (SIMS–saturated
come well validated, fewer papers are concerned with
surface). Dating by SIMS-SS has not seen wide appli-
the specifics of instrumentation. Similarly, as regions cation, but a series of publications, including the one become intensively studied a focus on the develop-presented here, has clarified the theory and applica-
ment of geochemical databases for natural glasses
tion of the method. The SIM-SS dating method is
loses its place as the primary objective. Rather, as we highly advantageous because the hydrogen profile
see here, multiple forms of instrumentation are com-
is a proxy for the impinging parameters of ground
bined to invent new analytical protocols such as the
temperature and soil relative humidity. SIMS analy-
combined use of portable-XRF and the more reliable
sis is not always affordable, and for more conven-
techniques such as instrumental neutron activation
tional applications of OHD that require numerical
analysis (INAA). This confidence in the accuracy
estimates of temperature, we have included a chap-
and precision of analytical methods that form large
ter on estimating regional ground temperatures
databases now allows for broad regional syntheses of
from meteorological data. This first section finishes
how raw materials were acquired, transported, and
with a review paper that brings the readers up to
exchanged. Many of the chapters in this volume illus-
date on obsidian studies on the African continent,
trate how populations interacted over time and space
a region of the world unfamiliar to many of the
and provide much-needed detail on the dynamics of
world’s archaeologists.

human interaction. Regional interaction studies are

Part 2 contains 10 papers on provenance stud-
generally the norm and have become increasingly
ies that look at regional patterns of glass acquisition, challenging as larger data sets from well-controlled
production, or exchange. Each contribution provides
archaeological contexts are required. However, sig-
a case example that uses one or more instrumental
nificant challenges remain to acquire a representative methods to characterize materials of an ancient soci-picture of this interaction, and these tasks include the ety. We have subdivided these papers into the study
appropriate sampling of assemblages to capture the
of natural glasses (e.g., basalt or obsidian) or man-
full variability in the flow of material culture that
made glasses. The papers on manufactured glasses
may not be incorporated into artifacts of one type or
refer to the provenance and technology of Roman
size category. A continued attention to problems of
glasses in the ancient world, a compositional and
provenance and chronology will serve to make dia-
technological study from Kenyan glass vessels and
chronic interaction studies a central, and informa-
beads (AD 900–1750), and production techniques
tive, undertaking associated with the study of past
and provenance of Rhodian (Aegean) and Thebean
cultural systems.

Editor’s Introduction | xix

To close the book, we present a chapter writ-
on archaeological science and social archaeology.

ten by M. Steven Shackley, whose long-term expe-

He critically examines the areas of obsidian dat-
rience and historical perspective provide some
ing and provenance, referring to various analytical
insight to the trajectory of glass studies in archae-
techniques (XRF, INAA, PIXE-PIGE, LA-ICP-MS)

ology. His chapter deals with the value of natural
employed by authors in the volume, and discusses
and manufactured glass studies in third-millennium
the artificial glasses studies covered in the volume
archaeology, and brings to this field his perspective
and their future prospects.

P A R T I

OBSIDIAN

HYDRATION DATING

Chapter 1

Aspects of Secondary Ion Mass Spectrometry (SIMS)

Depth Profiling for Obsidian Hydration Dating

Steven W. Novak and Christopher M. Stevenson

Abstract
important parameter is the thickness of the hydra-
tion layer, as measured at the ½ fall of the H profile.

The SIMS technique provides an ideal tool for mea-

Repeat measurements indicate this thickness can be
suring hydrogen (H) profiles for use in obsid-
measured to within ±1% on some samples. Excellent
ian hydration dating (OHD). The measurement
correlation between SIMS and IR measurements
of a natural obsidian fracture surface by SIMS is
indicate the ability of SIMS to provide highly quan-
not straightforward, however, and subject to sev-
titative measurement of H in obsidian.

eral factors. Measurements have been collected
using both magnetic-sector and quadrupole-based

1. Introduction

SIMS instruments, with comparable results. The
quadrupole-based instrument may provide a some-

Over five decades ago Friedman and Smith (1960)

what simpler analysis in terms of charge com-
noted that freshly exposed surfaces of obsidian arti-
pensation and requiring less sample preparation.

facts begin to absorb water immediately, eventually

Although early measurements were made using
forming a water-rich hydrated layer in the range of
negatively charged oxygen (O-) bombardment with

1–10 micrometers (μm). If the ground temperature,
positive ion detection, modern instruments using
soil relative humidity, and rate of water diffusion in cesium (Cs) bombardment with negative ion detec-obsidian are accurately known, an age may be calcu-
tion should provide superior backgrounds for H
lated for the creation of the artifact from a measure-
anal ysis. Analysis of natural obsidian surfaces may
ment of the hydrated layer thickness (Friedman and
be subject to problems due to surface roughness,

Long 1976). The measurement of obsidian hydration
cracking, or the presence of natural inclusions or
rims for the purpose of dating has been undertaken
vesicles. Measurements by atomic force microscopy
for many years now. Initial efforts used physical

(AFM) indicate root mean square (RMS) rough-
cross-sections and optical measurement, but more
ness values as low as 5 nanometers (nm) for con-
recently a number of advanced analytical methods
choidal fracture surfaces. Rippling that develops
have been used including nuclear reaction analysis,
within the SIMS craters due to ion bombardment
sputter-induced optical emission, and secondary ion
causes RMS roughness of about 40–50 nm. These
mass spectrometry (SIMS). Among these techniques,
values are similar to the rate of fall of the H profile SIMS should provide the most accurate and detailed
for deep profiles. Sputtering rates measured for a
measurement of the diffusion profile shape, due to
suite of obsidians from archaeological sites show a
the nature of the profiling technique. In this chapter variation of less than 4%, indicating that an external we will summarize work done to date on SIMS profil-obsidian standard can be used to calibrate the sput-
ing of archaeological obsidian samples, discuss some
tering rate within the typical measurement error.

aspects of the technique that may affect the accuracy

For the hydration layer thickness measurement, the
of the measured profiles, and present some new data

3

4 | OBSIDIAN HYDRATION DATING
on sputtering rates of obsidian and the roughness of
in the late 1970s, SIMS has become a highly devel-
fracture surfaces by atomic force microscopy (AFM)

oped measurement technique, particularly in the

(see also Liritzis and Laskaris 2011; Liritzis et al.

semiconductor industry, and it is widely applied

2008a, 2008b). We hope to give readers a means to
to problems in metallurgy, ceramics, geology, and
understand what is required for a SIMS analysis of a
mineralogy. As pointed out by Tsong et al. (1978),
sample and the parameters that affect the accuracy of
the ability to sputter the sample with a high-current
the measurements. In addition to the measurement
ion beam yields the ability to measure hydration
of artifacts, we have performed a number of labo-
profiles to 10 microns in a reasonable amount of
ratory hydration experiments on obsidian to better
time, making SIMS a versatile technique.

define three parameters: (1) What is the effect of glass Because of the ease of cutting and polishing
density and composition on the calibration used to
obsidian and measuring the hydration rims opti-
estimate crater depth? (2) What is the effect of sur-
cally, a large number of obsidian hydration measure-
face roughness on the precision of SIMS measure-
ments have been performed in the 1970s through
ments? and (3) Can the calibration between infrared
the present day (Jackson 1984; Meighan et al. 1974;
photoacoustic spectroscopy (IR-PAS) absorbance

Meighan and Vanderhoeven 1978; Meighan and
measurements and depth be improved?

Russell 1981; Meighan and Scalise 1988; Stevenson
and Ayres 2000; Hull 2001). Although this method

2. Previous work
seemed to give good absolute ages for some studies

(Stevenson 2000), practitioners of the measure ment

Initial development of the obsidian hydration dating
point to significant errors in other cases (Ridings
method used cross-sectional polishing of the glass

1996). The major problems seemed to be the sub-
and optical width measurement of the hydrated
jective nature of determining the thickness of the
rim. For relatively thick hydration layers present on
hydration layer by eye, the low resolution of the
very old artifacts, this method at times produced
op tical microscope (Scheetz and Stevenson 1988),
good linear correlation between layer thickness and
and the correlation between the optical image and
hydration age (e.g., Meighan et al. 1968; Hull 2001).

the actual depth of water diffusion (Anovitz et al.

The first modern surface analysis technique applied

1999; Stevenson et al. 1989, 2002; Tokoyama et al.

to measuring hydration rim thickness was by Lee

2008). As these problems were being discovered,
et al. (1974) and Lanford (1977), who measured the
newer techniques such as infrared spectroscopy
hydrogen profiles using nuclear reaction analysis.

were being developed to measure the water content

This method showed good correlation between
of hydrated obsidian (Stevenson and Novak 2011).

hydration layer thickness and hydration tempera-

Infrared spectroscopy has been used to measure the
ture and provided quantitative H values. Curiously,
bulk water content of obsidian (Newman et al. 1986;
this high-quality technique was not widely applied

Zhang et al. 1996) with the photoacoustic method
to the measurement of hydrated obsidians, possibly

(IR-PAS) used to quantify the depth of surface water
due to the lack of high-energy accelerators required
diffusion (Stevenson et al. 2001). The latter approach for the nuclear reaction measurement. In addition,
to hydration layer depth assessment has been cali-
the technique is useful only within about 2 microns
brated relative to SIMS and shown to have a high
of the surface, restricting its use for younger arti-
precision estimated at 0.05 μm.

facts in which the hydrated layer is thinner than

2 microns. At nearly the same time, Tsong et al.

3. SIMS measurements

(1978) demonstrated the use of sputter-induced
optical emission for obsidian hydration profiling.

SIMS has been used to measure trace element con-

This technique is similar to SIMS in that it uses
tents, including H, in minerals and glasses almost
an ion beam to sputter the sample; however, the
since the inception of the technique (Anderson and
detected signal is the light emitted during the bom-

Hinthorne 1973; Delaney and Karsten 1981; Honig
bardment process. In the years since its inception

1995), and there has been a significant proliferation

Aspects of Secondary Ion Mass Spectrometry (SIMS) | 5
of papers using SIMS in geochemis-
try in the last 15 years as the technique
has become more accepted. Detailed
descriptions of the SIMS technique can
be found in Benninghoven et al. (1987)

and Wilson et al. (1989). A review of

SIMS as applied in geochemistry is
given by Ireland (1995), and Compston
and Clement (2006) detail the most
recent developments in the highly
developed SIMS instruments used for
isotope ratio measurements. Because
most instruments previously used for
geochemical analysis are magnetic-sec-
tor instruments, and because we have
used a quadrupole-based instrument,
some detailed description of each tech-

Figure 1.1. Diagram of a magnetic sector (CAMECA) SIMS instrument.

nique will be given here.

There are basically two types of

SIMS instruments in common use,
those with magnetic-sector mass spec-
trometers (figure 1.1) and those with
quadrupole-based mass spectrometers

(figure 1.2). The major difference lies
in the design of the mass spectrometer
used to filter the secondary ion signals.

Magnetic-sector instruments use a
curved ion flight path through a uni-
form magnetic field to mass-resolve
molecular ion signals. The design allows
for high mass resolution to eliminate
overlaps from interfering molecular
ions, which are not important for analy-
sis of H. Quadrupole-based instruments Figure 1.2. Diagram of a quadrupole-based SIMS instrument (Phi).

have lower extraction efficiencies for
secondary ions, which make them less
sensitive, and they have only unit mass
resolution. Quadrupole-based instru-
studies have been published on measuring hydra-
ments have not intrinsically been designed for dif-
tion of archaeological materials using a magnetic-
ferent purposes; however, their design makes them
sector instrument (e.g., Anovitz et al. 1999, 2004).

easier to use for analysis of insulating materials, like Studies using quadrupole-based instrument include
glasses, and they have the ability to bombard the

Stevenson et al. (2001, 2004). Recent studies of glass sample with lower primary ion beam energies. For
hydration using SIMS include Dowsett (2004) and
the purposes of measuring H profiles in obsidian,

Fearn et al. (2006). An extensive study measur-
the ability to analyze insulating samples is impor-
ing water contents of geological samples has been
tant, but other differences between the two types of
published by Hauri et al. (2002) using a modern
instrument are not as important. Several previous

CAMECA magnetic-sector instrument.

6 | OBSIDIAN HYDRATION DATING

The SIMS technique consists simply of bombard-
strong field gradient in magnetic-sector instruments
ing a solid with a focused ion beam within a vacuum
is greatly affected by the tilt and shape of the analysis chamber and detecting the ions emitted from the
surface, and small differences in sample positioning
surface using a mass spectrometer. Most early ana-
may greatly affect the analysis (Lux 1990; Chi and
lytical work on minerals and glasses used magnetic-

Simons 1990). In quadrupole-based instruments the
sector CAMECA instruments. In order to minimize
sample stage can be tilted to aid in sample position-
charge buildup on the sample, these analyses used a
ing, and the lower field gradient means that there is
negatively charged oxygen beam and the sample was
less effect due to curved sample surfaces.

coated with a conductive layer, typically gold. More

One additional difference between the two types
recent CAMECA designs allow the use of a Cs beam;
of instruments germane to analysis of archaeologi-
however, a gold coat is still necessary. Analyses for H
cal samples is that the sample stage in the magnetic-
in quadrupole instruments typically use a Cs beam,
sector instrument is fixed in place and will only
and no conductive coating is needed. The primary ion
allow samples less than 25 mm in diameter to be
beam having a current of several nA (nanoamperes)

held within the sample holder. In the quadrupole-
to 100’s of nA is focused to a beam size of microns to based instrument the sample stage is movable in all

10’s of microns. Usually this beam is raster-scanned
three dimensions and can be tilted, allowing curved
across the surface of the sample to form a flat-
samples to be readily aligned beneath the beam.

bottomed crater, but for microanalysis the beam may

There is much more freedom in sample size due
be unrastered. For any depth profiling application,
to this arrangement and samples much larger than
such as the hydrogen profiles acquired on hydrated

25 mm can be introduced without resorting to cut-
obsidians, the beam must be raster-scanned, and
ting smaller pieces from them.

secondary ions accepted into the mass spectrometer

Analysis of insulating samples is much more
must be limited to those emitted from the central part difficult than analysis of conductive samples in SIMS
of the crater. In magnetic-sector instruments, the ion because the sample is bombarded with a charged
acceptance is limited by apertures within the mass
ion beam (Werner and Morgan 1976; Wittmaack
spectrometer. In quadrupole-based instruments, ion

1979). Because insulating samples do not conduct
acceptance is done by electronic gating, in which ions away the charge, it builds up in the area of ion
are only counted by the mass spectrometer when
bombardment. This buildup changes the energy of
the beam is in the central part of the rastered area.

ions leaving the surface, which strongly affects ion

Typically less than 40% of the rastered area is used as transmission through the mass spectrometer. Severe
the acceptance area for analysis.

charge buildup will deflect the primary ion beam,

One significant difference between the two types
preventing analysis of the sample. Compensating
of SIMS instruments that may affect the ability to
for this charge buildup is usually done by coating
reproducibly analyze archaeological samples has to
the sample with a conductive layer, as is often done
do with the design of the extraction lens and field
for SEM imaging, and by bombarding the sample
in front of the sample. Magnetic-sector instruments
with a secondary electron beam. For analysis with
have the extraction lens spaced 5 mm from the sam-
magnetic-sector instruments, it is generally neces-
ple surface and a voltage of 4500 V is used to extract sary to coat the sample with a conductive layer, a
secondary ions into the mass spectrometer. It is this
procedure that is perhaps undesirable for valuable
high voltage gradient that makes it difficult to com-
archaeological artifacts. Ion bombardment may be
pensate for charge buildup on insulating samples
with negatively charged oxygen (Anovitz et al. 1999)

in a magnetic-sector instrument. In contrast, the
or, more recently with Cs bombardment (Hauri et al.

quadrupole-based instrument may have the extrac-

2002; Stevenson et al. 2001). For quadrupole-based
tion lens several millimeters from the sample and an
instruments it is much more straightforward to
extraction potential of several hundred to 1000 V.

compensate for charge buildup with only electron

The surface of archaeological obsidian samples,
bombardment, eliminating the need to coat the
although generally smooth, is typically curved. The
samples with a conductive layer.

Aspects of Secondary Ion Mass Spectrometry (SIMS) | 7

Early comments on factors important for analy-
to methods published for magnetic-sector SIMS
sis of H by SIMS include Magee and Botnick (1981),
instruments (Anovitz et al. 1999; Hauri et al. 2002;
who note the importance of a low chamber vac-

Riciputi et al. 2002).

uum to reduce the H background. Analyses of H

Profiles are acquired using Cs bombardment,

(or water) in glasses and methods for SIMS analy-
typically with a 5-kiloelectron-volts (keV) impact
sis have been published by Delaney and Karsten
energy and an incidence angle of 60º relative to the

(1981), Hervig and Williams (1988), and Ottolini
surface normal. Ion beam current is typically 500–
et al. (1995). These authors used magnetic-sector

800 nA. The system has a typical base pressure of less instruments with O- bombardment and positive ion
than 7 x 10-10 torr and an operating pressure of about detection. Optimal analyses are achieved by using

2 x 109 torr. The system typically achieves operating
high-energy secondary ions in order to filter abun-
pressure within about 15 minutes of sample intro-
dant positive H ions from electron beam bombard-
duction. Because the sample stage can be adjusted in
ment, which may cause a high H background. There

X, Y, Z, and tilt, it is relatively easy to reproducibly have been continuous improvements in the instru-position a reflective surface in the analysis position ments and methods over the succeeding years. More

(figure 1.3).

recently Hauri et al. (2002) describe a method of

Typical SIMS depth profile results for H profiles

H analysis using Cs bombardment with negative ion
in obsidian artifacts are given in figure 1.4 (Stevenson detection in a CAMECA magnetic-sector instru-et al. 2004). These profiles show similar profile
ment. Improved analytical conditions and instru-
shapes in having a thin surface layer (up to 200 nm)

ments have allowed routine measurements of H in
in which the H content falls sharply, followed by a
minerals and glasses to as low as 4 parts per million
more gradually sloped profile that may extend many

(ppm) (Koga et al. 2003; Rhede and Wiedenbeck
microns into the sample depending on the age of the

2006). These studies have also documented the
artifact. Finally the H profile falls sharply at some
improved backgrounds achieved with Cs bombard-
depth that is also dependant on the age of the arti-
ment when contrasted with O- bombardment and
fact. The surface peak may, at least partially, result have shown that high electron beam energies result
from the adsorbed hydrocarbon layer detected on
in high backgrounds due to electron-stimulated
every air-exposed surface, commonly referred to as
desorption of H. Although these effects should not
the adventitious carbon layer. However even smooth,
affect the accuracy of hydration profiles in obsidian
polished, laboratory-hydrated obsidian samples show
or glass, the very high H contents of hydrated obsid-
this surface peak, suggesting it is a fundamental
ian surfaces may cause high backgrounds if the elec-
feature of water diffusion into obsidian. Figure 1.4
tron gun parameters are not optimized.

also shows hydration layer thicknesses estimated by
standard optical measurements. Note that the opti-

4. Quadrupole SIMS
cally determined thicknesses are always less than the
depth profiles
depth at which the H profiles fall, indicating that the optical technique consistently underestimates the true We have performed several studies of archaeological
hydration layer thickness.

artifacts and laboratory hydrated glasses using quad-
rupole-based SIMS (Stevenson et al. 2001; Liritzis et

5. Crater depth calibration and
al. 2004; Ambrose et al. 2004). These dynamic SIMS
sputtering rate differences
measurements were carried out using Phi 6300 and

6600 quadrupole-based SIMS instruments. Samples

Conversion of sputtering time to depth in SIMS
are held by clips and screws to minimize damage,
profiles is typically done by measuring the analyt-
but may also be held with silver paste. Samples held
ical crater depths using a stylus profilometer. Re -
with silver paste are typically dried in an oven for
peat measurements of calibration standards have

30–60 minutes at 60–80 ºC. No gold or other con-
demonstrated that the stylus profilometer itself
ductive coating is applied to the samples, in contrast is precise to within 1%. A round-robin study of

8 | OBSIDIAN HYDRATION DATING

Figure 1.3. Photomicrograph of SIMS craters on Figure 1.4. Quadrupole SIMS depth profile measure-an oriented obsidian surface. The craters are
ments of hydrated obsidians from a variety of sources.

approximately 225 microns on a side and about

Arrows show hydration layer thicknesses measured

7 microns deep.

optically (Stevenson et al. 2004).

profilometry measurements of SIMS craters in flat
stylus profilometry, to calculate the sputtering rate

(i.e., polished semiconductor) samples shows that
for a given analytical run. The standard is analyzed in this procedure is accurate to within 5% (Simons
each analytical run so as to correct for small varia-

1997). For hydrated obsidians, repeat measurements
tions in instrument conditions from run to run. The
of polished samples have shown an error of 3% for
advantages of using this method include simplicity,
flat samples (Riciputi et al. 2002). However, this
avoiding cutting the sample, and good reproducibil-
latter procedure requires cutting and polishing a
ity. Using this method for depth calibration avoids
piece of material to ensure accurate measurements.

errors that may be introduced by stylus profilometer

Direct profilometry measurements can be made of
measurements of rough artifact surfaces.

craters on artifact surfaces. However, roughness

In order to assess the variation in sputtering
and tilt of typical artifact surfaces commonly have
rate for different glasses, we depth profiled polished larger errors than flat, polished surfaces.

samples of 6 glasses from widely distributed obsid-

In our studies we have chosen to calibrate the
ian geological sources in a single analytical run.

concentration and depth axes by using a deuterium-

The results are given in table 1.1 and show that these implanted high-silica nonhydrated obsidian (KSW-glasses have a 1 sigma relative standard deviation

354) (Novak and Mahood 1986) as a standard mate-

(RSD) of 3.6% of the average rate for all glasses. Note rial. The use of ion-implanted standard materials is
that these glasses have OH+H O contents that range

2
common for quantitative SIMS analyses in the semi-
from 0.08% to 1.54%, suggesting that this range of
conductor industry (Wilson et al. 1989). Calibration
water contents has little effect on sputtering rate. The of the depth scale simply involves using the known

RSD of 3.6% is comparable to the error in stylus pro-
peak depth of the implant, previously established by
filometer measurements alone. While this is only a

Aspects of Secondary Ion Mass Spectrometry (SIMS) | 9

Table 1.1. SIMS sputtering rates on obsidians of different structural water content Sample Locality

OH+H2O (wt.%)

Density (g/ml)

Sputtering rate (A/s)

Argentina

0.08

2.3446

11.64

Mt. Hicks, NV, USA

0.08

2.3412

12.14

Queen, NV, USA

0.11

2.3510

11.61

Chivay, Peru

0.14

2.3468

11.71

Rio Hondo, Columbia

0.77

2.3278

10.96

Red Hill, NM, USA

1.54

2.3217

12.24

Average

11.72± .42 (3.6%)

small sample of natural glasses used for artifacts, the even the minimal diffusion of water at 10 ºC to be
results suggest that use of an ion-implanted standard
measured accurately. Note that the slope of the hydra-
for calibration of the depth scale does not introduce
tion front becomes less steep with increasing depth
any larger error into the depth axis than other cali-
and temperature. If these hydration layers were mea-
bration methods and may actually avoid errors intro-
sured optically, it seems likely that the differing slopes duced by direct measurements of craters on irregular
of the H profiles might affect the optical appearance
archaeological surfaces.

of the hydration front.

In contrast to the optical measurements, hydra-

6. Infrared photoacoustic
tion layer thicknesses measured by SIMS agree
depth measurement
well with those measured by IR-PAS (figure 1.6;

Stevenson et al. 2001). The excellent linear corre-

Our initial study utilizing SIMS profiling was under-
lation of the two techniques demonstrates the
taken to compare hydration layer thicknesses as
improved accuracy of both measurements and the
measured by the traditional optical method, pho-
wide range of the linear relationship. However, this
toacoustic infrared spectroscopy (IR-PAS), and

SIMS depth profiling (Stevenson et al. 2001, 2002).

The IR-PAS signal should quantitatively measure
the total amount of hydrogen incorporated into the
sample, as will the integrated H signal measured
by SIMS. This study showed that hydrated layer
thicknesses measured using the traditional optical
method systematically underestimate the H diffu-
sion depth when compared to SIMS (figure 1.4). We
propose that the underestimation derives from a
sharp decrease in the stress-induced birefringence of
the glass that prevents the full extent of the hydrated layer from being optically visible. A similar explanation was proposed by Riciputi et al. (2002).

Systematically conducted hydration experiments
support this explanation for optical errors. An exam-
ple of such a study is given in figure 1.5 (Ambrose et al.

2004). In this experiment fresh obsidian flakes were
hydrated at temperatures between 10 ºC and 40 ºC for

Figure 1.5. SIMS profiles of laboratory hydrated 26 years. The high depth resolution of SIMS allows
obsidian samples from Ambrose et al. (2004).

10 | OBSIDIAN HYDRATION DATING
number for nonhydrated glass. The main point in
including these measurements is to show the excel-
lent correlation between the two sets of measure-
ments, reinforcing the accurate depth calibration of
the SIMS profiles.

7. Surface roughness

The accuracy with which the SIMS profiles reflect
the true distribution of hydrogen (or H O) within an

2
obsidian sample is affected by the roughness of the
obsidian surface. This roughness has two aspects:

(1) initial roughness of the obsidian surface, and

(2) roughness induced by sputtering during the SIMS
measurement. We have measured archaeological
ob sidian surfaces and SIMS craters in obsidians using Figure 1.6. Correlation of hydration layer thickness atomic force microscopy (AFM) to measure both ini-measured by SIMS versus infrared photoacoustic
tial surface roughness and crater bottom roughness.

spectroscopy (Stevenson et al. 2001).

Measurements were made on a Digital Instru-
ments Nanoscope IIIa in tapping mode. Typical mea-
surements are given in figure 1.7. This image shows
figure also shows that the relationship between SIMS
a conchoidally fractured artifact surface, which is
and IR-PAS absorbance intensities does not result in
surprisingly smooth with a root mean square (RMS)

a regression line that passes through the origin. The
roughness of 5 nm. Representative archaeological
positive intercept on the IR axis is due to an instru-
obsidian surfaces have RMS roughness values from
mental background signal that gives a small positive

5 nm to 10 nm. Similar measurements by Liritzis et al.

Figure 1.7. AFM image
of a conchoidal fractured
obsidian surface.

Aspects of Secondary Ion Mass Spectrometry (SIMS) | 11

Figure 1.8. AFM image of an

1122.12 nm

561.56 nm
obsidian artifact showing

0 µm
roughness due to pitting.

16.84 µm

8.42 µm

16.84 µm

8.42 µm

0 µm

0 µm

(2008a, 2008b) found RMS roughness values of

6–82 nm for artifact surfaces from various locations in Greece. The highest roughness values came from artifacts that show pitting on a small scale, such as shown in figure 1.8. Obviously surfaces as smooth as the one shown in figure 1.7 are ideal for SIMS depth profiling.

However, a surface such as that shown in figure 1.8 will cause distortion of the real H profile when measured
by SIMS. The net effect of pits or cracks in the surface will be to smear out the details of the profile, particularly at the sharp fall of the H profile. An example of this distortion is shown in figure 1.9, which compares a normal profile with one smeared out due to surface
roughness. Such profiles should be used cautiously or
eliminated for dating purposes.

AFM images of the bottom of SIMS craters show
ripple formation similar to those documented in
many types of ion-bombarded materials. A number

Figure 1.9. Comparison of two SIMS profiles, one of recent studies show how initially very smooth
normal (lower) and one showing distortion (upper)

polished silicon surfaces develop roughness dur-
due to significant surface roughness.

ing SIMS measurements using either oxygen beams

(Stevie et al. 1988; Fares et al. 2006) or cesium
beams (van der Heide et al. 2003). Typically these
initial surface roughness for most obsidian artifacts.

ripples reach RMS roughness values of 50–60 nm

It is not yet clear at what depth this roughness devel-for ion beam conditions similar to those we have
ops. It is unlikely that roughness of 50–60 nm devel-
used for obsidian measurements. Our measurements
ops within the initial 200 nm of the profiles, as the
show that SIMS craters in obsidian develop RMS
steeply sloping H profiles would be strongly affected
roughness of 45 nm as well. Ripple formation appears
by such roughness. However it is nearly certain that
to be a feature common to ion bombardment of most
the steep fall of the H profiles may be affected by this solids and the RMS roughness appears to reach simi-roughness. The measured rate of fall of the H profiles lar values regardless of the material for like ion beam range from 18 nm per decade for shallow profiles to
conditions. Therefore the roughness developed in

50 nm per decade for deeper profiles. Therefore the
the bottom of the SIMS craters due to ion beam sput-
slope of H profiles at the falloff of the H profile may tering appears to be significantly greater than the
be controlled by roughness developed in the SIMS

12 | OBSIDIAN HYDRATION DATING
crater bottom rather than by the true rate of fall of

References
the H distribution. Additional work will be required
to detail the impacts of crater roughness on profile

Ambrose, W., Novak, S.W., Abdelrehim, I., 2004. Jour
shape (Liritzis et al. 2008b, 2009).

nal of Mediterranean Archaeology and Archaeometry 4, 17–31.

Anderson, C.A., Hinthorne, J.R., 1973. 207Pb/206Pb ages 8. Summary and conclusions
of individual mineral phases in Luna 20 material

The use of dynamic SIMS profiling to measure
by ion microprobe mass analysis. Geochimica et Cosmochimica Acta 37, 745–754.

hydration profiles in obsidian offers a significant

Anovitz, L.M., Elam, M., Riciputi, L., Cole, D., 1999. The increase in accuracy over the standard optical
failure of obsidian hydration dating: Sources, impli-
method. Perhaps most important, a SIMS depth
cations, and new directions. Journal of Archaeological profile yields the shape of the H profile over the

Science 26, 735–752.

entire hydrated layer. This allows detailed features of Anovitz, L.M., Elam, M., Riciputi, L., Cole, D., 2004.

the diffusion process to be examined (e.g., Anovitz

Isothermal time-series determination of the rate of
et al. 1999, 2004). Profiles can be acquired over tens diffusion of water in Pachuca obsidian. Archaeometry of microns within 1–2 hours, but may also be used to

46, 301–326.

examine very shallow profiles within the top micron

Benninghoven, A., Rudenauer, F.G., Werner, H.W., 1987.

of a sample. This feature will become increasingly

Secondary Ion Mass Spectrometry: Basic Concepts, important when used to examine relatively young

Instru mental Aspects, Applications, and Trends. Wiley, obsidian or glass archaeological artifacts. The use

New York.

Chi, P.H., Simons, D.S., 1990. Factors that affect reproof a quadrupole-based SIMS instrument allows the
ducibility in SIMS analysis of semiconductors. In:

examination of large and irregular samples without

Benninghoven, A., Huber, A.M., Werner, H.W.

the need to coat the artifact surface with a conductive (Eds.), Secondary Ion Mass Spectrometry SIMS VII.

metal layer. Results obtained using magnetic-sector

Wiley, Chichester, UK, pp. 127–130.

instruments appear to yield profiles similar to those

Compston, W., Clement, S.W.J., 2006. The geological
using the quadrupole instrument except in the near
microprobe: The first 25 years of dating zircons.

surface region, which may be affected by the metal

Applied Surface Science 252, 7089–7095.

coating required for charge compensation on these

Delaney, J.R., Karsten, J.L., 1981. Ion microprobe studies instruments. Measurements of a series of artifacts
of water in silicate melts: Concentration dependent
having water contents ranging from 0.08% to 1.54%
water diffusion in obsidian. Earth and Planetary Sci
show that the sputtering rates of these glasses have a ence Letters 52, 192–202.

Dowsett, M., Adriaens, A., 2004. The role of SIMS in
relative standard deviation of 3.6%, which is similar
cul tural heritage studies. Nuclear Instruments and to the error in stylus profilometer crater measure-Meth ods in Physics Research Section B: Beam Inter
ments. AFM measurements show that artifact sur-
actions with Materials and Atoms 226, 38–52.

faces can be as smooth as 0.5 nm; however, SIMS

Fares, B., Dubois, C., Gautier, B., Dupuy, J.C., Cayrel, F., craters in obsidian artifacts show ripple formation in Gaudin, G., 2006. AFM study of the SIMS beam
the crater bottom similar to that seen in many other
induced roughness in monocrystalline silicon in
solids. These ripples have an RMS roughness value
presence of initial surface or bulk defects of nano-
of 50–60 nm and may control the ability to measure
metric size. Applied Surface Science 252, 6448–6451.

the H slope in the deepest part of the H profile.

Fearn, S., McPhail, D.S., Morris, R.J.H., Dowsett, M.G., 2006. Sodium and hydrogen analysis of room tem-Acknowledgments
perature glass corrosion using low energy Cs SIMS.

Applied Surface Science 252, 7070–7073.

Thanks to Charles Magee for numerous discussions

Friedman, I., Smith, R.L., 1960. A new dating method
about SIMS and for a review of this manuscript.

using obsidian: Part I, the development of the method.

American Antiquity 25, 476–493.

Friedman, I., Long, W., 1976. Hydration rate of obsidian.

Science 159, 347–352.

Aspects of Secondary Ion Mass Spectrometry (SIMS) | 13

Hauri, E., Wang, J., Dixon, J., King, P., Mandeville, C., Liritzis, I., Laskaris, N., 2009. Advances in obsidian Newman, S., 2002. SIMS analysis of volatiles in sili-hydration dating by secondary ion mass spectrome-
cate glasses: 1. Calibration, matrix effects and com-
try: World examples. Nuclear Instruments and Meth
parisons with FTIR. Chemical Geology 183, 99–114.

ods in Research Section B: Beam Interactions with Hervig, R.L., Williams, P., 1988. SIMS microanalysis of Materials and Atoms 267, 144–150.

minerals and glasses for H and D. In: Benninghoven,

Liritzis, I., Laskaris, N., 2011. Fifty years of obsidian A., Huber, A.M., Werner, H.W. (Eds.), Secondary Ion hydration dating in archaeology. Journal of Non

Mass Spectrometry SIMS VI. Wiley, Chichester, UK, Crys talline Solids 357, 2011–2023.

pp. 961–964.

Lux, G., 1990. Reproducibility of the quantitative SIMS

Honig, R.E., 1995. Stone age mass spectrometry. Inter
analysis of ion-implanted Si wafers. In: Benninghoven, national Journal of Mass Spectrometry and Ion Pro

A., Huber, A.M., Werner, H.W. (Eds.), Secondary Ion cesses 143, 1–10.

Mass Spectrometry SIMS VI. Wiley, Chichester, UK, Hull, K.L., 2001. Reasserting the utility of obsidian
pp. 123–126.

hydra tion dating: A temperature-dependent empiri-

Magee, C.W., Botnick, E., 1981. Hydrogen depth pro-
cal approach to practical temporal resolution with
filing using SIMS—problems and their solutions.

archaeological obsidians. Journal of Archaeological Journal of Vacuum Science and Technology 19, 47–52.

Science 28, 1025–1040.

Meighan C.W., Foote, L.J., Aiello, P.V., 1968. Obsidian Ireland, T.R., 1995. Ion microprobe mass spectrometry: dating in west Mexican archaeology. Science 160, Techniques and applications in cosmochemistry, geo-1069–1075.

chemistry, and geochronology. In: Hyman, M., Rowe,

Meighan, C.W., Findlow, F., De Atley, S., 1974. Obsidian M. (Eds.), Advances in Analytical Geochemistry. JAI Dates I. Archaeological Survey Monograph 3. Depart-Press, Greenwich, CT, pp. 1–118.

ment of Anthropology, UCLA.

Jackson, R.J., 1984. Current problems in obsidian hydra-Meighan, C.W., Vanderhoeven, P.I., 1978. Obsidian Dates tion analysis. In: Hughes, R.E. (Ed.), Obsidian Studies II. Monograph 6. Institute of Archaeology, UCLA.

in the Great Basin. Contributions to the University Meighan, C.W., Russell, G., 1981. Obsidian Dates III.

of California Archaeological Research Facility 45.

Mon o graph 16. Institute of Archaeology, UCLA.

UCARF, Berkeley, pp. 103–116.

Meighan, C.W., Scalise, J.L., 1988. Obsidian Date IV.

Koga, K., Hauri, E., Hirschmann, M., Bell, D., 2003.

Monograph 29. Institute of Archaeology, UCLA.

Hydro gen concentration analyses using SIMS and

Newman, S., Stolper, E., Epstein, S., 1986. Measurement FTIR: Comparison and calibration for nominally
of water in rhyolitic glasses: Calibration of an infrared anhydrous minerals. Geochemistry, Geophysics, and spectroscopic technique. American Mineralogist 71, Geosystems 4, 1019.

1527–1541.

Lanford, W., 1977. Glass hydration: A method of dating Novak, S.W., Mahood, G., 1986. Rise and fall of a basalt-glass objects. Science 196, 975–976.

trachyte-rhyolite magma system at the Kanes Springs

Lee, R.R., Leich, D.A., Tombrello, T.A., Ericson, J.E., Wash Caldera, Nevada. Contributions to Mineralogy Friedman, I., 1974. Obsidian hydration profile mea-and Petrology 94, 352–373.

surements using a nuclear reaction technique. Nature Ottolini, L., Bottazzi, P., Zanetti, A., Vannucci, R., 1995.

250, 44–47.

Determination of hydrogen in silicates by secondary

Liritzis, I., Bonini, M., Laskaris, N., 2008a. Obsidian ion mass spectrometry. Analyst 120, 1309–1313.

hydration dating by SIMS-SS: Surface suitability

Rhede, D., Wiedenbeck, M., 2006. SIMS quantifica-
criteria from atomic force microscopy. Surface and tion of very low hydrogen contents. Applied Surface Interface Analysis 40, 458–463.

Science 252, 7152–7154.

Liritzis, I., Laskaris, N., Bonini, M., 2008b. Nano- and Riciputi, L.R., Elam, M.J., Anovitz, L.M., Cole, D.R., 2002.

micro-scale resolution in ancient obsidian artefacts

Obsidian diffusion dating by secondary ion mass
surfaces: The impact of AFM on the obsidian hydra-
spectrometry: A test using results from Mound 65,
tion dating by SIMS-SS. Physica Status Solid 5(c) Chalco, Mexico. Journal of Archaeological Science 29, (12), 3704–3707.

1055–1075.

Liritzis, I., Diakostamatiou, M., Stevenson, C.M., Novak, Ridings, R., 1996. Where in the world does obsidian hydra-S.W., Abdelrehim, I., 2004. The dating of hydrated
tion dating work? American Antiquity 61, 136–148.

obsidian surfaces by SIMS-SS. Journal of Radioanalytical and Nuclear Chemistry 261, 51–60.

14 | OBSIDIAN HYDRATION DATING

Scheetz, B.E., Stevenson, C.M., 1988. The role of res-

Stevie, F.A., Kahora, P.M., Simons, D.S., Chi, P., 1988.

olution and sample preparation in hydration rim

Secondary ion yield changes in Si and GaAs due to
measurement: Implications for experimentally deter-
topography changes during O+ or Cs+ ion bombard-

2
mined hydration rates. American Antiquity 53, 110–117.

ment. Journal of Vacuum Science and Technology A6

Simons, D.S., 1997. The depth measurement of craters

(1), 76–80.

produced by secondary ion mass spectrometry—

Tokoyama, T., Okumura, S., Nakashima, S., 2008. Hydra-
results of a stylus profilometry round-robin study.

tion of rhyolitic glass during weathering as char-

In: Benninghoven, A., Hagenhoff, B., Werner, H.W.

acterized by IR microspectroscopy. Geochimica et (Eds.), Secondary Ion Mass Spectrometry, SIMS X.

Cosmochimica Acta 72, 117–125.

Wiley, Chichester, UK, p. 435.

Tsong, I.S.T., Houser, C.A., Yusuf, N.A., Messier, R.F., Stevenson, C.M., 2000. Estimating Easter Island obsid-White, W.B., Michels, J.W., 1978. Obsidian hydration
ian hydration rates from glass composition. In:

profiles measured by sputter-induced optical emis-

Stevenson, C.M., Ayres, W.S. (Eds.), Easter Island sion. Science 201, 339–341.

Archa eology: Research on Early Rapanui Culture.

Van der Heide, P.A.W., Lim, M.S., Perry, S.S., Bennett, J., Easter Island Foundation, Los Osos, CA, pp. 205–210.

2003. A systematic study of the surface roughening

Stevenson, C.M., Ayres, W.S., 2000. Easter Island Arch
and sputter rate variations occurring during SIMS
aeology: Research on Early Rapanui Culture. Easter ultra-shallow depth profile analysis of Si with Cs+.

Island Foundation, Los Osos, CA.

Nuclear Instruments and Methods in Physics Research Stevenson, C., Scheetz, B.E., Dinsmore, D., 1989. An

Section B: Beam Interactions with Materials and inter-laboratory comparison of hydration rim mea-Atoms 201, 413–425.

surements. Bulletin of the International Association Werner, H.W., Morgan, A.E., 1976. Charging of insula-for Obsidian Studies 1, 7–13.

tors by ion bombardment and its minimization for

Stevenson, C.M., Abdelrehim, I.M., Novak, S.W., 2001.

secondary ion mass spectrometry (SIMS) measure-

Infra-red photoacoustic and secondary ion mass
ments. Journal of Applied Physics 47, 1232.

spectrometry measurements of obsidian hydration

Wilson, R.G., Stevie, F.A., Magee, C.W., 1989. Secondary rime. Journal of Archaeological Science 28, 109–115.

Ion Mass Spectrometry: A Practical Handbook for Stevenson, C., Liritzis, I., Diakostamatiou, M., 2002.

Depth Profiling and Bulk Impurity Analysis. Wiley, Inves
tigations towards the hydration dating of

New York.

Αegean obsidian. Mediterranean Archaeology and Wittmaack, K., 1979. Primary-ion charge compensation

Archa eometry 2 (1), 93–109.

in SIMS analysis of insulators. Journal of Applied Stevenson, C.M., Abdelrehim, I., Novak, S.W., 2004.

Phy sics 50, 493.

High precision dating of obsidian from the Hopewell

Zhang, Y., Belcher, R., Ihinger, P.D., Wang, L., Xu, Z., Site and Mound City Group earthworks using sec-Newman, S., 1996. New calibration of infrared mea-
ondary ion mass spectrometry. American Antiquity surement of dissolved water in rhyolitic glass. Geo

69, 555–568.

chimica et Cosmochimica Acta 61, 3089–3100.

Stevenson, C., Novak, S.W., 2011. Obsidian hydration
by infrared spectroscopy: Method and calibration.

Journal of Archaeological Science 38, 1716–1726.

Chapter 2

Obsidian Hydration Chronometrics Using SIMS
and Optical Methods from 26-year Temperature-
controlled Exposures

Wallace Ambrose and Steven W. Novak

Abstract
provides an enhanced measurement system and is
combined here with experimentally determined rate

Obsidian samples from three separate volcanic
constants to independently cross-check radiocarbon
provinces in Papua New Guinea have been exposed
dates and site temperature calculation at an approxi-
in normal air and water vapor pressure to controlled
mately 2100 BP archaeological site from Papua New
temperatures of 10 ºC, 20 ºC, 30 ºC, and 40 ºC, for

Guinea.

up to 26 years. The purpose of the experiment was
to provide hydration rate constants at normal ter-

1. Introduction
restrial temperatures for archaeological dating
purposes. When the experiment began, nuclear pro-

Obsidians from the Papua New Guinea sources of
filing was being used to measure obsidian hydration

West New Britain and Manus (figure 2.1) have the
depths to below the approximately 0.7 μm thickness
distinction of a distributional range of over 6000
and approximately 0.2 μm resolution for conven-
kilometers (km) from Borneo to Fiji between 2000
tional optical methods. This was seen as an oppor-
and 3000 years ago. Within these two main source
tunity for determining hydration rates for obsidian
regions, obsidian has been used for at least 30,000
artifacts without the use of radiocarbon dates from a
and 12,000 years respectively, while obsidians from
specific archaeological site or stratigraphic location, the D’Entrecasteaux Islands have a briefer history of
that being the usual practice at the time. The trial
use and a shorter distributional range. The chemis-
was not intended to continue for 26 years but the
try of the Papua New Guinea obsidian sources has
promise of nuclear profiling kept it running. Greatly
been extensively analyzed during the last 40 years by
improved instrumental analysis through second-
most of the standard procedures from XRF, INAA,
ary ion mass spectrometry, SIMS, has now allowed

PIXE-PIGE (proton-induced X-ray emission–
hydration depth and resolution measurements to
proton induced gamma-ray emission), SEM (scan-
be made below the optical threshold, and therefore
ning electron microscopy), and LA-ICP-MS so that
over relatively short exposure times and at normal
the main outline of the changing distributional range
terrestrial temperatures, including those applied in
of obsidians as artifacts over time can be presented
the present study. The results confirm the value of

(Summerhayes 2004). The chronology of obsidian
the strategy by providing basic hydration rate con-
source exploitation in Melanesia is usually found
stants for obsidian specimens from each of the three
from archaeologically associated radiocarbon dates
major Papua New Guinea sources. In an archaeo-

(Fullagar and Torrence 1991; Summerhayes 2004;
logical context these data still require calibration for Torrence and Summerhayes 1997); in contrast, hydra-optical microscopy hydration measurement. SIMS
tion dating has been used on a limited scale employing 15

16 | OBSIDIAN HYDRATION DATING

Figure 2.1. Map showing the three main obsidian source areas in Papua New Guinea. Material from each of the sources was used for the experimental hydration program. In particular the Lou Island source is used to evaluate hydration rate and temperature constraints from a site on the island’s south coast where the obsidian was used for the manufacture of spear points.

standard microscopy for the basic hydration depth
been underlined (Stevenson et al. 1993, 1998) and
measurement (Torrence and Stevenson 2000) and
reaffirmed (Stevenson and Novak 2011). However,
digital microscopy (Ambrose 1994; Ambrose and
obsidians still need to be independently assessed for

McEldowney 2000). The tropical climate of the
specific rate determination to validate these models.

region can promote rapid obsidian hydration but also

Four obsidian sources from three source islands in
brings aggressive surface weathering that can reduce

Papua New Guinea were exposed to normal water
the developing hydration depth, sometimes with its
vapor pressure in controlled temperatures within
complete removal. This reduction is not a problem
the normal terrestrial range of 10 ºC, 20 ºC, 30 ºC,
confined to tropical environments, but by being more
and 40 ºC for up to 26 years in order to find rate
obvious it does emphasize the need for weathering
constants for samples of these chemically different
losses to be taken into account in any program of
sources (table 2.1). The samples included are from
obsidian hydration dating.

West New Britain (Mt. Bao), from West Fergusson

Island in the D’Entrecasteaux group (Igwageta), and

2. Empirical rate determination
from Lou Island, Manus (Umleang and Wekwok).

The well-known modifiers of obsidian hydration rate

3. Method
are temperature, chemical composition, and water
vapor pressure. While temperature and vapor pres-

Several small obsidian flakes were struck from each
sure can be independently related to rate changes
of the four blocks of source material, and those with

(Jones et al. 1997; Rogers 2007), the effect of chemi-
clean fracture surfaces were placed in 10 milliliter
cal composition on hydration velocity is not so

(ml) borosilicate beakers and housed in the base of
easily found. General element oxide contributions
four rectangular stainless steel cases. Each case was
to the hydration rate have been indicated (Liritzis
immersed in its temperature-controlled water bath

2006; Liritzis and Ganetsos 2006), and in parti-
controlled to within ±0.02 ºC, periodically checked
cular the crucial role of compositional water has
with secondary reference thermometers. The base

Obsidian Hydration Chronometrics | 17

Table 2.1 SEM EDX analysis of the experimentally hydrated obsidians*

Oxide

Igwageta

Wekwok

Mt Bao

Umleang

n4
n31
n6
n15

%

± %

± %

± %

±

Na2O

5.23

0.02

4.96

0.14

3.97

0.13

5.20

0.07

MgO

0.16

0.04

0.22

0.04

0.17

0.01

0.23

0.03

Al O

14.51

0.10

13.66

0.21

12.78

0.05

14.17

0.07

2 3

SiO

73.20

0.10

73.23

0.28

76.44

0.12

72.06

0.16

2

Cl

0.03

0.03

0.26

0.07

0.17

0.02

0.33

0.03

K O

4.55

0.04

4.14

0.09

3.93

0.05

4.10

0.07

2

CaO

0.68

0.03

1.08

0.05

1.13

0.05

1.21

0.07

TiO

0.29 0.06

0.31 0.05

0.26 0.03

0.33 0.05

2

MnO

0.04

0.05

0.05

0.06

0.04

0.05

0.04

0.06

FeO

1.35 0.04

1.97

0.22

1.11

0.07

2.33

0.10

H2O

-

0.10

0.13

0.09
d g/cm3

3 2.372 ±0.007

2.380

±0.011

2.353

±0.007

2.391

±0.011

* Major chemical content for four sources from Papua New Guinea glass from the Talasea area of West New Britain. Umleang used for long-term hydration and SIMS profiling. The analyses obsidian is from an area mined on Lou Island, Manus Province, were performed on an ANU EDS unit and all oxide values are in traditionally used for spear manufacture. Igwageta obsidian is weight percent. Wekwok 2000 is a local standard used for check-from the western end of Fergusson Island in the D’Entrecasteux ing the calibration of results from obsidian studies. The source is a Islands. Water was determined by Dr. Chris Stevenson with IR
boulder of clean glass from Lou Island, Manus Province. Obsidian spectroscopy, and density ( d) is in g/cm3 as described in Ambrose from Mount Bao, also known as the Kutau-Bao source, is a clean and Stevenson (2004).

level of each case was 14 cm below the bath’s water

4. Hydration measurement
surface with the top 2 cm above it, so that the tem-
perature of the circulating water is transferred to the The use of the hydration penetration depth as a
stainless case through the base and sidewalls. Each
chronometric introduces the critical task of defining
case had a 2–3 mm depth of distilled water kept on
the hydration boundary. Conventional thin-section
its floor where the 10 ml beakers and their flakes
microscopy used by the originators (Friedman and
were placed so that 100% humidity was maintained.

Smith 1958) is still being employed, but the unequal

A stainless steel internal liner above the beakers shed visual capacity of different operators and their
any condensation down the sidewalls to the case floor
need to arbitrarily define the hydration boundary
and away from the enclosed samples. Each tank had a
are obstacles to consistent measurement accuracy
covering lid capped by thermal insulation.

(Jones 2002a; Rogers 2007; Stevenson et al. 1989).

At different times during the 26-year run obsid-

The usual assessment of the measurement limit
ian flakes were added while others were removed
in optical microscopy is based on the resolving power
for measurement. After about four years flakes were
of the microscope. This limit for obsidian hydra-
removed for nuclear profile measurement (Duerden
tion is given as a normal range of ±0.2 μm, but as
et al. 1982). After 10 years thin-section slides were

Rogers (2006:1699) has shown, this range could be
made of a few 30 ºC and 40 ºC pieces for measure-
up to ±0.5 μm. The precision can be increased by
ment by digital microscopy, while the 10 ºC and 20 ºC
adopting the nonvisual measurement procedure of
specimens had insufficient hydration for optical mea-
digital image scanning across strips of the hydration
surement at any stage.

band (Ambrose 1993). With a pixel size equivalent

18 | OBSIDIAN HYDRATION DATING
of 0.015 μm from a captured image of a 1260 x

960 bitmap, Jones (2002a:126) demonstrated in
a double blind experimental run that the hydra-
tion depth on 5 obsidian artifacts gave a reading
error of less than ±0.05 μm, bringing it to within
the range of secondary ion mass spectrometry

(SIMS). Higher density pixel arrays offer further
reduction in the optical reading limit. Jones’s

(2002b) image analysis RimBuster software pro-
vides a statistically robust system for determin-
ing the hydration boundaries from bitmap files.

If alternative systems such as SIMS and
optical microscopy arrive at the same hydration
depth, the result is likely to be coincidental as the
measurements are dimensions of different effects,
one being from hydrogen concentration and the Figure 2.2a. The reproducibility of the SIMS analysis (Igwageta other from changed refractive index (Leach and
source) is clearly shown by the concordance of the result for Naylor 1981:36; Rogers 2006:1704). The hydra-the 30 °C obsidian specimen from three separate SIMS profiles.

tion profiles derived by an early application of a
nuclear reaction technique to obsidian artifacts

(Lee et al. 1974:45) were given depth values based
who provides a system based on fundamental micro-
on the midpoint of the profile segment with the
scope optics.

maximum gradient. Riciputi et al. (2002:1064) pro-

One study claims that “it is unlikely that optical
vides a more systematic identification of the alter-
measurements will ever provide a useful means of
native characteristic measuring points using their
obtaining quantitative dates from hydrated obsid-

ODDSIMS (obsidian diffusion dating by secondary
ian” (Anovitz et al. 1999:736). As Hull (2001) has
ion mass spectrometry) dating system.

argued, despite the statistical problems of creating

The definition of the hydration boundary can
hydration dating as a self-contained chronometric
be arbitrary in any of the measurement systems
system, the archaeological case for its employment
because the boundary is diffuse, and the act of mea-
rests on its use in conjunction with other informa-
surement can itself add systematic imprecision. This
tion including radiometric and stratigraphic com-
problem can be partly overcome by introducing
ponents. In a thorough study, Jones (2002a:784)

calibration factors that align alternative systems that likewise refines the claim for limitations in obsid-measure different hydration effects. The comparison
ian hydration as an absolute dating system. Despite
of hydration results from the optical and ODDSIMS
the constraints, his conclusion is that relative dif-
systems illustrates the discrepancy in measurement
ferences in digital optical measurement, combined
calibration of the standard visual optical reading and in Bayesian analysis with radiocarbon dating and
its derived chronology (Riciputi et al. 2002:fig. 15).

stratigraphic details, can provide valuable insights

This chapter ascribes the hydration depth to the
for individual sites without making comprehensive
inflection point where the steepest gradient changes to claims for absolute dating.

a lower gradient in the SIMS profile (e.g., figure 2.2a).

Liritzis (Liritzis 2006; Liritzis et al. 2008; chap -

For the optical measurements in this chapter, the
ter 3 in this volume) describes a further improvement
sum of the pixel count between the arbitrary gray-
by indicating a relationship between a developing non-
scale surface minimum and the internal minimum
time-dependent “surface saturation” component of
is converted to depth values in μm (e.g., figure 2.4).

a hydration diffusion profile measured by SIMS and

The pixel width in μm was calibrated by multiple
the time-dependent diffusion depth. The SIMS-SS
digital scans across a stage micrometer. A better
method aims to give artifact-specific hydration
approach to pixel calibration is that of Jones (2002a), rates promising an obsidian hydration chronometric

Obsidian Hydration Chronometrics | 19
inde pendent from reliance on other dating systems
the results in table 2.2 show that temperature/rate
or the need for calibrations with environmental
calibration can be achieved with SIMS on a terrestrial factors. While these developments promise a great
range of experimentally exposed obsidians. The sen-
advance on traditional methods, the problem of
sitivity of the hydration rate to temperature makes it environmental constraints at archaeological sites
possible to estimate long-term site temperature if the still persists in the form of obsidian surface dam-hydration date can be closely aligned stratigraphically age from natural causes. Liritzis et al. (2008) uses
with a radiocarbon date (e.g., Anovitz et al. 2006).

atomic force microscopy (AFM) to evaluate surface

As a corollary it could also be used to corroborate or deterioration and roughness to ensure that the pro-reject a date given by the obsidian artifact’s associated file used in SIMS-SS is not depleted to the extent
context with the radiocarbon-derived age. The appli-
that the surface saturation component is displaced.

cation of these data to details related to archaeological AFM is a valuable system for assessing the suit-specimens requires an additional strategy to deal with ability of any obsidian artifact that is intended for
obsidians exposed to the rigors of site conditions.

hydration dating.

6. Hydration as a weathering
factor

5. SIMS results from the

Obsidian, as a natural volcanic glass, is thermody-
experimental series
namically unstable compared with its mineralogical
rock form, and will devitrify slowly at a geological

SIMS is well suited to the shallow submicron depth
time scale. Research aimed at understanding the
of short-term, laboratory-based obsidian hydration.

weathering of glass in order to impede its dissolu-

In this case “short term” is 10 years at normal ter-
tion at a shorter time scale and to promote long-term
restrial temperature but could also include hydra-
storage and preservation is necessarily a study of the tion induced within weeks at higher temperatures
between 60 ºC to 90 ºC.

Two examples of SIMS (figure 2.2a, fig ure

2.2b) demonstrate the reproducibility of the sys-
tem where 3 profiles of the 30 ºC specimen from
the Igwageta source, West Fergusson Island, show
the same hydration depth at the inflection point

(figure 2.2a). The profiles of the 10 ºC and 30 ºC
specimens from the Umleang source, Lou Island,

Manus, are similarly replicated in figure 2.2b. The
exposure time and SIMS depth details from the
hydrogen profiles from 20 obsidian flakes are
given in table 2.2. The Mt. Bao series were from

4 SIMS runs each on the approximately 16-year
and approximately 26-year specimens with the
average of the 2 runs used to calculate hydra -
tion rate (k) values (figure 2.3). The analysis used
the following conventional relationships where

X = hydration depth in μm, k = hydration rate,
t = years, and T = Kelvin, with a intercept and b slope. Intermediate k values are derived from Figure 2.2B. Figure 2b is confirmation of the reproducibility of two SIMS runs on the 10 ºC and two on the 30 ºC obsidian equation 2.

flakes from the Umleang source that has provided data for From X2 = k × t,

(1)

the assessment of age–temperature status of the Sasi (GDY) and k = exp ( a + (− b ×1/T)),

(2)

archaeological site.

20 | OBSIDIAN HYDRATION DATING

Table 2.2 SIMS profile depths and regression results for hydrated obsidians*

T (ºC)

time (Yr)

Depth (μm)

Rate

Intercept

Slope
r2

Source
t

X
k
a
b

Igwageta

-

-

-

28.0433+ -9489.00

-0.999

10

26.198

0.33

0.00416

20

26.103

0.59

0.01334

30

25.618

0.99

0.03826

30

25.618

1.01

0.03982

30

25.618

1.02

0.04061

40

25.673

1.62

0.10222

Wekwok

-

-

-

27.2147+

-9309.88

-0.999

10 15.441 0.23

0.00343

20

15.581

0.41

0.01079

30

15.581

0.69

0.03056

40

11.756

0.97

0.08004

Mt Bao

-

-

-

27.0909+

-9283.30

-0.998

10

25.969

0.29

0.00324

10

16.882

0.25

0.00370

20

26.103

0.50

0.00958

20

16.786

0.41

0.01001

30

25.618

0.85

0.02820

30

16.301

0.71

0.03092

40

25.673

1.40

0.07634

40

16.356

1.15

0.08086

Umleang

-

-

-

26.9095+

-9288.10 -0.999

10

26.198

0.26

0.00258

10

26.198

0.27

0.00278

20

26.103

0.48

0.00883

30

25.618

0.78

0.02375

30

25.618

0.79

0.02436

40

25.673

1.27

0.06282

* These data give the regression results from SIMS profile depth readings on the 20 obsidian flakes at their respective 10ºC, 20ºC, 30ºC and 40ºC temperatures. The exposure times have varied but the hydration rates calculated from the different specimens from the same geological sample have not appreciably altered. In the case of the two Mt. Bao collections there is evidence for fall-off in the rate over time. The twenty flakes include triplicate 30ºC runs on the Igwageta specimen, and duplicate 30ºC and 10ºC runs on the Umleang specimens. The eight Mt. Bao flakes comprise a ~16 year and ~26 year group combined to give average values for the regression analysis.

time-dependent factors that determine surface ero-
for estimating the material’s longevity (Ambrose
sion. Many laboratory-based studies of the hydroly-
et al. 2004). Stability is particularly important for
sis and ion-exchange of manufactured glasses under
nuclear-waste-form glasses where storage for mil-
different controlled conditions are made with short
lennia is required and where a large literature is
exposure periods at elevated temperatures, or with
dedicated to understanding glass weathering over
powdered samples at lower temperatures intended
long residence times in specialized repositories.

Obsidian Hydration Chronometrics | 21
obsidian chemistry and site temperature as
the main determining variables.

In many cases both an intact internal fis-
sure that can be used for dating and a depleted
surface are present on the same artifact. The
positive result from this circumstance is that
the surface dissolution rate of an obsidian
artifact can be calculated. The use of derived
secondary rate factors by aligning hydration
thickness measurements to a radiocarbon-
dated archaeological context will always
have the uncertainty of the true association
of the artifact and the date. The comparison
of a radiocarbon assay with an intact sur-
face hydration depth is the basis for relative
hydration dating, but it perpetuates the origi-

Figure 2.3. The major element chemistry of the four obsidian nal uncertainty of the shared context into any
sources (table 2.1) differs sufficiently to produce differences in related population of hydration dates. In this
their hydration rates as shown in this Arrhenius regression diagram. The data comprising this figure are presented in chapter we have used an example from a site
table 2.2. An important feature of these results is that the pre-where the dated context is secure to examine
diction of intermediate hydration rates is possible from the SIMS
the potential of SIMS to quantify uncertainty
data, and that they can be aligned with rates derived from the in both dating and environmental tempera-same material assessed by digital microscopy, with the appli-ture. Our example of this approach is given
cation of these to archaeological specimens. This strategy is in the case of obsidian and C14 chronologies
applied to produce the results presented in table 2.4.

from the Sasi archaeo logical site from Lou

Island, Manus Province, Papua New Guinea.

The use of obsidian as an analogue to waste glass

(Mazer et al. 1992) cites the archaeological witness

7. Application of the
of obsidian artifacts where long-term weathering

SIMS analysis to an
effects in natural environments can be examined.

archaeological site

Time-dependent weathering rate factors can be
acquired when the degree of deteriora tion of an aged

The equatorial (147º20’E: 2º23’S) Lou Island Sasi site object is dated, and this is where archaeology can be

(Ambrose 1988) is a habitation layer sealed beneath
a useful contributor to the field of materials analysis.

5 meters (m) of volcanic ash and pumice. Sev eral

When attempt ing to utilize the state of preservation
vol canic events spanning about 500 years buried the
of an unknown-age, archaeologically recovered item,
layer containing hundreds of obsidian spear points
complications immediately arise as many factors can
and debitage flakes. Three radiocarbon dates from
contribute to its deterioration. This inherent diffi-
charcoal give a calibrated weighted average of 2095
culty was strongly emphasized when obsidian hydra-

±55 BP, while 2 calibrated shell determinations give
tion dating was first proposed (Zeuner 1960:343).

2025 ±90 BP. Fifteen obsidian flakes from within the

Friedman and Smith’s earlier publication (1960) of

20-cm-thick habitation layer were chosen for having
hydration dates from Egypt noted surface loss on
percussion-point microfissures or undetached flakes
some of the specimens but did not attempt to quan-
that could hide unweathered hydration surfaces
tify or identify incipient or unrecognizable loss.

acceptable for measurement. Thin sections were

Surface loss is identified as an important factor in
cut with a 0.2 mm diamond wire saw oriented nor-
glass hydration dating (Ambrose 1976, 1994; Liritzis
mal to the hydration surface; the sections were then
et al. 2008; Morganstein et al. 1999). These issues still mounted and prepared as microscope slides. Digital
intrude on a dating system that initially saw only
scanning optical hydration depth measurements

22 | OBSIDIAN HYDRATION DATING
about 20 cm, and was formed on a prior
volcanic ash deposit. Obsid ian at the loca-
tion consisted of points, and flakes from
their manufacture. The 10 obsidians (table

2.3) show a weak two-phase difference in
hydration thickness that is expressed in the
calculated age profile of the site. The range is
within what might be expected from deposit
mixing in a shallow working floor.

8. Discussion

The radiocarbon dates give the Sasi site

(GDY in the Papua New Guinea site record-
ing scheme) an age of 2095 ±55 BP and

2025 ±90 BP. The annual monthly mean

Figure 2.4. Average curve of 5 scans (A–B) across an external hydration band giving a depth of 5.3 µm. Average curve of 3 scans (A–D) air temperature of the Momote station on
across an internal fissure with a width of 11.6 µm, with the scan Manus Island is 27.2 ºC ±0.2 (McAlpine et
midpoint (A–C) taken to be the unweathered hydration depth al. 1983: 183). The closest alignment of the
of 5.8 µm. Each pixel interval is equivalent to 0.11032 µm.

radio carbon dates with hydration ages and
temperature is between 26 ºC to 27 ºC as
shown in the calculated values presented in
were made on the hydration sections on both the
table 2.4 and table 2.5. Based on these results,
protected and the exposed hydration bands to pro-
the volcanism that produced the 5 m of overlying ash
vide an estimation of hydration loss. Five artifacts
and pumice has not greatly affected the long-term
were found to have weathering effects within “pro-
temperature assessment.

tected” zones or to have oblique hydra-
tion edges unsuited to measurement.

The measurements were taken at 1000x Table 2.3 Hydration layer thicknesses on flake internal fissures from the Sasi site*
magnification and recorded at 0.11032
µm x pixel dimensions. Examples of

Group No.

scans
μm

StDev Gp 1

Gp 2
depth
the gray-scale hydration profiles of an

1

5049 4

5.45 0.09 5.45 0–10cm
external surface and an internal fissure

1

5051 7 5.39 0.10 5.39 0–10cm
from flake 5059 are shown in figure 2.4.

2

5054

3

5.70 0.19

5.70 0–10cm

The artifact obsidians are all from the

1

5056 6 5.40 0.14 5.40 0–10cm
local Lou Island Umleang source ana-

2

5057

9

5.57 0.23

5.57 0–10cm
lyzed by SIMS in this report. These data

1

5058 6 5.41 0.17 5.41 0–10cm
provide an opportunity to compare the

2

5059

3

5.81 0.05

5.81 10–20cm
results of radiocarbon dating, hydra-

1

5060 7 5.37 0.05 5.37 10–20cm
tion dates, and the predicted tempera-

1

5062 6 5.38 0.15 5.38 10–20cm
tures needed to produce the resulting

2

5063

3

5.83 0.18

5.83 10–20cm
hydration depths.

Count Mean StDev Min Max Range

Although a sample of 10 pieces is

1

6 5.40 0.03 5.37 5.45 0.08
small, the group should have a simi-

2

4 5.73 0.12 5.57 5.83 0.26
lar hydration development from being
all

10 5.53 0.18 5.37 5.83 0.46
sealed for about 2100 years beneath

* The hydration depth readings in μm and stratigraphic depth in cm show a bi-model the 5-m-deep tephra overburden. The
range. The reason for this has not been assessed but could be related to the time occupation layer was relatively thin,
span of occupation at the site. A larger sample size would be required to test this.

Obsidian Hydration Chronometrics | 23

Table 2.4 Calculated age in years for the Sasi obsidian flakes at different temperatures*

T °C

25.0

25.5

26.0

26.5

27.0

27.5

28.0

28.5

StD

± yrs

± yrs

± yrs

± yrs

Index

5049

2340 80 2220

2110 75 2010

1900 60 1810

1720 50 1630

5051

2290 90 2180

2060 80 1960

1860 70 1770

1680 60 1600

5054

2560 180 2430

2300 170 2190

2080 160 1980

1880 140 1790

5056

2300 120 2180

2070 110 1970

1870 100 1780

1690 90 1600

5057

2450 200 2320

2200 190 2090

1990 180 1890

1790 150 1710

5058

2310 150 2190

2070 140 1980

1880 130 1780

1690 110 1610

5059

2660 50 2530

2390 50 2280

2160 40 2060

1950 40 1860

5060

2280

50 2160

2040 30 1950

1850 30 1760

1670 30 1590

5062

2280 130 2170

2050 120 1950

1860 100 1760

1670 90 1590

5063

2680 170 2550

2410 160 2290

2180 130 2070

1970 120 1870

* Calculated age is rounded to the nearest 10 years. As there are readings (n = 5, k = 0.0602, StD 0.0030, range 0.008). The no SIMS analyses for the archaeological specimens, microscopy calibration factor is therefore 1.061 x SIMS k at 40 °C. The error was used to measure these. As SIMS and microscopy measure

± figure in the table indicates the wide divergence from hydration different effects, it is necessary to calibrate readings between the reading error alone. The additional temperature-based error is two methods. Five hydration microscope digital depth measure-even greater than the reading error and underlines the critical ments of Umleang source flakes exposed from ~12 to 18 years influence of temperature in attempting to derive absolute age at 40 °C were used to calibrate k values against the SIMS 40 °C
values from obsidian hydration dating.

Table 2.5

Sasi site hydration readings partitioned by group*

T °C

Grp

No

Mean

StDev

StErr

Min

Max Range

Yrs

±

25.0 1 6 2300 23 9 2280

2340

60

25.5 1 6 2183 21 8 2160

2220

60

26.0

1

6

2067

24

10

2040

2110

70

26.5 1 6 1970 23 9 1950

2010

60

27.0 1 6 1870 18 7 1850

1900

50

27.5 1 6 1777 19 8 1760

1810

50

28.0 1 6 1687 19 8 1670

1720

50

28.5 1 6 1603 15 6 1590

1630

40

25.0

2

4

2588

106

53

2450

2680

230

25.5

2

4

2458

106

53

2320

2550

230

26.0

2

4

2325

96

48

2200

2410

210

26.5

2

4

2213

93

47

2090

2290

200

27.0

2

4

2103

87

43

1990

2180

190

27.5

2

4

2000

84

42

1890

2070

180

28.0

2

4

1898

81

41

1790

1970

180

28.5

2

4

1808

74

37

1710

1870

160*

* The hydration depth of the 10 obsidian flakes divides into two groups, and although the population is small they differ statistically. The 200- to 300-year difference expressed in these figures between the two groups requires further artifacts to be measured and tested for confirmation or rejection of the apparent separation.

24 | OBSIDIAN HYDRATION DATING

The results from the combined SIMS analysis on
his tory. Australian National University, Canberra,
the long-term 10 ºC to 40 ºC experimental obsidians,
pp. 79–84.

and from digital microscopy on the 10 archaeological

Ambrose, W., 1994. Obsidian hydration dating of a Pleis-flakes, are within the range of both the radiocarbon
to cene age site from the Manus Islands, Papua New
determinations and the meteorological tempera-

Guinea. Quaternary Geochronology ( Quater nary Sci
ture record. At the same time the results confirm the
ence Reviews) 13, 137–142.

relatively short time span of occupation. There is no

Ambrose, W., McEldowney, H.P., 2000. An age assess-
ment for Lapita form obsidian at the Mouk Island
date for the underlying volcanic ash bed on which

Site, Manus. In: Anderson, A., Murray, T. (Eds.), Aus
the obsidian workshop site was established, but the
tralian Archaeologist, Collected Papers in Honour of obsidian results do indicate, on the 26 ºC to 27 ºC

Jim Allen. Coombs Academic Publishing, Australian figures, that it was at least 200 years prior to the approx-National University, Canberra, pp. 268–278.

imately 2100 BP eruption.

Ambrose, W., Novak, S.W., Abdelrehim, I., 2004. Pow-

The special value of the SIMS analysis lies in its abil-dered obsidian for determining hydration rates and
ity to assess the essential hydration rate charac teristics site thermometry. Mediterranean Archaeology and of different obsidian sources. Although this study has Archaeometry 4 (2), 17–31.

used obsidians from low temperature and long dura-

Ambrose, W., Stevenson, C.M., 2004. Obsidian density,
tion, SIMS can equally serve shorter-duration, experi-
connate water and hydration dating. Mediterranean
mentally treated obsidians to provide extrapolated

Archaeology and Archaeometry 4 (2), 5–16.

hydration rates from higher temperatures. By adopting

Anovitz, L.M., Elem, J.M., Riciputi, L.R., Cole, D.R., 1999.

The failure of obsidian hydration dating: Sources,
the SIMS hydration rates to calibrate dates calculated implications, and new directions. Journal of Archa e
from digital microscopy image analysis, on concealed
ological Science 26, 735–752.

obsidian surfaces not accessible to SIMS, a fair assess-Anovitz, L.M., Elam, J.M., Riciputi, L.R., Cole, D.R., and ment of temperature and time constraints at an archae-Fayek, M., 2006. Obsidian hydration: A new paleo-
ological site can be achieved.

thermometer. Geology 34, 7:517–520.

Duerden, P., Cohen, D.D., Ambrose, W., 1982. The

Acknowledgments
mea surement of hydration profiles in obsidian. In:

Ambrose, W., Duerden, P. (Eds.), Archaeometry: An We are grateful to the February 2008 Delphi confer-Aus tralasian Perspective. Department of Prehis tory, ence organizers—Professor Ioannis Liritzis, Nikolaos

Australian National University, Canberra, pp. 236–242.

Laskaris, and Dr. Christopher Stevenson—for pro-

Friedman, I., Smith, R.L., 1958. The hydration of obsidian viding the opportunity in a splendid venue for the
artifacts. Transactions of the American Geophysical presentation of a version of this chapter. Kay Dancey, Union 39 (3), 515.

Friedman, I., Smith, R.L., 1960. A new dating method

RSPAS Cartographic Services ANU, produced the
using obsidian: Part 1, the development of the meth-
figure 2.1 map. The people of Lou Island were an
od. American Antiquity 25, 476–522.

invaluable help in the success of the fieldwork needed Fullagar, R., Torrence, R., 1991. Obsidian exploitation at for this study.

Umleang, Lou Island. In: Allen, J., Gosden, C. (Eds.), Report of the Lapita Homeland Project. Department References
of Prehistory. Australian National University, Can-
berra, pp. 113–143.

Ambrose, W., 1976. Intrinsic hydration rate dating of

Hull, K.L., 2001. Reasserting the utility of obsidian
obsid ian. In: Taylor, R.E. (Ed.), Advances in Obsidian hydration dating: A temperature-dependent empiri-Glass Studies: Archaeological and Geochemical Per
cal approach to practical temporal resolution with
spectives. Noyes Press, Park Ridge, NJ, pp. 81–105.

archaeological obsidians. Journal of Archaeological Ambrose, W., 1988. An early bronze artefact from Papua Science 28, 1025–1040.

New Guinea. Antiquity 62, 483–491.

Jones, M., Sheppard, P.J., Sutton, D.G., 1997. Soil tem-Ambrose, W., 1993. Obsidian hydration dating. In:

perature and obsidian hydration dating: A clarifi-

Fankhauser, B.L., Bird, J.R. (Eds.), Archaeometry: cation of variables affecting accuracy. Journal of Current Australasian Research. Department of Pre -

Arch aeological Science 24, 505–516.

Obsidian Hydration Chronometrics | 25

Jones, M., 2002a. A Brief Prehistory of Time. Ph.D. dis-Rogers, A.K., 2007. Effective hydration temperature
sertation, University of Auckland, New Zealand.

of obsidian: A diffusion theory analysis of time-

Jones, M. 2002b. RimBuster software. In: A Brief Pre
dependent hydration rates. Journal of Archaeological history of Time. Ph.D. dissertation, University of Science 34, 656–665.

Auck land, New Zealand.

Stevenson, C.M., Dinsmore, D., Scheetz, B.E., 1989.

Leach, B. F., Naylor, H., 1981. Dating New Zealand obsid-An inter-laboratory comparison of hydration rind
ians by resonant nuclear reactions. New Zealand measurements. International Association for Obsid

Journal of Archaeology 3, 33–49.

ian Studies, Newsletter, 1.

Lee, R.R., Leich, D.A., Tombrello, T.A., Ericson, J.E., Stevenson, C.M., Novak, S.W., 2011. Obsidian hydration Friedman, I., 1974. Obsidian hydration profile mea-by infrared spectroscopy: Method and calibration.

surements using a nuclear reaction technique. Nature Journal of Archaeological Science 38, 1716–1726.

250, 44–47.

Stevenson, C.M., Knaus, E., Mazer, J.J., Bates, K.K., 1993.

Liritzis, I., 2006. SIMS-SS, a new obsidian hydration

Homogeneity of water content in obsidian from the
dating method: Analysis and theoretical principles.

Coso volcanic field: Implications for hydration dat-

Archaeometry 48, 533–547.

ing. Geoarchaeology 8, 371–384.

Liritzis, I., Ganetsos, Th., 2006. Obsidian hydration dat-Stevenson, C.M., Mazer, J.J., Scheetz, B.E., 1998. Laboring from SIMS H+ profiling based on saturated sur-
atory obsidian hydration rates: Theory, method and
face (SS) layer using new software. Applied Surface application. In: Shackley, M.S. (Ed.), Archaeological Science 252, 7144–7147.

Obsidian Studies: Method and Theory. Advances Liritzis, I., Bonini, M., Laskaris, N., 2008. Obsidian in Archaeological and Museum Science 3. Plenum
hydration dating by SIMS-SS: Surface suitability cri-

Press, New York, pp. 181–204.

teria from atomic force microscopy. Surface and Inter

Summerhayes, G.R., 2004. The nature of prehistoric
obsidian importation to Anir and the development of
face Analysis 458–463, online, DOI 10.1002/sia2672, a 3000 year old regional picture of obsidian exchange

15 Jan. 2008.

within the Bismarck Archipelago, Papua New Guinea.

Mazer, J., Bates, J., Stevenson, C., Bradley, C., 1992.

Records of the Australian Museum, Supple ment 29, Obsid ians and tektites: In natural analogues for water 145–156.

diffusion in nuclear waste glass. Materials Research Torrence, R., Stevenson, C.M., 2000. Beyond the beach: Society Symposium Proceedings 257, 513–520.

Changing Lapita landscapes on Garua Island, Papua

McAlpine, J.R., Keig, G., Falls, R., 1983. Climate of Papua New Guinea. In: Anderson, A., Murray, T. (Eds.), Aus

New Guinea. CSIRO, Australian National University tralian Archaeologist, Collected Papers in Honour of Press, Canberra.

Jim Allen. Coombs Academic Pub lish ing, Austral-Morganstein, M.E., Wicket, C.L., Barkatt, A., 1999. Conian National University, Canberra, pp. 324–345.

siderations of hydration-rind dating of glass artifacts: Torrence, R., Summerhayes, G.R., 1997. Sociality and

Alteration morphologies and experimental evidence
the short distance trader: Intra-regional obsidian
of hydrogeochemical soil-zone pore water control.

exchange in the Willaumez region, Papua New

Journal of Archaeological Science 26, 1193–1210.

Guinea. Archaeology in Oceania 32 (1), 74–84.

Riciputi, L.R., Elam, J.M., Anovitz, L.M., Cole, D.R., 2002.

Zeuner, F.E., 1960. Advances in chronological research.

Obsidian diffusion dating by secondary ion mass

In: Heizer, R.F., Cook S.F. (Eds.), The Application of spectrometry: A test using results from Mound 65,

Quantitative Methods in Archaeology. Quadrangle, Chalco, Mexico. Journal of Archaeological Science 29, Chicago, pp. 325–343.

1055–1075.

Rogers, A.K., 2006. Induced hydration of obsidian: A
simulation study of accuracy requirements. Journal of Archaeological Science 33, 1696–1705.

Chapter 3

The SIMS-SS Obsidian Hydration Dating Method

Ioannis Liritzis and Nikolaos Laskaris

Abstract

1. Introduction

In 1960, Friedman and Smith recognized the obsid-

1.1 Previous obsidian hydration
ian hydration phenomenon and proposed a dating
dating methods
method based on the conversion of the hydration

For nearly four decades, obsidian hydration dating
depth to an absolute age. Two subsequent refine-

(OHD) has been part of the archaeological toolbox
ments of obsidian hydration dating (OHD)—empir-
even if the reported ages were of high uncertainty.

ical rate dating and intrinsic rate dating—improved

In 1960, Friedman and Smith publish the first report
the method. Later, secondary ion mass spectrometry
about OHD. They noted that an obsidian artifact

(SIMS) was employed to accurately define the hydra-
absorbs water, that the hydrated rim in a thin section tion depth. Liritzis and Diakostamatiou (2002) pro-is visible under high-power microscopic magnifica-
posed a novel alternative method based on the SIMS
tion, and finally, that the width of the rims depends

H+ profile and on the formation of a saturation layer
on the absorbance time, glass chemical composi-
near the surface, termed SIMS-SS. Since then, essen-
tion, and temperature. The mathematical formula
tial evaluations of SIMS-SS have been presented,
they suggested to describe the process was
producing a sound basis for the new diffusion age
equation. Here, we present an updated version for

X2 = kt

(1)

the age calculation containing some new elements
where X is the thickness of the obsidian hydration rim regarding suitability criteria derived from atomic
in μm, k is the hydration rate in μm2 per 1000 years,
force microscopy, scanning electron microscopy,
and t is the age in years. However, for the estimation polarized light microscopy, proper plots of certain
of k, the development of calibrations to compensate
parameters derived from the sigmoid shape, and an
for variation in external environmental variables has
improved software for the Windows environment
proven to be difficult. This has been the major imped-
created via Matlab for all calculations including age.

iment to making OHD a fully chronometric dating

Previous ages are recalculated and some new ones
method comparable to radiocarbon dating.

presented, making a total of 18 obsidian specimens

Two later innovations in the dating method were
from all over the world. A linear correlation between
proposed to solve the problems associated with tem-
the SIMS-SS ages and the archaeological/14C ages
perature calibration and variation in glass composi-
reinforces the validity and wide applicability of the
tion. The empirical rate approach correlated the width new dating method.

of optically measured rims on chemically similar
glasses to independent chronometric data, such as
radiocarbon dates. The second, more complex tech-
nique, known as intrinsic rate development, required experimentally determined rate constants coupled

26

The SIMS-SS Obsidian Hydration Dating Method | 27
with a measurement of site temperature to arrive

SIMS-SS. This latter dating approach is based on
at an estimated age. However, the precision of the
modeling the hydrogen profile, following Fick’s dif-
ambient temperature diffusion coefficient obtained
fusion law, and the formation of the surface satura-
through extrapolation from higher-temperature (i.e.,
tion layer (appendix A). Here new steps in the dating

150–200 ºC), laboratory-hydrated obsidians has been
protocol process are presented, such as the use of
questioned (Anovitz et al. 1999). The scientific back-
cubic spline fitting, the use of a successively repeated ground has illustrated the complexity of the hydra-3rd-order fitting of the sigmoid tail length for detertion process, and revised working assumptions for
mination of the best polynomial, the multiple 3rd-

OHD have been proposed (Stevenson et al. 1998,
order polynomial fittings in the diffused region of the 2000; Mazer et al. 1991). However, in spite of more
profile to locate the saturation layer, and an updated than 50 years of development and application, neither
version of the software, which incorporates all the
approach has produced consistently reliable results.

essential parameters of the age calculation.

In some cases, ages have so contradicted other well-
established chronometric data that the utility of the

2. The diffusion process and
obsidian as a chronometer has been questioned
saturation layer in hydrated

(Braswell 1992; Anovitz et al. 1999, 2004). In our opin-obsidian glasses
ion, the problems with OHD are due, in part, to the
use of analytical techniques that involved: (1) nonsys-The diffusion coefficient of water in rhyolitic glasses tematic errors arising from the inherent imprecision
is strongly correlated with the concentration of
of optical measurements, (2) the experimental condi-
water within the surface hydration layer (Drury et
tions used to establish intrinsic hydration rates, and al. 1962; Lanford 1977; Nogami and Tomozawa 1984)

(3) an undeveloped model of the hydration process.

and is referred to as concentration-dependent dif-

For a 50-year review, see Liritzis and Laskaris (2011).

fusion. The anhydrous component of the glass has
little influence on the mobility of water (Behrens
and Nowak 1997). Above the glass transition tem-

1.2 The SIMS approach
perature, the structural relaxation of the glass is fast Anovitz et al. (1999) presented a model for age
enough for a rapid establishment of local equilib-
determination that relied solely on compositionally
rium for the water species. Below the glass transition dependent diffusion, following numerical solutions
temperature, equilibrium may not be rapidly estab-

(finite difference [FD] or finite element) elaborating lished because the process is too slow in relation
on the H+ profile acquired by SIMS. A positive eval-
to the rate of water diffusion (Anovitz et al. 2008).

uation of this approach was completed using results

Under ambient or low temperature conditions the
from Mound 65, Chalco, Mexico, by Riciputi et al.

diffusion coefficient is not static over time and may

(2002). This technique uses numerical calculations
vary during the initial period of hydration (Anovitz
to model the formation of the entire diffusion pro-
et al. 2004; Stevenson and Novak 2011). Therefore, in
file as a function of time and is fitted to the profile the early stages of hydration a range of diffusion
as a whole. In general, the FD equations are based
coefficients may describe the diffusion process. For
on a number of assumptions about the behavior of
longer durations, the diffusion coefficient may be
water as it diffuses into the glass and were applied to proportional to concentration at the level of satura-a characteristic point analysis of the SIMS H+ dif-
tion. This results in the formation of an S-shaped
fusion profile. This treatment was a turning point
concentration-depth profile (Tsong et al. 1980; Lee
for OHD, and a revival of obsidian dating studies
et al. 1974; Anovitz et al. 1999, 2004) (figure 3.1).

emerged (Liritzis 2002; Melos Workshop 2003).

We have suggested (Liritzis et al. 2004) that

Another approach using SIMS, initially proposed
the model of water diffusion in amorphous sili-
by Liritzis and Diakostamatiou (2002), was based on
cates developed by the late Robert Doremus is the
the surface saturation layer formed by the diffused
most appropriate descriptor of water diffusion in
water. It introduced an alternative approach termed
obsidian at low temperature because it accounts for

28 | OBSIDIAN HYDRATION DATING
cause problematic diffused regions and, therefore,
produce uncertain ages. According to our model,

H O molecules choose various diffusion paths in a

2
nonhomogeneous way, as the size-dependent mecha-
nism assumes that water molecules of radius r = 0.15
w
μm occupy interstitial sites of the obsidian and pass
through “doorways” of radius r jumping from one

D
doorway to another. The r = 0.1 μm derives from an

D
equation regarding activation energy E, which is rec-
ognized as the elastic energy to dilate a spherical cavity from radius r to r. Therefore, cavities, holes, and D
troughs of surface topological anomalies will have an
impact by distorting initial SIMS profiles that include the SS layer.

Thus there are cases where the location of SS and/

Figure 3.1. A SIMS hydrogen profile.

or the polynomial fitting will be problematic. The
uncertain ages are linked to the surface topography.

the patterning in much of the experimental data

An approach to minimize such problems is the use of

(Doremus 1969, 1995). The model states that molec-
atomic force microscopy (AFM) (Liritzis et al. 2008a,
ular water enters the glass network and reacts with

2008b). The suitability of surface data obtained
the silicon-oxygen network to form SiOH groups:

by SIMS is supported by SEM (scanning electron
microscopy) investigations focused on the presence

Si-O-Si + H O = SiOH + OHSi

(2)

2
of microlithic inclusions and other structural issues

Molecular water is the mobile species while the newly
recorded on the depth profiles. The simultaneous
formed OH groups are relatively fixed. It is assumed
tracing of cations such as carbon (C), magnesium
that OH group formation lags behind the movement

(Mg), aluminum (Al), oxygen (O), and fluorine (F),
of mobile water molecules but eventually reaches
as part of the H+ depth profiles, and their correlation equilibrium. It is also assumed in model development
help assess the suitability of specimens for SIMS-SS
that the initial concentration of water in the glass is purposes (Liritzis and Laskaris 2011).

zero. However, it is well documented that many natu-

The combined factors of the faster diffusion rate
ral glasses contain initial water concentrations that
of water at the obsidian surface, the kinetics of the
may range between 0.1% and 3.0% by weight (Silver
diffusion mechanism for the water molecules, and
et al. 1990; Newman et al. 1986) and serve to expo-
the specific chemical structure of obsidian, as well as nentially increase the diffusion coefficient as concen-the external conditions for the diffusion (e.g., tem-
tration increases (Stevenson et al. 1998; Stevenson
perature, relative humidity, pressure) (Smith and Van
and Novak 2011). The occurrence of greater amounts

Hess 1987), all result in the formation of an approxi-
of SiOH in the network may weaken the neighbor-
mately constant boundary concentration value in the
ing Si-O-Si bonds, causing them to break easily and
external surface layers. This is the surface saturated therefore to lower the overall activation energy.

layer (SS layer). This layer forms on the first 1–3 μm Even though SIMS is a high-precision, non-of the obsidian surface due to the different rate of
optical, depth profiling technique for measuring
the two diffusion mechanisms. The first mechanism
the width of the hydration rim, depth resolution is
transfers the ambient water from the environment
limited by atomic mixing effects and the flatness of
into the exterior surface of the obsidian and the sec-
the analyzed area. Also, the dynamic range of depth
ond mechanism is responsible for the diffusion pro-
profiles is limited by crater edge effects, neutral
cess into the interior of the artifact.

beam effects, and several types of instrumental back-

The saturation layer on the surface forms to a
ground. Irregular and/or inhomogeneous sur faces
certain depth depending on the above-mentioned

The SIMS-SS Obsidian Hydration Dating Method | 29
parameters. Within a short time after the start of
is then fitted to the SIMS data using TABLECURVE
the diffusion process, a narrow layer saturated with

2D software and takes the form of a polynomial with
water is formed. The time required for this forma-
exponential terms. The water diffusion coefficient
tion is considered equal to t = 0. This formation
at any particular moment is expressed by the first
period is very short in comparison to the total dif-
derivative of the hydrogen profile. Its inverse ratio is fusion time and can therefore be ignored. Following
the apparent hydration rate. The average X and C
s
s
this period, the saturated layer increases over time
obtained from the determination of the SS layer give
to a greater depth. The saturation conditions on the
the overall error attached to the SIMS-SS ages.

surface represent the average conditions of the physi-

Using the end product of diffusion, a phenom-
cal surroundings for the diffusion system during the
enological model has been developed, based on cer-
elapsed time in the particular archaeological setting.

tain initial and boundary conditions and appropriate

It has been shown (Liritzis 2006) that physicochemical mechanisms, that expresses the H O

2
although all of the S-like H+ profiles are similar in
concentration versus depth profile as a diffusion/
form, this is their only shared property. Despite the
time equation. The modeling of this diffusion pro-
fact that they are derived from the same geological
cess is a one-dimensional phenomenon, whereby the
source and are near the same age, close inspection of

H O molecules invade a semi-infinite medium in a

2
the shape of the profiles suggests definite differences.

perpendicular direction to the surface. The model is

These derive from the considerable impact of environ-
based on the idea that in the SS layer found near the
mental and intrinsic effects that may alter the form of sample surface—that is, in the first half of the sigmoid the SIMS hydrogen profile. It is these slight variations curve—the value of C is assumed as constant along a
in the profile that are specific to each case considered, very short distance. Thereafter C gradually decreases
and this is the important observation that the calcu-
following the trend of the sigmoid.

lated age by SIMS-SS method relies upon. Therefore,

In brief, the three principia for dating are: (a) the
any age calculation is based on this diffusion profile, comparison of a nondimensional plot with a fam-which is unique for every obsidian sample.

ily of curves of known exponential diffusion coef-
ficients (figure 3.2); (b) the correlation between the 3. The SIMS-SS dating method
rate of transfer (diffusion) from the surface with the in brief
diffusion duration, the saturation concentration C ,
s
the intrinsic (pristine) water concentration C , the
i

In order to model the form of the diffusion profile,
diffusion coefficient D (defined as the flux/gradient, s

Crank’s (1975) theoretical diffusion curves were con-
where the gradient or tangent = dC/dx), and follow-
sulted. Th ey de
y d rive from the solution of a diff
n o
e
f a diff ren-
n-
ing Boltzmann’s transformation and auxiliary vari-
tial equation that describes the diffusion process
ables, such as the y = (x/2(D t)1/2), which indicates s
s
based on the modeling of the water distribution into
a rate dependence on the square root of time (equa-
the obsidian surface. A detailed presentation of the
tions 3 and 4); and (c) the modeled curve of diffusion mathematics involved is given elsewhere (Liritzis et
profile (concentration versus depth) (equation 5;
al. 2004; Liritzis 2006). Here, in brief, we introduce figure 3.1) (see Liritzis et al. 2004).

the main points of the diffusion age equation. For the non–steady state condition considered here, a col-

-D (∂C/ ∂x) = -1/2 (D /t)1/2 (C -C )(dC/dy )y = 0
s
x = 0
s
i
s
s
s
lection of sigmoid-shaped curves has been produced

(3)

for nondimensional distance and concentration.

Our SIMS profiles were replotted as nondimensional

(dC/dy ) = 1.128/(1–0.177r) and r = kC /C (4)

s
i
s

(standardized to 1) diagrams of C/C versus x/x and
s
s
were matched to the appropriate profile of our pro-

C = e a + bx + cx2 + dx3 (5)

duced curves, guided by the end point of C along the

The dating equation that has been proposed by
x-axis (figure 3.2). In this way a k-value can be cal-

Liritzis and Diakostamatiou (2002), incorporating
culated from any particular sigmoid shape. A curve
all the above mentioned parameters, is

30 | OBSIDIAN HYDRATION DATING

Figure 3.2. A nondimensional profile (a: left) with Crank’s theoretical curves (b: right).

4. Other surface techniques

( C – C )2 1.128
i
s

0.177 kCi
applied to obsidian

T =

∙ Cs ∙

1 –

(6)

2

Very important parameters in the dating process are

4 Dseff dC
calculation of the saturation attributes X and C .

s
s

∙ ∙
dx x-0

Often the obsidian surface at the micro- and nano-
where C is the intrinsic concentration of water, C
scale is not smooth, which influences the diffusion
i
s
the saturation concentration, dC/dx the diffusion
of water and as a result the SIMS profile. Polarized
coefficient for depth equal to zero, D the empirical
light microscopy (PLM), scanning electron micros-
s,eff
effective diffusion coefficient derived from equation
copy (SEM), and atomic force microscopy (AFM)

7 as the effective value of the diffusion coefficient
have been used to examine the obsidian surface

Ds for C = C , and k is derived from the family of
and investigate the relationship between the surface
s

Crank’s curve (figure 3.2).

roughness and the SIMS measurements (Liritzis et
al. 2008a, 2008b). The PLM and SEM techniques

D = a*D + b/(1022*D )

(7)

s,eff
s
s
reveal information about the structure of the
where D = (1/(dC/dx))*10-11 assuming a constant
obsidian, such as the existence of crystallites at the s
flux and taken as unity (Brodkey and Liritzis 2004).

micrometer scale (figures 3.3 and 3.4) although they

The SIMS-SS Obsidian Hydration Dating Method | 31

Figure 3.3. A Polarised Light Microscope (PLM) image Figure 3.4. SEM backscattering image of Youra Island of a Melian obsidian surface (scale: 10X, length of

(Cyclop’s Cave) Melian obsidian. Numbered spots
photo 1.35 mm).

refer to biotite grains (1, 5, 6), feldspar or plagioclase (3), and the glass matrix (4).

are not as detailed as the AFM image (figure 3.5).

the pronounced is the dispersion of the data points to The AFM features consisted of cracks and voids that
either side of the trend line and the smoother the SIMS
are within the first 10 μm of the tool surface. This
diffusion profile. The surface roughness measured by
is within the expected hydration depth of about the
the AFM instrument is linearly correlated with the
last 10,000 years.

standard deviation of the residuals between the data

As it is proposed by Liritzis et al. (2008a, 2008b),
points (H+ values of gmole or atoms/cc) and the linear a linear regression fit of the SIMS data points in the fit in the diffused region of SIMS. This proportional-diffused region (y = a + bx) defines the dispersion,
ity aids the selection of appropriate obsidian samples/
which reflects the degree of roughness and sputter-
surfaces for dating and also for the proper choice of
ing (figure 3.6). The smoother the surface, the less
the spot where the SIMS analysis is performed.

Figure 3.5. AFM topographic image.

32 | OBSIDIAN HYDRATION DATING
during time. This methodology occasionally gave
good results and at other times a result with a high
uncertainty. This is a consequence of the fitting pro-
cess, because as the software tries to fit the experi-
mental data, it stretches the fitting polynomial in
order to pass through all points. This stretching
causes a displacement of the first derivative’s peak,
and as a result a mismatch between the derivative
peak and the real saturation layer. This explanation is further reinforced by the fact that in all samples the saturation layer is always at a depth smaller than the depth of the derivative’s peak. On the other hand, the linear regression method applied to the whole profile
is far more reliable and pinpoints the saturation layer, but at the expense of execution time.

Here, we represent a new way of locating the
saturation layer that uses a combination of the
above two methods and includes a cubic spline fit.

It is much faster than the simple linear regression

Figure 3.6. Linear fit to the hydration region for the method, and it is based on the idea of using the
calculation of Rstd.

derivatives to determine a narrow band in the SIMS
profile for applying the linear regressions. Initially the SIMS profile is fitted by a cubic spline with the

5. The SIMS-SS dating procedure

Savitziky-Golay algorithm (figure 3.7a). Once com-
pleted, the user takes the first derivative and finds

5.1. The location of SS layer
the inflection point (0.0001 cm). According to basic

According to the SIMS-SS dating method, one of the
obsidian hydration dating theory, the diffusion takes
crucial points in the dating process is the location
place, as a result of (a) a chemical reaction of water of the saturation layer. As was mentioned above,
with silica (equation 2), and (b) the mass transport
this layer is formed because of the difference in
size-dependent mechanism relevant to our model
the two diffusion rates. Assuming that the second
that assumes that water molecules of radius r
w
rate—from the saturation layer to the interior of the
occupy the interstitial sites of the obsidian and pass obsidian—follows Fick’s 2nd law of diffusion, the
through “doorways” of radius r , jumping from one

D
attributes of the layer (concentration and depth) are

“doorway” to another (Liritzis 2006:536–537). Thus
very important as initial/boundary conditions.

the inflection point is the depth where this chemical

There are several different ways to locate the sat-
reaction takes place. It is clear from figures 3.7a and urated surface (SS) layer, such as the first derivative 3.7b that the Savitziky-Golay algorithm points to the
of a 3rd-order polynomial that models the SIMS pro-
inflection point with high reliability. The next step is file or repeated linear regressions using data points
to calculate a 3rd-order polynomial from the begin-
of the SIMS profile (Liritzis et al. 2005; Liritzis and ning of the SIMS profile until the inflection depth

Ganetsos 2006; Liritzis et al. 2008a). Regarding the

(figure 3.8a). From this fitting the first derivative and 3rd-order polynomial fit, the method refers to the
the respective depth of its peak are calculated (fig-
calculation of the polynomial’s first derivative, and
ure 3.8b). The next step is to repeat the 3rd-order
it assumes that this first derivative gives a peak cor-polynomial fitting from the beginning of the SIMS
responding to the depth where the saturation layer
until the depth of the previous derivative peak. This
lies. The first derivative has a physical meaning, as
is repeated to obtain a derivative with no peak, or the it reflects the rate of change of the concentration
very beginning of the profile.

The SIMS-SS Obsidian Hydration Dating Method | 33

Figure 3.7. Savitziky-Golay fit (a: top) and the first derivative of the Savitziky-Golay (b: bottom). The inflection is located at 0.0001 cm depth.

34 | OBSIDIAN HYDRATION DATING

Figure 3.8. (a) Fitting until the inflection depth (top); (b) First derivative of the 3rd-order polynomial (bottom).

The SIMS-SS Obsidian Hydration Dating Method | 35
the archaeological term of non-
destructive analysis). For our
needs the instrument measures
the secondary ions of hydrogen.

In all cases (except for a few
with highly disturbed profiles;
see section 8 below) the profile
approximates its ideal theo-
retical shape (figure 3.10) and
has a sigmoid (S-like) shape.

In the SIMS-SS dating method
this sigmoid profile is modeled
with a 3rd-order polynomial.

The reason for this is to create a
polynomial that describes best
the experimental data and to
use it for the calculation of the
diffusion coefficient D . A very
s
important factor in this fitting

Figure 3.9. Results from the linear regression. Slope values versus data points.

procedure is the sufficient mod-
eling of the hydrated region and

The final step is to run successive linear regres-
the tail, because the hydrated region represents the
sions between the two depths: the depth of the peak
present condition while the tail represents the initial, for the first calculated derivative and the depth of the nonhydrated, phase of the artifact.

peak for the last calculated derivative. To choose the In section 5.1 above, the effort to fit the data was
saturation layer we turn to a linear regression graph
described. There the polynomial was stretched and

(figure 3.9), and choose the area with the maximum
the derivative was displaced, but it does not prevent
number of continuous data points with a linear
the need of a polynomial with high modeling rank
regression value (slope) near zero. In this area, the
mean value of the concentrations and their standard
deviation (sd) is calculated in order to produce the
saturation concentration (C ) and the mean value
s
of the depths, also with their standard deviation,
in order to define the saturation depth (X ). Lastly,
s
the mean value of the final 10–20 points in the tail
along with a standard deviation is calculated and the
intrinsic concentration (C ) is obtained.

i

5.2. The crucial modeling
procedure of the SIMS profile
with a 3rd-order polynomial:

A detailed account

The hydration profile H+ data are experimentally mea-
sured with SIMS. The method involves bombardment
of the sample with a beam of primary ions and mea-
surement of the backscattered secondary ions that
have emerged from the miniscule formed crater (thus

Figure 3.10. An ideal SIMS profile.

36 | OBSIDIAN HYDRATION DATING
of the experimental data. However, even having
the last active point on the tail and also the fitting’s a polynomial that described perfectly the experi-R parameter, and adds a point on the tail. The 3rd-
sq
mental data is not possible because of the difference
order polynomial fitting is then re-run (figure 3.11b).

between the experimental data and the theoreti-

The new number of the last active point on the tail
cal curve. Therefore, for the data modeling, it is
with the corresponding R is also recorded. This
sq
assumed that if the 3rd-order polynomial is the best
procedure, of adding a point on the tail and running
fitting of the whole SIMS profile, then its first deriva-a new fitting is repeated up to the end of the tail (fig-tive also serves the purpose for our calculation of the ure 3.11c, figure 3.11d).

D coefficient.

A determination of the best-fit polynomial can
s To calculate this best fitting polynomial, one has
be decided using a plot of R to identify the “hyper-
sqr
to eliminate a few initial points that are due to sput-bola turning point” or a change in the trend of R
sqr
tering effects. After this, the entire tail is cut away values. For example, if for every new point on the tail and the first fitting of a 3rd-order polynomial is com-the new R is continuously higher and then declines
sqr
pleted (figure 3.11a). Then one records the number of
from a specific point onward, the R plot for the tail sq

Figure 3.11. Repeated polynomial fittings (a–d).

The SIMS-SS Obsidian Hydration Dating Method | 37

Figure 3.12. Hyperbola bell shape, normal (a: left) and reversed (b: right).

section would be similar to figure 3.12a. This is a “pos-6. The dating software:

itive hyperbola” and the polynomial with the highest

Analytical presentation

R is the best for further calculations. Occasionally, sqr
trying to locate the “hyperbola turning point” can

As is clear from the above-mentioned steps, the pro-
result in a very different trend. Here, R may start at cess for the calculation of an artifact’s age is a time-sqr
high values and continuously decrease to an inflec-
consuming process. Therefore, the development of
tion point where it then rapidly increases. This func-
appropriate novel software for the execution of all
tional behavior is plotted in figure 3.12b and the best such calculations was an indispensable requirement.

polynomial is the one with the lowest R . Such a

The motive for the development of such software was
sqr
plot of R data points is called a “reversed hyper-
to simplify the calculation of the age, especially for sqr
bola.” In all cases it was found that the polynomials
nonspecialists.1 The first attempt at constructing a
selected in this manner were the best for our dating
dating software was presented by Liritzis et al. (2004) purposes. Such a polynomial was used in equations 5
as a graphical environment created with Matlab;
and 6 to find the diffusion coefficients D and dC/dx.

since that time an additional update was made
s

The former is the solution of the first derivative for (Liritzis and Ganetsos 2006). Here we present the
x = X , and the latter is for x = 0.

newer and more complete version of the SIMS-SS
s

On many samples the tail of the hydrogen profile
software. It is developed by using the Graphical User
is very small as a result of reduced sputtering time.

Interface Development Environment of Matlab and

To overcome this problem, artificial extrapolation
built as a stand-alone application (.exe extension) in of data points in the tail is needed in order to find
order to work outside the Matlab environment as
the “hyperbola turning point.” New data points can
a distributable software. Before end users can use
be added to the last point by a random selection of
this software, they need to install the MCR (Matlab
concentration values from the last existing 20 data

Component Runtime) if it is not already present.

points and pasting them onto the end to create an

MCR is a stand-alone set of shared libraries that
extended profile. With this technique one can create
enables the execution of Matlab-created executable
tails of unlimited depth. The application of equations software. Figure 3.13 is a screen image of the soft-3–7, after the calculation of all the above-mentioned
ware. It is a main window separated into six sections, parameters, now makes it possible to estimate a date
and it also contains a menu bar. In the menu bar are

(equation 6) from the hydrated artifact.

the File, Tool, and Help options. In the File option

38 | OBSIDIAN HYDRATION DATING

Figure 3.13. Screen image of the SIMS-SS software.

one may find subroutines such as Load Data for
program fits the data with the selected polynomial
loading data files of different types and in the Tools and plots the first derivative’s values versus the num-option there are subroutines for creating a graph of
ber of the data sets (figure 3.14c). The second step is Crank’s curves or for the creation of a notepad (.txt
for the calculation of a 3rd-order polynomial fit with extension) file for keeping notes during the dating
its first derivative between two distant data points of process.

the SIMS profile as follows. Initially, we prefer to run The first section, and first step, of the software a curve fit from the beginning of the SIMS profile
is for the calculation of the 3rd-order polynomial.

until the inflection point. However, if the users need Here we have two options: Either enter a polyno-a fast calculation of the SS layer that avoids many
mial calculated with another program or arrange for
repeated fittings, they may run a fit from the begin-
the program to calculate a 3rd-order polynomial by
ning of the profile until the data point identified at entering the order of the fit in the appropriate field the peak of the first derivative produced in step 1. In and then pushing the Fit Order button. When enter-order to narrow the range of the SS layer in the SIMS
ing the coefficients of the polynomial, one has to hit profile, the fitting from the beginning of the profile the Fit Coefs button. For these two options, the result until the data point of the new peak is repeated. This is the same and two graphs are generated: one with
procedure continues until reaching a derivative with
the data and the fitted polynomial (figure 3.14a) and
no peak near the very beginning of the SIMS profile.

one with the data and the first derivative of the fitted With the third step, successive linear regressions are polynomial (figure 3.14b). With the Fit 1D button, the run between the newer calculated derivative peak

The SIMS-SS Obsidian Hydration Dating Method | 39

Figure 3.14. Fitting with the “fit coef” button of the SIMS-SS software (a: top). First derivative of the
fitting polynomial (b: middle). First derivative only
with derivative values (y axis) versus data points

(x axis) of the SIMS profile (c: bottom).

and the calculated one in step 2. It is worth men-
tioning that in some cases the length of this area
is short, and in other cases longer, and depends on
the total length of the SIMS profile, the maximum
concentration, and generally on the profile’s shape.

The result from the linear regression is a graph of
the linear regression’s slope versus the data points

(a)

(figure 3.9). The SS layer was defined as the area
with the larger number of continuous successive
data points near zero slope. In the fourth step, we enter the first and the last point of the SS layer and the program returns the values for the saturation
concentration, C , the saturation depth, X ± error
s
s

(standard deviation), and also the concentration
of the intrinsic water, C . The saturation attributes
i
are calculated as mean values and the intrinsic
concentration as the mean value of the last 10–20
values of the tail. In the fifth step we enter the saturation depth and the saturation concentration
and the program calculates a nondimensional
plot of the SIMS profile. From the comparison
with the Crank’s curves (figure 3.1), the ek value
is estimated. Lastly, in the sixth step, the four (b)

parameters (C , X , C , and ek) are re-entered and
s
s
i
the software calculates the age with its associated
error. The age is calculated in years before pres-
ent (BP) and the error is calculated according to

Taylor’s Rules for the error propagation.

7. Dating results

The validity of these new procedures is tested
through a comparison with independently derived
age determinations. As a first step in this direc-
tion, we have assembled a suite of samples from

Easter Island (Chile), Mexico, Greece, Japan, and

Asia Minor, derived from archaeological contexts
dated by the radiocarbon method or ceramic asso-
ciations. Indeed, the convergence between the two

(c)

dating methods is high (figure 3.15). The SIMS-SS

40 | OBSIDIAN HYDRATION DATING

Neolithic/Early Bronze Age settlement on the
island of Andros; and finally, those of YR-1 to YR-3
originate from the island of Youra, Cyclop’s Cave at

Alonissos, Greece (Sampson 1998; Facorellis et al.

1998). The Ulucak samples are from near Smyrna,

Asia Minor (see a special volume on Ulucak in the

Journal of Mediterranean Archaeology and Archaeometry 5 (3), 2005, www.rhodes.aegean.gr/maa_
journal), and sam ple 1993-76 is from Easter Island

(Rapa Nui), Chile. The sample from Rapa Nui was
excavated from a site occupied in the 14th to 16th
centuries. Finally, samples from Talasea—West New

Britain and West Fergusson islands—were experi-
mentally hydrated for 15–25 years, and the result-
ing ages are within the dating error of the SIMS-SS

Figure 3.15. Ages calculated with SIMS-SS method versus method (±100 years).

expected archaeological ages.

8. Nondated samples
age estimates fall within the expected age ranges for

Occasionally, SIMS profiles are not properly sig-
the archaeological contexts for all samples.2
moid in shape and this affects the dating results. As

Samples and their data are shown in table 3.1.

mentioned above, a major problem can arise from

The 16 out of the 18 samples are new and 2 are recom-
the irregular sample surface, but there are instances
puted with the improved approach of the SIMS-SS
in which the SIMS profile lacks the expected pro-
dating method. Initially a hyperbola point was
file shape even though the surface is smooth. In
found for every sample with its corresponding 3rd-
other cases, the SIMS profile seems to be shorter
order polynomial and then the SS attributes were
than expected for an archaeological artifact. These
also found. Finally, all parameters for every sample
unsuitable samples can be grouped into two catego-
were put into the SIMS-SS software for the age cal-
ries according to their deficiencies.

culation. In figures 3.16a–d the error in the age for a The first category samples have an eroded sur-

+ 10% change of SS attributes is observed. For every
face that can be caused by abrasion from an acciden-
change in an attribute we kept constant the other
tal hit or generated by aggressive surface dissolution three attributes. It is seen that a 10% change in C
within alkaline soils. SIMS profiles on samples with-
s

(saturation concentration) produces a 21% change
out an exterior surface are shown in figure 3.17. Here, in age, while a 10% change in X (saturation depth),
although it is easy to observe the hydrated region,
s

C , and ek produces 6%, 0.6%, and 0.35% respectively
the initial part of the sigmoid curve is missing. In
i
error in age (i.e., age errors are insensitive to C and the majority of these cases such small profiles are not i
eK, and reduced from respective C and X ).

datable because this hydrated region is too small to
s
s

The samples from Japan are from various sites
produce an archaeological age. Recent surfaces can
in that country.3 These archaeological obsidian
be created by the reprocessing of an older artifact,
specimens originated from cultural layers dated
and this may be expected to occur mostly in areas
by AMS and range in age from 30,000 BP to 4500
with no easy access to obsidian sources. A good

BP. The specimens have been identified as coming
example of this is the samples coded Lamo (from
from the same obsidian source through analysis of

Lamia, central Greece). These samples are from an
elemental data by EDXRF and INAA (Watanabe
excavation in central Greece many hundreds of kilo-
et al. 2006). Samples from Greece are from Lamo-7,
meters from Melos Island, the Greek island that is
a Mesolithic settlement; from Strofilas, a Final
the predominant source of obsidian in Greece.

The SIMS-SS Obsidian Hydration Dating Method | 41

Table 3.1 Samples, locations, SIMS-SS dates, and archaeological ages

Location

Sample

Xs (μm)

Cs

Ci
ek

Ds

Age

14C/

(atoms/cc)

(atoms/cc)

(years Calendar

BP)

(years

BP)

Japan

2-3 0

00012

0.0009232

0.0001647

240

9.3 e-13

29,208

±4.61 e-6

±6.78 e-6

±3.31 e-6

±1,650

29,000*

Japan

5-1 9

98e-5

0.0008783

0.0001829

130

9.4 e-13

8,033

8,000*

±3.52 e-6

±9.9 e-6

±5.72 e-6

±676

Japan

7-2

0.0000979

0.00085

0.0002373

60

7.5 e-13

5,085

5,000*

±5.7 e-6

±7.8 e-6

±9.78 e-6

±905

Japan

9-2

5.36e-5

0.00129

0.00021

320

3.01 e-12

6,138

5,000*

±1.8 e-6

±1.39 e-5

±8.97 e-6

±259

Greece

Lamo-7,

6.22e-5

0.001167

0.00017

240

1.25 e-12

15,660 Prehistoric

D13032,

±6.24 e-6

±2.46 e-5

5.86 e-6

±2790

(8,000–

Regini,

12,000)**

Phthiotis

Greece

YR-1, Youra

3.76e-5

0.001679

0.0004051

40

1.24 e-11

11,160

10,000

island

±3.25 e-6

±2.66 e-5

±1.10 e-5

±650

12,000*

Asia Minor,

Ulucak

0.000117

0.002072

0.000394

140

1.96 e-12

7,419

6,000–
near Smyrna

(RHO-8)

±1.95 e-6

±5.11 e-5

±2.20 e-5

±2428

8,000*

BVE-IVa-

Lu4a

(32029-13),

RHO-8/

Chile

1993-76

3.05e-5

0.000632

0.0001082

280

3.01 e-12

482

301–526*

±3.3 e-6

±1.96 e-5

±4.42 e-6

±76

Mexico

1993-153s

5.18e-5

0.0003423

1.297e-6

380

1.53 e-12

1,389

835–1330

*Xaltocan,

±3.85 e-6

5.14 e-6

±2.017 e-6

±12

Mexico

Talasea West

Mt. Bao

1.11e-5

0.0007806

0.0001150

30

3.70 e-11

33

25***

New Britain

287_33

±1.39 e-6

±3.72 e-5

±6.21 e-6

±4

Talasea West

Mt. Bao

2.313e-5

0.0006925

0.00011433

30

6.25 e-12

23

25***

New Britain

287_35

±2.6 e-6

±1.9 e-5

±4.8 e-6

±2

Talasea West

Mt. Bao

2.97e-5

0.0008258

0.00011368

30

3.44 e-12

52

25***

New Britain

287_36

±2.41 e-6

±1.26 e-5

±5.8 e-5

±3

Talasea West

Mt. Bao

1.20e-5

0.001069

0.0001363

50

3.14 e-11

12

15***

New Britain

287_42

±8.83 e-7

±1.26 e-5

±5.26e-6

±1

West

Igwageta

3.11e-5

0.001423

0.0001997

40

7.95 e-12

27

25***

Fergusson

302_22

±2.32 e-6

±2.74 e-5

±6.16 e-6

±3

Island

West

Igwageta

1.5432e-5

0.001985

0.0002044

10

8.44 e-11

36

25***

Fergusson

302_25

±9.03 e-7

±7.92 e-5

±6.16 e-6

±3

Island

West

Wekwok

5.702 e-6

0.0003163

5.33 e-8

140 1.0025 e-11

15

15***

Fergusson

91070-56

±6.71 e-6

±6.193 e-6

±1.36 e-23

±1

Island

West

Wekwok

1.71 e-5

0.0002913

1.32 e-7

10

1.47 e-12

87

15***

Fergusson

91070-57

±1.83 e-6

±8.20 e-6

±1.85 e-7

±19

Island

West

Wekwok

2.046 e-5

0.0002760

6.92e-7

60

1.63 e-12

49

15***

Fergusson

91070-58

±1.06 e-6

±5.31 e-6

±1.31 e-6

±17

Island

* Calibrated 14C dates; ** archaeological ceramic typology dates; *** duration in years for experimental hydration.

42 | OBSIDIAN HYDRATION DATING

(a)

(b)

(c)

(d)

Figure 3.16. Sensitivity of age for four parameters (a–d): ek, C , X , and D .

s
s
s,eff

The second category samples have distorted SIMS
is not satisfactory due to the disturbed profile. Thus profiles. Figure 3.18 shows a sample with a different
the diffusion coefficient (D ) and the age are not accu-s
type of disturbance. A major reason for this irregular-rately computed. In any case, even a best 3rd-order
ity may be the existence of crystallites in the obsidian fitted polynomial with high R does not guarantee
sqr
matrix or the irregular surfaces. This sample does not precision due to this high scatter. The preferred analy-have a regular sigmoid shape and has a disturbed sec-
sis for such types of samples is with the aid of other tion in the initial profile region. The successive linear techniques (see section 4, AFM, SEM, PLM) and the
regression procedure for the entire profile helps to
acquisition of SIMS hydrogen profiles with other cat-
locate the saturation layer, yet the fitted polynomial ions (C, Mg, Al, O, and F).

The SIMS-SS Obsidian Hydration Dating Method | 43
all intrinsic and environmental characteristics that
reflect the burial history of the artifact. The model-
ing of the C versus X diffusion profile based on Fick’s Laws of diffusion and auxiliary variables and initial
boundary conditions for non–steady state, one-
dimensional diffusion, is expressed with an equation
that provides the age when the artifact was made.

Age estimates from the SIMS hydrogen profile can
be negatively impacted by the presence of crystal-
lites in the obsidians, by corroded surface layers, and by natural irregular surfaces. However, these drawbacks can be monitored with other surface imag-
ing techniques (e.g., AFM, PLM, and SEM), and
hydrogen profiles are grouped into acceptable and
nonacceptable categories. In this way the processing
of a SIMS profile is secure and the samples can be

Figure 3.17. Samples without a developed hydration layer dated using a new software based upon a Matlab for-compared to a normal diffusion profile (Lamo-5).

mat. Errors amount to a few percent and stem from
determinations of the predominant variables, which
are the intrinsic water content, the surface saturation concentration, the depth of the hydration layer, and
the goodness of fit for the cubic spline and the 3rd-
order polynomial. The application of the method to
an additional 18 samples from a variety of worldwide
contexts has provided excellent results and supports
the future application of the method in the study of
prehistoric chronology.

Acknowledgments

We thank Professor Minoru Tomozawa and the late

Professor Emeritus Robert Doremus for helpful
comments and Dr. Christopher Stevenson for useful
discussions.

Figure 3.18. Disturbed SIMS profile: Sample YR-3 from Appendix A. SIMS instrument

Youra Island, Greece.

conditions and methods

SIMS profiles presented in this discussion were

9. Conclusions
conducted at the commercial laboratory of Evans

East, East Windsor, New Jersey, where the profiles

The availability of SIMS instrumentation that records
were collected using PHI model 6300 and 6600
the hydrogen profile on obsidian surfaces has made
quadrupole-based secondary ion mass spectrom-
possible a new dating technique based on the sur-
eters. A 5 KeV Cs+ primary ion beam with an impact
face saturation layer. The sigmoid profile of con-
angle of 600 with respect to surface normal was
centration versus hydration depth incorporates
used and negative secondary ions were detected.

44 | OBSIDIAN HYDRATION DATING

The measurements were performed using a 300 x

Behrens, H., Nowak, M., 1997. The mechanisms of water

300 micron ion beam raster. The chamber pressure
diffusion in polymerized silicate melts. Contributions during ion running was 2E-9 torr. The sputtering
to Mineralogy and Petrology 126, 377–385.

rate used to measure samples was 24 A/sec, which

Brodkey, S.R., Liritzis, I., 2004. The dating of obsidian: A is fairly typical. Conversion of ion counts to con-possible application for transport phenomena (a tuto-
centration is done using an ion-implanted obsidian
rial). Mediterranean Archaeology and Archaeometry 4
standard. The same material is used to calibrate the

(2), 67–82.

Braswell, G.E., 1992. Obsidian hydration dating, the Coner sputtering rate, and therefore there are no direct cra-Phase and revisionist chronology at Copan Honduras.

ter depth measurements of archaeological samples.

Latin American Antiquity 3 (2), 130–147.

This method provides very good control of the depth

Doremus, R.H., 1969. The diffusion of water in fused
scale and avoids the problems of direct measurement
silica. In: Mitchell, J.W., Devries, R.C., Roberts, R.W., of a rough surface. For polished test samples, crater

Cannon, P. (Eds.), Reactivity of Solids. Wiley, New depths are measured using a Dektak 6M stylus pro-York, pp. 667–673.

filometer that is responsible to within 1% on flat, well-Doremus, R.H., 1995. Diffusion of water in glass. Journal controlled samples (Liritzis et al. 2004). The depth
of Materials Research 10, 2379–2389.

scale accuracy by SIMS for archaeological samples

Drury, T., Roberts, G.J., Roberts, J.P., 1962. Diffusion of is within 5–10%. This translates into an estimated

Water in Silica Glass. Papers of the 6th International error of ±0.05 μm. This value is not equivalent to the Con gress on Glass. Plenum Press, New York, pp.

±0.01–0.03 μm standard deviation usually associated

249–255.

with SIMS because of the irregular surface topogra-

Facorellis, G., Maniatis,Y., Kromer, B., 1998. Apparent 14C
ages of marine mollusc shells from a Greek island:

phy present on naturally cleaved samples.

Calculation of the marine reservoir effect in the

Aegean Sea. Radiocarbon 40 (2), 963–973.

Notes

Friedman, I., Smith, R., 1960. A new dating method using obsidian: Part 1, the development of the method.

1. Our software is for scientific/educational pur-

American Antiquity 25, 476–522.

poses and may not be used for commercial ventures.

Lanford, W.A., 1977. Glass hydration: A method of dating One may freely use a trial software package on our web-glass objects. Science 196, 975–976.

site (http://www.rhodes.aegean.gr/tms/sims-ss), making Lee, R.R., Leich, D.A., Tombrello, T.A., Ericson, J.E., proper acknowl edgment of the present work.

Friedman, I., 1974. Obsidian hydration profile meas-

2. The reference year for 14C ages is 1950; for SIMS-SS
urements using a nuclear reaction technique. Nature it is the years 2004–2005.

250, 44–47.

3. The samples were kindly provided by Pro fessor

Liritzis, I., Diakostamatiou, M., 2002. Towards a new

Masao Suzuki, Rikkyo University, Tokyo.

method of obsidian hydration dating with secondary
ion mass spectrometry via a surface saturation layer

References
approach. Mediterranean Archaeology and Archaeometry 2 (1), 3–20.

Anovitz, L.M., Elam, J.M., Riciputi, L.R., Cole, D.R., 1999.

Liritzis, I., 2002. Revival of obsidian studies, editorial The failure of obsidian hydration dating: Sources,
addendum. Mediterranean Archaeology and Archae
implications and new directions. Journal of Archaeometry 2 (2), 79–81.

ological Science 26, 735–752.

Liritzis, I., Diakostamatiou, M., Stevenson, C.M., Novak, Anovitz, L.M., Elam, J.M., Riciputi, L.R., Cole, D.R., 2004.

S.W., Abdelrehim, I., 2004. Dating of hydrated obsid-

Isothermal time-series determination of the rate of
ian surfaces by SIMS-SS. Journal of Radioanalytical diffusion of water in Pachuca obsidian. Archaeometry and Nuclear Chemistry 261, 51–60.

46, 301–326.

Liritzis, I., Ganetsos, T., Laskaris, N., 2005. Review and Anovitz, L.M., Cole, D., Fayek, M., 2008. Mechanisms of software assessment of the recent SIMS-SS obsidian
rhyolitic glass hydration below the glass transition.

hydration dating method. Mediterranean Archae

American Mineralogist 93, 1166–1178.

ology and Archaeometry 5 (2), 75–91.

The SIMS-SS Obsidian Hydration Dating Method | 45

Liritzis, I., 2006. SIMS-SS, a new obsidian hydration

Riciputi, L., Elam, J.M., Anovitz, L.M., Cole, D.R., 2002.

dating method: Analysis and theoretical principles.

Obsidian diffusion dating by secondary ion mass

Archaeometry 48, 533–547.

spectrometry: A test using results from Mound 65,

Liritzis, I., Ganetsos, T., 2006. Obsidian hydration dat-Chalco, Mexico. Journal of Archaeological Science 29, ing from H+ profiling based on saturated surface (SS)

1055–1075.

layer using new software. Applied Surface Science 252

Sampson, A., 1998. The Neolithic and Mesolithic Occu pa

(19), 7144–7147.

tion of the Cave of Cyclop’s, Youra, Alonnessos, Greece.

Liritzis, I., Bonini, M., Laskaris, N., 2008a. Obsidian British School of Athens (BSA), 93.

hydration dating by SIMS-SS: Surface suitability cri-

Silver, L., Ihinger, P., Stolper, E., 1990. The influence of teria from atomic force microscopy. Surface and Inter
bulk composition on the speciation of water in sili-
face Analysis 40, 458–463.

cate glasses. Contributions to Mineralogy and Petrol

Liritzis, I., Laskaris, N., Bonini, M., 2008b. Nano- and ogy 104, 142–162.

micro-scale resolution in ancient obsidian artefacts

Smith, J.M., van Hess, H.C., 1987. Introduction to Chem
surfaces: Th

: e

Th imp
e im act o
t f
o AFM o
f AFM n the o
e b
o sidian hy
n h dra-
dra-
ical Engineering Thermodynamics. 4th ed. McGraw-tion dating by SIMS-SS. Physica Status Solidi 5(c) Hill, New York.

(12), 3704–3707.

Stevenson, C.M., Mazer, J.J., Scheetz, B., 1998. Laboratory Liritzis, I., Laskaris, N., 2011. Fifty years of obsidian hydra-obsidian hydration rates: Theory, method and appli-
tion dating in archaeology. Journal of Non Crys talline cations. In: Shackley, M.S. (Ed.), Archaeological

Solids 357, 2011–2023.

Obsid ian Studies: Method and Theory. Plenum Press, Mazer, J.J., Stevenson, C.M., Ebert, W., Bates, J., 1991.

New York, pp. 181–204.

The experimental hydration of obsidian as a func-

Stevenson, C., Novak, S.W., 2011. Obsidian hydration
tion of relative humidity and temperature. American by infrared spectroscopy: Method and calibration.

Antiquity 56, 504–513.

Journal of Archaeological Science 38, 1716–1726.

Melos Workshop, 2003. International Specialized Work-

Stevenson, C.M., Gottesman, M., Macko, M., 2000. Rede-
shop, “Recent advances in obsidian dating and char-
fining the working assumptions of obsidian hydra-
acterization,” Melos Island, 2–6 July 2003 (edited
tion dating. Journal of California and Great Basin abstract book by I. Liritzis, 30 pp.), Department of

Anthropology 22 (2), 223–236.

Mediterranean Studies, Lab of Archaeometry, Uni-

Tsong, I.S.T., Houser, C.A., Tsong, S.S.C., 1980. Depth versity of the Aegean, Rhodes, Greece.

profiles of interdiffusing species in hydrated glasses.

Michels, J.W., Tsong, L.S.T., Smith, G.A., 1983. Exper-Physics and Chemistry of Glasses 21, 197–198.

imentally derived hydration rates in obsidian dating.

Watanabe, K., Suzuki, M., Liritzis, I., Ganetsos, T.,

Archaeometry 25 (2), 107–117.

Novak, S.W., Laskaris, N., Sasaki, K., Ikeya, N.,

Newman, S., Stolper, E., Epstein, S., 1986. Measurement 2006. Hydrogen ion profiling of obsidian hydra-of water in rhyolitic glasses: Calibration of an infration layer using secondary ion mass spectrometry.

red spectroscopic technique. American Mineralogist International Congress of the Indo-Pacific Pre-71, 1527–1541.

history Association, 20–26 March, Manila, Phil ip-

Nogami, M., Tomozawa, M., 1984. Diffusion of water in
pines (abstract book).

high silica glasses at low temperature. Physics and Chem istry of Glasses 25, 82–85.

Chapter 4

Temperature Correction for

Obsidian Hydration Dating

Alexander K. Rogers

Abstract
equations computed from obsidian-radiocarbon
asso ciations, but could be employed with other mea-

Hydration of obsidian is a diffusion-reaction pro-
surement techniques.

cess, the rate of which is dependent on temperature.

Temperature at an archaeological site varies both

Chronological analyses based on obsidian hydra-
diurnally and annually, which causes corresponding
tion must therefore account for the effects of the
variations in hydration rate. The effect of this vari-
temperature history to which the artifact has been
ability is summarized by the effective hydration tem-
subjected. For chronological analyses, the tempera-
perature, or EHT: a constant temperature yielding the
ture history is summarized by the concept of effec-
same hydration outcome as the actual time-varying
tive hydration temperature (EHT). Prior studies,
temperature over the same period of time. EHT is
cited herein, have developed a mathematical model
always higher than the mean temperature; further, a
of the hydration process that relates EHT to obsid-
higher EHT corresponds to a greater hydration rate
ian characteristics and temperature parameters at
and thus a larger rim thickness for a given age.

an archaeological site, and the model has been vali-

Historically, the primary method used to esti-
dated with measured temperature data. Drawing
mate EHT has been the Lee equation (Lee 1969:430,
on these results, this chapter summarizes a model-
eq. 12). It was originally developed for estimating
based method for calculating EHT of an artifact and
mean temperature for forestry monitoring and uses
for applying a correction to the measured hydration
data from a Pallmann cell, a device that measures an
rim value prior to computing age. The correction
effective reaction temperature based on a sucrose
process accounts for the effects of burial depth, local chemical reaction. Lee developed his equation to
temperature conditions, and paleoclimatic change.

convert the reaction temperature of the Pallmann cell
to arithmetic mean temperature, the reverse of the

1. Introduction
way it is typically applied in archaeology. The chief
limitation of Lee’s equation, fully discussed by Lee,

Computing the age of an obsidian artifact based on
is that it is based on a single period of temperature
measurement of hydration rim thickness requires
variation, while there are actually two, annual and
correcting for its temperature history. This chap-
diurnal; Lee attempted to account for annual varia-
ter describes an analytical technique for determin-
tion by summing the two variations, but admitted it
ing the temperature correction factor, based on
was not really successful, and suggested limiting the
recent advances in the theory of hydration (Anovitz
use of the cells to a single season. For obsidian analy-et al. 1999; Doremus 2002; Rogers 2007a, 2008a).

sis it has a second limitation, in that the activation The method was developed for use with hydration
energy of the sucrose reaction is not the same as the
rims measured by optical microscopy, and for rate
activation energy for obsidian hydration.

46

Temperature Correction for Obsidian Hydration Dating | 47

The method described here avoids both these
al. 1991; Doremus 2000, 2002; Haller 1963; Stevenson
problems. The discussion below presents a summary
et al. 1989, 1998; Zhang et al. 1991). No other form
of hydration theory and a method of computing EHT
of functional dependence is currently suggested by
derived from a consideration of time-dependent
theory, and this analysis explicitly assumes the qua-
hydration rates. A method of computing temperature
dratic form, without fractional exponents or linear
parameters at a site based on regional temperature
or higher-order terms. Further discussion of the
scaling is described, with an example. Cor rection fac-physics of diffusion may be found in Crank (1975),
tors for rock shelters and caves are suggested, as are a Doremus (2002), and Rogers (2007a), all of which
correction for paleoclimatic change and a systematic
support the form of equation 1.

process for chronological analysis.

The hydration rate is temperature-dependent,
and is customarily described by the Arrhenius equa-

2. Hydration theory
tion (e.g., Friedman and Long 1976):

D = A exp(-E/RT)

(2)

When a freshly exposed surface of obsidian is exposed
to water, either liquid or vapor, water molecules dif-
where E is the activation energy associated with dif-
fuse into the glass at a predictable rate (Doremus
fusion, R is the universal gas constant per mole, T

2002; Stevenson et al. 1998). As the water diffuses into is absolute temperature, and A is a pre-exponential
the glass it causes a change in refractive index in the proportionality constant. It is based on an idealized
hydrated layer; if a small cross-sectional sample is cut model of a single-stage process, so it is only approxi-from the obsidian, mounted on a microscope slide,
mate for the diffusion-reaction case. Doremus (1994)

and polished to transparency, the interface between
showed its approximate validity across a range of
hydrated and unhydrated volumes (the “hydration
glasses, and Stevenson et al. (1989, 2004) showed
front”) can be observed under a polarizing micro-
this equation to be applicable to obsidian, within
scope (Anovitz et al. 1999; Scheetz and Stevenson
experimental error. It is an adequate model over the

1988). The hydrated volume is referred to as the
range of temperatures encountered archaeologically.

hydration rim, and its thickness in most archaeo-

The diffusion process is described by the equation
logical cases is of the order of microns. If the rate of

∂C/∂t = ∂/∂x (D∂C/∂x)

(3)

hydration is known or can be inferred, the time since
the surface was exposed can be estimated.

where C is concentration of diffusing molecular

The rate of hydration is dependent on the obsidian
water, t is time, D is the diffusion coefficient, and x is chemistry (Friedman and Smith 1960; Friedman and
depth into the glass (Crank 1975; Doremus 2002). To

Trembour 1983), the intrinsic water content of the glass include the effects of reaction, the right side of equa-

(Mazer et al. 1992; Stevenson et al. 1993; Stevenson et al.

tion 2 must include a factor of ∂S/∂t, where S is the

2000), and temperature and relative humidity (Ebert
concentration of water molecules that have reacted
et al. 1991; Friedman and Long 1976; Friedman et al.

with atoms of the glass matrix and become immo-

1994; Hull 2001; Mazer et al. 1991; Rogers 2007a, 2008c; bile. However, at temperatures of archaeological

Stevenson et al. 1993, 2000). Since the diffusion of
interest, this term is small enough to be negligible
water into glass is accompanied by chemical reaction,

(Doremus 2002). The analysis herein is based on the

Doremus (1968, 1994, 1995, 2000, 2002) characterized
diffusion model, equation 3.

it as a “diffusion-reaction” process.

The validity of equation 1 as a description of

The physics and chemistry of the hydration pro-
hydration has been questioned (e.g., Anovitz et al.

cess suggest that the relationship between age and

1999), because its classic derivation (Crank 1975)

rim thickness should be quadratic, i.e., of the form
results from a solution of equation 3 under the
assumption that the diffusion coefficient D is a con-
x2 = D t

(1)

stant. For the case of hydration in glass, it is known where t is age in years, x is rim thickness in microns, that D is not a constant, but is a function of concen-and D is a constant, the hydration rate (e.g., Ebert et tration C (Anovitz et al. 1999; Doremus 2002; Haller

48 | OBSIDIAN HYDRATION DATING

1963). However, it can be shown that equation 1 is

V at a depth z is related to variation at the surface
valid even if D is a function of C, so the form of equa-

(V ) by (Carslaw and Jaeger 1959:81)

0
tion 1 is assumed herein (Crank 1975; Rogers 2007a;

V = V exp (-kz)

(8)

Wagner 1950).

0
where k is an attenuation factor, defined by

3. Effective hydration

k = √ (πf / κ) (9)

temperature
where f is the frequency of the variation and κ is
thermal diffusivity of the soil (Carslaw and Jaeger

Equation 2 above gives the dependence of D on tem-

1959:65, eq. 7). Recent measurements by the author
perature T. For time-varying T, the effective diffu-
in desert conditions yield a value of thermal diffu-
sion coefficient over a time interval t is
sivity of 0.005 ±0.001 cm2 per sec, which is consis-

D = (1/t) A ∫ exp{-E/[RT(t′)]} dt′ (4)

tent with published data for normal soil (Carslaw
eff
and Jaeger 1959:497, app. 6); for this value, equation where T(tʹ) is the time-varying temperature and the

8 becomes
integral is taken over the interval 0 → t (Crank 1975).

This equation is an exact solution, subject only to the V = V exp (-0.44z)

(10)

a
a0
validity of the diffusion-reaction model of hydra-
and
tion. There is no general closed-form solution to this equation, but it can be solved numerically for any

V = V exp (-8.5z).

(11)

d
d0
specific time series T(t ) by
i

Here z is in meters and V and V represent surface
a0
d0

D = (1/N) A ∑ exp{-E/[RT(t )]} (5)

conditions. For conditions with higher soil mois-
eff
i
ture, values of κ can be obtained from tables of soil
with the sum being taken over the hydration time in
data such as Carslaw and Jaeger (1959:497, app. 6).

N increments of ∆t = t -t . The effective hydration i+1
i

The model described by equation 6, with the
temperature (EHT) is then
climate model of equation 7, was used to generate a

EHT = -(E/R)/ln{(1/N) ∑ exp[E/RT(t )]}

(6)

large number of cases of EHT over a range of param-
i
eters. The sum in equation 6 was taken over one full

The variation of temperature over time can be
cycle of the lowest-frequency variation, which was
approximated to any desired degree of accuracy as
one year. An algebraic equation was then devel-
a Fourier series (Carslaw and Jaeger 1959), but the
oped to fit these data to facilitate practical computa-present analysis retains only the first-order terms.

tions by the archaeologist (Rogers 2007a). Analysis

The temperature model is
showed that the significant variables are the annual

T(t ) = T + 0.5V sin{[2π/(24x365)]

i
a
a
average temperature and the sum of the squares of

t } + 0.5V sin[(2π/24) t ]

(7)

i
d
i
the annual and diurnal variations. An algebraic fit is where T(t ) is the temperature at time t , T is annual (Rogers 2007a)

i
i
a
mean temperature, V is annual temperature varia-
a

EHT = T (1-.8×10-5 y) + 0.0096 y0.95 (12a)

a
tion (July mean minus January mean), V is mean
d
diurnal temperature variation (average of the diur-

y = V 2 + V 2

(12b)

a
d
nal temperature variation for January and July),
where T is annual average temperature, and y is the
a
and t is in hours (Rogers 2007a). The adequacy of
sum of the squares of the annual and diurnal tem-
i
this model has been demonstrated with field data
perature variation, modified for depth by equations

(Rogers 2008b).

8 and 9. Depth correction for EHT is desirable, even

For buried artifacts, T does not change but V
in the presence of site turbation (Rogers 2007b).

a
a
and V must now represent the temperature varia-

Equations 12a and 12b give values of EHT that
d
tions at the artifact depth. The temperature variation agree with those of equations 6 and 7 to within

Temperature Correction for Obsidian Hydration Dating | 49

Table 4.1. Temperature data summary in degrees Centigrade for years 2000–2005, Amargosa Desert Research Site, 845 m altitude

Parameter

Air Temperature

Surface Temperature

Offset

T 18.3

21.5 3.2
a

V 24.2

31.0 6.8
a

V 15.3

25.2 9.9
d

<±0.1 ºC over a range of T between 1 ºC to 25 ºC, V
practice recommends a 30-year history of tempera-
a
a
between 0 ºC and 25 ºC, and V between 0 ºC and
ture data (Cole 1970); such data are available gratis
d

25 ºC (Rogers 2007a).

from the websites of the Regional Climate Centers.

The temperatures used in the above analysis

The data are air temperatures, measured 2 meters
should be surface temperatures (Onken 2006;
above the ground in an enclosure that shelters the

Stevenson et al. 1989), which require some judgment
sensor from direct sunlight, again normal meteoro-
to estimate. Frequently, surface temperatures at
logical practice.

brush-covered sites are closely approximated by air

Temperature sensors placed at a site are some-
temperatures, so the latter may be used as a surro-
times used to estimate temperature parameters, but
gate. For open desert sites, surface temperatures can
have the drawback that they do not even approach the
be approximated by adding an offset to air tempera-

30-year standard of meteorology. If they are used, their ture parameters, as shown in table 4.1 (based on data
data should be carefully compared to recent regional
from Beatty, Nevada, from Johnson et al. (2002)).

data to ensure the results are not anomalous. Digital

Whichever is used for a particular site, EHT differ-
sensors, whose data can be correlated with meteoro-
ences between sites can be computed with either
logical records, are to be preferred over Pallmann or
air temperatures or surface temperatures, as long as

Ambrose cells, which do not provide such data.

they are used consistently (Rogers 2008b).

The analytical approach recommended is to

The effect of EHT on rim thickness is corrected
scale from a number of sites in a region of similar
by the rim correction factor R. If two items of identi-weather patterns. As an example, an analysis was per-
cal obsidian are exposed for the same length of time
formed for 13 sites in the southwestern Great Basin
to temperature histories with different EHT, they
and northern Mojave Desert, with altitudes ranging
will develop different rim thicknesses. Suppose one
from 287 m (940 ft) to 3600 m (11,811 ft); the region
rim, exposed to EHT , is regarded as the reference
is approximately 200 km east-west by 300 km north-
r
case, and develops rim x ; the other rim, exposed
south. The data were from the Western Regional
r
to EHT, develops a rim thickness of x. This rim can

Climate Center, using the database from 1971 to 2000
then be related to reference conditions by the equa-

(table 4.2), and values of T , V , and V were com-
a
a
d
tion (Rogers 2007a)

puted for each site as described previously (equation

x = x
exp[0.06(EHT—EHTr)] .

(13)

7 above). For sites in the same circulation patterns,
r
uncorr
altitude is the dominant parameter affecting mean
temperature, so a least-squares fit was made for each

4. Regional temperature scaling
parameter against altitude. Plots are shown in figures 4.1 through 4.4.

Frequently there are no long-term meteorological

The annual average temperature was found to
records for the immediate area of an archaeological
be predicted by the equation
site, so the temperature parameters must be scaled
from other sites that lie in a similar weather pat-

T = 22.25-1.80x

(14)

a
tern and do have records. Standard meteorological
where x is altitude in thousands of feet (figure 4.1),

50 | OBSIDIAN HYDRATION DATING
with an error standard deviation of 0.79 ºC. The

Verde, and found diurnal temperature variation of
annual temperature variation (figure 4.2) was found
only 5 ºC at an exposed location in a rock shelter,
to be predicted by
with smaller variations within structures in the rock
shelter. Annual variation was not reported. Recent

V = 22.63-.70x

(15)

a
unpublished data measured by the author in the Ray
with x defined as above; the error standard deviation

Cave, a small rock shelter in the Coso Range of east-
is 0.76 ºC. The best fit between V and altitude is poor, ern California, showed an annual variation inside
d
as seen in figure 4.3, and, in the absence of other data the shelter that was approximately 75% of the varia-about a site, the most robust estimate is to use the
tion outside. Until other data are available, these
average for the region, or 15.8 ºC; the error standard are reasonable parameter values to use in analyses
deviation of this estimate is 1.79 ºC, 1-sigma. Finally, if involving caves or rock shelters.

T is known for a site, V is predicted by
a
a

V = 1.65 + 0.94T (16)

6. Paleoclimatic change
a
a
with an accuracy of 0.27 ºC (figure 4.4). Thus, if alti-It is known that mean temperature has varied over
tude of a site in this region is known, the three tem-
archaeological time scales, which would affect the
perature parameters required for EHT computation
hydration rate of obsidian. The analysis leading to
can be calculated from equations 14 and 15 (plus the
equations 12a and 12b assumes T , V , and V are
a
a
d
value of V ). When these equations are used to gen-
constants; however, if the parameters change slowly
d
erate parameter inputs for equations 12a and 12b, the
over time, the effect can be approximated as a series
error standard deviation for EHT is 0.81 °C for this
of stepwise changes.

regional case.

The theory behind the computational approach

This technique has been applied successfully in
starts with equation 5 above, and is based on effec-
other regions. However, it is often noticed in areas
tive hydration rate. Since the pre-exponential fac-
such as the Central Valley of California and its foot-
tor A plays no role in the time-varying process, it is hills that valid scaling curves with altitude cannot be convenient for the purposes of analysis to define a
developed; this is probably due to the effects of the
normalized hydration rate as K = D /A:

e
e
temperature inversion layer in such areas. In such

K = (1/N) ∑ exp{-E/[RT(t )]} .

(17)

cases the best procedure is to compute the tempera-
e
i
ture parameters for surrounding weather stations,

This equation gives an effective hydration rate con-
and then compute average values for T , V , and V ;
stant at any point in time (Rogers 2007c). For paleo-
a
a
d
these values can then be used in equations 8–10 to
climatic analysis the input time series for equation
compute EHT at the site of interest.

17 can be developed from a temperature history

In summary, the regional scaling approach makes
trend line such as shown in West et al. (2007:17, fig.

best use of the aggregate of meteorological data from

2.2). After assuming a baseline average temperature
a region; however, it is important for the researcher
for the region of interest in the present, deviations
to tailor the analysis to the particular area of interest can be measured from the graph and average tem-and take into account the factors that dominate local

perature as a function of time computed. Annual
weather patterns.

variation in a region may then be computed from
equation 16, and mean diurnal variation may be set

5. Caves and rock shelters
to the present value.

Paleoclimatic change can be treated as a low-

Artifacts in rock shelters or other similar areas
frequency phenomenon: temperature parameters are
show different hydration characteristics than those
modeled as constant for some interval (for example,
in the open. Everett-Curran et al. (1991) measured

500 years for ages before 1000 BP and 50 years after
temperature variation within rock shelters at Mesa

1000 BP), after which a shift up or down occurs. For

Temperature Correction for Obsidian Hydration Dating | 51

Figure 4.1. Relationship between
site altitude and average temper-
ature variation, northern Mojave

Desert sample.

Figure 4.2. Relationship between
site altitude and annual tempera-
ture variation, northern Mojave

Desert sample.

Figure 4.3. Relationship between
site altitude and mean diurnal
temperature variation, northern

Mojave Desert sample. Note
poor correlation.

Figure 4.4. Relationship between
average annual temperature and
annual temperature variation,
northern Mojave Desert sample.

52 | OBSIDIAN HYDRATION DATING

Table 4.2 Weather data from 13 stations in the southwestern Great Basin and Northern Mojave Desert

Station

Alt, ft

Mean

Mean

Annual

Jul

Jul

Jan

Jan

Ta, Va, Vd,

Max, ºF Min, ºF Ave, ºF

Max, ºF Min, ºF Max, ºF Min, ºF

ºC

ºC

ºC

Baker

940

86.2

54.0

70.1

110.0

74.9

63.4

34.9

21.17

21.56

17.67

Trona 1700 80.1 54.0 67.1 102.0 73.6 59.0 36.1 19.47

19.82

14.25

Daggett

1930

81.7

54.4

68.1

104.2

73.4

61.3

37.5

20.03

20.61

15.17

Apt

Cantil

1960

80.1

47.5

63.8

104.3

69.2

58.9

28.9

17.67

18.51

18.08

Barstow

2140

79.8

47.1

63.5

101.9

66.0

60.2

31.7

17.47

18.31

17.89

Armitage 2240

80.5

47.0

63.8

100.6

67.2

59.9

32.3

17.64

18.33

16.94

Fld

Inyokern

2440

80.9

47.4

64.2

102.4

65.9

60.5

31.1

17.86

18.32

18.31

Mojave

2740

75.9

49.5

62.7

96.6

68.3

57.7

33.6

17.06

17.81

14.56

Haiwee

3282

73.6

45.1

59.4

95.7

63.8

52.7

29.1

15.19

15.74

15.42

Randsburg

3570 74.7 50.5 62.6 97.4 67.6 54.3 36.4 17.00

17.74

13.25

Wildrose

4100

72.3

45.2

58.8

95.0

63.4

51.6

30.1

14.86

15.57

14.75

Mtn Pass

4740

70.7

45.0

57.9

92.3

65.3

51.1

29.4

14.36

15.29

13.53

White Mtn 11811

46.7

20.4

33.6

66.6

37.0

33.5

8.6

0.86

2.46

15.14

Table 4.3 Paleoclimatic correction factors, P(n), for age computation (rcybp, radiocarbon years before present)

Age, rcybp

Factor

Age, rcybp

Factor

Age, rcybp

Factor

50 0.9598 1000 1.0088 10500 0.9902

100 0.9664 1500 1.0102 11000 0.9977

150

0.9988

2000

1.0136

11500

1.0070

200 1.0191 2500 1.0183 12000 1.0132

250 1.0209 3000 1.0256 12500 1.0179

300 1.0288 3500 1.0310 13000 1.0197

350 1.0306 4000 1.0276 13500 1.0260

400 1.0363 4500 1.0094 14000 1.0375

450 1.0402 5000 0.9907 14500 1.0500

500 1.0431 5500 0.9757 15000 1.0636

550 1.0431 6000 0.9645 15500 1.0760

600 1.0428 6500 0.9573 16000 1.0878

650 1.0394 7000 0.9557 16500 1.1000

700 1.0333 7500 0.9583 17000 1.1115

750 1.0290 8000 0.9643 17500 1.1236

800 1.0235 8500 0.9697 18000 1.1357

850

1.0195

9000

0.9713

900

1.0161

9500

0.9707

950

1.0136

10000

0.9750

1000

1.0088

10500

0.9902

Temperature Correction for Obsidian Hydration Dating | 53
each interval, denoted by i, a value of K (i) can be
assumptions of the rate equation, because the EHT
e
computed from equation 17, representing the hydra-
on which the equation is based becomes the refer-
tion rate that prevails during interval i. If an artifact ence EHT (EHT ) in the calculations below.

r
was created in interval n, the effective rate that has The first step in any chronological analysis is to
occurred since the item was created, K (n), is the
ensure the data set is complete. The site altitude and m
weighted mean of K (i) for all the coeval and subse-
context (open air, rock shelter, cave) should be known, e
quent intervals, or
the obsidian specimens should be sourced and rim
measurements available, and the burial depth of each

K (n) = Σ[K (t )∆t ]/Σ(∆t ) (18)

m
e i
i
i
specimen known.

where the sum is taken over all the intervals from 1

A set of temperature parameters (T , V , V ) for
a
a
d

(the present) to n (the age of interest).

the site must then be calculated, based on a regional

For a given rim thickness x, variation in K causes
temperature scaling analysis. Judgment is required
m
variation in age, by equation 1. Since age is generally in this analysis, because of the variation in weather
unknown, however, applying this to a computation
patterns in different parts of the world. If sufficient requires an iterative process: the age is first computed altitude relief exists, the altitude scaling may be the based on current conditions; a correction for that age best; otherwise an averaging technique may be pref-is computed, resulting in a new age value; this new
erable. In the latter case it is important to average the age value is then used to compute a second paleocli-temperature parameters, not the EHT.

matic correction, which results in a second age. This

Next, the EHT for each specimen is computed,
process is continued until the change of ages between
using equations 10–12, yielding a set of values EHT . i successive steps is sufficiently small.

If the specimens are from a rock shelter or cave, the

In practice it is found that the computation con-
values of V and V must be modified appropriately.

a
d
verges to an error of less than 0.05% in three iterations The rim correction factor for the ith specimen then
or fewer, and generally the first correction alone is
is computed as
within 0.1%. This permits simplification to a two-step R = exp[0.06(EHT -EHT )] (21)

calculation: the age of an artifact is computed based
i
i
r
on current climatic conditions, and then multiplied

If each uncorrected rim value is denoted x , the value i
by a paleoclimatic change factor P(n),
corrected for current EHT conditions xc is
i

P(n) = K (n) / K (1)

(19)

xc = x × R

(22)

i
i
i
m
m
where K (1) represents the rate at present condi-
and the corresponding age estimate (based on cur-
m
tions. Values of P(n) have been computed using
rent temperature conditions) is, from equation 20,
equation 19 and the data of table 4.2, and are pre-

tp = k × x 2 (23)

i
ci
sented in table 4.3.

Finally, an approximate paleoclimatic correction
may be applied by using the data of table 4.3. The

7. Recommended analytical
value of tp is entered into table 4.3, interpolating
i
procedure
between table entries as necessary, and a paleocli-
matic correction factor P is read. The final estimate It is assumed that, prior to any analysis, rate equa-i
of age is then
tions are known for the types of obsidian to be ana-
lyzed. Such an equation will generally be of the form
t = tp × P (24)

i
i
i

The computational steps described above can

t = kx2 (20)

be conveniently implemented in a spreadsheet pro-
where k is the hydration constant in years per μ2 or
gram such as Excel or QuatroPro. Alternatively, the
millennia per μ2 (i.e., the reciprocal of the hydra-
full iterative procedure can be implemented in a
tion rate). It is also important to know the EHT
software package such as Matlab or Mathematica.

54 | OBSIDIAN HYDRATION DATING

8. Conclusions

Doremus, R.H., 1995. Diffusion of water in glass. Journal of Materials Research 10, 2379–2389.

The preceding discussion has described a compu-

Doremus, R.H., 2000. Diffusion of water in rhyolite glass: tationally simple method for correcting obsidian

Diffusion-reaction model. Journal of NonCrys talline hydration data for the probable temperature his-Solids 261, 101–107.

tory to which the artifact was exposed. When used

Doremus, R.H., 2002. Diffusion of Reactive Molecules in with chemical sourcing of the obsidian and EHT-Solids and Melts. Wiley Interscience, New York.

specific hydration rates, it removes a major part of

Ebert, W.L., Hoburg, R.F., Bates, J.K., 1991. The sorp-the variability in an obsidian hydration data set.

tion of water on obsidian and a nuclear waste glass.

The correction does not remove all sources of vari-

Physics and Chemistry of Glasses 34 (4), 133–137.

ability, especially hydration rate differences aris-

Everett-Curran, L., Milo, R.G., Quiatt, D., 1991. Micro-ing from intrasource chemical variability (Rogers
geo graphic comparisons of climate today afford
inferences concerning past behavior: An overview of

2008a; Stevenson et al. 1993, 1998); also, the method
data and applications from a study of Chapin Mesa
requires inferring the temperature history of an

(Mesa Verde National Park) climate. In: Hutchinson,
artifact, which is subject to uncertainty. With these

A., Smith, J.E. (Eds.), Anasazi Symposium 1991. Mesa caveats, however, the procedure yields results that

Verde Museum Association, Mesa Verde, CO, pp.

are archaeologically reasonable.

109–116.

Friedman, I., Smith, R.A., 1960. A new method of dat-

Acknowledgments
ing using obsidian; Part 1, the development of the
method. American Antiquity 25, 476–522.

A work such as this necessarily draws on the exper-

Friedman, I., Long, W., 1976. Hydration rate of obsidian.

tise of many people. I especially wish to thank my col-Science 191, 347–352.

leagues Tim Carpenter, Alan Garfinkel, Tom Origer,

Friedman, I., Trembour, F.W., 1983. Obsidian hydration Craig Skinner, and Chris Stevenson for sharing data
dating update. American Antiquity 48, 544–547.

and for fruitful discussions on obsidian hydration.

Friedman, I., Trembour, F.W., Smith, F.L., Smith, G.I., And I am deeply indebted to Robert Doremus, who

1994. Is obsidian hydration affected by relative humid-literally wrote the books on the materials science of
ity? Quaternary Research 41, 185–190.

water in glass, for his patience and many clarifications.

Haller, W., 1963. Concentration-dependent diffusion
coefficient of water in glass. Physics and Chemistry of Glasses 4, 217–220.

References

Hull, K.L., 2001. Reasserting the utility of obsidian
hydration dating: A temperature-dependent empiri-

Anovitz, L.M., Elam, J.M., Riciputi, L.R., Cole, D.R., 1999.

cal approach to practical temporal resolution with

The failure of obsidian hydration dating: Sources,
archaeological obsidians. Journal of Archaeological implications, and new directions. Journal of Archa

Science 28, 1025–1040.

eological Science 26, 735–752.

Johnson, M.J., Mayers, C.J., Andraski, B.J., 2002. Selected Carslaw, H.S., Jaeger, J.C., 1959. Conduction of Heat in Micrometeorological and SoilMoisture Data at Amar

Solids. 2nd ed. Clarendon Press, Oxford, UK.

gosa Desert Research Site in Nye County near Beatty, Cole, F.W., 1970. Introduction to Meteorology. Wiley, Nevada, 1998–2000. U.S. Geological Survey Open-File New York.

Report 02–348. USGS, Carson City, NV (with CD

Crank, J., 1975. The Mathematics of Diffusion. Oxford containing meteorological data records).

University Press, Oxford, UK.

Lee, R., 1969. Chemical temperature integration. Journal Doremus, R.H., 1968. The diffusion of water in fused sil-of Applied Meteorology 8, 423–430.

ica. In: Mitchell, J.W., DeVries, R.C., Roberts, R.W., Mazer, J.J., Stevenson, C.M., Ebert, W.L., Bates, J.K., 1991.

Cannon, P. (Eds.), Reactivity of Solids. Proceedings of The experimental hydration of obsidian as a func-the 6th International Symposium on the Reactivity
tion of relative humidity and temperature. American of Solids. Wiley Interscience, New York, pp. 667–674.

Antiquity 56, 504–513.

Doremus, R.H., 1994. Glass Science. 2nd ed. Wiley-Mazer, J.J., Bates, J.K., Stevenson, C.M., Bradley, C.R., Interscience, New York.

1992. Obsidians and tektites: Natural analogues for

Temperature Correction for Obsidian Hydration Dating | 55
water diffusion in nuclear waste glasses. Materials meas urement: Implications for experimentally deter-Research Society Proceedings 257, 513–520.

mined hydration rates. American Antiquity 53, 110–117.

Onken, J., 2006. Effective Hydration Temperature and Stevenson, C.M., Carpenter, M.J., Scheetz, B.E., 1989.

Rel ative Humidity Variation within the Nevada Test Obsidian dating: Recent advances in the experimen-and Training Range, Southern Nevada. Technical tal determination and application of hydration rates.

Report 06-50. Statistical Research Inc., N.p.

Archaeometry 31, 1193–1206.

Rogers, A.K., 2007a. Effective hydration temperature

Stevenson, C.M., Knauss, E., Mazer, J.J., Bates, J.K., 1993.

of obsidian: A diffusion-theory analysis of time-

The homogeneity of water content in obsidian from
dependent hydration rates. Journal of Archaeological the Coso Volcanic Field: Implications for obsidian

Science 34, 656–665.

hydration dating. Geoarchaeology 8, 371–384.

Rogers, A.K., 2007b. A tale of two gophers: Depth cor-

Stevenson, C.M., Mazer, J.J., Scheetz, B.E., 1998. Labor-rection for obsidian effective hydration temperature
atory obsidian hydration rates: Theory, method, and
in the presence of site turbation effects. International application. In: Shackley, M.S. (Ed.), Archaeological Association for Obsidian Studies Bulletin, no. 37.

Obsidian Studies: Method and Theory. Advances Rogers, A.K., 2007c. Did the Altithermal Affect Obsid
in Archaeological and Museum Science 3. Plenum
ian Hydration Rates? A ModelBased Study of the Press, New York, pp. 181–204.

Hy dra tion Process and Paleoclimatic Change. Pro-Stevenson, C.M., Gottesman, M., Macko, M., 2000.

ceed ings of the Second Three-Corners Confer ence,

Rede fining the working assumptions for obsidian

Las Vegas, NV.

hydration dating. Journal of California and Great Rogers, A.K., 2008a. Obsidian hydration dating: Accu-Basin Anthropology 22, 223–236.

racy and resolution limitations imposed by intrinsic

Stevenson, C.M., Abdelrehim, I.M., Novak, S.W., 2004.

water variability. Journal of Archaeological Science, High precision measurement of obsidian hydration
doi:10.1016/j/jas.2008.01.006. Rogers, A.K., 2008b.

layers on artifacts from the Hopewell site using sec-

Field data validation of an algorithm for computing
ondary ion mass spectrometry. American Antiquity obsidian effective hydration temperature. Journal of 69, 555–568.

Archaeological Science 35, 441–447.

Wagner, C., 1950. Diffusion of lead chloride dissolved in Rogers, A.K., 2008b. Field data validation of an algo-solid silver chloride. Journal of Chemistry and Phy
rithm for computing obsidian effective hydration
sics 18, 1227–1230.

temperature. Journal of Archaeological Science 35, West, G.J., Woolfenden, W., Wanket, J.A., Anderson, R.S., 441–447.

2007. Late Pleistocene and Holocene environments.

Rogers, A.K., 2008c. Obsidian hydration dating and rel-In: Jones, T.L., Klar, K.A. (Eds.), California Pre history: ative humidity: An issue and a suggested protocol.

Colonization, Culture, and Complexity. Altamira International Association for Obsidian Studies Bull

Press, Walnut Creek, CA, pp. 11–34.

etin, no. 38.

Zhang, Y., Stolper, E.M., Wasserburg, G.M., 1991. Diffu-Scheetz, B.E., Stevenson, C.M., 1988. The role of resosion of water in rhyolitic glasses. Geochimica et Cos
lu tion and sample preparation in hydration rim
mochimica Acta 55 (2), 441–456.

Chapter 5

Obsidian Dating and Source Exploitation

Studies in Africa

Implications for the Evolution of Human Behavior

Stanley H. Ambrose

Abstract
hunter-gatherers, and exchange patterns and territo-
rial boundaries of Neo lithic pastoralists. Obsidian in Obsidian occurs in the eastern Rift Valley region

Egyptian sites as early as the Predynastic era reflect of Ethiopia, Eritrea, Kenya, and Tanzania, and in
long-distance contacts with Ethiopia and Eritrea.

a restricted region of West Africa, in Cameroon.

Source locations and chemical compositions are best
documented in Kenya and Tanzania, and significant

1. Introduction
advances are now being made in Ethiopia. Several

The primary purpose of this paper is to review stud-
sites have been dated by obsidian hydration, one
ies of African obsidian source chemical composition
by fission tracks and four by radiogenic argon iso-
and hydration, fission track, and radiogenic argon
tope ratios. Hydration dating appears to be limited
methods of dating of archaeological sites. Changes
to sites younger than 120,000 years. Although the
in obsidian source exploitation patterns through-
most advanced methods of hydration dating have not
out the 2.6 million–year-long African archaeologi-
been applied in this region, radiometric dating dem-
cal record are also reviewed. Table 5.1 provides a
onstrates that the Middle to Later Stone Age transi-
brief summary of the chronology and terminology of
tion in eastern Africa is substantially older than the Afri can Stone Age industrial complexes. Obsidian

Middle to Upper Paleolithic transition in western
chemical characterization and dating research in

Eur asia. Obsidian was first used for flaked stone-tool Africa has lagged far behind that of other regions,
manufacture during the Early Stone Age (Oldowan),
but has demonstrated great potential for address-
more than 1.7 million years ago. Rare instances of
ing outstanding issues in paleoanthropology. The
long-distance transport of obsidian occurred during
results of these studies have important implications
the Oldowan at Olduvai Gorge and during the early
for the evolution of modern human behavior during

Acheulean in Kenya and Ethiopia. However, substan-
the late Quaternary in Africa, for Holocene hunter-
tial amounts of obsidian were not transported long
gatherer ecology, and for Neolithic pastoral territo-
distances until the second half of the Middle Stone
rial boundaries and trade patterns.

Age (MSA). The increase in long-distance transport

Chronometric dating of the long African archa-
of obsidian during the late MSA reflects the African
eological record with obsidian hydration remains
origin and development of large-scale regional social
problematic because hydration layers on exposed
networks, which is an important milestone in the evo-
artifact surfaces rarely survive more than 120,000
lution of modern human behavior. Patterns of obsid-
years (Michels et al. 1983). Temperature histories must ian use in Kenya and Tanzania during the Holocene
be known in order to calculate accurate hydration
may reflect adaptations to changing environments by
ages. Late Quaternary temperatures were often lower

56

Obsidian Dating and Source Exploitation Studies in Africa | 57

Table 5.1 Age ranges of major Stone Age industrial complexes in Sub-Saharan Africa, with equivalent names used in Northern Africa and J.G.D. Clark’s (1969) equivalent lithic technology modes*

Industrial Complex

Mode Age Range1

Hominid species

(North African equivalent)

Earlier Stone Age - ESA

(Lower Paleolithic) Oldowan

1

2.6–1.5 Ma

Homo habilis, H. erectus/ergaster

Australopithecus aethiopicus

A. boisei, A. robustus

Acheulean

2

1.7–0.3 Ma

H. erectus/ergaster

H. heidelbergensis/rhodesiensis

Middle Stone Age - MSA

3

0.3–0.27 Ma

H. sapiens, “H. helmei” 2

(Middle Paleolithic)

Later Stone Age - LSA

4, 5

50–1 ka

H. sapiens

(Upper /Epi- Paleolithic,

Mesolithic, Neolithic)

Neolithic/LSA herders/ farmers

5

7–1 ka

H. sapiens

* See Barham and Mitchell (2008) and Phillipson (2005) for reviews of the classification, terminology, and chronology of the culture-stratigraphic sequence of Sub-Saharan Africa.

Notes

1. Ma = million years ago; ka = thousand years ago.

2. H. helmei is considered to be intermediate between H. rhodesiensis and H. sapiens, but the validity of this taxon is disputed (White et al. 2003; Barham and Mitchell 2008).

during the late Pleistocene (Kiage and Liu 2006), so
great distances (Roberts 2003), and source materials
dates based on modern temperatures are substan-
can be displaced great distances by fluvial transport
tially underestimated. However, where artifacts can

(Minichillo 2006). Inferences about mobility, territo-
be dated independently by radiometric methods,
riality, and regional interaction patterns drawn from
hydration may be an effective paleothermometer for
frequencies of presumed “exotic” lithic raw materials
the last glacial era (Ambrose 1998a). Temperature-
in southern African sites thus remain speculations
corrected hydration dates show that the Middle Stone

(Ambrose 2006; Minichillo 2006).

Age/Later Stone Age (MSA/LSA) transition is older

Obsidian source and artifact chemical charac-
than 46,000 BP, which supports an East African ori-
terization research has great potential for defining
gin for the earliest Upper Paleolithic technologies of early hominid home range sizes, and changes in extent

Western Eurasia (Ambrose 1998a; Bar-Yosef 1998;
of interaction spheres and boundaries of prehistoric

McBrearty and Brooks 2000).

social networks during the evolution of modern human

Lithic raw material site-to-source distances are
behavior (Ambrose 2001, 2002; Merrick et al. 1994).

widely used to infer forager mobility, trade, and

This research is also a useful tool for understanding
exchange and interaction patterns, but inferences are
the relationship between environment and social and
rarely explicitly evaluated with respect to null models territorial organization among Holocene hunter-gath-

(Brantingham 2006). Obsidian source locations are
erers. Rates of decrease in obsidian frequencies with
usually well-defined points on the landscape and have
distance from source areas can provide information on
distinctive chemical fingerprints. Obsidian is thus ideal interaction, spacing behavior, and the organization of for tracing mobility, interaction, and exchange pat-hunting bands (Wilmsen 1973). Distance-decay curves
terns in eastern African prehistory. In southern Africa, (Renfrew 1977) for the MSA and LSA reflect changes in
source locations are dispersed and chemical composi-
social and territorial organization and interaction pat-tions of raw materials such as silcretes are similar over terns during the evolution of modern human behavior.

58 | OBSIDIAN HYDRATION DATING

The greatest increase in amounts of obsidian trans-

Figure 5.1 shows the distribution of sources in
ported over long distances in eastern Africa occurred

Kenya and Tanzania, and major sites mentioned in
during the early last glacial era, near the end of the MSA.

the text. Minor sources occur on Mt. Kilimanjaro in

It may reflect the innovation of macroregional interac-northern Tanzania, and in the Turkana basin and
tion and exchange networks among hunter-gatherers

Suguta Valley of northern Kenya. Michels (1990)

(Ambrose 2002). Changes in frequencies of obsidian
analyzed 47 sources by atomic absorption spectros-
transported over long distances during the Holocene
copy of major elements, and classified them into 16
may also reflect differences in social and territorial petrological groups; another source was identified
organization in response to environmental change.

among the artifacts. Petrological group chemical

Another substantial increase in long-distance trans-
composition data for most sources remain unpub-
port of obsidian occurred with the advent of Neolithic lished. Merrick and Brown (1984a, 1984b; Merrick et
pastoralism in Kenya and Tanzania. Moreover, source
al. 1990, 1994) summarized research on the petrol-
exploitation patterns differed significantly between
ogy of obsidians in Kenya and Tanzania prior to
two major Neolithic cultural complexes, reflecting the 1980, and documented the distribution, charac-position of a territorial boundary (Merrick et al. 1990; ter, and major and minor element composition of

Ambrose 2003).

more than 80 discrete obsidian sources in Kenya
and Tanzania. Some source chemical compositions

2. Obsidian source regions

2.1 West Africa

Obsidian has been reported from a restricted area
of West Africa, on Manengouba Mountain, Camer-
oon (Tchoua 1970). Artifacts made of obsidian are
extremely rare in archaeological sites in Cameroon.

They comprise less than 1% of the flaked stone artifacts in each stratigraphic level throughout the >30,000
year sequence of LSA and Neolithic industries at Shum

Laka rock shelter (figure 5.1) (Cornelissen 1996), and less than 0.2% of the mid-Holocene LSA assemblage
in Abeke rock shelter (de Maret et al. 1987). These sites are located approximately 75–100 km northeast of

Mt. Manengouba (N5º02′ E9º50). Chemical analy-
ses have not been performed on these artifacts, so
their provenance remains unconfirmed. The volcanic
highlands of Cameroon are extensive, so additional
sources of obsidian may exist. If Mt. Manengouba
is the closest source of obsidian at Shum Laka and

Abeke, then long-distance transport of obsidian was
insignificant in Cameroon. However, the archaeolog-
ical record of Cameroon is known from only a small
number of excavated sites, so this conclusion rests on a narrow foundation.

2.2 Kenya and Tanzania

Figure 5.1. Map of East Africa, showing obsidian sources and archaeological sites. Elevations are in

Obsidian sources are extremely common within and
meters. Inset map of Africa shows the location of
adjacent to the highlands of the eastern (Gregory) Rift major archaeological sites in Cameroon and Ethiopia

Valley of Kenya (Merrick and Brown 1984a, 1984b).

discussed in the text.

Obsidian Dating and Source Exploitation Studies in Africa | 59
were compiled from previous publications.

Brown and Merrick could not reanalyze
several previously reported sources, which
raises questions about comparability with
their analyses. Earlier methods of source
identification such as refractive index, spe-
cific gravity, and color proved unreliable.

The majority of their chemical composition
data on sources was obtained by XRF analy-
ses of 10–13 elements. Electron microprobe
analysis was performed on a large number
of obsidian artifacts. Iron (Fe O ), calcium

2 3

(CaO), and titanium (TiO ) oxides provided

2
reasonable discrimination of most sources.

At least 35 chemically distinct petrologi-
cal groups were recognized. The majority
of sources that were widely used in prehis-
tory were located in the central Rift Valley

(figure 5.2), in the vicinity of lakes Nakuru
and Naivasha, Mt. Eburu, and Hell’s Gate

(Njorowa Gorge). At least 20 sources are
known only from artifacts (Merrick et al.

1994). Older assemblages (Acheulean and

Figure 5.2. Map of the Lake Naivasha basin in the central Rift Valley of Kenya, showing major obsidian source areas and MSA) have a higher proportion of unknown
archaeological sites discussed in the text.

sources. Several new obsidian sources, in-
cluding two with Acheulean handaxes, have
been discovered in the central Rift Valley
of Kenya since 2001, some of which may be

Kedong Valley sources, which occur 15–65 km south-
previously unknown sources (Ambrose and Steele in
east of the translucent gray west/south lake sources,
preparation).

appear virtually opaque black, but in very thin sec-

Central Rift obsidian source minor element
tion they are dark coffee brown in transmitted light.

chem
ical compositions are remarkably diverse

Many chemically different sources from different

(Merrick and Brown 1984b). Therefore most sources
regions have similar colors, so color is an unreliable can be differentiated by minor element composi-indicator of provenance.

tions rather than by trace elements. For example iron

Most sources occur as discrete, localized flows

(Fe O ) ranges from less than 2% on the west side of
and chill zones above or below lava flows. In some

2 3

Lake Naivasha at the Sonachi crater to nearly 10%
sources the raw material outcrops as smaller blocks
on Mt. Eburu, only 15 km away on the north side
and nodules called bombs (>64 mm diameter) or
of the lake basin. Source groups can be crudely but
small (2–64 mm) lapilli within welded tuffs and
not reliably differentiated by color. For example, the ignimbrites. They may have the same chemical com-west and south Naivasha (Njorowa Gorge) sources
position over vast areas. For example, the Highlands
are typically translucent gray, but different parts of source group (Merrick and Brown 1984a, Group 12,
the same block may be streaked with opaque gray,
green glass) occurs in outcrops of gray welded tuff
brown, or black, with no significant difference in
that are separated by up to 160 km. Small bombs
elemental composition. Sources in the vicinity of
and lapilli were frequently used for LSA microlithic

Mt. Eburu are usually varying shades of green and
industries in Kenya (Merrick and Brown 1984a;
may be translucent to semiopaque. Mt. Suswa and

Barut 1996). Glass textures vary from coarse, with

60 | OBSIDIAN HYDRATION DATING
phenocrysts and air bubbles, to glassy, with or with-

Addis Ababa. Among the 31 MSA artifacts from Porc
out phenocrysts. Remelted, compressed pumice

Epic analyzed by Negash and Shackley (2006), many
clasts (fiamme) within welded tuffs resemble bombs
could be assigned to three sources that are located
and lapilli, but are typically porous and flattened,

150–250 km from the site. However, known sources
and have limited utility for flaked stone artifact
located within 20–100 km of the site and the Modjio
manufacture.

source were not represented among the samples
analyzed, and approximately one-third of the arti-

2.3 Ethiopia and Eritrea
facts could not be assigned to a known source. Many

High-quality obsidian sources are common within

Ethiopian obsidian sources remain to be discovered.

and adjacent to the main Ethiopian Rift and the Afar

Triangle. Sources include those associated with lava

3. Fission track, hydration,
flows, but also include bombs, lapilli, and fiamme in
and 40Ar/39Ar dating
tuffs, and marekenite (Job’s tears), which are lapilli-sized residual cores of blocks and nodules of heavily

3.1 Fission Track Dating
weathered perlitic glass (Negash and Shackley 2006).

The only published study of fission track dating of

Compared to Kenya, fewer Ethiopian sources
archaeological artifacts in Africa was performed
and artifact assemblages have been chemically char-
on a burned obsidian blade from the “Mesolithic”

acterized (Muir and Hivernel 1976; Clark et al. 1984;

Elmenteitan culture horizon at Gamble’s Cave in the

Negash and Shackley 2006; Negash et al. 2006). As
central Rift Valley of Kenya (Fleischer et al. 1965).

in Kenya, a wide range of chemical compositions

The Elmenteitan is now considered to belong to the
and colors has been observed. At Melka Konture,

Neolithic era and is associated with domestic animals.

located in the upper Awash River Valley near Addis

No radiocarbon dates were run on the Elmenteitan lev-

Ababa, Muir and Hivernel (1976) used wet chemical
els at Gamble’s Cave. The oldest reported uncalibrated techniques for analysis of major and minor elements
radiocarbon dates on the Elmenteitan are 3090 ±65 BP
of two specimens, and optical spectrography for
and 3165 ±100 BP from Njoro River Cave (Merrick
analysis of trace elements of nine artifacts, obtained and Monaghan 1984). Their tree-ring corrected ages
mainly from MSA and LSA occurrences. No sources

(CalPal 2007) are 3298 ±74 and 3386 ±119, respectively.

were analyzed, but they concluded the artifacts all

Assuming that the specimen from Gamble’s Cave is
came from the nearby (7 km) source of Balchitt.

as old as the Njoro River Cave Elmen teitan, then its

Agazi Negash (Negash and Shackley 2006; Negash
fission track date of 3700 ±400 BP is less than one
et al. 2006) has conducted the first systematic survey standard deviation away from the calendar age of the
and characterization of source chemical composi-
earliest Elmenteitan radiocarbon date.

tions, using ED-XRF (energy-dispersive X-ray fluo-

Two pieces of obsidian from level 1 of Oldowan
rescence) to analyze the chemical composition of
site HWKE at Olduvai Gorge were submitted for

25 sources and artifact assemblages from eight sites.

fission track dating (Leakey 1971:89), but they were

Six Oldowan and four Acheulean artifacts analyzed
devitrified and unsuitable for analysis.

from Melka Konture all matched the nearby Balchitt
source (Negash et al. 2006).

3.2 Hydration Dating

Michels reported atomic absorption spectros-

All published obsidian hydration studies in Africa
copy (AAS) analyses of the major and minor ele-
have been performed in Kenya and Ethiopia by
ment composition of six MSA artifacts from Porc

Joseph Michels (Michels et al. 1983; Michels 1990;

Epic Cave, located near Dire Dawa in the eastern

Clark et al. 1984; Ambrose 1998a). In Kenya, 8 of the
highlands of Ethiopia (Clark et al. 1984). He found

17 chemically identified groups have been subjected
a match between one artifact and the previously
to induced hydration experiments at high temper-
reported composition of the Modjio source, located
atures and pressures to determine their intrinsic

320 km from the site in the western highlands, near
hydration rates (Michels 1990).

Obsidian Dating and Source Exploitation Studies in Africa | 61

Results of analyses of artifacts from several
a more comprehensive program of hydration rate
horizons in the long archaeological sequence at
determination of each source, coupled with mea-

Prospect Farm (Michels et al. 1983) reveal the limi-
surements of intrinsic water content of glass, which
tations of hydration dating of Pleistocene sites in
is highly correlated with hydration rate (Stevenson
which thick hydration layers may have weathered,
et al. 1998).

eroded, and spalled. Prospect Farm is located at an

Michels et al. (1983) demonstrated that Group A
elevation of 2130 m on Mt. Eburu in the central Rift
glass has a lower hydration rate than Group B. How-

Valley. Artifacts were analyzed from Phases 1–4 of
ever, Group A glass is highly susceptible to etching
the MSA Prospect Industry, an MSA/LSA transi-
and spalling, so artifacts older than 50,000 years from tion occurrence, a terminal Pleistocene LSA, an early
this source were undatable. Group B artifacts older

Holocene LSA (phase 2 of the Eburran Industry),
than 120,000 BP were also undatable. The strategy
and a Savanna Pastoral Neolithic (SPN) occupa-
of dating hydration rinds in cracks in artifacts devel-tion. The MSA began prior to 284,000 BP in East
oped by Wallace Ambrose (1998) may be able to over-

Africa (Deino and McBrearty 2002), so this sample
come the problem of etching and spalling.

set could span three interglacial and two glacial eras.

Some Prospect Farm assemblages contain many

Although same effective hydration temperature
artifacts that are scratched, pitted, and etched, reflect-

(EHT) was used for all assemblages, temperatures
ing long surface exposure, weathering, and trampling
were likely to have been slightly higher in the middle before burial. They may have complex depositional
and early Holocene (4000–12,000 BP) and the last
and thermal histories that render most artifacts
two interglacials (Marine Oxygen Isotope [MIS]

unsuitable for hydration measurement. Dating of
stage 5, 74,000–128,000 BP, and stage 7, 190,000–

Phases 1 and 2 of the MSA Prospect Industry was

245,000 BP), and 6–8 ºC cooler during the last two
unsuccessful because no original hydration layers
glacial periods (MIS stages 2–4, 12,000 to 74,000 BP,
were preserved. Phase 3 also had heavily etched and
and MIS stage 6, 128,000–190,000 BP) (Bonnefille
spalled surfaces, but some isolated intact hydration
et al. 1990; McManus et al. 1999). Dates on all pre-
layers produced three clusters of dates: 120,000 BP

Holocene assemblages are undoubtedly substantially
at the interface between layers 9 and 10; 106,300 to
underestimated because hydration rates were slower

108,600 BP in layer 9; and 46,500 to 51,800 BP in
during the Pleistocene due to colder temperatures
layer 8. Dates for Phase 3 span almost 70,000 years,

(Ambrose 1998a). Independent dating of the arti-
implying an incredibly conservative technology.

facts by another method can be used to calibrate

Phase 4 MSA artifacts in layers 6–7 produced dates
hydration dates because EHT can be calculated from
of 46,700 to 53,600 BP. Michels et al. (1983) describe hydration rind thickness if the age is known. Such
this assemblage as transitional between the MSA and
calibrations are only possible for the Neolithic and
the LSA. However, Phase 4 apparently lacks backed

Eburran occurrences at Prospect Farm because they
microliths, which are a primary feature of LSA and
have associated radiocarbon dates. However, such

MSA/LSA transition industries in Kenya (Ambrose
corrections are relatively trivial because tempera-

2002), so it is probably a late MSA industry. Layer 2
tures did not vary significantly during the Holocene.

contains an early LSA industry with hydration dates

Artifacts from Prospect Farm were assigned to
of 21,800 to 30,800 BP. Layer 1 has an LSA Eburran
two petrological groups by a combination of AAS

Phase 2 industry with hydration dates of 14,100–
and color sorting (Michels et al. 1983). Considering

14,500 BP. Dates on the Eburran Phase 2 industry
the diversity of obsidian compositions in the vicin-
range from 9900 to 10,800 BP, which is consistent
ity of this region, and the poor covariance of color
with the associated radiocarbon date of 10,560 BP.

with chemical composition, it is likely that the

Hydration dates on the SPN fall into two groups:

experimentally determined hydration rates for these

2800–3280 BP, and 2570 ±100 BP, which are concor-
petrological groups were not appropriate for some
dant with associated uncorrected radiocarbon dates
specimens. East African archaeology clearly needs
of 2690 ±80 and 2910 ±110 BP (Cohen 1970).

62 | OBSIDIAN HYDRATION DATING

Hydration dates were determined on three arti-

The MSA at Porc Epic Cave has also been dated
facts from late Pleistocene LSA and MSA/LSA tran-
by obsidian hydration of six artifacts (Clark et al.

sition industries at Enkapune Ya Muto (EYM) rock

1984). As in Kenya, the EHT is likely to be inappli-
shelter, located at 2400 m on the Mau Escarpment
cable to the later Pleistocene. Michels and Marean
west of Lake Naivasha (Ambrose 1998a). Because

(Clark et al. 1984) thus consider the dates of 61,000 to late Pleistocene temperatures may have been up to

77,500 to underestimate the true age by about 20,000

6–8 ºC lower than those of the Holocene, hydra-
years. This site contains a human mandible that was
tion dates were calculated using the present mean
initially considered a Neandertal because of its asso-
annual temperature and an EHT 5 ºC lower than
ciation with the MSA. However, it is now considered
at present. Dates calculated with the modern EHT
anatomically modern, and its great age makes it an
were 53% of the ages calculated with an EHT of
important fossil for understanding the origin and

T-5 ºC (table 5.1). The sample from the early LSA
evolution of anatomically modern humans.

Sakutiek Industry in Stratum DBL1.3 was associated

In the Lemek-Mara region of southwest Kenya,
with radiocarbon dates that permitted independent

Michels (1990) performed hydration dating on

estimation of EHT. DBL1.2 had a radiocarbon date

64 artifacts from 22 Neolithic-era sites. Sources of
of 35,800 ±550 BP, and DBL1.3 had dates of 37,000

12 specimens were determined by AAS, and the rest

±1100 and 39,900 ±1600 BP on the outer and inner
were assigned to source by color alone. Speci mens
layers, respectively, of a sample of ostrich eggshell
were assigned to only three sources. Microprobe
fragments. The older date is considered more reli-
analysis of 248 artifacts from four of these sites shows able (Ambrose 1998a). Large standard deviations
that four obsidian sources were used (Merrick et al.

on these radiocarbon dates make temperature

1990). More than half of the dated artifacts (33) were calibration imprecise. The temperature-corrected
collected on site surfaces or were recently “eroded
hydration age of the DBL 1.3 specimen was 35,350
out.” These artifacts are likely to have endured more

±2180 BP. Because this date is 1650–4550 years
variable thermal histories and thus have more vari-
younger than the associated radiocarbon dates, it
able ages than those that were recovered in situ (Jones is likely that the true EHT is somewhat more than
et al. 1997). Most of the dates obtained are within

5 ºC lower than at present. Moreover, if the associ-
the time range of the Neolithic era, which spans
ated radiocarbon ages underestimate true ages due
approximately 3300–1200 BP (Ambrose 1984, 2003).

to increased cosmogenic nuclide flux (Taylor 1995),

Several sites with single-occupation horizons should
then the radiocarbon dates are approximately 3000
have had narrow age ranges, but had anomalously
years too young and the EHT even lower than esti-
wide time spans (Michels 1990). For example: 76 BC
mated above.

to AD 911 at Oldorotua 1 (n = 7); 1083 BC to AD 1078

Extrapolation of sedimentation rates from the
at Oldorotua 3 (n = 7); and 977 BC to AD 410
early LSA levels at EYM indicates the MSA/LSA
at Ngamuriak (n = 8, all in situ). The wide range of
transition is at approximately 56,000 BP, which is
ages for the in-situ artifacts at Ngamuriak, which is
almost 10,000 years older than the Middle to Upper
associated with radiocarbon ages of 2135 and 1940 BP,

Paleolithic transition in the Levant and 16,000 years
indicates the hydration dating technique needs
older than this transition in Europe (Ambrose 1998a;
further development in this region, including sys-

Bar-Yosef 1998). These dates are consistent with the
tematic assignment of artifacts to sources by chemi -
hypothesis of an East African origin for modern
cal fingerprinting.

human technology. Temperature calibration should
also be applied to the Prospect Farm Pleistocene

3.3 Radiogenic argon isotope dating

LSA and MSA dates. Assuming the Prospect Farm

Chronometric dating of the long African archaeo-

Phase 4 hydration dates can be corrected by sub-
logical record with radiogenic argon isotope (40Ar/
tracting 5 ºC from the present EHT, then the age

39Ar) measurement of obsidian is useful for assign-
of this late MSA occupation is likely to be approxi-
ing minimum ages of archaeological sites that can-
mately 88–101,000 BP.

not be dated by other methods (Vogel et al. 2006;

Obsidian Dating and Source Exploitation Studies in Africa | 63

Morgan et al. 2009). The archaeological occurrence

Obsidian is also common in the younger Acheulean
must be younger than the youngest obsidian flow
sites (Negash et al. 2006). As noted above, this obsid-exploited for artifacts. However, hydration, fission
ian came from the nearby source area of Balchitt,
track recoil during irradiation, and mass-dependent

7 km away (Negash et al. 2006; Muir and Hivernel
fractionation during and after cooling of the molten

1976; Piperno et al. 2009).

glass present surmountable challenges for accurate

Féblot-Augustins (1990) has reviewed evidence
dating (Morgan et al. 2009). Artifacts from four
for lithic raw material exploitation patterns in the

MSA sites in Ethiopia have been dated by this tech-

Afri can Acheulean, and notes the presence of obsid-
nique. Several artifacts from Porc Epic Cave that
ian in four sites, two of which are in Ethiopia. Merrick had been identified as coming from the Kone source
et al. (1994) and Merrick and Brown (1984a) report

(Negash and Shackley 2006) do not match the age
obsidian at five Acheulean sites in Kenya. Four obsid-
of this source, nor do they closely match its chemi-
ian handaxes were recovered from Acheulean occur-
cal composition (Vogel et al. 2006). Hereto, in the
rences in the southeastern highlands of Ethiopia at

Middle Awash Valley, is the type-site for Homo sapi

Gadeb, which date to between 1.48 and 0.7 Ma. The
ens idaltu (White et al. 2003), and is dated to 160,000
closest sources are estimated to be approximately
years ago by correlation with a dated volcanic ash

100 km away (Clark 1987), but chemical methods of

(Clark et al. 2003). Among the 18 artifacts that were
sourcing these artifacts have not yet been reported.

dated by 40Ar/39Ar, 3 are dated substantially younger

As noted above, the obsidian source at Melka Konture
than 160,000 years ago (Morgan et al. 2009). How-
is 7 km away (Piperno et al. 2009).

ever their standard deviations (10,000 ±60,000 BP,

Obsidian comprises 15% of the Acheulean assem-

70,000 ±60,000 BP, and 110,000 ±100,000 BP) are
blage at Kariandusi, located in the Nakuru basin of
so large that they do not present a significant chal-
the central Rift Valley of Kenya (Merrick and Brown
lenge to the published age for this site.

1984a). This site is older than 780,000 and younger
than 970,000 BP (Evernden and Curtis 1965; Trauth

4. Obsidian use patterns through
et al. 2005). Known sources for the 11 artifacts
time in East Africa
are 15–30 km from this site (Merrick et al. 1994).

Obsidian comprises an insignificant proportion of

4.1 Early Stone Age (Oldowan
the Acheulean artifacts at Kilombe, Kaptabuya, and
and Acheulean)

Kapthurin, which are located farther north in the

The earliest record of obsidian use comes from

Kenya Rift. One obsidian artifact was analyzed at

Old uvai Gorge. Two “fair-sized pieces” of obsidian
each site. Only Kaptabuya, near Lake Baringo, has

(Leakey 1971:89) were recovered from the Oldowan
an identifiable source, which has outcrops located

Industry site HWKE level 1, dated to approximately

10 km and 17 km from the site (Merrick et al. 1994).

1.75 million years (Walter et al. 1991). The closest

The only obsidian artifact from the extensive exca-
sources known at the time were in the central Rift
vations at Isenya on the Athi-Kapiti Plains of Kenya

Valley of Kenya, over 270 km away (Hay 1976:185).

came from the closest known source, at Kedong,

This is the only evidence for long-distance transport

60 km away. Three obsidian bifaces were found
of lithic raw materials in the Oldowan.

at Olorgesailie in the southern Kenya Rift, at least

Oldowan sites at Melka Konture (Chavaillon 1980;

26 km from the nearest source (Féblot-Augustins

Chavaillon et al. 1979; Negash et al. 2006; Piperno et 1990). Chemical sourcing has apparently not been
al. 2009) date to between 1.9 and 1.4 million years BP
performed on these specimens, so the source dis-

(Ma). The oldest site, Gombore 1B2, is dated between
tance remains unverified.

1.9 and 1.6 Ma, based on faunal correlation and paleo-

The overall pattern of obsidian source exploita-
magnetism, and 31.5% of the artifacts are made of
tion during the Oldowan and Acheulean differs sig-
obsidian (Piperno et al. 2009). Obsidian is the most
nificantly from that in later periods. Long-distance
abundant raw material for Oldowan artifacts (50.1%)

transport of any lithic material is exceptionally
at Garba IV (Piperno 1980; Piperno et al. 2009).

rare, with the exceptions of Melka Konture and

64 | OBSIDIAN HYDRATION DATING

Kariandusi, where it is locally available. During the
obsidian comprises only 5.5% of the lithic raw materi-

Acheulean rarity may in part reflect its poor durabil-
als at Porc Epic, the diversity and great distances to ity for heavy-duty tools and large cutting tools such as sources have significant implications for understand-handaxes and cleavers. At Olduvai Gorge the majority
ing mobility and interaction patterns in the evolution of Oldowan igneous and metamorphic stone artifacts
of modern human behavior. However, many more
came from within 2–4 km of the sites. The maximum
sources need to be identified and many more artifacts
site-to-source distances are approximately 15–20 km
analyzed to obtain a clear picture of source exploi-
for the Oldowan (Blumenschine et al. 2003) and
tation, mobility, and interaction patterns in the late 11–17 km for the Acheulean (Hay 1976). Compared

MSA of Ethiopia.

to Homo sapiens, the home range size of H. habilis Diachronic change in obsidian frequencies in
was smallest, and that of H. erectus was also generally MSA sites in Ethiopia can only be assessed at the
small. Early hominids may have lacked the cognitive

Aduma site complex in the Middle Awash Valley
abilities to sustain reciprocal exchange relationships (Yellen et al. 2005). This sequence contains typologi-between local groups, and territorial boundaries may
cally and stratigraphically early, middle, and late MSA have been defended. They may have been organized
industries. Frequencies of obsidian range from 7% to
more like territorial primate troops, which typically

36% in nine in-situ occurrences, but there is no trend lack intergroup cooperation, rather than like human
toward higher frequencies of obsidian through time.

tribes, which are often characterized by networks of

Chem ical source analyses have not been reported,
interaction and exchange between local groups.

so site-to-source distances cannot be accurately esti-
mated. The nearest sources documented by Negash

4.2 Middle Stone Age
and Shackley (2006) are approximately 200 km away,

During the early MSA, prior to approximately
but closer sources may exist.

125,000 BP, small amounts of obsidian are found at

Mumba rock shelter, located near Lake Eyasi, and
great distances from sources in archaeological sites

Nasera rock shelter in the Serengeti Plains of north-
in Ethi opia, Kenya, and Tanzania. Although this is
ern Tanzania, provide evidence for the longest MSA
widely cited to be a significant advance in the evo-
obsidian transport distances in East Africa. Exact
lution of modern human behavior (McBrearty and
counts of obsidian cannot be determined because

Brooks 2000), the quantities of obsidian transported
obsidian was lumped with “other” raw materials
are small. For example, at the undated early MSA

(Mehlman 1989). Three specimens from the Mumba
occurrence of Member 6 at Muguruk in western
level VI-B early MSA Sanzako Industry assemblage

Kenya, they comprise 0.09% of the lithic assemblage

(230Th/231Pa date of 131,700 BP) came from the central (McBrearty 1986:211). The Muguruk obsidian arti-Rift in Kenya, 320 or 305 km away (Mehlman 1989:

fact sources are located 185–190 km away, in the cen-

197; Merrick et al. 1994). Eleven artifacts from the
tral Rift Valley (Merrick and Brown 1984a).

MSA Kisele Industry (>66,000 BP) were also sourced

Quantitative chemical data on source exploita-
to the central Rift. Ten artifacts of the Kisele Industry tion for the MSA of Ethiopia are currently available
from Nasera (56,000 BP) have also been sourced to
only for a small number of artifacts from Porc Epic
the central Rift, 240 km from this site.

Cave, Ethiopia (Negash and Shackley 2006; Clark et

Obsidian comprises 8.4% of the undated MSA
al. 1984). As noted above, Negash and Shackley (2006)

Industry A at Lukenya Hill (Kenya) site GvJm16
identified artifacts from sources 150–250 km from the

(Merrick 1975). Of the 97 obsidian artifacts ana-
site, and one specimen analyzed by Michels was from
lyzed, 42% came from the local source (Group 12
the Modjio source located 320 km away (Clark et al.

High lands). The major central Rift sources, located

1984). Because the identification of the Modjio source 65–135 km away, comprise the remainder of the
was not based on chemical analysis of artifacts and
obsidian (Merrick et al. 1994) and thus approxi-
sources in the same lab by the same methods, and few
mately 5% of the entire assemblage.

sources had been analyzed, the identity of the source

Prospect Farm shows a typical pattern of lower
of this specimen remains inconclusive. Although
frequencies of artifacts from more distant sources

Obsidian Dating and Source Exploitation Studies in Africa | 65

(Merrick et al. 1994). Among the 376 artifacts ana-

Enkapune Ya Muto is located 10–20 km from the
lyzed, 73 came from five unknown sources. Artifacts
most intensively exploited major obsidian sources in
from known sources in phases 1, 2, and 4 (82, 119, and the Naivasha basin, so chemical fingerprinting of arti-93 pieces, respectively) produced normal distance-
facts was considered redundant. However, consider-
decay or fall-off curves (Ambrose 2001) resembling
ing the unusual results at Prolonged Drift, assuming a those assumed to reflect direct access in the supply
normal supply-zone mode of source exploitation may
zone of a source (Renfrew 1977). The most distant
be unwarranted. Nonlocal materials such as quartz,
source exploited was 75 km in each assemblage, but
whose closest sources are Pre cambrian Basement sys-
it comprised only 1 artifact in each assemblage ana-
tem rocks that outcrop in the Loita Plains approxi-
lyzed. Average site-to-source distances increased
mately 60 km from the site, and cherts, whose closest
through time, reflecting larger home ranges and per-
sources are in the Lake Magadi basin approximately
haps greater intergroup interaction from the early to

110 km away, provide evidence for variation in amounts the late MSA. However, almost all obsidian in each
of materials from distant sources. In the MSA/LSA
assemblage was manufactured on sources located
transition Endingi Indus try (>56,000 BP), chert and within 40 km of the site. If Gamble’s (1993) estimate
quartz comprise 2% of the artifact assemblage. In the
of approximately 40 km for the maximum radius of
overlying late Pleisto cene early LSA (>35,000 BP) and hunter-gatherer home range sizes can be applied to

Holocene LSA and Neolithic (6350–1250 BP), quartz
the MSA, then almost all of the lithic raw materials
and chert comprise a maximum of only 0.5% of the
found at Prospect Farm could have been obtained
lithic assemblages (Ambrose 2001).

within a hunter-gatherer group’s home range, either

In southwest Kenya at Ntumot (GvJh11, Ntuka
by embedded procurement (Binford 1979) while

River 3), located 60–90 km from the main central
foraging or by intentional provisioning at quarries

Rift obsidian sources, obsidian comprises 64% of the

(Gould and Saggers 1985).

flaked stone artifacts in Stratum 15 (Ambrose 2002).

Throughout most of the early MSA in sites out-

Downstream 1.4 km from Ntumot at Norikiushin
side of the supply zone, distant obsidian sources

(GvJh12, Ntuka River 4), the MSA/LSA transition
comprise a very small proportion of the lithic arti-
industry contains 44.5% obsidian, almost entirely
facts in eastern Africa, suggesting low rates of move-
derived from the Sonachi source, 70 km away on the
ment of materials across local group boundaries and
west side of Lake Naivasha (Ambrose and Steele in
thus weak intergroup interactions.

preparation). This industry is notable for its resem-

Lithic raw material source use patterns change
blance to the Mumba (Tanzania) and Howiesons
dramatically at the end of the MSA and during the

Poort (South Africa) industries, which also have very

MSA/LSA transition in Kenya. Prolonged Drift,
large backed geometric microliths and are dated to
located on the west side of the central Rift in the

60–70,000 BP (Ambrose 2002).

Nakuru basin north of Mt. Eburu, is considered
to be late MSA (Merrick 1975; Merrick et al. 1994).

4.3 Later Stone Age

Approx imately 95% of the 90 artifacts analyzed

Obsidian source exploitation patterns have been
came from sources south of Mt. Eburu on the south-
reported only for one LSA site in Ethiopia (Negash
west side of the Naivasha basin, 45–50 km away from
et al. 2007). Twenty artifacts from the terminal Pleis-the site (Merrick et al. 1994). The farthest source is tocene/early Holocene levels at Lake Besaka site
the most abundant, so the frequency distribution

FeJx4 were sourced by XRF and electron microprobe
forms an inverse distance-decay curve (Ambrose to sources at Fantale and Kone, about 30 and about

2001). Almost all artifacts came from beyond the

15 km from the site, respectively. The Abadir source,
maximum distance for supply zone procurement as
located about 35 km from the site, was not represented defined by Gamble (1993) and by Gould and Saggers
in this small assemblage despite its high quality, and (1985), suggesting intensive, perhaps even obligate,
three artifacts came from unknown sources.

intergroup exchange rather than down-the-line ex-

LSA sites in Kenya located 50–150 km outside
change (Ambrose 2001).

of the central Rift typically have 10–30% obsidian,

66 | OBSIDIAN HYDRATION DATING
compared to less than 10% in MSA horizons in the

Normal distance-decay patterns suggest down-the-
same localities, and the closest sources usually pre-
line exchange (Renfrew 1977) between local hunter-
dominate in LSA levels (Merrick and Brown 1984a).

gatherer populations. Most sites in the Lake Turkana

The early LSA industry at Naisiusiu, Olduvai
basin in northern Kenya have either locally available

Gorge, is notable for the history of obsidian research or unknown sources (Merrick and Brown 1984a).

because Merrick and Brown’s sourcing program

Some of the unknowns may be Ethiopian.

began here with a request by Mary Leakey to Frank

Early and middle Holocene LSA assemblages in

Brown to find the source of its obsidian artifacts. The Kenya and Tanzania have different rates of down-lithic assemblage is 5.9% obsidian (Leakey et al. 1972), the-line decrease in abundance of obsidian. Figure 5.3
and all artifacts analyzed came from the Sonachi
illustrates the utility of distance-decay graphs for
source, 240 km away on the west side of Lake Nai-
evaluating the relationship between hunter-gatherer
vasha in Kenya (Merrick and Brown 1984a). This
range size, intergroup interaction patterns, and envi-
site is also notable because the original radiocarbon
ronmental productivity. Dyson-Hudson and Smith
dates of 17,000 and 17,500 BP (Leakey et al. 1972) have (1978) provide a useful synthesis of ecologically
been supplanted by radiocarbon dates of >42,000 BP
based variation in socioterritorial organization and
and average ESR (electron spin resonance) dates of
exchange among hunter-gatherers, and Wiessner

59,000 ±5000 BP (early uptake) to 62,000 ±5000 (late

(1982, 1983) describes additional examples for Kalahari uptake) (Skinner et al. 2003). These dates reinforce

San groups. Such studies show that when primary
chronometric evidence from Enkapune Ya Muto and
productivity is high and resources are predictable

Mumba for the great antiquity of the LSA (Ambrose
and dense, then hunter-gatherers should have small,

1998a; Mehlman 1989), and for the Sub-Saharan Afri-
defended home ranges and minimal intergroup inter-
can origin of Upper Paleolithic–style lithic technolo-
actions, including infrequent exchange of materials
gies (Ambrose 2002; Bar-Yosef 1998).

and information. Conversely, when primary produc-

The early LSA sequence in strata 8–10 of the
tivity and predictability decline, hunter-gatherer
main trench at Ntumot (GvJh11, Ntuka River 3) is
range sizes should expand, territorial defense should
older than 30,000 BP. Obsidian comprises only 16%
be relaxed, and intergroup interaction should increase of these assemblages (Ambrose 2002). The youngest

(Ambrose and Lorenz 1990).

LSA industry, dated to 29,975 BP in upper Stratum 8,

Figure 5.3 plots obsidian frequencies in Holocene
is a microblade industry characterized by tiny

LSA occurrences in southern Kenya and northern
bladelets and burin spalls struck from nucleaform

Tanzania at several distances from the central Rift.

burins and burinoid cores. Although

32% of the artifacts in upper Stratum 8
are made of obsidian, this substantially
overestimates the amount transported
from distant sources. The lateral dorsal
margins of many obsidian microblades
and microcores are weathered and
patinated, and several of the micro-
blade cores were originally larger MSA
flakes that could have been scavenged
from nearby sites. These recycled MSA
artifacts must be considered a locally
available source for the makers of the
microblade industry.

The closest sources usually predom-

Figure 5.3. Distance-decay curves for percentages of obsidian (by inate in LSA sites located outside the
number) in archaeological sites, plotted as average distance from central Rift (Merrick and Brown 1984a).

the central Rift sources. Site locations are shown on figure 5.1.

Obsidian Dating and Source Exploitation Studies in Africa | 67

During the early Holocene wet phase, obsidian fre-

Rift during the Neolithic era compared to the early
quencies decrease with distance from the central

Holocene wet phase and the middle Holocene dry

Rift at a faster rate than during the middle Holocene
phase. This may reflect a larger-scale exchange sys-
dry phase. The lower slope for the early Holocene
tem than for early and middle Holocene hunter-
may indicate that in a productive environment less
gatherers, perhaps aided by transport of raw
obsidian moved between defended territories, or
materials with pack animals such as cattle and don-
that it moved through a larger number of smaller
keys. A similar pattern prevails in the Turkana basin, territories. Conversely, middle Holocene aridity and
where five early Holocene fishing sites have less than environmental risk may have favored larger territo-1% obsidian, while four Neolithic era sites have 14%
ries, higher mobility, and more intergroup coopera-
to 95% obsidian (Barthelme 1985).

tion and exchange.

Among the 28 artifacts from three Neolithic

Flake stone artifact assemblages from Early/
sites on the east side of Lake Turkana, 23 came from

Middle Holocene sites outside of the southern/
the local Suregei source, 4 came from two unknown
central Kenya highlands all have less than 1% obsid-
sources, and 1 came from the Ileret Stone Bowl site
ian. Mumba rock shelter in the Eyasi basin of north-

(FwJj4), which is located close to the Ethiopian bor-
ern Tanzania is 320 km from the central Rift sources.

der and has a chemical composition similar to that

Shell middens on the east side of Lake Victoria have
of the Masai Gorge area obsidian in the central Rift
artifacts from central Rift sources that are up to

Valley of Kenya (Merrick and Brown 1984a). One

230 km away. Fishing sites with bone harpoons in
artifact from Kisima Farm KFR-AR 1/2 in the Kenya
the Turkana basin also have extremely low frequen-
highlands east of the Rift came from the Suregei
cies of obsidian, mainly from a local source on the
source in East Turkana, 430 km away (Merrick and

Suregei Plateau. However, 37.5% of the 16 artifacts

Brown 1984a). The Turkana region thus apparently
analyzed from Lowasera are from an unknown
had weak interactions with the highlands. Northern
source (Merrick and Brown 1984a). LSA sites

Kenyan Neolithic herders may have belonged to a
located more than 320 km north of the central Rift
different interaction sphere, possibly encompassing
in the Turkana basin in northern Kenya do not con-
southern Ethiopia.

tain southern and central Kenya highland obsid-

Obsidian source use in the Neolithic era in high-
ian. The farthest distance obsidian was transported
land Kenya is notable because it may reveal the
during the early Holocene is 320 km, to Mumba,
geographic boundary between two contemporane-

Tanzania. This distance corresponds to the bound-
ous Neo lithic cultures. Elmenteitan Neolithic sites
ary where savanna grasslands and grassy wood lands
are known from the west side of the central Rift
on volcanic-derived soils are replaced by woodland
and from the highlands and plains west of the rift
and savanna woodland ecosystems on soils formed
in southern Kenya. The Savanna Pastoral Neolithic
from metamorphic Basement System rocks in Tan-

(SPN) is far more widely distributed within the Rift
zania. The northern Kenya lowlands societies of the
and in open grasslands between Lake Eyasi and the

Lake Turkana basin may have belonged to a differ-

Turk ana basin of northern Kenya (Ambrose 1984,
ent interaction sphere. The maximum size of north-

2003). Elmenteitan sites have predominantly green
ern and southern East African highland interaction
obsidian, obtained from sources on top of Mt. Eburu,
spheres thus seems to be less than approximately
between the lowland Nakuru and Naivasha basin

400 km.

sources. Most SPN sites (but not all) have predomi-
nantly gray obsidians from west and south of Lake

4.4 Neolithic Era

Naivasha (Merrick and Brown 1984a). This contrast

Neolithic sites usually have higher frequencies of
in source use is seen regardless of proximity of sites obsidian than LSA sites at similar distances from
to sources within the central Rift, and in sites of each the central Rift (Merrick and Brown 1984a). Figure

Neolithic culture that are located close to each other 5.3 shows a significantly slower rate of decrease in
outside the Rift, as at Lemek, 100 km from the cen-
obsidian frequencies with distance from the central
tral Rift (Merrick et al. 1990). Upper Eburu green

68 | OBSIDIAN HYDRATION DATING
sources were probably within Elmenteitan territory,

1984) and also the African origin of LSA technol-
while the rift floor sources were within SPN terri-
ogy, which is considered to mark the final step in the tory (Ambrose 1984, 2003).

transition from Archaic to modern human behavior

The SPN and Elmenteitan also differ in amounts

(Ambrose 2002; McBrearty and Brooks 2000).

of obsidian transported from their respective source

Almost nothing is known about obsidian
areas. Outside the central Rift, SPN sites tend to have source distribution and exploitation through time
lower frequencies of obsidian than Elmenteitan sites
in West Africa (de Maret et al. 1987). Systematic
at similar distances from sources (Ambrose 2003).

research is just beginning in Ethiopia (Negash and

This tendency may reflect a difference in regional

Shackley 2006; Negash et al. 2006, 2007), and is rel-
interaction patterns. SPN sites tend to have highly
atively advanced in Kenya and Tanzania (Merrick
variable local ceramic traditions, which may also
and Brown 1984a, 1984b; Merrick et al. 1990, 1994).

reflect less long-distance interaction. Conversely,

Results thus far demonstrate that long-distance

Elmenteitan pottery style varies much less between
transport of obsidian is known for one site in the
sites. Consistently high frequencies of obsidian in

Oldowan and is extremely rare in the Acheulean,

Elmenteitan sites and low variance in ceramic style
but was a consistent feature of the MSA. During the
may reflect greater macroregional integration and
late MSA and MSA/LSA transition, a sharp increase
intergroup exchange (Ambrose 2003).

in frequencies of obsidian and other materials that
were transported long distances suggests a quali-

5. Obsidian use in Egypt
tative difference in macroregional social and ter-
ritorial organization (Ambrose 2001, 2002). This

Aston et al. (2000) provide a useful summary of obsid-
difference may reflect the transition from a strategy
ian use in Egypt since 6500 BP. Obsidian appears as
of predominantly territorial defense during the last
flakes and blades in the predynastic Naquada 1 period
interglacial to one of intergroup cooperation for

(4500 BC) in Upper Egypt. During the Dynastic
survival during the early last glacial (Marine Isotope through New Kingdom periods it was carved and

Stage 4). This troop-to-tribe transition may have
shaped into amulets, beads, scarabs, vessels, eyes in
been initiated by the catastrophic climatic events
statues and funerary masks, small statues, and other
and population crash that may have been caused
artifacts. Most obsidian has been sourced either to
by the supereruption of Toba, Sumatra, 73,000 BP
northern Ethiopia (Aston et al. 2000) or to the Arafali (Ambrose 1998b).

source on the Buri peninsula in Eritrea (Tykot 1996),

Frequencies of obsidian in LSA sites in Kenya and
at least 1300 km to the south. Some obsidian in Lower

Tanzania can be plotted on distance-decay curves to

Egypt may have been obtained from non-African
reveal the relationship of environment to mobility and sources (Aston et al. 2000).

socioterritorial organization strategies. The maximum
distance of obsidians from sources provides a useful

6. Conclusions
measure of the maximum sizes of interaction spheres.

Differences in source use patterns of synchronic

Obsidian dating and source exploitation research

Elmenteitan Neolithic and Savanna Pastoral Neolithic
in Africa has barely begun to achieve its potential.

cultures appear to reflect the location of a territorial Fission track dating has remained unexploited since
boundary in the obsidian source area of the central
the 1960s (Fleischer et al. 1965). Hydration dating

Rift Valley, and also differences in macroregional inte-has not yet exploited the latest developments in mea-
gration and trade. These case studies require more
suring hydration layers (Liritzis 2006) or in recover-
data from more sites in order to fill in geographical
ing well-preserved hydration layers (Stevenson et al.

gaps in the distance-decay curves. However, they sug-

1998; Ambrose 1998a). However, the few hydration
gest the great potential of obsidian source exploitation dating results available demonstrate the great antiq-studies to make important contributions to anthropo-
uity for the MSA (Michels et al. 1983; Clark et al.

logical archaeology in eastern Africa.

Obsidian Dating and Source Exploitation Studies in Africa | 69

Acknowledgments
bal Perspectives on Microlithic Tech nologies. Arch -
aeological Papers of the American Anthro pological

This paper was initially presented at the 2004 “Obsid-

Association, no. 12, pp. 9–29.

ian Summit” in Tokyo and Nagano, and I sincerely

Ambrose, S.H., 2003. East African Neolithic. In: Peregrine, thank Professor Masao Suzuki for inviting me to

P.N., Ember, M. (Eds.), Encyclopedia of Prehistory.

participate and for his patience during the long ges-

Kluwer Academic, New York, pp. 97–109.

tation of this paper. This paper is dedicated to the

Ambrose, S.H., 2006. Howiesons Poort lithic raw material memory of Mary Leakey, who initiated Frank Brown
procurement patterns and the evolution of mod ern
and Harry Merrick’s valuable obsidian source studies
human behavior: A response to Minichillo (2006).

in East Africa, and to the memory of Richard Hay,

Journal of Human Evolution 50, 365–369.

who pioneered research on Early Stone Age lithic

Ambrose, S.H., Lorenz, K.G., 1990. Social and ecologi-
raw material source transport distances to reconstruct cal models for the Middle Stone Age in southern
the land use patterns of early hominids at Olduvai

Africa. In: Mellars, P. (Ed.), The Human Revolution: Behavioral and Biological Perspectives in the Origins Gorge. Research in Kenya has been supported by
of Modern Humans. Edinburgh University Press, grants from the National Science Foundation (BNS-Edinburgh, pp. 3–33.

8118026, BNS-8707150, SBR-9812158, BCS-0113565);

Ambrose, W., 1998. Obsidian hydration dating at a recent the L.S.B. Leakey Foun dation; the National Geo-age obsidian mining site in Papua New Guinea. In:

graphic Society; and the University of Illinois Research Shackley, M.S. (Ed.), Archaeological Obsidian Stud

Board, Anthropology Department, and Center for
ies. Plenum, New York, pp. 205–222.

African Studies. I thank the Office of the Pres ident

Aston, B.G., Harrell, J.A., Shaw, I., 2000. Stone. In: of Kenya for permission to conduct research, and the

Nicholson, P.T., Shaw, I. (Eds.), Ancient Egyptian National Museum of Kenya and the Department of

Mater ials and Technology. Cambridge University History, University of Nairobi, for logistical support, Press, Cambridge, UK, pp. 5–77.

staff assistance, and use of facilities.

Barham, L., Mitchell, P., 2008. The First Africans. Cambridge University Press, Cambridge, UK.

References

Barthelme, J.W., 1985. FisherHunters and Neolithic Pastoralists of East Turkana, Kenya. B.A.R. Inter national Ambrose, S.H., 1984. The introduction of pastoral adap-Series 254, Archaeopress, Oxford, UK.

tations to the central highlands of East Africa. In:

Barut, S., 1996. Obsidian source use in the Later Stone Clark, J.D., Brandt, S.A. (Eds.), From Hunters to Age at Lukenya Hill, Kenya. In: Pwiti, G., Soper, R.

Farmers: Considerations of the Causes and Conse

(Eds.), Aspects of African Archaeology. University of quences of Food Production in Africa. Univer sity of Zimbabwe Publications, Harare, pp. 297–305.

Cali fornia Press, Berkeley, pp. 212–239.

Bar-Yosef, O., 1998. On the nature of transitions: The Ambrose, S.H., 1998a. Chronology of the Later Stone

Middle to Upper Paleolithic and the Neolithic revo-

Age and food production in East Africa. Journal of lution. Cambridge Archaeological Journal 8, 141–163.

Archaeological Science 25, 377–392.

Binford, L.R., 1979. Organization and formation pro-

Ambrose, S.H., 1998b. Late Pleistocene human popula-
cesses: Looking at curated technologies. Journal of tion bottlenecks, volcanic winter, and the differen tia-Anthropological Research 35, 255–273.

tion of modern humans. Journal of Human Evo lution Blumenschine, R.J., Peters, C.R., Masao, F.T., Clarke, R.J., 34, 623–651.

Deino, A.L., Hay, R.L., Swisher, C.G., Stanistreet, I.G., Ambrose, S.H., 2001. Middle and Later Stone Age settle-Ashley, G.M., McHenry, L.J., Sikes, N.E., van der
ment patterns in the central Rift Valley, Kenya: Com-

Merwe, N.J., Tactikos, J.C., Cushing, A.E., Deocamplo, parisons and contrasts. In: Conard, N. (Ed.), Settlement D.M., Njau, J.K., Ebert, J.I., 2003. Late Pliocene

Dynamics of the Middle Paleolithic and Middle Stone Homo and hominid land use from western Olduvai Age. Kerns Verlag, Tübingen, Germany, pp. 21–43.

Gorge, Tanzania. Science 299, 1217–1221.

Ambrose, S.H., 2002. Small things remembered: Origins

Bonnefille, R., Roeland, J.J., Guiot, J., 1990. Temperature of early microlithic industries in Subsa haran Africa.

and rainfall estimates for the past 40,000 years in

In: Elston, R., Kuhn, S. (Eds.), Think ing Small: Glo
equatorial Africa. Nature 346, 347–349.

70 | OBSIDIAN HYDRATION DATING

Brantingham, J., 2006. Measuring forager mobility. Cur

Féblot-Augustins, J., 1990. Exploitation des matieres
rent Anthropology 47, 435–459.

premieres dans l’Acheuleen d’Afrique: Perspectives

CalPal, 2007. CalPal2007 Hulu. Cologne Radiocarbon comportmentales. Paléo 2, 27–42.

Cali bration and Paleoclimate Research Package, http://

Fleischer, R.L., Price, P.R., Walker, R.M., Leakey, L.S.B., www. calpal-online.de/index.html.

1965. Fission track dating of a Mesolithic knife.

Chavaillon, J., 1980. Chronologie archéologique de

Nature 205, 1138.

Melka-Kunturé (Ethiopie). In: Leakey, R.E., Ogot,

Gamble, C., 1993. Exchange and local hominid networks.

B.A. (Eds.), Proceedings of the Eighth Panafrican Con

In: Scarre, C., Healy, F. (Eds.), Trade and Exchange in gress of Prehistory and Quaternary Studies. Interna-Prehistoric Europe. Oxbow Monographs 33. Oxbow tional Louis Leakey Memorial Institute, Nairobi,

Books, Oxford, UK, pp. 35–44.

pp. 200–201.

Gould, R.A., Saggers, S., 1985. Lithic procurement in

Chavaillon, J., Chavaillon, N., Hours, F., Piperno, M., central Australia: A closer look at Binford’s idea of

1979. From the Oldowan to the Middle Stone Age at
embeddedness in archaeology. American Antiquity Melka-Kunturé (Ethiopia): Understanding cultural

50, 117–136.

changes. Quaternaria 21, 87–114.

Hay, R.L., 1976. Geology of the Olduvai Gorge. University Clark, J.D., 1987. Transitions: Homo erectus and the Ache-of California Press, Berkeley.

ulian: The Ethiopian sites of Gadeb and the Middle

Jones, M., Sheppard, P.J., Sutton, D.G., 1997. Soil tem-Awash. Journal of Human Evolution 16, 809–826.

perature and obsidian hydration dating: A clarifi-

Clark, J.D., Williamson, K.D., Michels, J.W., Marean,
ca tion of variables affecting accuracy. Journal of C.W., 1984. A Middle Stone Age occupation site at

Arch aeological Science 24, 506–516.

Porc Epic cave, Dire Dawa (east-central Ethiopia).

Kiage, L.M., Liu, K.-B., 2006. Late Quaternary paleoenAfrican Archaeological Review 2, 37–71.

vironmental changes in East Africa: A review of

Clark, J.D., Beyene, Y., WoldeGabriel, G., Hart, W.K., multiproxy evidence from palynology, lake sedi-Renne, P.R., Gilbert, H., Defleur, A., Suwa, G.,
ments, and associated records. Progress in Physical Katoh, S., Ludwig, K.R., Boisserie, J.R., Asfaw, B.,

Geography 30, 633–658.

White, T.D., 2003. Stratigraphic, chronological and

Leakey, M.D., 1971. Olduvai Gorge, Volume 3. Cambridge behavioural contexts of Pleistocene Homo sapiens University Press, Cambridge, UK.

from Middle Awash, Ethiopia. Nature 423, 747–752.

Leakey, M.D., Hay, R.L., Thurber, D.L., Protsch, R.,

Clark, J.G.D., 1969. World Prehistory: A New Outline.

Berger, R., 1972. Stratigraphy, archaeology and age of Cambridge University Press, Cambridge, UK.

the Ndutu and Naisiusiu Beds, Olduvai Gorge, Tan-

Cohen, M.N., 1970. A reassessment of the Stone Bowl
zania. World Archaeology 3, 328–341.

Cultures of the Rift Valley, Kenya. Azania 5, 27–38.

Liritzis, I., 2006. SIMS-SS, a new obsidian hydration

Cornelissen, E., 1996. Shum Laka (Cameroon): Late
dating method: Analysis and theoretical principles.

Pleis tocene and early Holocene deposits. In: Pwiti,

Archaeometry 48, 533–547.

G., Soper, R. (Eds.), Aspects of African Archaeology.

McBrearty, S., 1986. The archaeology of the Muguruk

University of Zimbabwe Publications, Harare, pp.

site, western Kenya. Ph.D. dissertation, University of 257–263.

Illinois, Urbana.

De Maret, P., Clist, B., Van Neer, W., 1987. Résultats des McBrearty, S., Brooks, A.S., 2000. The revolution that premières fouilles dans les abris de Shum Laka et
wasn’t: A new interpretation of the evolution of mod-
d’Abeke au nord-ouest du Cameroun. L’Anthropologie ern human behavior. Journal of Human Evolution 39, 91, 559–584.

453–563.

Deino, A., McBrearty, S., 2002. 40Ar/39Ar dating of the McManus, J.F., Oppo, D.W., Cullen, J.L., 1999. A 0.5-Kapthurin Formation, Baringo, Kenya. Journal of million-year record of millennial-scale climate vari-Human Evolution 42, 185–210.

ability in the North Atlantic. Science 283, 971–975.

Dyson-Hudson, R., Smith, E.A., 1978. Human territor-

Mehlman, M.J., 1989. Late Quaternary archaeological
iality: An ecological reassessment. American Anthro
sequences in northern Tanzania. Ph.D. dissertation,
pologist 80, 21–41.

University of Illinois, Urbana.

Evernden, J.G., Curtis, G.H., 1965. Potassium-argon dat-Merrick, H.V., 1975. Change in later Pleistocene lithic ing of late Cenozoic rocks in East Africa and Italy.

industries in eastern Africa. Ph.D. dissertation,

Current Anthropology 6, 343–385.

University of California, Berkeley.

Obsidian Dating and Source Exploitation Studies in Africa | 71

Merrick, H.V., Brown, F.H., 1984a. Obsidian sources and Piperno, M., 1980. Le sols d’occupations oldowayens évo-patterns of source utilization in Kenya and north-
lués de Garba IV, Melka-Kunturé, Ethiopie (fouilles
ern Tanzania: Some initial findings. African Archa

1972–1976). In: Leakey, R.E., Ogot, B.A. (Eds.), Proeological Review 2, 129–152.

ceed ings of the Eighth Panafrican Congress of Pre

Merrick, H.V., Brown, F.H., 1984b. Rapid chemical char-history and Quaternary Studies. International Louis acterization of obsidian artifacts by electron micro-Leakey Memorial Institute, Nairobi, pp. 202–204.

probe analysis. Archaeometry 26, 230–236.

Piperno, M., Collina, C., Galotti, R., Raynal, J.-P., Kieffer, Merrick, H.V., Brown, F.H., Connelly, M., 1990. Sources G., le Bourdonnec, F.-X., Poupeau, G., Geraads, D.,
of the obsidian at Ngamuriak and other south-

2009. Obsidian exploitation and utilization during
western Kenyan sites. In: Robertshaw, P.T. (Ed.),
the Oldowan at Melka Kunture (Ethiopia). In: Hovers,

Early Pastoralists of Southwestern Kenya. Memoir E., Braun, D.R. (Eds.), Interdisciplinary Approaches to no. 11. British Institute in Eastern Africa, Nairobi,
the Oldowan. Springer, Berlin, pp. 111–128.

pp. 173–182.

Renfrew, C., 1977. Alternative models for exchange and Merrick, H.V., Brown, F.H., Nash, W.P., 1994. Use and
spatial distribution. In: Earle, T.K., Ericson, J.E.

movement of obsidian in the Early and Middle Stone

(Eds.), Exchange Systems in Prehistory. Academic Ages of Kenya and northern Tanzania. In: Childs,

Press, New York, pp. 71–90.

S.T. (Ed.), Society, Culture, and Technology in Africa.

Roberts, D.L., 2003. Age, Genesis and Significance of South MASCA 11 (supplement), pp. 29–44.

African Coastal Belt Silcretes. Memoir 95. Coun cil for Merrick, H.V., Monaghan, M.C., 1984. The date of the cre-Geoscience, Pretoria, South Africa.

mated burials in the Njoro River Cave. Azania 19, 7–11.

Skinner, A.R., Hay, R.L., Masao, F., Blackwell, B.A.B., Michels, J.W., Tsong, I., Nelson, C.M., 1983. Obs

Ob idi
d an d
ian at-
dat-

2003. Dating the Naisiusiu Beds, Olduvai Gorge, by
ing and East African archaeology. Science 219, 361–366.

electron spin resonance. Quaternary Science Reviews Michels, J.W., 1990. Obsidian dating in the Lemek-Mara 22, 1361–1366.

region. In: Robertshaw, P.T. (Ed.), Early Pastoralists Stevenson, C.M., Mazer, J.J., Scheetz, B.E., 1998. Labor-of Southwestern Kenya. Memoir no. 11. British Insti-atory obsidian hydration rates: Theory, method, and
tute in Eastern Africa, Nairobi, pp. 52–53, appendix 1.

application. In: Shackley, M.S. (Ed.), Archaeological Minichillo, T., 2006. Raw material use and behavioral

Obsidian Studies. Plenum, New York, pp. 181–204.

modernity: Howiesons Poort lithic foraging strate-
gies. Journal of Human Evolution 50, 359–364.

Taylor, R.E., 1995. Radiocarbon dating: The continuing Morgan, L.E., Renne, P.R., Taylor, R.E., WoldeGabriel, G., revolution. Evolutionary Anthropology 4, 169–181.

2009. Archaeological age constraints from extrusion

Tchoua, F., 1970. Découverte d’obsidienne dans le Mont ages of obsidian: Examples from the Middle Awash,

Manengouba (Cameroun). Cameroun Université An

Ethiopia. Quaternary Geochronology 4, 193–203.

nale Faculté de Science 4, 23–30.

Muir, I.D., Hivernel, F., 1976. Obsidians from the Melka-Trauth, M.H., Maslin, M.A., Deino, A., Strecker, M.,

Konture prehistoric site, Ethiopia. Journal of Archae

2005. Late cenozoic moisture history of East Africa.

ological Science 3, 211–217.

Science 309, 2051–2053.

Negash, A., Alene, M., Brown, F.H., Nash, B.P., Shackley, Tykot, R., 1996. The geological source of an obsidian ear M.S., 2007. Geochemical sources for the terminal

(04.1941) from the Museum of Fine Arts, Boston.

Pleistocene/early Holocene obsidian artifacts of

Revue d’Égyptologie 47, 177–179.

the site of Beseka, central Ethiopia. Journal of Arch

Vogel, N., Nomade, S., Negash, A., Renne, P., 2006. For-aeological Science 34, 1205–1210.

ensic 40Ar/39Ar dating: A provenance study of Middle

Negash, A., Shackley, M.S., 2006. Geochemical prov-

Stone Age obsidian artifacts from Ethiopia. Jour nal of enance of obsidian artefacts from the MSA site of

Archaeological Science 33, 1749–1765.

Porc Epic, Ethiopia. Archaeometry 48, 1–12.

Walter, R.C., Manega, P.C., Hay, R.L., Drake, R.E.,

Negash, A., Shackley, M.S., Alene, M., 2006. Source prov-Curtis, G.H., 1991. Laser-fusion 40Ar/39Ar dating of
enance of obsidian artifacts from the Early Stone Age

Bed 1, Olduvai Gorge, Tanzania. Nature 354, 145–149.

(ESA) site of Melka Konture, Ethiopia. Jour nal of White, T.D., Asfaw, B., DeGusta, D., Gilbert, H., Richards, Archaeological Science 33, 1647–1650.

G.D., Suwa, G., Howell, F.C., 2003. Pleistocene Homo

Phillipson, D.W., 2005. African Archaeology, 3rd ed.

sapiens from Middle Awash, Ethiopia. Nature 423, Cambridge University Press, Cambridge, UK.

742–747.

72 | OBSIDIAN HYDRATION DATING

Wiessner, P., 1982. Risk, reciprocity and social influ-Wilmsen, E.N., 1973. Interaction, spacing behavior, and ences on !Kung San economics. In: Leacock, E., Lee,
the organization of hunting bands. Journal of Anthro

R. (Eds.), Politics and History in Band Societies. Cam-pological Research 29, 1–31.

bridge University Press and Editions de la Mai son

Yellen, J., Brooks, A.S., Helgren, D., Tappen, M., Ambrose, des Sciences de l’Homme, Cambridge and Paris,

S.H., Bonnefille, R., Feathers, J., Goodfriend, G.,
pp. 61–84.

Ludwig, K., Renne, P., Stewart, K., 2005. The archa eol-Wiessner, P., 1983. Style and social information in Kala-ogy of Aduma: A Middle Stone Age site in the Awash
hari San projectile points. American Antiquity 48, Valley, Ethiopia. Paleoanthropology 10, 25–100.

253–276.

P A R T I I

OBSIDIAN AND GLASS

PROVENANCE

Chapter 6

Provenance of Peruvian Wari Obsidian:

Comparing INAA, LA-ICP-MS, and Portable XRF

Patrick Ryan Williams, Laure Dussubieux, and Donna J. Nash Abstract

1. Introduction

For the past several years, researchers on the bor-

There is often a conflict between what is best to do
der between the two largest pre-Inca civilizations
and what is possible to do. This statement is particu-
in the Andes, Wari and Tiwanaku, have been inves-
larly true in regards to setting up a strategy to per-
tigating the role of long-distance exchange in the
form chemical analysis on archaeological artifacts
development of early empires. Obsidian has played
to address, for example, questions related to their
a principal role in this research. Early work focused
provenance. In this particular case, many param-
on destructive analysis that yielded high-precision
eters beyond the control of the investigator have to
results, though analysis could only be undertaken
be taken into account. For example, it is not always
on small retouch flakes recovered in excavation and
possible to move a representative sample of artifacts
survey. This sample includes 89 flakes processed via
from the field to a lab fitted with suitable equipment INAA reported by Burger et al. (2000) from surface
to fulfill the goal of the investigation. The sampling collections and 15 retouch flakes processed via INAA
is often biased by considerations related to the size
collected in excavations by Williams and Nash. More
of the objects or to what is permitted to export (e.g., recently, LA-ICP-MS was employed to test prov-fragments vs. whole objects). Another parameter is
enance of 25 flakes from excavation contexts exca-
the destructiveness of the investigation tool that will vated by Williams and Nash. None of these samples,
be selected. Often destructive analysis is totally for-though, was based on characterizing whole obsid-
bidden, and only non-destructive or very minimally
ian tools. The assumption that characterizations of
destructive techniques are permitted. Financial con-
obsidian debitage actually represent the sources of
sid erations have also an important role in the decision-raw materials for tools remained untested. However,
making process and may limit the options. As a
recent use of non-destructive portable XRF, though
consequence, when an archaeologist tries to find the
less precise and less accurate than other techniques,
best way to address a question such as provenance,
allowed us to characterize 235 obsidian tools recov-
she/he is very often forced to compromise but needs
ered in more than a decade of excavations from the
to keep in mind that the decision she/he takes about
sites. The combination of high-precision results on
sample selection and the best analytical technique to
small flakes and non-destructive surveys of whole
use may have an important impact on the results and
artifacts provides a compelling argument for the
therefore on the interpretation derived from them.

employment of multiple methodologies in assessing

The recent availability of portable instruments
obsidian provenance in the Andes.

that can be easily brought to the field without any

75

76 | OBSIDIAN AND GLASS PROVENANCE
customs restrictions, the possibility they offer to
the mirror, and the detector voltages were adjusted
determine a wide range of elements in a totally non-
using an auto-optimization procedure. For better
destructive manner, and the low cost associated with
sensitivity, helium is used as a gas carrier in the laser.

their use that allows for the measurement of large

To be able to determine elements with concentra-
samples of objects remove many of the constraints
tions in the range of ppm and below with minimal
listed above and therefore open the door to exciting
destructive impact, we used the single-point analysis
research opportunities. However, there is no per-
mode with a laser beam diameter of 55 µm, operat-
fect analytical tool, and this is particularly true for ing at 70% of the laser energy (0.2 mJ) and at a pulse portable (or handheld, as they are also called) X-ray
frequency of 15 Hz. A pre-ablation time of 20 s was
fluorescence (p-XRF) instruments that have been
used in order, first, to eliminate the transient part
gaining a huge popularity in museum and archae-
of the signal, and second, to be sure that a possible
ology communities during the past few years (e.g.,
surface contamination or corrosion did not affect

Dussubieux et al. 2005; Notis et al. 2007).

the results of the analysis. For each glass sample, an This study on obsidian from the Wari sites of
average of four measurements corrected from the

Cerro Baúl, Cerro Mejia, and Mejia Ladera in Peru
blank was considered for the calculation of concen-
compares results obtained at the Field Museum of
trations. The 29Si isotope was used for internal stan-

Natural History with laser ablation–inductively cou-
dardization. Concentrations for major elements,
pled plasma–mass spectrometry (LA-ICP-MS) and
including silica, were calculated assuming that the
in the field with p-XRF. Because of the difficulties of sum of their concentrations in weight percent in
exporting archaeological material from Peru, only 26
glass is equal to 100% (Gratuze 1999).

retouch flakes (and not actual objects) were brought

Three different series of standard reference
to the Field Museum and analyzed with LA-ICP-MS.

materials were used to determine the concentra-

More than 200 objects were subsequently analyzed
tions of major, minor, and trace elements. The first
in the field in a totally non-destructive way using
series of external standards were NIST SRM 610 and
p-XRF. The protocol of analysis for LA-ICP-MS and

612. Both these standards are soda-lime-silica glass
p-XRF will be described first and then the reliabil-
doped with trace elements in the range of 500 ppm
ity of the results obtained by p-XRF on obsidian will

(SRM 610) and 50 ppm (SRM 612). Certified values
be assessed. The discussion will deal with the inter-
are available for a very limited number of elements.

pretation of the results obtained with LA-ICP-MS

Concentrations from Pearce et al. (1997) were used
and p-XRF and will also include results obtained
for the other elements. The second series of standards by instrumental neutron analysis (INAA) by Burger
were manufactured by Corning. Glasses B and D best
et al. (2000) and abbreviated INAA carried out at
match the compositions of ancient glass (Brill 1999,
the Archaeometry Laboratory at the University of

2:544). Two obsidian samples from Sierra Pachuca,

Missouri Research Reactor by Michael Glascock.

State of Hidalgo, Mexico, and from the Little Glass

Buttes source, Lake County, Oregon, USA, were also

2. LA-ICP-MS protocol
used (Glascock 1999). The detection limits range from
of analysis
less than 1 ppb to 2 ppm for copper and are generally
under 1 ppm for most of the elements. For glass, accu-

The analyses carried out at the Field Museum
racy and reproducibility are generally better than 10%
involved a Varian ICP-MS and a New Wave UP213

(Dussubieux et al. 2009).

laser, for direct introduction of solid samples. The
parameters for ICP-MS were optimized to ensure

3. Portable XRF protocol
a stable signal with a maximum intensity over the
of analysis
full range of masses of the elements and to minimize
oxides and double ionized species formation (XO+/

XRF analyses were conducted using an Innov-X Alpha

X+ and X++/X+ <1 to 2%). For that purpose the argon Series portable instrument. The excitation source
flows, the RF power, the torch position, the lenses,
is an X-ray tube with a tungsten anode. The Si PiN

Provenance of Peruvian Wari Obsidian | 77

Table 6.1 Comparison of the results on two obsidian samples from Sierra Pachuca, State of Hidalgo, Mexico, and from the Little Glass Buttes source, Lake County, Oregon, USA (Glascock 1999)

Sierra Pachuca

Little Glass Buttes

p-XRF

LA-ICP-MS

Relative
p-XRF

LA-ICP-MS

Relative

(Orléans)

deviation

(Orléans)

deviation

Glascock 1999

Glascock 1999

K

33376 ±789

34500 ±300

3%

30168 ±656

34300 ±500

12%

Ca

593 ±130

2362 ±105

75%*

5134 ±188

6813 ±69

25%

Ti

874 ±81

1190 ±7

27%

572 ±70

595 ±5

4%

Mn

991 ±27

1048 ±40

5%

277 ±12

269 ±5

3%

Fe

15375 ±259

16600 ±100

7%

5408 ±87

6840 ±280

21%

Zn

212 ±10

219 ±2

3%

32 ±4

26.5 ±0.5

21%

Rb

217 ±6

203 ±1

7%

101 ±4

97 ±1

4%

Sr

<LOD

1.86 ±0.08

73 ±3

52 ±0.5

40%

Zr

965 ±13

1058 ±143

9%

91 ±3

83 ±7

10%

Nb

75 ±3

116 ±9

35%

6 ±2

9.1 ±0.1

34%

* The LA-ICP-MS measurement for calcium in the Sierra Pachuca sample is quite likely overestimated, as the other published values range from 640 to 1160 ppm.

diode detector has an energy resolution of less than
unprepared samples is often questioned, we com-

230 eV FWHM at 5.95 keV Mn Kα line. We used the
pared the results obtained by our p-XRF for the
soil mode with the Light Element Analysis Pro gram
samples from Sierra Pachuca, State of Hidalgo,

(LEAP) and an aluminum filter for the determination

Mex ico, and from the Little Glass Buttes source,
of elements in light matrix samples. The voltage was

Lake County, Oregon, USA, with the results pub-

40 kV and the current 20 μA. This setting allows anal-
lished in Glascock (1999). We also measured with
ysis down to phosphorus and the measurement of
p-XRF a set of 22 samples that were analyzed with

32 elements (P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, LA-ICP-MS at the Field Museum. In both cases,

Cu, Zn, As, Se, Rb, Sr, Zr, Nb, Mo, Ba, Hf, Ta, W, Re, only a reduced number of elements were consid-Pt, Au, Hg, Pb, Bi, U). Total acquisition time was 120 s ered based on their presence in the list of elements
in total. Quantitative results are calculated, using fun-determined by p-XRF, their concentrations, and
damental parameters, by the software provided with
their relevance for the study of obsidian provenance.

the instruments.

Nine elements were selected: K, Ca, Ti, Mn, Fe, Zn,

The aperture of the instrument is approximately

Sr, Zr, Nb.

1 cm2 and ideally should be totally covered by the

Table 6.1 reports the values obtained by p-XRF
sample presenting a flat and polished surface. The
and by LA-ICP-MS (Centre National de la Recherche
samples were not subject to any preparation; how-

Scientifique, Orléans, France), the error of measure-
ever, they were generally cleaned so that no dirt
ments, and the relative deviations between the two
remained at the surface.

methods for each element determined in the Sierra

Pachuca and the Little Glass Buttes obsidians. Aside

4. Reliability of the
from the relative deviation for calcium in the Sierra
p-XRF results

Pachuca obsidian that is 75% and that is quite likely
due to the overestimation of the calcium concentra-

As the use of p-XRF in the field of archaeology
tion obtained by LA-ICP-MS in Orléans, the maxi-
is still new and the reliability of the quantitative
mum relative deviation is 40%; however, for most of
data obtained using fundamental parameters and
the elements the relative deviations is 10% or less.

78 | OBSIDIAN AND GLASS PROVENANCE

We compared also the Table 6.2 Deviations between the LA-ICP-MS and p-XRF results with results obtained with p-XRF on
the range of concentrations in the samples tested for

22 obsidian samples measured
each element.

by LA-ICP-MS at the Field Mu-

Range of

Average relative deviation
seum. Table 6.2 summarizes
concentrations
between the LA-ICP-MS
the range of concentrations for

and p-XRF results
each element of interest and K

31,300 – 43,500 ppm

7%
the average deviation between

Ca

2000 – 9000 ppm

41%
the LA-ICP-MS and the p-XRF

Ti

120 – 1500 ppm

10%
results. Rela tive deviations for

Mn

170 – 14,600 ppm

9%
these two series of results are in

Fe

4500 – 8000 ppm

7%
the same range as the relative

Zn

30 – 150 ppm

14%
deviations calculated above for

Rb

150 – 510 ppm

12%
the Sierra Pachuca and the Little

Glass Buttes obsidians.

Sr

10 – 210 ppm

28%

The degree of agreement Zr

50 – 230 ppm

41%
between the LA-ICP-MS and Nb

20 – 190 ppm

15%
the p-XRF values varies accord-
ing to many factors. Limits of
detections are significantly higher for light elements LA-ICP-MS and p-XRF strontium concentrations
when using XRF, and the measurement of low
are very different when they are below approximately
concentrations of lighter elements will be signifi-

5 ppm, as measured by LA-ICP-MS. The same obser-
cantly less reliable for this reason. Fig ures 6.1a and vation applied to manganese for concentrations of

6.1b compare results measured for manganese
approximately 20 ppm.

and strontium. Manganese is an element significantly

Figures 6.2a and 6.2b report the relative error
lighter than strontium. Results between p-XRF and
on the measurements of the strontium and manga-

LA-ICP-MS diverge for strontium around 10–20 ppm
nese values measured by p-XRF. We observe a rapid
and below, whereas we observe the same phenom-
increase of these relative errors as the concentra-
enon at around 100 ppm and below for manganese.

tions get lower (around 10–20 ppm for strontium

Figure 6.1a (left) and 1b (right). Relative deviations between the LA-ICP-MS and the p-XRF measurements for strontium and manganese.

Provenance of Peruvian Wari Obsidian | 79

Figure 6.2a (left) and 2b (right). Relative errors on the p-XRF measurements for strontium and manganese.

and 25 ppm for manganese), indicating that the
residence on the north slope of the mountain adja-
instrument is getting closer to its limit of detection.

cent to ancient agricultural fields and a Wari village Other parameters will have an influence on
on the west slope of the mountain known as Pampa
the reliability of the p-XRF results: the presence of
del Arrastrado.

elemental or matrix interferences and the size and

Twenty-five samples, all debitage flakes, were
the shape of the samples. For example, some of the
analyzed at the Field Museum with LA-ICP-MS. A
samples did not present a very flat surface or were
vast majority of obsidian objects recovered at these
too small to cover the aperture of the p-XRF.

three sites, 235 obsidian artifacts, were analyzed

For the elements that we use for this study—Sr,
using p-XRF in Peru. Table 6.3 shows the repartition

Rb, and Mn—the deviation between the LA-ICP-MS
of the samples per site. Most of the samples were
and the p-XRF results are at maximum 28%.

excavated at Cerro Baúl.

5. Samples

6. Results

This study deals with material coming from three

Based on the results of published research, we selected different locations: the provincial center at Cerro
manganese (Mn), strontium (Sr), and rubidium (Rb)

Baúl, the intermediate elite residences at Cerro
as elements able to discriminate the different obsid-

Mejia, and the local households on the slopes of
ian sources generally present in this area (Glascock et Cerro Mejia, Mejia Ladera. The contexts sampled
al. 2007). Three sources, Alca, Quispisisa, and Chivay, from Cerro Baúl include a palatial residence atop
provided most of the obsidian found in southern
the great mesa summit, adjacent
specialist residences around the
palace, and two D-shaped tem-

Table 6.3

Number of samples tested by LA-ICP-MS and p-XRF from
ple annexes also on the summit.

each site: Cerro Baúl, Cerro Mejia, and Mejia Ladera.

The Cerro Baúl samples also
include two contexts from the

Cerro Baúl

Cerro Mejia

Mejia Ladera
lower slopes of the mountain

LA-ICP-MS 11

4

10
that contained whole obsid-
ian artifacts: a terraced Wari
p-XRF 205 12 18

80 | OBSIDIAN AND GLASS PROVENANCE

Figure 6.3a. Graph reporting the concentration of rubidium and strontium measured for the samples from Cerro Baúl with p-XRF and LA-ICP-MS and the values measured by XRF for the same elements for three obsidian sources: Alca, Chivay, and Quispisisa.

Figure 6.3b. Graph reporting the concentration of manganese and strontium measured for the samples from Cerro Baúl with p-XRF and LA-ICP-MS and the values measured by XRF for the same elements for three obsidian sources: Alca, Chivay, and Quispisisa.

Peru (Burger et al. 2000). Mn, Sr, and Rb were also
three obsidian sources mentioned earlier are also
found appropriate because they are all determined by
reported on figure 6.3a (Glascock et al. 2007). For the LA-ICP-MS and p-XRF and also because the agree-Alca source, three different compositions were iden-
ment between the two techniques for these elements
tified and the Alca-1 composition best matches our
was found to be reasonably good.

results. The obsidian found at Cerro Baúl comes from

We first consider the results for the site of Cerro
three different sources. The use of Sr and Mn leads to Baúl. Figure 6.3a represents the concentrations of
the same conclusion (figure 6.3b).

rubidium and strontium for the samples of Cerro Baúl

Among the 205 artifacts investigated with
analyzed by LA-ICP-MS and p-XRF. Three groups are
p-XRF from Cerro Baúl, a closer examination of the
distinguishable. The average values for these two ele-
data casts doubt on the attribution of two samples.

ments measured by XRF on samples taken from the

Although they have Sr, Rb, and Mn concentrations in

Provenance of Peruvian Wari Obsidian | 81

Figure 6.4a. Graph reporting the concentration of rubidium and strontium measured for the samples from Cerro Mejia and Mejia Ladera with p-XRF and LA-ICP-MS and the values measured by XRF for the same elements for three obsidian sources: Alca, Chivay, and Quispisisa.

Figure 6.4b. Graph reporting the concentration of manganese and strontium measured for the samples from Cerro Mejia and Mejia Ladera with p-XRF and LA-ICP-MS and the values measured by XRF for the same elements for three obsidian sources: Alca, Chivay, and Quispisisa.

the same range as the samples attributed to the Alca

For Cerro Mejia and Mejia Ladera, we used the
group, they have lower barium concentrations. The
same elements—Sr, Rb, and Mn—to group the sam-
average barium concentration for the Alca samples
ples (figures 6.4a and 6.4b). Cerro Mejia samples split is 680 ppm. Sample Cb02-09-1047 contains 306 ppm
into two groups with compositions characteristic of
of barium and Cb01-09-3681-2 has its barium con-
the Alca and Quispisisa sources. At this site, two Alca centration below the detection limit for this element.

samples have barium concentration in the range of

These two samples will be categorized as “other”

300 ppm instead of 700 ppm. They will be catego-
because no other source attribution can be proposed
rized as “other” as were the Cerro Baúl samples that
based on the compositions in Glascock et al. (2007).

presented the same feature. The Mejia Ladera samples

82 | OBSIDIAN AND GLASS PROVENANCE

Table 6.4 Number of samples from each site attributed to each source according to the analytical technique used (LA-ICP-MS or p-XRF)

Cerro Baúl

Cerro Mejia

Mejia Ladera

LA-ICP-MS p-XRF

LA-ICP-MS p-XRF

LA-ICP-MS p-XRF

Alca

3 177

3 8

3 10

Quispisisa 8 17

1 2

6 7

Chivay 0 9

0 0

1 1

Other

0

2 0

2 0

0
analyzed with LA-ICP-MS can be traced to the Alca
a higher percentage than expected from the over-
and the Quispisisa sources, whereas for those ana-
all distribution of obsidian sources from the three
lyzed with p-XRF, Chivay obsidian was also identi-
sites as measured on whole artifacts by p-XRF. A
fied. Table 6.4 presents the group attribution for the chi square test indicates that these p-XRF results are different sites according whether they were analyzed
statistically different from the expected distribution.

using LA-ICP-MS or p-XRF.

While the flake sample may have been insuf-

The larger sample of artifacts analyzed by p-XRF
ficient to represent Quispisisa obsidian at Mejia
for the Cerro Baúl site exhibits a different pattern than Ladera, the totality of whole artifacts also suggests
the small sample of flakes analyzed by LA-ICP-MS. A
that people at Mejia Ladera had increased access to
large majority of the artifacts are from the Alca obsid-Quispisisa obsidian. Radiocarbon dates from Mejia
ian source for the former while the sample of debitage Ladera (Nash 2002) indicate it was occupied in the
flakes suggests a preponderance of the Quispisisa
early period of Wari expansion and was abandoned
source for the latter. The same inversion is observed
by AD 800. Perhaps these settlers had increased
at Mejia Ladera, with the p-XRF data suggesting
access to the Ayacucho source as direct immigrants
that a majority of artifacts are from the Alca source, from that region or increased trade with the Wari
whereas the LA-ICP-MS data suggest a predominance
heartland. Those hypotheses await further testing.

of Quispisisa obsidian. Cerro Mejia, the site with the At Cerro Baúl, p-XRF analyses of the different
smaller sample (only 4 debitage flakes analyzed with
contexts sampled all followed the dominant pattern

LA-ICP-MS and 11 artifacts analyzed with p-XRF),
of a large majority of Alca obsidian, with a minor rep-yielded a majority of Alca obsidian samples no matter
resentation of Quispisisa and the rare Chivay imple-
which analytical technique was adopted.

ments. Most of the obsidian from Cerro Baúl came
from the palace or adjacent residences (n = 111). The

7. Discussion
next largest mode was the Temple Annex (n = 40).

All the contexts on Cerro Baúl were statistically likely We first discuss the results for the locations of Cerro to have been randomly sampled from the overall dis-Mejia and Mejia Ladera. There are no comparative
tribution of obsidian sources with one exception. The
data available in the literature for these locations.

north slope residence (unit 21) had 5 obsidian points

The obsidian recovered at Cerro Mejia is mostly
with a characteristic tang that all were sourced to the from the Alca source whether actual objects or deb-Chivay group (figure 6.5). A chi square test indicates itage flakes are considered. A chi square test indicates that this distribution is statistically distinct from all that the distribution of obsidian sources at Cerro
other obsidian source distributions we sampled.

Mejia does not differ from the overall distribution of This point form is rare in obsidian forms at Cerro
obsidian at the three sites in any statistically signifi-Baúl, but it is predominant in this small assemblage.

cant way. At Mejia Ladera, LA-ICP-MS data from

Points of this form have been found occasionally in
flakes suggest a preponderance of Quispisisa obsid-
other contexts at Cerro Baúl and Cerro Mejia, made
ian. Likewise, Quispisisa obsidian is represented in
of both obsidian and chert. This form has also been

Provenance of Peruvian Wari Obsidian | 83

Figure 6.5. Examples of projectile point types from Cerro Baúl (drawing by B. Vining).

documented at the Wari and Tiwanaku sites them-

The two larger studies (with XRF and with INAA
selves. However, it is intriguing that all examples of by Burger et al. [2000]) exhibit similar patterns with this form in obsidian from this context were sourced
a high proportion of Alca obsidian (respectively 86%
to Chivay, the source associated overwhelmingly
and 79%) and only 8% of Quispisisa obsidian (table
with Tiwanaku but extremely rare at Cerro Baúl. This

6.5). Approximately the same percentage of samples
may indicate an exchange relationship between the
was attributed to the Chivay source. Nine percent of
occupants of this house and Tiwanaku or other high-
the debitage flakes investigated by Burger were attrib-land specialists from outside Moquegua; Tiwanaku
uted to the Andahuaylas group, which corresponds
houses both around Cerro Baúl and in the rest of the
to the source named Potreropampa (Glascock et al.

Moquegua Valley have little to no obsidian and cer-

2007). The study by Burger et al. (2000) is the only
tainly much less than even this small household. It is one to have identified such a source. It is also the only unlikely there was a local Tiwanaku economic source
study using surface-collected material. If we consider for this material.

only the two other studies conducted on a limited

Aside from the analyses with LA-ICP-MS
number of debitage flakes (11 for the LA-ICP-MS
and p-XRF included in this chapter, we include in
study and 15 for the abbreviated INAA study), we
the discussion the results reported in Burger et al.

have a very dissimilar picture. In these two cases,

(2000) on 89 surface collection debitage flakes ana-
no Chivay obsidian was identified. The abbreviated
lyzed by INAA and results obtained on 15 debitage

INAA study suggests that Alca and Quispisisa obsidi-
flakes obtained by abbreviated INAA carried out at
ans had similar importance at Cerro Baúl whereas the
the Archaeometry Laboratory at the University of

LA-ICP-MS results show the preponderance of the

Missouri Research Reactor by Michael Glascock.

Quispisisa obsidian. This is likely a sampling problem

84 | OBSIDIAN AND GLASS PROVENANCE

Table 6.5 For the site of Cerro Baúl, proportions of samples attributed to different sources using different analytical techniques

Number of

Chivay

Alca

Andahuaylas

Quispisisa

Other
samples

LA-ICP-MS

11

0%

27%

0%

73%

0%
p-XRF

205

4%

86%

0%

8%

1%

Burger et al. 2000

89

3%

79%

9%

8%

1%

Abbreviated INAA

15

0%

53%

0%

47%

0%
on two fronts. The sampling of multiple flakes from
valley came from Cerro Baúl and the majority of
similar contexts may increase the representation of a
that came from the palace and adjacent residences
single object that was flaked in situ. The small sample and temples suggests obsidian distribution may
size also likely was insufficient to represent the popu-have been centralized through the palace economy.

lation of obsidian from a particular site or context.

This is especially true for intermediate elite groups
around Cerro Baúl, like the residences on the sum-

8. Conclusion
mit of Cerro Mejia.

A different pattern emerged at the local settle-

This study shows the reliability of p-XRF for the idenment of Mejia Ladera, where a greater percentage
tification of obsidian sources for artifacts recovered of Quispisisa obsidian than expected was docu-at Wari sites dated from the Middle Horizon. Even
mented both in flakes and in whole implements. We
if this technique does not exhibit the same degree of
hypothesize that this distinction may reflect obsid-
reliability as INAA, the low rate of unattributed sam-
ian procurement patterns of the early occupancy of
ples (1%) shows that p-XRF is not an obstacle to the
this region by the Wari; Mejia Ladera was one of the
study of that type of material.

earlier occupations and was no longer occupied

This study also shows that a larger sample is
after AD 800.

best to get a representative picture. The reliability of Overall, p-XRF permitted these patterns to
p-XRF is dependent on the limited number of sources
be documented by sampling whole artifacts non-
present at the site and their chemical distinction on a destructively. Higher-precision techniques such as
few element pairs. INAA and LA-ICP-MS were criti-

INAA and LA-ICP-MS that require destructive sam-
cal in confirming the patterns. The p-XRF patterns
pling were only processed on flake tools and are much
on large numbers of excavated implements revealed
more expensive to run. They were, however, impor-
two interesting diversions from the normal pattern
tant tools for reconfirming the veracity of the p-XRF
of obsid ian acquisition.

data. Using p-XRF to make preliminary determina-

One house using a relatively rare obsidian point
tions and following up with a more refined technique
type obtained the material for this form from the
to test the determinations made via XRF proved to be
least common source. That source has been most
a valuable strategy for the Wari provenance study at
often associated with Wari’s rival polity, the Tiwan-

Cerro Baúl.

aku. This pattern leads us to hypothesize that a very
few individual households like this one may have

Acknowledgments
had access to special limited exchange networks
from which they obtained their materials.

The LA-ICP-MS laboratory was built with funds

The overall pattern of obsidian procurement
from the National Science Foundation (NSF) (BCS-
at Cerro Baúl, and in the region in general, is one

0320903), the Anthropology Alliance and an anony-
in which obsidian distribution among sources was
mous donation. The portable XRF instruments were
standard across the site and across the region. The
purchased with a grant from the Grainger Founda-
fact that over 80% of all obsidian recovered in the
tion. Funding for fieldwork was provided by the NSF

Provenance of Peruvian Wari Obsidian | 85

(BCS-0079410), the National Endowment for the

Glascock, M.D., Speakman, R.J., Burger, R.L., 2007. Sour-Humanities (RZ-50048), the Heinz Foundation, and
ces of archaeological obsidian in Peru: Des crip tion
the Bruno Foundation. Joe Szymczak processed the
and geochemistry. In: Glascock, M.D., Speakman, R.J.,

LA-ICP-MS samples.

Popelka-Filcoff, R.S. (Eds.), Archa e ological Chem istry: Analytical Methods and Archa eological Inter pretation.

References

ACS Publication Series 968. American Chemical

Society, Washington, D.C., pp. 522–552.

Brill, R.H., 1999. Chemical Analyses of Early Glasses.

Gratuze, B., 1999. Obsidian characterization by laser abla-Corn ing Museum of Glass, Corning, NY.

tion ICP-MS and its application to prehistoric trade in Burger, R.L., Mohr Chávez, K.L., Chávez, S.J., 2000.

the Mediterranean and the Near East: Sourc es and dis-

Through the glass darkly: Prehispanic obsidian pro-
tribution of obsidian within the Aegean and Anatolia.

curement and exchange in southern Peru and north-

Journal of Archaeological Sci ence 26, 869–881.

ern Bolivia. Journal of World Prehistory 14 (3), 267–362.

Nash, D., 2002. The archaeology of space: Places of power Dussubieux, L., Pinchin, S.E., Tsang, J.-S., Tumosa, C.S., in the Wari Empire. Ph.D. dissertation, Department

2005. Non-destructive elemental analysis: Reliability
of Anthropology, University of Florida.

of a portable X-ray fluorescence spectrometer for

Notis, M., Shugar, A., Herman, D., Ariel, D.T., 2007.

museum applications. 14th Triennial Meeting The

Chem ical composition of the Isfiya and Qumran coin

Hague, ICOM Committee for Conservation, Sep-
hoards. In: Glascock, M.D., Speakman, R.J., Popelka-
tember 2005. Preprints vol. 2. International Coun cil

Filcoff, R.S. (Eds.), Archaeological Chem istry: Anal y
of Museums, Rome, pp. 766–773.

tical Methods and Archaeological Inter pretation. ACS

Dussubieux, L., Robertshaw, P., Glascock, M.D., 2009.

Publication Series 968. Ameri can Chemical Society,

LA-ICP-MS analysis of African glass beads: Labor-

Washington, D.C., pp. 258–274.

atory inter-comparison with an emphasis on the

Pearce, N.J.G., Perkins, W.T., Westgate, J.A., Gorton, M.T., impact of corrosion on data interpretation. Inter na

Jackson, S.E., Neal, C.R., Chenery, S.P., 1997. A compi-tional Journal of Mass Spectrometry 254, 152–161.

lation of new and published major and trace element

Glascock, M.D., 1999. An inter-laboratory comparison
data for NIST SRM 610 and SRM 612 glass reference
of element compositions for two obsidian sources.

materials. Geostandards Newsletter 21, 114–115.

International Association for Obsidian Studies Bulletin 23, 13–25.

Chapter 7

New Perspectives on Obsidian Procurement
and Exchange at Tiwanaku, Bolivia

Michael D. Glascock and Martin Giesso

Abstract

1. Introduction

Tiwanaku was an important center of Andean civi-

Archaeologists seeking to reconstruct past human
lization from AD 500 to AD 1000. Its urban inhab-
behavior and interaction commonly examine the
itants had access to exotic lithic raw materials,
materials that early peoples used. Artifacts made
including obsidian. Samples from three obsidian
from stone materials (e.g., basalt, chert, obsidian)

quarries, 147 obsidian artifacts from eight different
are undoubtedly the most widely studied archaeo-
sectors in the prehistoric city of Tiwanaku, and 33
logical materials because they occupied an impor-
obsidian artifacts from seven other locations within
tant role in the material culture of most prehistoric
the Titicaca Basin region were analyzed by neutron
peoples. Although nearly every type of stone was
activation analysis and X-ray fluorescence. The new
used by one prehistoric culture or another, naturally
data were compared to the MURR (University of
occurring obsidian glass offers archaeologists one

Missouri Research Reactor) database and artifacts
of the most definitive types of evidence concerning
were traced to known sources in Peru, Bolivia, and
contact between different cultures.

Argentina. Chemical abundance data are presented

Its glassy consistency, predictable fracturing
for several new obsidian source types. In addi-
characteristics, and sharp working edge contributed
tion, evidence is presented that the inhabitants of
to obsidian’s being highly sought after to produce

Tiwanaku used obsidian from a large number of
various implements (e.g., tools, weapons) as well
sources, some brought from very distant regions
as ornamental items such as jewelry. Because it is
located outside of the Tiwanaku state sphere. Most
unstable and devitrifies over time, losing its fractur-samples analyzed were traced to the Chivay source
ing qualities, raw obsidian suitable for tool produc-
in southern Peru, but a total of 11 other sources
tion is generally restricted to tectonic regions that
were present as well, mostly in non-elite areas.

experienced volcanism since the Tertiary period. In

Here we compare obsidian access by elite, elite-
addition to the limited number of sources, obsid-
related, and non-elite groups, as well as that present ian has a number of attributes that give it a signifi-in two ceremonial structures, and we suggest that
cant role in archaeology, including the following: (1) while the Tiwanaku elites obtained and distributed
artifacts made from obsidian are well preserved in

Chivay obsidian, and used for themselves materi-
most archaeological contexts; (2) the fragile nature
als from this source exclusively, non-elite groups
of obsidian causes it to have a high replacement rate; obtained materials from other sources through

(3) individual sources are, with few exceptions, com-
local networks.

positionally homogeneous; (4) different sources are
compositionally distinct; and (5) through precise
chemical analysis, it is possible to link artifacts to 86

New Perspectives on Obsidian Procurement and Exchange | 87
sources with a high degree of certainty. Analytical
to have reached more than 30,000 people (Kolata
techniques such as proton-induced X-ray emission

1993). More than 350,000 people are thought to

(PIXE), X-ray fluorescence (XRF), and neutron
have lived in the region immediately surrounding
activation analysis (NAA) are widely recognized for

Lake Titicaca, giving this region one of the high-
their contributions to the reconstruction of ancient
est population densities in all of South America at
obsidian distribution systems around the world
that time.

(Bird et al. 1978; Stross et al. 1983; Hughes 1984;

The environmental conditions of the altiplano

Francaviglia 1988; Cobean et al. 1991; Shackley 2005).

presented continual threats of famine ranging from

Progress on archaeological research in western
frost and drought to occasional flooding from the

South America has increased recently, especially in
waters of Lake Titicaca. Key factors that made it

Peru, Bolivia, Argentina, and Chile, with the loca-
possible for large population and cultural centers
tion of several obsidian sources (Burger et al. 1998a, to develop in the altiplano were (1) the presence of

1998b; Burger and Glascock 2000; Burger et al. 2000;

Lake Titicaca, which moderated the extreme tem-

Glascock et al. 2007; Seelenfreund 1996; Tripcevich
peratures and supplied fish; (2) cultivation of suit-

2007; Yacobaccio et al. 2002). In this chapter we
able agricultural plants, mostly highland tubers and
describe our most recent findings regarding obsid-
other frost-resistant crops such as quinoa ( Chen o
ian trade and exchange in the Tiwanaku region.

podium sp.); (3) the domestication of animals unique to the highlands—e.g., the llama and the alpaca; and

2. Background

(4) an economic strategy of direct access to com-
plementary resources in the lower-lying ecological

As the location of the world’s highest-altitude prehis-zones (Browman 1978; Kolata 1993).

toric city, the archaeological site of Tiwanaku aston-

The latter economic strategy for access to maize,
ishes travelers and explorers who contemplate the
fish, fruits, beans, coca, and other goods from the
remains of magnificent temples and pyramids built
lower altitudes involved kinship groups (locally
there during the period from AD 300 to AD 1000.

known as ayllus) who resided temporarily in one Lake Titicaca is situated in the northern portion of
of the lower ecological zones to harvest products
the Bolivian high plateau, or altiplano, between two unavailable in the altiplano. Through direct access
towering cordillera, at an altitude of about 3810 m
to distant products, the Tiwanaku people were less
above sea level. Because the Tiwanaku state col-
subject to the uncertainties of climatic crisis (e.g., lapsed several centuries prior to the Spanish con-frost, drought) and fragile trading relationships.

quest and there are no written records, the nature

The availability of raw materials in the Lake
of Tiwanaku’s influence over the political, economic,

Titicaca region for the production of stone tools
and religious aspects of contemporaneous societies
was also limited because the adjacent mountains
in the south-central Andes is not well understood.

are primarily made of quartzite and cryptocrystal-

Tiwanaku (figure 7.1) was located at the cen-
line silicates. However, there is evidence that the
ter of a network of hierarchically organized settle-

Tiwanaku state may have exerted substantial influ-
ments located in three contiguous valleys: the
ence over the procurement and distribution of stone

Pampa Koani to the north, the Tiwanaku valley
tools made from obsidian and basalt, which were
in the center, and the Desaguadero River to the
brought to Tiwanaku—in the case of obsidian—
south. The central area of the city of Tiwanaku (fig-
in the form of small nodules that were worked to
ure 7.2) includes the Akapana Pyramid and other
produce flakes and projectile points. Obsidian was
religious complexes including the Kalasasaya, the
one of the materials used to make the tools neces-

Semi-Subterranean temple, the Putuni palace, and
sary for daily subsistence activities and weapons for
the Puma Punku, which when combined cover less
use in warfare. Obsidian was most certainly used for
than 5% of the approximately 6 km2 urban area. At
butchering animals and shearing domesticated cam-
its zenith, the population of Tiwanaku is estimated
elids for their wool (Ann DeMuth Webster, personal

88 | OBSIDIAN AND GLASS PROVENANCE

Figure 7.1. Map of Tiwanaku and
other archaeological sites in the

Lake Titicaca basin mentioned
in this study.

Figure 7.2. Topographic map of
archaeological sites within the
boundaries of Tiwanaku men-
tioned in this study: 1-Akapana,

2-Semi-Subterranean Temple,

3-Kalasasaya, 4-Putuni,

5-Chunchukala, 6-Kheri Kala,

7-Puma Punku, 8-Mollo

Kontu Mound, 9-Mollo Kontu

South, 10-Akapana East 1M,

11-Akapana East 1, 12-Akapana

East 2, 13-Marcapata, 14-Cj’iji

Jawira, 15-Kk’arana, 16-La K’arana.

Contour interval on the base
map is 1 meter.

communication). In general, only about 1% of the

In early obsidian studies, Burger et al. (2000)

surface-collected lithic materials at Tiwanaku are
analyzed obsidian artifacts from sites surrounding
made from obsidian. Obsidian debris and tools form

Lake Titicaca by NAA and XRF. Their work con-
up to about 5% of the flaked lithic assemblage exca-
cluded that two sources were responsible for sup-
vated at Tiwanaku and neighboring sites. The great-
plying obsidian to the Lake Titicaca region, with the
est frequencies occur in the ceremonial precincts

Chivay source being the most important, followed

(i.e., Akapana Pyramid and Mollo Kontu Mound)

by the Alca source. Materials from the latter source

(Giesso 2003a).

were found only in the northern basin. Figure 7.3

New Perspectives on Obsidian Procurement and Exchange | 89

Figure 7.3. Map showing the
locations of obsidian sources
mentioned in this study.

shows a map with the locations of sources men-

Neutron activation analysis of obsidian at MURR
tioned in this study.

consists of two irradiations by neutrons followed by
three measurements of the emitted gamma radia-

3. Materials and methods
tion. The first irradiation for 5 seconds was applied
to samples weighing about 100 mg encapsulated in a

The obsidian artifacts reported in this study were
polyethylene vial using a thermal neutron flux of 8 x
analyzed over a number of years beginning in 1992.

1013 n cm-2 s-1. This short irradiation was followed by The earliest analyses were made using neutron acti-a 25-minute decay and 12-minute count that allowed
vation analysis exclusively. However, beginning with
measurement of 7 short-lived elements (Al, Ba, Cl, Dy, availability of an X-ray fluorescence spectrometer

K, Mn, and Na). The second irradiation was applied
in 2005, we analyzed a number of samples using
to a bundle of obsidian samples and standards weigh-
either XRF or NAA or both methods depending
ing between 50 and 250 mg that were encapsulated in
upon the key advantages for each method (i.e., non-
high-purity quartz vials and subjected to a long irra-
destructiveness for XRF and sensitivity for NAA).

diation of 70 hours using a thermal neutron flux of

As a result, we have had greater success at obtaining

5 x 1013 n cm-2 s-1. The long irradiation was followed by permission to analyze unique archaeological sam-2 gamma-ray counts. The first count was performed
ples and determining the provenance of a greater
between 7 and 8 days after the end of irradiation, using percentage of the overall obsidian inventory. A total
a sample changer to count each sample for 30 min-
of 82 artifacts were analyzed by XRF and 98 artifacts
utes, to detect 7 medium-lived elements (Ba, La, Lu,
were analyzed by NAA. Five of the artifacts analyzed

Nd, Sm, U, and Yb). The second count was performed
by XRF were also analyzed by NAA for confirma-
about four weeks after the end of irradiation, using
tion. Samples from three quarries in Bolivia were
the sample changer for 3 hours per sample, to detect
analyzed by both XRF and NAA.

15 long-lived elements (Ce, Co, Cs, Eu, Fe, Hf, Rb, Sb,

90 | OBSIDIAN AND GLASS PROVENANCE

Sc, Sr, Ta, Tb, Th, Zn, and Zr). When the long irradia-to being a non-destructive analysis, the analyses by
tion is performed, the barium concentration from

XRF are rapid and less expensive than those by NAA.

measurement of the medium-lived isotope (i.e.,

The main drawbacks are less ability to differentiate

133Ba) is normally superior and it is used in lieu of
between chemically similar sources and that the sam-
the value for Ba measured following the short-lived
ples must be greater than 0.8 cm in width and length.

irradiation. The data from all three measurements
were converted to concentrations by comparing the

4. Results and discussion
unknown samples to the count rates for standards
counted with the samples. All concentration data

The XRF and NAA data for the artifacts and source
were compiled into a spreadsheet.

specimens in this study were tabulated using a

Non-destructive analysis of obsidian artifacts by
spreadsheet program to enable the generation of
energy-dispersive X-ray fluorescence (ED-XRF) was
bivariate plots showing different combinations of
performed using an ElvaX desktop spectrometer. The
element pairs. Inspection of the bivariate plots and
instrument consists of an X-ray generator, X-ray detec-comparisons between the new data and earlier NAA
tor, and multichannel analyzer (MCA). The detector is
work reported by Burger and Asaro (1977) facili-
a solid state Si-pin-diode with an area of 30 mm2 and a tated assignments of artifacts to previously known
resolution of 180 eV at 5.9 keV (at a count rate of 1000
obsidian source types as well as the identification
counts per second). The solid state detector uses a ther-of several new source types. The Berkeley labora-
moelectric (Peltier) cooling system, which eliminates
tory and MURR data were intercalibrated through
the need for liquid nitrogen, and because the unit weighs the analyses of Perlman’s Standard Pottery made in
about 22 kg it is relatively easily to transport from one each laboratory.

location to the next. The output signal of the detector The bivariate plots for Cs versus Hf and Sc versus
is formed by a time-variant time processor with pile-

Eu from NAA are shown in figures 7.4 and 7.5, respec-
up rejector, baseline restorer, and automatic adaptation tively, and are illustrative of this work. Figure 7.6
of shaping time to the input count rate. The MCA
shows a plot of Rb versus Sr for the artifacts analyzed consists of a fast shaping amplifier (FSA) and a 4096-by XRF. By inspecting the three plots, we identified
channel spectrometric analog-to-digital converter
a total of 12 different chemical types (i.e., sources) (ADC), built as a successive approximation ADC
among the artifacts in this study. Tables 7.1 and 7.2
with a 32-bit per channel buffer RAM, “sliding scale”

show a breakdown of the provenance assignments
linearization of differential nonlinearity, and dead-
for obsidian artifacts from locations within Tiwanaku
time correction circuit. The X-ray tube is an air-cooled, and outside the boundaries of Tiwanaku, respec-tungsten anode with a 140 µm beryllium end-window.

tively. Source assignments for the artifacts were made The analyses in this study were conducted at 35 kV
by comparing the artifact data to the source data as
using a tube current of 45 µA and operating time of
described in Glascock et al. (1998).

400 seconds. Concentrations were reported in parts

The largest single group of artifacts (n = 145)

per million using the ElvaX regression program
belong to the Chivay source, referred to earlier by
based on the quadratic regression model from a series

Burger and Asaro (1977) as the Titicaca Basin–type
obsidian reference samples previously characterized
obsidian. The Chivay obsidian quarry is located in the by XRF and NAA. The analysis permits quantifica-Colca Valley, Arequipa, Peru, about 300 km north-
tion of the 11 elements (K, Ti, Mn, Fe, Zn, Ga, Rb,
west of Tiwanaku. Discovery of the Chivay source

Sr, Y, Zr, and Nb). All analyses using this instrument was initially reported by Brooks et al. (1997). An inde-were non-destructive. The equipment also projects
pendent discovery of the Chivay source by Burger et
the X-ray spectra on a computer screen, which allows
al. (1998a) described the source in greater detail.

for visual comparisons between the spectrum cur-

Five artifacts were provenanced to the source at
rently being acquired with spectra for samples mea-

Quispisisa, Peru, previously characterized by Burger
sured previously. This capability often leads to rapid and Glascock (2000). The Quispisisa source was the
identification of the sources for samples. In addition most important source in all of Peru as obsidian from

Figure 7.4. Bivariate plot of the
elements Cs and Hf measured by NAA
on obsidian artifacts described in this
study. Solid ellipses were calculated at
the 95% confidence interval for sources.

Dashed ellipses were estimated at the

95% confidence level.

Figure 7.5. Bivariate plot of the
elements Sc and Eu measured by NAA
on obsidian artifacts described in this
study. Solid ellipses were calculated at
the 95% confidence interval for sources.

Dashed ellipses were estimated at the

95% confidence level.

Figure 7.6. Bivariate plot of the
elements Rb and Sr measured by XRF
on obsidian artifacts described in this
study. Solid ellipses were calculated at
the 95% confidence interval for sources.

92 | OBSIDIAN AND GLASS PROVENANCE

Table 7.1 For the site of Tiwanaku, proportions of samples attributed to different sources using different analytical techniques

Ceremonial Areas

Elite and elite-related areas

Non-elite areas

Totals

Sources

Akapana

Mollo Kontu

Putuni

Akapana

Akapana E2,

Pyramid

East

Chiji Jawira,

Marca Pata,

and K’karaña

Chivay

24

40

29

11

23

126

Quispisisa

0

2

0

2

0

4

Zapaleri

0

1

1

0

0

2

Sora Sora

0

1

0

1

1

3

Charaña

0

1

0

0

1

3

Sopocachi

0

0

0

0

1

1

Unknown-1

0

0

0

0

3

3

Unknown-2

0

0

0

0

1

1

Unknown-3

0

0

0

0

0

0

Unknown-4

0

3

0

0

0

3

Unknown-5

0

0

0

0

0

0

Unknown-6

0

0

0

1

0

1

TOTAL

24

48

30

15

30

147

Table 7.2 Provenance of obsidian artifacts from sites external to Tiwanaku

Khonkho Chiripa

Guaqui

Iwawi

Kallamarka Lukumarta Obsidiana Charazani

Wankane

Chivay

6

3

1

1

2

3

3

1

Quispisisa 0 0 0 0 0 1 0 0

Zapaleri 0 0 0 0 0 0 0 0

Sora

Sora 0 0 0 0 0 0 0 0

Charaña 9 0 0 0 0 0 0 0

Sopocachi 1 0 0 0 0 0 0 0

Unknown-1

1 0 0 0 0 0 0 0

Unknown-2

0 0 0 0 0 0 0 0

Unknown-3

1 0 0 0 0 0 0 0

Unknown-4

0 0 0 0 0 0 0 0

Unknown-5

0 0 0 0 0 1 0 0

Unknown-6

0 0 0 0 0 0 0 0

TOTAL

18

3

1

1

2

5

3

1

New Perspectives on Obsidian Procurement and Exchange | 93

Quispisisa is found at archaeological sites through-
located inside the first moat surrounding the civic-
out that country. The distance from Quispisisa to
ceremonial center. The Akapana East 2 sector is

Tiwa naku, Bolivia, is about 800 km, serving as a clear located in between the first and second moats. Marca
indication of long-distance exchange.

Pata is located between the second and third moats,

Three of the Tiwanaku artifacts are chemi-
and Chiji Jawira and K’karaña are located outside of
cally similar to source samples analyzed from the
the third moat (Chiji Jawira to the east and K’karaña

Sora Sora quarry located about 200 km south of
to the north). To the south, it is uncertain whether

Tiwanaku. Two other artifacts were found to agree

Mollo Kontu was located outside the moat system.

with the composition of the Zapaleri source located

Status can be defined based on the architecture and
about 700 km south of Tiwanaku, along the inter-
the goods associated with the different sectors. The
national border where Bolivia, Argentina, and Chile
only elite area is Putuni. The ceremonial areas are
intersect. Twelve artifacts were found to match a

Akapana Pyramid and Mollo Kontu Mound, and
source named Char aña, recently discovered in the
the elite-related area is Akapana East 1. The non-elite upper section of the Mauri River, close to the Chilean areas are Akapana East 2, Marca Pata, Chiji Jawira,
border, some 100 km southwest of Tiwanaku. And
and K’karaña.

one artifact agrees chemically with a second newly

According to the INAA and XRF data presented
discovered source name Sopocachi, located about
here (table 7.1), we observe the following for the cer-100 km south of Tiwanaku.

emonial, elite/elite related, and non-elite areas:

The remaining 11 artifacts were grouped into
six different chemical types. None of these chemi-

1. 86% of all obsidian used at Tiwanaku came
cal types was found to be chemically similar to any
from Chivay, and the remaining 14% came
of the unassigned samples reported by Burger and
from nine other sources.

Asaro (1977). We labeled the six unknown source

2. All areas within Tiwanaku (except for Marca
groups as Unknown-1 through Unknown-6. The

Pata) have Chivay obsidian.

group identified as Unknown-1 is represented by

3. The ceremonial center, Akapana Pyramid,

4 artifacts, 3 of which were discovered in the non-
has only Chivay obsidian.

elite areas at Tiwanaku and 1 of which was found

4. Outside of Tiwanaku all sites, except for
at the site of Khonkho Wankane. The group iden-

Lukurmata and Khonkho Wankane, have
tified as Unknown-4 contains three specimens that

Chivay obsidian only.

were found in the ceremonial area at Mollo Kontu.

5. When we compare the two mounds, Akapana

The remaining four groups of unassigned artifacts

Pyramid has only Chivay obsidian, while
contain 1 specimen for each of four different sites as Mollo Kontu has the largest number of obsid-summarized in tables 7.1 and 7.2.

ian types in Tiwanaku. Mollo Kontu was a

This study shows that Tiwanaku inhabitants
local shrine, while access to the summit of
obtained obsidian from a large number of sources

Akapana was limited to the religious elite.

ranging in a wide area from central Peru (Quispisisa)

6. In Tiwanaku all areas except for K’karaña
to southern Bolivia (Zapaleri). In most cases the
and Marca Pata, have two-thirds or more
sources are located outside of the Tiwanaku terri-

Chivay obsidian.

tory, suggesting exchange between Tiwanaku and

7. In the valley region surrounding Tiwanaku
other polities, including the Wari state.

we observe in the data (table 7.2) that

Obsidian from Tiwanaku comes from eight sec-

Khonkho Wankane and Lukurmata have
tors identified in figure 7.2. We grouped these sectors higher percentages of non-Chivay obsidian
according to location and status for presentation in
than Tiwanaku.

table 7.1. Location is defined based on the presence

8. Of the six unknown sources, Unknowns #1
of three moats that surround the civic-ceremonial
and #4 are the most common. Unknown #1
center. The elite sector consisting of the Putuni, the is found in Tiwanaku and at Khonkho

Akapana Pyramid, and the Akapana East sectors are

Wankane; Unknown #4 is found only in

94 | OBSIDIAN AND GLASS PROVENANCE

Tiwanaku. Unknown #1 matches one artifact
sites of the region, but that it was more available to from Jiskairumoko, a Late Archaic–Early
inhabitants of the largest settlements than to those

Formative site located 100 km to the north-
in rural areas (Giesso 2000, 2003b). Our data sug-
west (Craig et al. 2007).

gest that elites controlled the flow obsidian from the 9. Only inhabitants from the largest centers,

Chivay source into their territory. At the same time,
those who lived in Tiwanaku, Khonkho
local groups, particularly at the large centers with

Wankane, and Lukurmata, utilized non-
ceremonial precincts (Tiwanaku, Lukurmata, and

Chivay obsidian.

Khonkho Wankane), obtained obsidian from other
sources, most of them located south of Tiwanaku

When comparing the use of Bolivian and Peru-
and in areas inhabited by other groups. For exam-
vian obsidian by the Tiwanaku people, we observe
ple, we know from bioanthropological research that
that in Late Formative times Bolivian obsidian was

Tiwanaku populations were not present in the San
more commonly used than in later periods (Tiwan-

Pedro de Atacama oasis (Knudson 2007).

aku IV and V), indicating that connections with new

The Chivay source was one of the most impor-
groups to the north became stronger after the emer-
tant obsidian sources in southern Peru. People
gence of the Tiwanaku state around AD 500. The
began exploiting it in the Middle Preceramic, around

Bolivian sources (Charaña, Sopocachi, Sora Sora, and

4200 BC in areas close to the Colca valley. Findings at Zapaleri) are not present on sites in the central

Ch’uxuqullu, a site with Late Preceramic occupations
and northern Titicaca basin, in both pre-Tiwanaku
in the Island of the Sun, indicate that Chivay obsidian and Tiwanaku times, suggesting that they were exclu-was used in the Titicaca basin from at least 1800 BC
sively used by Khonkho Wankane, and Tiwanaku

(Stanish et al. 2002). The Formative urban center of
heartland exchange networks. Two of the Bolivian

Pukara, and other sites contemporaneous to the earli-
sources (Charaña and Sopocachi) are located along
est phases of Tiwanaku, such as Chiripa, also imported trade routes linking the Titicaca basin with Arica, and Chivay obsidian, indicating a long-term relationship

Zapaleri is along the route to San Pedro de Atacama.

with the inhabitants of the upper Colca valley.

Both regions have had a long history of circulation of The new information showing the presence of
goods with the Titicaca basin. There is no evidence of Bolivian obsidian in the southern Titicaca basin sug-Tiwanaku settlements in or around any of the known
gests that local networks were established throughout
obsidian quarries, suggesting indirect mechanisms of
the altiplano during Late Formative times and contin-
procurement through local groups or polities. At the
ued into the Tiwanaku period. The earliest evidence
site of Tiwanaku there is a contraposition between
of Bolivian obsidian in the southern Titicaca basin
the major source in southern Peru and the smaller
sites comes from the Late Formative occupations of
sources in central and southern Bolivia. This suggests Khonkho Wankane (AD 200–500). With the urban
that local groups (elite-related, non-elite, and the
expansion of Tiwanaku after AD 500, these types of

Mollo Kontu mound area) obtained obsidian through
obsidian begin to appear in most sectors of the city
local networks with other regions.

(elite: Putuni; elite-related: Akapana East; ceremo-
nial: Mollo Kontu mound; non-elite: Akapana East 2,

5. Conclusions

Marca Pata, K’karaña). Thus we propose that these
goods circulated by means of long-distance exchange

Obsidian was utilized from the beginning of the
with other polities or communities, and that Tiwanaku

Early Formative (1500–700 BC) and continued until
elites did not establish colonies or exploitation centers the historic period. There is no evidence of pre-at or near the obsidian quarries.

Formative use of obsidian in the Titicaca basin, but
this might reflect the small sample (only in Island

Acknowledgments
of the Sun). Obsidian was an important raw mate-
rial for the Tiwanaku people. Micro- and macro-

The authors wish to acknowledge support for this
debitage suggest that obsidian was present in most
project received from a series of laboratory-support

New Perspectives on Obsidian Procurement and Exchange | 95
grants (nos. 9102016, 9503035, 9802366, 0102325, and
southern Peru. Journal of Archaeological Science 34, 0504015) from the National Science Foundation. We

2012–2024.

also thank the Dirección Nacional de Arqueología de

Francaviglia, V., 1988. Ancient obsidian sources on Pan-Bolivia for allowing us to analyze the obsidians in the telleria (Italy). Journal of Archaeological Science 15, USA, to the Jach’a Machaqa project, and to Vanessa

109–122.

Jimenez and Alejandra Martinez for providing sam-

Giesso, M., 2000. Stone Tool Production in the Tiwanaku ples from the Charaña and Sopocachi sources.

Heartland: The Impact of State Emergence and Ex -
pan sion on Local Households. Ph.D. dissertation,

References

Department of Anthropology, University of Chicago.

Giesso, M., 2003a. Stone tool production in the Tiwanaku Bird, J.R., Russell, L.H., Scott, M.D., Ambrose, W.R., heartland. In: Kolata, A.L. (Ed.), Tiwanaku and Its 1978. Obsidian characterization with elemental anal-Hin terland: Archaeological and Paleoecological Inves
ysis by proton induced gamma-ray emission. Analtigations in the Lake Titicaca Basin of Bolivia. Vol. 2.

ytical Chemistry 50, 2082–2084.

Smithsonian Series in Archaeological Inquiry. Smith-

Brooks, S., Glascock, M.D., Giesso, M., 1997. Source of sonian Institution, Washington, D.C., pp. 363–383.

volcanic glass for ancient Andean tools. Nature 386, Giesso, M., 2003b. Las industrias líticas expeditivas en 449–450.

sitios urbanos Tiwanaku. Section of Anthropology

Browman, D.L., 1978. Toward the development of the
and Archaeology, Universidad Mayor de San Andrés,

Tiahuanaco (Tiwanaku) state. In: Browman, D. (Ed.),

La Paz, Bolivia. Textos Antropológicos 14 (2), 31–46.

Advances in Andean Archaeology. Mouton, The Hague, Glascock, M.D., Braswell, G.E., Cobean, R.H., 1998. A
pp. 327–349.

systematic approach to obsidian source characteriza-

Burger, R.L., Asaro, F., 1977. Trace element analysis of tion. In: Shackley, M.S. (Ed.), Archaeological Obsid ian obsidian artifacts from the Andes: New perspectives

Studies. Advances in Archaeological and Museum on pre-Hispanic economic interaction in Peru and

Science 3. Plenum Press, New York, pp. 15–65.

Bolivia. Laboratory Report-6343. Lawrence Berkeley

Glascock, M.D., Speakman, R.J., Burger, R.L., 2007.

Laboratory, Berkeley, CA.

Sources of archaeological obsidian in Peru: Descrip-

Burger, R.L., Asaro, F., Salas, G., Stross, F.H., 1998a. The tions and geochemistry. In: Glascock, M.D., Speak-Chivay obsidian source and the geological origins of
man, R.J., Popelka-Filcoff, R.S. (Eds.), Archa eological Titicaca Basin type obsidian artifacts. Andean Past Chemistry. Analytical Techniques and Archae olog i cal 5, 203–223.

Interpretation. ACS Symposium Series 968. Amer ican Burger, R.L., Asaro, F., Trawick, P., Stross, F., 1998b.

Chemical Society, Washington, D.C., pp. 522–552.

The Alca obsidian source: The origin of raw material

Hughes, R.E., 1984. Obsidian sourcing studies in the Great for Cuzco type obsidian artifacts. Andean Past 5, Basin: Problems and prospects. In: Hughes, R.E. (Ed.), 185–202.

Obsidian Studies in the Great Basin. Con tri butions of Burger, R.L., Chavez, K.M., Chavez, S., 2000. Through
the glass darkly: Prehispanic obsidian procure-
the University of California Archa eological Research ment and exchange in southern Peru and northern

Facility 45, 1–19.

Bolivia. Journal of World Prehistory 14, 267–362.

Kolata, A.L., 1993. The Tiwanaku: Portrait of an Andean Burger, R.L., Glascock, M.D., 2000. Locating the Quis pi-Civilization. Basil Blackwell, Oxford, UK.

sisa obsidian source in the Department of Aya cucho,

Knudson, K.J., 2007. The influence of Tiwanaku en San

Peru. Latin American Antiquity 11, 258–269.

Pedro de Atacama: An investigation using strontium

Cobean, R.H., Vogt, J.R., Glascock, M.D., Stocker, T.L., isotope analysis. Estudios Atacameños 33, 7–24.

1991. High-precision trace-element characterization

Seelenfreund, A., Rees, C., Bird, R., Bailey, G., Barcena, of major Mesoamerican obsidian sources and further

R., Duran, V., 1996. Trace-element analysis of obsid-
analyses of artifacts from San Lorenzo Tenochtitlan,
ian sources and artifacts of central Chile (Maule River Mexico. Latin American Antiquity 2, 69–91.

Basin) and western Argentina (Colorado River). Latin Craig, N., Speakman, R.J., Popelka-Filcoff, R.S.,

American Antiquity 7, 7–20.

Glascock, M.D., Robertson, J.D., Shackley, M.S.,

Shackley, M.S., 2005. Obsidian. Geology and Archaeology Aldenderfer, M.S., 2007. Comparison of XRF and
in the North American Southwest. University of Ari-PXRF for analysis of archaeological obsidian from
zona Press, Tucson.

96 | OBSIDIAN AND GLASS PROVENANCE

Stanish, C., Burger, R.L., Cipolla, L.M., Glascock, M.D., Tripcevich, N., 2007. Quarries, Caravans, and Routes

Quelima, E., 2002. Evidence for early long-distance
to Complexity: Prehispanic Obsidian in the South-
exchange and watercraft use from the southern Lake

Central Andes. Ph.D. dissertation, Department of

Titicaca basin of Bolivia and Peru. Latin American Anthro pology, University of California, Santa Barbara.

Antiquity 13, 444–454.

Yacobaccio, H.D., Escola, P.S., Lazzari, M., Pereyra, F.X., Stross, F.H., Sheets, P., Asaro, F., Michel, H.V., 1983.

2002. Long-distance obsidian traffic in northwest-

Pre cise characterization of Guatemalan obsidian
ern Argentina. In: Glascock, M.D. (Ed.), Geochemi
sources, and source determination of artifacts from
cal Evi dence for LongDistance Exchange. Bergin and Quir igua. American Antiquity 48, 323–346.

Garvey, Westport, CT, pp. 167–203.

Chapter 8

Volcanic Glass Procurement and Use in the Late

Paleolithic, Central Primorye, Far East Russia

Trudy Doelman, Robin Torrence, Vladimir Popov,

Nikolai Kluyev, and Igor Sleptsov

Abstract

Late Paleolithic in northeast Asia (e.g., Kobayashi

1970; Bleed 1996, 2002; Goebel 2002; Hong and

Microblade technologies played an important role

Kononenko 2005; Lee 2006; Pantukhina 2007;
in supporting mobile foragers during the Late

Doelman 2008). A number of scholars have argued

Paleolithic in northeast Asia. The use of insets into
convincingly that microblade industries were wide-
larger tools made from bone, antler, or wood pro-
spread because they provided an effective technologi-
vided the lethal, durable, and easily maintained
cal strategy for reducing the high risks resulting from equipment required for capturing large, mobile ania dependence on large, mobile, seasonal game, a situ-
mals. In these settings the failure to obtain sufficient ation exacerbated by the long, harsh winters charac-resources within the time frames set by a highly sea-
teristic of this region (e.g., Kuhn and Elston 2002:2; sonal environment had deleterious consequences.

Bleed 2002; Elston and Brantingham 2002:112).

Tactics for raw material procurement and use there-

Microblade technology has a number of impor-
fore had to be selected to help reduce these risks. To tant properties that assist in the effective exploitation understand the potential roles of raw material choice
of large animals. First, the use of small stone blades in northeast Asian microblade industries, we inves-inset into very strong and durable hafts of wood,
tigate the strategies used within the central Primorye bone, or antler creates a highly lethal tool with sharp region of the Russian Far East to obtain and utilize
edges that cause serious damage and increase blood
volcanic glass from both local and distant sources.

loss (Elston and Brantingham 2002:104). This tool

Using a combination of geochemical analyses, geo-
type therefore helps reduce the risks of failing to
archaeological studies of volcanic glass sources, and
acquire resources during the limited time when they
analyses of stone-tool technology, we investigate
are available (Torrence 1989). Second, composite tools how specialized stone-working techniques applied
optimize performance as they combine the properties
to different kinds of sources provided the flexibility of both reliability and maintainability (Bleed 1986;
required for minimizing the risks that would have

Myers 1989). Microblade technology functions effec-
been encountered by small populations living within
tively over a long time period and, in addition, if one challenging northeast Asian environments.

inset fails, the others are still operational (reliable).

When time can be allocated for repair, the standard-

1. Microblade industries and
ized insets are easy to replace (maintainable). These
volcanic glass
dual strategies reduce the time and energy required
for tool production, allowing more time for hunting,

Stone-tool assemblages dominated by the produc-
particularly during the critical periods when game
tion of microblades derived from several highly spe-
is available. Third, the typical microblade core yields cialized core morphologies are characteristic of the
multiple blades with a longer total cutting edge per

97

98 | OBSIDIAN AND GLASS PROVENANCE
unit of raw material than the cutting edge of bifaces
reduce the costs of retooling. Our project combines

(Elston and Brantingham 2002:107). The production
multiple approaches to investigate how the creative
of many insets at one sitting is also helpful as these and flexible procurement and uses of volcanic glass
spare parts are standardized in size and easily stored contributed to the variable requirements of foragers
and/or transported. The result is not only a long-
to minimize the risk of failure to acquire supplies of lasting tool, but a user well prepared for the worst-food. These approaches include a geoarchaeological
case scenario (i.e., when it fails).

analysis of volcanic glass sources, geochemical char-

The advantages provided by microblades are
acterization of sources and artifacts, and a techno-
impressive, but do not come cheaply. The manu-
logical study of archaeological assemblages.

facture of microblades demands relatively long and
complex reduction sequences that require consider-

2. Study area
able amounts of raw material, time, and skills only
acquired after much practice and perhaps training.

The study area is situated in the Basaltic Plateau,

To compensate for these high costs, it seems likely
which formed as part of the Amuro-Ussury rift sys-
that people scheduled special times in the year
tem during the Late Tertiary (Neogene). It is sub-
to manufacture and repair their composite tools
divided by the Razdolnaya River into the Shkotovo

(Torrence 1989; Bleed 2002).

(east) and Shufan (west) plateaus (figure 8.1). Basaltic A notable feature of Late Paleolithic northeast
glass outcrops are found in both regions, but geo-

Asian microblade assemblages is the widespread use
archaeological survey has determined that only the
of volcanic glass (Dikov 1996; Hong and Kononenko
sources in the Shkotovo Plateau were appropriate for

2005; Pantukhina 2007; Bleed 2002; Izuho and Sato
stone-tool production (Doelman et al. 2008). The

2007). Although volcanic glass sources are sprin-

Shkotovo Plateau, covering an area of roughly 4550
kled across the region, the spatial extent of each
km2, reaches approximately 900 m above sea level at
one is relatively small even when supplemented by
its peak and then stretches as a single, relatively narthe wider distribution of secondary sources (e.g.,
row series of lava flows south from the central part

Kuzmin et al. 2002a, 2002b; Doelman et al. 2004,
of Primorye to the coast (figure 8.1). Systematic sur-

2008; Glascock et al. 2006; Izuho and Sato 2007;
veys along the Ilistaya, Poperechnaya, and Arsen-

Kim et al. 2007). It therefore seems likely that people i evka rivers and feeder streams and sea cliffs at
made the extra effort to preferentially select volca-

Obri visti on the coast located, described, and sam-
nic glass over other types of raw materials and that
pled the sources for geochemical analysis (Doelman
this valued resource may have been exchanged (e.g.,
et al. 2004, 2008) (figure 8.1 and figure 8.2).

Kuzmin et al. 2002a, 2002b). The popularity of vol-

Previous research on late and terminal Pleis to-
canic glass is first due to its extremely thin, sharp
cene sites by researchers from the Far Eastern Uni-
edges that make excellent lethal insets for compos-
versity and the Institute of History, Archaeology
ite weapons. Second, the fine-grained, homogenous
and Ethnography of the Peoples of the Far East in
character of volcanic glass creates excellent fractur-

Vladivostok within central Primorye indicated wide-
ing properties that reduce the costs involved in the
spread use of volcanic glass for microblade produc-
predictable, systematic production of the highly spe-
tion (see summaries in Kuzmin et al. 2002b; Kluyev
cialized microblade cores favored in northeast Asia.

and Sleptsov 2007; Pantukhina 2006a, 2006b, 2007).

To investigate the role of volcanic glass within

Following initial test pitting on a range of sites in the Late Paleolithic microblade assemblages, we exam-Tigrovy valley of the Ilistaya River, chosen because
ine source selection, procurement of raw mate-
it has the largest concentration of useable sources
rial, and preparation of microblades cores within
of volcanic glass, our recent research has focused on
the central region of Primorye in Far East Russia.

the systematic excavation of a quarry site and tech-

A comparison of how raw material was obtained
nological analysis of the assemblage. This field study from local and distant sources highlights the flex-has been supplemented with a geochemical analysis
ible strategies adopted by Late Paleolithic foragers to and the study of volcanic glass assemblages from a

Volcanic Glass Procurement and Use | 99

Figure 8.1. Location of the surveyed primary and secondary sources in the Shkotovo Plateau.

Figure 8.2. Location of the sites
in the study area showing the
zones of secondary volcanic
glass distribution in waterways
of the Shkotovo Plateau.

100 | OBSIDIAN AND GLASS PROVENANCE
further 25 previously excavated sites located in the

3.1 Primary Sources
neighboring region (table 8.1; figure 8.1). Artifacts

The basaltic glass was formed by a hyaloclastic
from these sites that were geochemically identified
process that involved the rapid cooling of lava on
were also technologically analyzed in order to pro-
contact with water or ice (figure 8.3). The glass was
vide detailed information on the movement of arti-
formed (1) around the rinds of pillow lavas, but also
facts. Due to the shallow stratigraphy of these open
rarely within the core of the pillows; (2) as fractured sites and the absence of well-preserved hearths, it has blocks of varying sizes resulting from an explosive
not been possible to obtain reliable radiocarbon chro-
contact with water; and surprisingly and again rarely
nologies. Based on the predominance of microblade

(3) in thin tongues of lava (figure 8.3). Volcanic glass technologies and their presence in other dated sites in derived from the pillow rinds are generally tabular in the region, the assemblages in our study belong to the shape (a slab form) and often have a pitted cortex on

Late Paleolithic period, which in central Primorye is
the exterior surface known as contact cortex (figure
only associated with two radiocarbon dates approxi-

8.4). A rough cortex, formed within fractures in the
mately 8000–13,000 BP (Pantukhina 2007:145).

lava, is also present (figure 8.5). Both these types of cortex are defined as primary. The fractured blocks

3. Assessment of local basaltic
occur in a greater range of sizes and angular shapes
glass sources
and also have a pitted, irregular “contact” cortex.

Fragments also break along cracks (internal flaws)

Late Paleolithic foragers visiting the Shkotovo Pla-
that were created during formation. This process is
teau had access to volcanic glass from both primary
exacerbated by extremes in summer (+30 ºC) and
outcrops (in situ exposures) and secondary deposits
winter temperatures (-30 ºC) and by the subsequent

(reworked, water-rolled cobbles in active and ancient
expansion of water during freezing in rock frac-
waterways). To understand why people chose par-
tures, which further fragments the volcanic glass.

ticular sources of raw material, we conducted a geo-

The color of the glass ranges from black through to
archaeological assessment of the sources in terms of
gray along with various shades of blue and opaci-
their accessibility and potential qualities for micro-
ties. Spherulites are uncommon. The basaltic glass
blade production.

has very good fracturing properties, with the black
material more brittle than the blue and gray vari-
eties, attributes that might have been exploited in
the past. The highest quality material available at

Table 8.1

Counts of artifacts from sites in the study
area that were geochemically and techno-
the outcrops is found in the rare central cores of the logically analyzed
pillow lava (figure 8.3). These cores can range up to

15–20 cm in diameter, lacking the internal flaws

Gorbatka-1

2

Tigrovy-6 44
commonly found in the tabular rinds or blocky frag-

Shekliaevo-6

136

Ivanovka-2 1
ments and having a low number of spherulites.

Gorbatka-2

31

Tigrovy-7 68

Individual exposures, situated within cliffs above

Tigrovy-1

6

Ivanovka-3 36
the streambeds or higher in the valley walls, are small Gorbatka-3

40

Tigrovy-8 40
in extent but are reasonably common. Some of the

Tigrovy-2

286

Kornilovaka-2 16
very steep, high cliffs were dangerous to quarry, but

Gorbatka-4

3

Timofeeka-6 2
many others provided easy access. Although acces-

Tigrovy-3

13

Molodeznaya-1 668
sibility was different during the late Pleistocene

Gorbatka-5

16

Ustinovka-3 1
because of changes in stream courses and the extent
of colluvial deposits, the modern situation is prob-

Tigrovy-4

3

Novovarvarovka 186
ably an accurate analogue for the types of situations

Ilistaya-1

6

Ustinovka-6 2
and frequency of outcrops. Table 8.2 provides a sum-

Tigrovy-5

140

Risovaya-1 107
mary of the basaltic glass outcrops sampled in the

Ivanovka-1

10

Total 1863

Shkotovo Plateau.

Volcanic Glass Procurement and Use | 101

Figure 8.3. A. Example of hyaloclastic formation profile in the Shkotovo Plateau about 4 m in height. B. Core of volcanic glass in pillow formation that is 30 cm long. C. Tongue of volcanic glass. D. Blocky fragments of volcanic glass. E. Rinds of volcanic glass.

3.2 Secondary Sources
upper reaches of the Tigrovy valley, but due to the
internal flaws these quickly break down. Cobbles

Secondary sources are derived from the volcanic
formed from the central cores of the pillow lava tend
glass outcrops: cobbles rounded to varying degrees
to be transported farther but will still reduce in size within stream and river courses (figure 8.4). In
with time and distance (figure 8.4). It is these cob-
contrast to the small, discrete primary exposures,
bles that were preferentially selected for microblade
secondary sources in waterways are more widely
core manufacture.

distributed, especially in the Ilystaya region and

As shown in table 8.3, our survey of the distribu-
the Arsenievka River valley, and therefore provide a
tion and characteristics of the volcanic glass available larger and more immediately available supply of raw
in the major rivers that drain the Shkotovo Plateau
material than the outcrops that require some form of
demonstrated a rapid decrease in the availability and
quarrying. Secondary sources vary widely in terms
size of the cobbles as the distance increases from the of the angularity and size of the cobbles depending
outcrops (Doelman et al. 2004). In addition, the ease
on the nature and length of time of their immersion
of finding useable raw material within a streambed
in a watercourse. Through time, cobbles become
varies greatly. Accessibility to volcanic glass nod-
rounded and develop a distinctive, smoothed cor-
ules in and along waterways is limited by seasonal
tex (figure 8.4). This type of cortex has been defined variations in visibility. For example, many of the
as secondary cortex. Tabular rinds and blocky frag-
small streams dry up during the summer, so that the
ments are common in the waterways found in the
cobbles become covered with mud and are difficult

102 | OBSIDIAN AND GLASS PROVENANCE

Spherulites
low
absent
absent
absent
absent
absent
absent
absent
absent
absent
bsent
bsent
bsent
bsent
bsent

Low

Low

Low

A

A

A

A

A
e rey,
lu g
e
rey
lu
rey
rey
rey
rey,
ark
rey, e
rey,

Color
e-g

e-g
e-g
e-g
e g
black, e-g blu
black
black
black
black
black
black
black
black
black
black
lu black
black, b
blu
dark b
blu
blu
blu
blu
dark g
lack, d
b
b

Mean size

0

0

0

0

0

0

0

0

0

0

0

0

0
mm

5-1

5-1

5-1

5-1

5-1

5-1

0-5

0-5

0-1

0-5

5-1

0-5

10-2

0-1

0-1

0-5

5-1

5-1

Maximum

lateau
size cm

15

15

7

20

12

15

10

30

15

8

2

10

25

10

10

5

15

15

kotovo P

Extraction

ange
he Sh
oderate
easy- oderate
hard
hard
oderate
oderate
hard
easy
hard
hard
oderate
hard
easy
easy- oderate
easy- oderate
oderate- hard
oderate
m
m
m
m
m
m
m
ide r
m
m
w
n t

ssessed i

Material

quality
poor- good
poor
edium
good
edium
edium
good
edium
poor
edium
good
good
good
good
edium- good
edium
edium- good
m
m
m
m
m
m
m
m
rces a

r
r

lass sou

Fracture
good
good
hackly
poor
good
good, poo
poor, hackly
good
good
good, poo
good
good
good
good
good
good
good
good

Topography

olcanic g
cliff
cliff
cliff
cliff
slope
cliff
cliff
cliff
cliff
cliff
cliff
cliff
cliff
cliff
cliff
cliff
cliff
cliff
hill
ary v

Outcrop

5

m

18

6
ri
extent m2

100

75

120

150

50

60

50

80

50

20

125

125

50

50

120

he p

f t
tream
team
team
team
n o
tream
tream
tream
tream
tream
tream
listaya
listaya,

Location
oi s
listaya, oi stream
listaya
listaya
listaya
listaya
listaya
ptio
yam
hoi s
hoi s
hoi s
hoi s
hoi s
hoi s
ri

Right I

Right I Pr

Right I Pryam

Suk

Tigrovy

Suk

Suk

Suk

Suk

Suk

Ivanovski s

Ivanovski s

Ivanovski s

Right I

Right I

Right I

Right I

Right I
esc D

Outcrop

Name

Ilystaya 1

Ilystaya 2

Ilystaya 2

Ilystaya 4

Ilystaya 3

Ilystaya 4

Ilystaya 4

Ilystaya 4

Ilystaya 4

Ilystaya 4

Ilystaya 4

Ilystaya 4

Ilystaya 4

Ilystaya 5

Ilystaya 5

Ilystaya 6

Ilystaya 6

Ilystaya 6

Table 8.2

Volcanic Glass Procurement and Use | 103

-

Low
edium
low edium
bsent
bsent
bsent
bsent
bsent

M
m

A

A

A

A

A
e
rey
lu
rey, k
rey, k
rey,
e-g

black
black
black
e-g blac
e-g blac
grey, e-g black
blu
black, b
blu
blu
blu

0

0

0

0

0

0

0

0

0-1

5-1

10-2

10-2

5-1

5-1

5-1

1-1

10

15

20

20

10

10

20

10

oderate
oderate
easy
oderate
hard
hard
hard
hard
m
m
m

edium

poor
edium
good
edium
poor
edium
poor
m
m
m
poor-m

poor
poor
good
poor
poor
poor
poor
poor

liff
cliff
cliff
cliff
cliff
cliff
cliff
cliff
sea c

Figure 8.4. Types of cortex found on the primary and 30
secondary sources in the study area. A. Blocky frag-

120

50

15

10

35

300

50
ment of volcanic glass found in the secondary sources
near the outcrops. B. Central cores of volcanic glass from a pillow lava. C. Contact cortex found on rinds
aya
aya
aya
ape
tream
tream
in
from primary sources. D. Highly water-rolled cobbles
listaya
of volcanic glass found 15 km downstream of primary
tkin S
tkin s
r
r
brivisti C
volcanic glass sources. Scale bars are 1 cm in length.

Right I

Na

Na

Konopelk

Poperechn River

Poperechn Rive

Poperechn Rive

O
aya
aya
aya

Table 8.3

Decrease in mean size of nodules
am

r
r
within secondary deposits with increasing
rsenievka
rsenievka
rsenievka
brivisti

Ilystaya 6

A

A

A stre

Poperechn River

Poperechn Rive

Poperechn Rive

O
distance from outcrops

Distance from

Size of nodule (cm)

Primary Source

Near outcrop

15-20

20km

5-8

>35km

2-4

104 | OBSIDIAN AND GLASS PROVENANCE
to distinguish from other types of stone. Equally, in
from 6 m2 excavated in 2006. Although cores were
winter, ice and snow obscure access to the cobble
discarded at varying stages of reduction, a high fre-
beds along the waterways.

quency of the intensively prepared cores (with >10
flake scars) were broken or represent unfinished

4. Flexibility in source use
microblade core preforms with the typical wedge-
shaped profile (n = 15, 18.5%). However, a number of

Foragers developed highly flexible strategies for using the wedge-shaped preforms had fewer than 5 flakes
the wide range of primary and secondary basaltic glass removed (n = 11), showing that knappers took advan-sources to produce microblades. Yubetsu, Horoko,
tage of the natural form of the available material to
and Togeshita microblade cores made from volcanic
fashion the wedge-shaped profile.

glass have been found at many Late Paleolithic sites

The formation of the basaltic glass influenced
in the study area (e.g., Pantuk hina 2006a, 2006b,
how it was reduced. The degree and direction of flak-

2007). The ability to be highly innovative and flexible ing was dictated by the shape and thickness of the
in microblade core preparation was an effective strat-
naturally fractured pieces and the amount and loca-
egy for reducing the risk of not having the required
tion of the cortex. Slabs (from rinds), blocks (angular tool at the right time (Doelman 2008). Each source
fragments), and flakes were all used to manufacture
had a unique set of challenges that needed to be over-
microblade cores (figure 8.5). The amount of work-
come during core preparation. The reduction of the
ing and direction was dictated by the original length, material is also related to distance from the primary
width, and thickness of the core body and the posi-
outcrops since the proportion of artifacts with cortex tion and amount of cortex. For example, to produce
from primary outcrops decreases markedly between
the wedge-shaped profile on a slab (a tabular rind
the 0–10 km and 10–20 km zones (table 8.4).

fragment) with a thickness of less than 25 mm, the

4.1 Primary Sources
slab was flaked across both cortical margins from one
platform to remove cortex and further thin the core

An example of the flexible methods used to prepare
face and/or bifacially flaked to fashion a keel from the microblade cores from a primary volcanic glass
opposite margin of the slab (figure 8.5).

source is found at Tigrovy-8. This quarry is located

A comparison of the microblade preforms
on a narrow, elevated, terraced ridge about 420 m
having a wedge-shaped profile and those with a
above sea level with a commanding view of the local
square section shows significant differences in the
region. The basaltic glass source at this location is
width ( t = 2.940, df = 190, p = 0.0037) and thickness currently covered by a shallow layer of recent col-

( t = 3.035, df = 190, p = 0.0027), but not in the length luvium but may have been exposed during the Late

( t = 0.3942, df = 190, p = 0.639). These results indi-Paleolithic period. The presence of large, eroded,
cate that the objective of microblade core prepara-
blocky fragments on the hill slope below the outcrop
tion was to produce a particular size (width and
indicates a nearby source. The source may also have
thickness) and profile, but that the length was main-
been exposed by tree falls, as was the case in our initained to maximize the amount of material available
tial survey in 2004.

for microblade manufacture (table 8.5). The micro-

Finished microblade cores, or microblades, are
blade cores also represent a continuum in the degree
rare within the assemblage of 5909 artifacts recovered of reduction shown by the minimum and maximum
values of the length (17.6–66.0 mm), width

(7.2–42.2 mm), and thickness (6.6–32.2 mm),

Table 8.4 Types of cortex (representing different source types) in sites from the different zones
indicating that the microblade cores them-
selves were discarded in varying stages of

0–10 km

20–40 km

40–80 km

count % count % count %
preparation.

Given the widespread availability of sec-

Primary

363 81.2 70 40.7 332 46.1
ondary sources in watercourses, the ques-

Secondary 84 18.8 102 59.3 388 53.9
tion arises as to why people exploited outcrop

Volcanic Glass Procurement and Use | 105

Figure 8.5. Examples of microblade preforms
found at Tigrovy-8. A. A blocky fragment
with rough cortex used to make a micro-
blade preform. B/C. Large flakes used to
make microblade preform. D. Slab with
contact cortex used to make a microblade
preform. Scale bars are 1 cm in length.

Table 8.5 Relationship between cross-section and size of microblade microblade cores was outweighed
core preforms at Tigrovy-8
by the abundance of raw material
at primary outcrop sources. Once

Length (mm)

Width (mm)

Thickness (mm)

Section Count

Mean

SD

Mean

SD

Mean

SD
discovered, Tigrovy-8 would have

Wedge

36

44.9

12.2

25.6

7.9

19.3

6.3
provided a large supply of good-
quality material that was easily

Square

156

45.9

13.9

31.0

9.9

23.6

7.6
accessible in the warmer months.

It is likely that special-purpose
trips were made to this quarry to
sources like Tigrovy-8? Generally the procurement
manufacture the easily transport-
of stone from a quarry reduces the time and labor
able microblade cores that would maintain a supply
costs involved in artifact manufacture. A quarry
of microblades when they were required. The goal
offers a predictable and relatively large supply of
was to prepare microblade cores and not to manu-
high-quality raw material that could be obtained
facture microblades at the quarry. It is likely that this with very little effort. As previously described,
activity was scheduled for another, more suitable
knappers also clearly took advantage of the natu-
time and place, an additional cost-saving strategy.

ral, tabular shape of volcanic glass rinds available

It seems likely that other subsistence activities took at this outcrop for producing microblade cores. In
place in the Tigrovy region, such as late summer/
addition, the high rate of failure expected due to the autumn collection of plants and nuts or hunting
complex and difficult manufacture of the specialized
during these visits to Tigrovy-8 (cf. Binford 1979).

106 | OBSIDIAN AND GLASS PROVENANCE

4.2 Secondary Sources
region. Within northeast Asia volcanic glass arti-

A wide range of core forms manufactured using
facts were quite commonly transported over con-
water-rolled cobbles from secondary sources dem-
siderable distances during the Late Paleolithic
onstrates skill and flexibility on the part of the Late (e.g., Kuzmin et al. 1999, 2002a, 2002b, 2008;

Paleolithic knappers (Doelman 2008). The direc-

Kuz min and Popov 2000; Kim et al. 2007; Izuho
tion and degree of core preparation were manipu-
and Sato 2007). Basaltic glass artifacts from our
lated to suit the size and shape of the original nodule study region were transported into east Primorye

(Doelman 2008). For example, if a cobble was a suit-
and north to the Amur River basin up to 700 km
able width and thickness, only a limited amount of
distant (Popov et al. 2006; Doelman et al. 2008).

preparation was needed to prepare the microblade

Although we have shown that the Shkotovo Pla-
core. Often the rounded form of the cobble was used
teau sources of volcanic glass are abundant and
advantageously to create a “natural” keel of water-
varied enough to have suited many different kinds
rolled cortex, supporting the core during microblade
of demands, previous geochemical studies of arti-
production. The ultimate aim was a microblade core
facts and source samples have demonstrated that
of a desired shape and size, achieved through flex-
rhyolitic volcanic glass (obsidian) from Paektusan
ibility in preparation rather than through following

Volcano, located on the border of North Korea
a prescribed set of procedures.

and China, was imported into the study area as

There are problems associated with the use of
well as into other regions of Far East Russia and
water-rolled cobbles: (a) they frequently contain inter-South Korea (figure 8.1; Kuzmin et al. 1999, 2002b;
nal, hidden fractures due to impacts in the stream-

Kuzmin and Popov 2000; Doelman et al. 2004,
bed, and (b) they are small in size and require consid-2008; Kim et al. 2007).

erable time and effort to find. As already noted, the

Volcanic glass from Paektusan Volcano cannot
collection of water-rolled cobbles was also seasonally be reliably differentiated from basaltic glass derived dependent due to visibility. It is also likely that their from the Shkotovo Plateau solely on the basis of mac-collection was opportunistic in nature due to the rar-
roscopic inspection. Our analysis employed two geo-
ity of finding the cobbles made from the central pil-
chemical techniques to characterize a reasonably large low cores; but when found, multiple flexible strategies sample of the artifacts from sites in the study area.

were used to manufacture the microblade cores.

5. Local vs. distant sources

Table 8.6 Results of the specific gravity tests (g/cm3) Having examined the use of local primary and

Basaltic Glass

Paektusan Volcano

Mean

2.739

2.362
secondary sources, we now turn to a comparison

STD

0.066

0.021
of local and distant volcanic glasses in the study

Table 8.7 Composition of elements found in the PIXE-PIGE samples from outcrops in the Shkotovo Plateau

F

Na

Al

Si

K

Ca

Ti

Mn

Fe

Zn

Rb

Sr

Y

Zr

Nb

Ilistaya River Sources

Mean (ppm)

227.6

25024.8

81218.1

240690.7

4738.4

60436.0

9054.7

1215.5

77808.9

150.1

11.4

332.5

13.7

87.7

0.0

STD

29.8 2892.9 7875.2 28842.6 606.0

9119.0

1240.1 87.4 5787.4 61.6 4.7 27.7

6.6

12.9

0.0

Tigrovy-8

Mean (ppm)

226.2

27283.3

83252.8

281917.6

4861.3

53458.9

8572.5

1315.5

76191.4

354.6

6.3

374.0

21.9

64.6

2.0

(Ilistaya-3

Source) STD

17.3

2276.1

6089.1 30829.7 947.5

10230.4 1435.5 239.1 9435.3 365.6 7.0 151.8 24.7 30.5 3.4

Arsenievka River

Mean (ppm)

214.0

23464.3

72627.0

247673.3

3694.3

46727.0

8162.3

1221.3

71880.0

207.7

5.7

353.7

23.3

66.1

0.0

STD

9.9 726.9 726.2

27051.1

1048.6

3245.6

433.5 21.1

2284.7

60.9

12.2

44.0

5.5

16.8

0.0

Poperechnaya River

Mean (ppm)

199.7

24823.7

80840.0

253663.7

3059.7

50456.3

8546.3

1252.2

73424.3

135.1

6.0

275.4

28.7

68.8

2.4

STD

17.3 1972.2 5088.7 6473.3 92.3

2959.8 197.2 30.5 1502.7 11.7 1.6 16.0 3.8 4.2

4.5

Volcanic Glass Procurement and Use | 107

Figure 8.6. Principal components analysis
of PIXE-PIGE results.

First, differences in specific gravity between the basal-Concentrations of the elements within the
tic (local) and rhyolitic (distant) volcanic glasses, as major sources are presented in table 8.7. Our com-established by previous research, were used to identify bined results of the specific gravity and PIXE-PIGE
the sources of nearly 2000 Late Paleolithic artifacts
characterization studies confirm the previous

(Doelman et al. 2008). Further testing established
identification of artifacts from Paektusan Vol cano
more accurately the range of specific gravity values
within the large assemblages of basaltic glass

found in 32 artifacts from the source area (table 8.6).

(cf. Kuzmin et al. 2002b; Doelman et al. 2004) and

Second, these results were verified and extended
provide the basis for comparing how volcanic glass
by the analysis of 60 geological source samples and
from the local and distant sources were used in the

117 artifacts from Late Paleolithic sites using the non-study area.

destructive PIXE-PIGE technique at the Australian

Nuclear Science and Technology Organisation

(ANSTO), Sydney. For a description of the method,

6. The use of distant and local
see Summerhayes et al. (1998). A plot of the first two volcanic glass sources
principal components from a multivariate analy-
sis of the ratios of Al/Na, Fe/Na, Mn/Fe, K/Fe, and

The importation of volcanic glass into a region al-

Ca/Fe confirms the excellent separation of samples
ready blessed with abundant sources seems coun-
from the Shkotovo Plateau and Paektusan Volcano
terintuitive until one considers raw material use
sources (figure 8.6).

by highly mobile foragers who need to cover large

Table 8.7 Composition of elements found in the PIXE-PIGE samples from outcrops in the Shkotovo Plateau

F

Na

Al

Si

K

Ca

Ti

Mn

Fe

Zn

Rb

Sr

Y

Zr

Nb

Ilistaya River Sources

Mean (ppm)

227.6

25024.8

81218.1

240690.7

4738.4

60436.0

9054.7

1215.5

77808.9

150.1

11.4

332.5

13.7

87.7

0.0

STD

29.8 2892.9 7875.2 28842.6 606.0

9119.0

1240.1 87.4 5787.4 61.6 4.7 27.7

6.6

12.9

0.0

Tigrovy-8

Mean (ppm)

226.2

27283.3

83252.8

281917.6

4861.3

53458.9

8572.5

1315.5

76191.4

354.6

6.3

374.0

21.9

64.6

2.0

(Ilistaya-3

Source) STD

17.3

2276.1

6089.1 30829.7 947.5

10230.4 1435.5 239.1 9435.3 365.6 7.0 151.8 24.7 30.5 3.4

Arsenievka River

Mean (ppm)

214.0

23464.3

72627.0

247673.3

3694.3

46727.0

8162.3

1221.3

71880.0

207.7

5.7

353.7

23.3

66.1

0.0

STD

9.9 726.9 726.2

27051.1

1048.6

3245.6

433.5 21.1

2284.7

60.9

12.2

44.0

5.5

16.8

0.0

Poperechnaya River

Mean (ppm)

199.7

24823.7

80840.0

253663.7

3059.7

50456.3

8546.3

1252.2

73424.3

135.1

6.0

275.4

28.7

68.8

2.4

STD

17.3 1972.2 5088.7 6473.3 92.3

2959.8 197.2 30.5 1502.7 11.7 1.6 16.0 3.8 4.2

4.5

108 | OBSIDIAN AND GLASS PROVENANCE
territories in risky environments. In these situations, As we have seen, reliable and maintainable tools are
people need to exploit game effectively during the
made at specific localities and then transported for
relatively short periods in which hunting is produc-
long periods in order to avoid conflicts between raw
tive. To achieve this, they make tools in advance
material procurement and more important activities
and transport them over long distances if necessary.

such as subsistence. This approach makes the Late

Efforts are also made to curate (i.e., manufacture the Paleolithic hunter-gatherers more effective and effi-tools well in advance of use and then maintain them
cient in managing their stone-tool resources.

as long as possible to maximize the time available for Curation of artifacts is apparent in the use of the
subsistence and other important activities) (Binford
distant volcanic glass from Paektusan Volcano. For

1977). During the time material was curated, the
example, the complete flakes from Paektusan Volcano
users covered enormous distances, described as
are significantly smaller than those from the local

“lifetime territories” by Binford (1983:114–117, 206).

basaltic glass sources (table 8.9; t = 200.16, df = 693, A comparison of the way local and distant vol-p = 0.0017), suggesting that they resulted from late-canic glass was consumed at 25 Late Paleolithic sites
stage core and/or tool rejuvenation (i.e., attempts to (figure 8.1, table 8.1) demonstrates the effects of cura-prolong tool or core use-life). In contrast, retouched tion. Most of these sites are located within 40 km of the tools from Paektusan Volcano were made from larger
primary sources of basaltic glass and less than 5 km
blank forms and were highly curated since the few
from secondary sources. The results from previous
complete retouched artifacts from the distant source
surveys, however, show that the 16 sites situated

(n = 6) are significantly larger than those from the local beyond a 20-km radius of the primary sources were
basaltic glass sources ( t = 3.057, df = 65, p = 0.0032).

unlikely to have had access to useable volcanic glass

The length of cores from local and distant sources
nodules in nearby waterways (Doelman et al. 2004).

does not differ significantly ( t = 0.2620, df = 293, Not surprisingly, a relatively low proportion of the
p = 0.7935). However, the large standard deviation total assemblage is derived from Paektusan Vol cano
of the core weights suggests that basaltic glass cores (8.2%, n = 153), and there is only a very weak relation-were discarded at varying stages during the manufac-
ship between the consumption of raw material and
turing sequence as opposed to those from Paektusan
distance from the local and distant sources (table 8.8).

Volcano, which only represent the final stage of use.

Often the location and intensity of tool manufacture

A comparison of the lengths of the cores, com-
and use among hunter-gatherers depend on where
plete flakes, and complete tools at varying distances
they carry out different activities, which may have
from the primary sources of basaltic glass in the
no direct connection to the location of stone sources.

Ilystaya region shows a significant decline between

Table 8.8 The characteristics of the basaltic glass and rhyolitic glass artifacts obtained from Paektusan Volcano as
distance increases from outcrops of basaltic volcanic glass

0–10 km

20–40 km

40–80 km

Length (mm)

Mean

SD

Mean

SD

Mean

SD

Core

48.4 14.4

30.2

9.4

35.7

9.5

Complete

22.0 10.5

18.9

6.5

18.3

8.8
flake

Complete

31.5 10.6

25.1 5.1

26.5 10.0
retouched artifact

Count %

Count

%

Count

%

Basaltic Glass

597 99.5

240 81.9

720 89.0

Paektusan

3 0.5

53 18.1

89 11.0

Volcano

Volcanic Glass Procurement and Use | 109

Table 8.9 The size and weight of the complete flakes, tools, and cores made from basaltic glass and rhyolitic glass
obtained from Paektusan Volcano

Basaltic Glass

Count

Length (mm)

Weight (g)

Mean

SD

Mean

SD

Complete flake

654

19.5

9.7

2.8

6.0

Complete

61

27.5

9.6

6.7

7.7
retouched artifact

Core

285

36.7

11.8

26.5

32.4

Total

1000

Paektusan Volcano

Complete flake

41

16.1

6.9

0.6

0.7

Complete retouched

6

40.3

11.8

7.2

4.3
artifact

Core

10

35.7

13.5

8.2

7.8

Total

67

zones 0–10 km and 40–80 km in the size of the cores
is also more variable, shown by the standard devia-

( t = 7.321, df = 234, p = <0.0001) and complete flakes ( t tion, and they are significantly thinner ( t = 4.184,

= 4.298, df = 513, p = <0.0001) (table 8.9). Interestingly, df = 693, p = <0.0001) than those from Paektusan the cores in the 40–80 km zone were larger than those

Volcano. These results indicate that complete flakes
in the 20–40 km zone ( t = 3.302, df = 229, p = 0.0011).

made from Paektusan Volcano glass were carefully

This result is due to the fact that hunters in northern manufactured through controlled flaking to pro-latitudes do not move gradually across an environ-
duce elongated flakes, potentially associated with
ment but frequently make single long-distance moves
blade production.

to access resources (cf. Binford 1980). A similar

Curated tools were also transported vast dis-
observation was made by Eerkens et al. (2008), who
tances from Paektusan Volcano. A high frequency of
noted that some sources (and hence some locations)

the artifacts from Paektusan Volcano were retouched
were bypassed in favor of more distant locations. It is (13.1%, n = 20) compared to those made from basal-likely that cores were transported to particular places tic glass (5.9%, n = 102). Most of the retouched flakes where scheduled production of tools took place at
made from Paektusan Volcano glass were broken
convenient times during the year. This pattern is
scrapers (concave, convex, and straight) or bifa-
emphasized by the increased frequency of artifacts
cial points (table 8.11). Bifacial points made from
with primary cortex (contact or rough cortex) in the

Paektusan Volcano glass were more common in the

40–80 km zone (table 8.4). A lack of change in the
assemblages than in those fashioned by the local
size of the complete tools regardless of distance from basaltic glass (table 8.10).

source ( t = 1.813, df = 252, p = 0.00711) is expected Most of the microblades from Paektusan Vol-within the context of a curated technology.

cano were broken into either medial or proximal

A more detailed study of the complete flakes
fragments (table 8.12), suggesting they had been
from the local basaltic glass sources and those from
purposefully snapped to become parts of compos-
the distant Paektusan Volcano shows that nearly half
ite tools and then transported. In contrast, more of
of those from Paektusan Volcano had an elongation
the basaltic glass microblades are complete, which
index (length/width) of 2 or greater (table 8.10),
may indicate that the assemblage includes some
whereas the complete flakes made from basaltic glass
broken during manufacture, others abandoned as
were shorter and wider. The thickness of these flakes
unsuitable, and the loss or discard of utilized and

110 | OBSIDIAN AND GLASS PROVENANCE

Table 8.10

The elongation of complete flakes made from basaltic glass as distance increases from outcrops of basaltic volcanic glass Elongation

Basaltic Glass

Paektusan Volcano

(length/width)

Count

%

Count

%

0.5–1

25

3.6

1

2.4

1–1.5

224

32.2

10

24.4

1.5–2

194

27.9

10

24.4

>2

252

36.3

20

48.8

Dimensions

Mean

STD

Mean

STD

Width (mm)

15.9

8.1

10.9

7.2

Thickness (mm)

4.4

3.5

2.1

1.4

Table 8.11 Types of tools made from basaltic glass as distance increases from the primary sources of basaltic volcanic glass

TOOL TYPE

BASALTIC GLASS

PAEKTUSAN VOLCANO

Count

%

Count

%

Bifacial point

9

8.8

4

20.0

Biface

3

2.9

1

5.0

Scraper

81

79.4

13

65.0

Drill

0

0

1

5.0

Notch/denticulate

3

2.9

0

0

Burin

6

5.9

1

5.0

Total

102

99.9

20

100
unutilized microblades. The microblades from Paek-
components of a successful subsistence strategy. This
tusan Volcano are also considerably smaller than
process is best demonstrated by the nature of the
those made from basaltic glass in terms of their
artifacts obtained from Paektusan Volcano, which
thickness ( t = 5.072, df = 134, p = <0.0001) and width potentially were curated over considerable periods

( t = 1.869, df = 134, p = 0.0638), although the latter of time and therefore moved over long distances. It is may be partially dictated by constraints set by the
important to identify the kinds of artifacts that were design of the haft. These results suggest that careful transported from Paektusan Volcano into Primorye.

and controlled working of the cores from Paektusan

Almost half of those found in the Late Paleolithic sites Volcano ensured that the number of microblades
in Far East Russia were related to microblade manu-
produced from each core was maximized, a situa-
facture (Doelman et al. 2008). In contrast, only 16%
tion that is predictable given the mobile, seasonal
of the basaltic glass artifacts were related to micro-
economy of Late Paleolithic foragers.

blade manufacture. Retouched flakes from Paektusan

The volcanic glass from Paektusan Volcano rep-

Volcano were also transported. Many had been bro-
resents the type of material that one would expect
ken and then discarded. Elongated flaking debris
to find in a highly curated technology in which tool
was produced from reworking the cores or tools.

use-life was prolonged, and in which repair kits,

These results suggest that volcanic glass artifacts from with microblade cores and microblades, were vital

Paektusan Volcano were typically transported as

Volcanic Glass Procurement and Use | 111

Table 8.12

Fragmentation of the tools made from basaltic glass as distance increases from the primary sources of basaltic volcanic glass

TOOL TYPE

BASALTIC GLASS

PAEKTUSAN VOLCANO

Count

%

Count

%

Compete tool

61

49.6

6

26.1

Broken tools

47

38.2

16

69.6

Core tools

13

10.6

1

4.3

Pebble tools

2

1.6

0

0

Total

123

100

23

100
designed, specialized, curated items that had a long
necessary goals. First, volcanic glass is not widely
use-life. In contrast, artifacts from the local basaltic distributed across large areas and so people found
glass sources were discarded through a variety of
ways to either make special-purpose trips to sources
processes including initial manufacture, microblade
or to embed procurement within other activities. The
manufacture, loss, and abandonment.

assemblage at Tigrovy-8 illustrates that groups vis-
ited the site specifically to procure microblade cores 7. Conclusions
that were either transported as part of a repair kit or were reduced at another location, perhaps as part of

Using a combination of methods to investigate the
a gearing-up strategy. The site was selected because
location, quality, and geochemistry of glass sources
of the predictable abundance of good-quality raw
and to analyze the manufacturing technology, we can
material and the tabular shape of the nodules that
better understand the role of volcanic glass within the were ideal for easy and quick conversion into micro-adaptive strategies of hunter-gatherer groups during
blade cores.

the Late Paleolithic in central Primorye, Far East

Second, although primary outcrops may have

Russia, and, by implication, of other contemporary
been specially targeted for microblade production,
societies in northeast Asia. We argue that people were people were not limited by a lack of access to these
highly adaptable and inventive in acquiring, work-
small locations, due to the need to spend time else-
ing, and using their stone resources. The detailed
where in order to satisfy more important goals.

study of volcanic glass procurement and use of local

Instead, they developed a wide range of flexible
and distant sources shows they developed flexible
methods for converting water-rolled cobbles from
strategies to solve raw material needs with the least
secondary-source nodules of many shapes and sizes
cost. Given the benefits conferred by lethal insets
into the desired core form. In this way they greatly
within compound tools that were reliable and eas-
extended their access to volcanic glass sources and
ily repaired, volcanic glass would have been a highly
helped reduce the risks of not having appropriate
desirable raw material for achieving these aims both
tools ready when required. However, it is likely that
because of the sharp edges typically produced and
the use of cobbles for microblade core manufacture
also because of the relative ease of flaking. The tool was limited by abundance, visibility, and the time and requirements, however, also created costs that had to
labor costs involved in collection.

be countered in a risky environment where time was

Third, the production of microblades required
relatively limited and/or during a time when groups
specialized core forms that also needed to be porta-
were exploring and colonizing new environments
ble. The choice of volcanic glass is important in this (Hiscock 1994).

regard because of its excellent fracturing properties.

The archaeological record provides ample evi-

However, the shape and size of the raw material can
dence of the ingenious solutions devised to achieve
set limits on what can be produced. The average size

112 | OBSIDIAN AND GLASS PROVENANCE
of obsidian nodules from primary and secondary
the International Development Fund, the University
sources is quite small and cortex is common. Once
of Sydney, and the Australian Institute of Nuclear
again the very flexible and clever reduction meth-

Science and Engineering (AINSE). At the Australian
ods used demonstrate that it was possible for skilled

Nuclear Science and Technology Organisation
and experienced knappers to ensure that the advan-

(ANSTO) we received assistance from Mihail Ionescu.

tageous properties of volcanic glass could be put to

Much help and support were provided by Nina
good use.

Kononenko, Peter White, and Irina Pantukhina. Ian

Finally, the analysis of artifacts derived from

Graham, Gayle Webb, and Ross Pogson (Geosciences,

Paektusan Volcano illustrates how hunter-gatherers

Australian Museum) gave advice about specific grav-
maintained a continuous, dynamic, and fluid process
ity. We are especially grateful to the many volunteers of raw material acquisition, production, and repair
who made the 2006–2007 fieldwork such a success.

over long periods of time and consequently across
vast distances. The limited number of artifacts, the

References
extensive use of local materials, and the overall small size and weight of the complete flakes indicate that

Binford, L., 1977. Forty-seven trips: A case study in the volcanic glass from Paektusan Volcano was part of
character of archaeological formation processes. In:

a technological strategy bent on maintaining and

Wright, R.V.S. (Ed.), Stone Tools as Cultural Markers.

extending the utility of the microblades, microblade

Australian Institute of Aboriginal Studies, Canberra,
cores, and large retouched flakes. The cores were
pp. 24–36.

subsequently reworked when material was needed

Binford, L., 1979. Organisation and formation processes: to repair tools, accounting for the presence of elon-Looking at curated technologies. Journal of Anthropological Research 35, 255–273.

gated, unretouched flakes in the assemblage. These

Binford, L., 1980. Willow smoke and dogs’ tails: Hunter-artifacts were subsequently exhausted, lost, or bro-
gatherer settlement systems and archaeological site
ken. Extending the utility of artifacts to this degree formation. American Antiquity 45, 4–20.

is a very effective risk-reduction strategy. Exchange

Binford, L., 1983. In Pursuit of the Past. Thames and among groups is also a useful strategy to ensure

Hudson, London.

access to a wider range of resources and therefore

Bleed, P., 1986. The optimal design for hunting weapons: to reduce subsistence risks. It is possible that volca-Maintainability or reliability. American Antiquity 51, nic glass from Paektusan Volcano was occasionally

737–747.

exchanged among highly mobile groups and that

Bleed, P., 1996. Risk and cost in Japanese microblade
this pattern extended its range.

technology. Lithic Technology 21, 95–107.

We conclude that volcanic glass was a popular

Bleed, P., 2002. Cheap, regular and reliable: Implica-
raw material during the Late Paleolithic in north-
tions of design variables in Late Pleistocene Japan-
eastern Asia as it played an important role in help-
ese microblade technology. In: Elston, R.G., Kuhn,

S.L. (Eds.), Thinking Small: Global Perspectives on ing highly mobile foraging groups to obtain a secure

Micro lithization. Archaeological Papers of the lifestyle. Groups found ways to take advantage of the

American Anthro pological Association, no. 12. Amer -
inherent properties of the glass while at the same
ican Anthro pological Association, Arlington, VA,
time adapted highly flexible strategies for overcoming pp. 97–102.

constraints posed by the limited distribution of this

Dikov, N.N., 1996. The Ushki sites, Kamchatka Peninsula.

raw material and the various types of source material

In: West, F.H. (Ed.), American Beginnings: The Pre
available in both primary and secondary contexts.

history and Palaeoecology of Beringa. University of Chicago Press, Chicago, pp. 244–250.

Acknowledgments

Doelman, T., 2008. Flexibility and creativity in microblade core manufacture in Southern Primorye, Far

This research was supported by grants from the

East Russia. Asian Perspectives 47 (2), 352–370.

Australian Research Council Discovery, the Wenner-

Doelman, T., Kononenko, N., Popov, V., Summerhayes,

Gren Foundation for Anthropological Research, Inc.,

G., Torrence, R., Bonetti, R., Guglielmetti, A.,

Volcanic Glass Procurement and Use | 113

Manzoni, A., Oddone, M., 2004. Acquisition and
the sources. Bulletin of the IndoPacific Prehistory movement of volcanic glass in the Primorye region

Association 27, 129–134.

of Far Eastern Russia. Russia and the Pacific 46, Kobayashi, T., 1970. Microblade industries in the Japan-112–125.

ese archipelago. Arctic Archaeology 7, 38–58.

Doelman, T., Torrence, R., Popov, V., Ionescu, M., Kluyev, Kuhn, S., Elston, R., 2002. Introduction: Thinking small N., Sleptsov, I., Pantyukhina, I., White, P., Clements, globally. In: Elston, R.G., Kuhn, S.L. (Eds.), Thinking M., 2008. Source selectivity: An assessment of vol-Small: Global Perspectives on Microlithization. Archa-canic glass sources in the southern Primorye region,
e ological Papers of the American Anthropological

Far East Russia. Geoarchaeology 23, 1–31.

Asso ciation, no. 12. American Anthropological Asso-

Eerkens, J.W., Spurling, A.M., Gras, M.A., 2008. Mea-
cia tion, Arlington, VA, pp. 1–7.

suring prehistoric mobility strategies based on obsid-

Kuzmin, Y.V., Tabarev, A.V., Popov, V.K., Glascock, M.D., ian geochemical and technological signatures in the

Shackley, M.S., 1999. Geochemical source analysis of

Owens Valley, California. Journal of Archae ological archaeological basaltic glass in Primorye (Russian Far Science 35, 668–680.

East). Current Research in the Pleistocene 16, 97–99.

Elston, R.G., Brantingham, P.J., 2002. Microlithic technol-Kuzmin, Y.V., Popov, V.K., 2000. Vulkanicheskie stekla ogy in Northern Asia: A risk-minimizing strategy of

Dalnego Vostoka Rossii: Geologicheskie I arkeol
the Late Paleolithic and Early Holocene. In: Elston,
gich eskie aspekty [Basaltic glass in the Russian R.G., Kuhn, S.L. (Eds.), Thinking Small: Global Far East: Geological and archaeological aspects].

Perspectives on Microlithization. Archaeological Dalnev o s tochny Geologichesky Institut DVO RAN, Papers of the American Anthropological Associa-Vladivostok.

tion, no. 12. American Anthropological Association,

Kuzmin, Y.V., Glascock, M.D., Sato, H., 2002a. Sources Arlington, VA, pp. 103–116.

of archaeological obsidian on Sakhalin Island (Russ-

Glascock, M.D., Speakman, R.J., Popov, V.K., Kuzmin,
ian Far East). Journal of Archaeological Science 29, Y.V., 2006. Geochemistry and provenance research

741–749.

on obsidian from the Kamchatka Peninsula. Trans

Kuzmin, Y.V., Popov, V.K., Glascock, M.D., Shackley,
actions of the American Nuclear Society 95, 483–484.

M.S., 2002b. Sources of archaeological volcanic glass

Goebel, T., 2002. The “microblade adaptation” and recolo-in the Primorye (maritime) province, Russian Far
nisation of Siberia during the Late Upper Pleistocene.

East. Archaeometry 44, 505–515.

In: Elston, R.G., Kuhn, S.L. (Eds.), Thinking Small: Kuzmin, Y., Speakman, R., Glascock, M., Popov, V.,

Global Perspectives on Micro lith ization. Archaeolog-Grebennikov, A., Dikova, M., Ptashinsky, A., 2008.

ical Papers of the American Anthro pological Associa-

Obsidian use at the Ushki Lake complex, Kamchatka
tion, no. 12, American Anthropological Association.

Peninsula (Northeastern Siberia): Implications for

Arlington, VA, pp. 117–131.

terminal Pleistocene and early Holocene human

Hiscock, P., 1994. Technological responses to risk in Holo-migrations in Beringia. In press doi: 10.1016/j.jas.

cene Australia. Journal of World Prehistory 8, 267–292.

2008.02.001.

Hong, M., Kononenko, N.A., 2005. Obsidian tools exca-

Lee, G.K., 2006. Lithic technology and the transition
vated from the Hopyeong-dong Upper Paleolithic
from the Middle to Upper Paleolithic in Korea.

site, Korea. Journal of the Korean Palaeolithic Society Arch ae ology, Ethnology and Anthropology of Eurasia 12, 1–30 (in Korean).

4, 31–37.

Izuho, M., Sato, H., 2007. Archaeological obsidian stud-Myers, A., 1989. Reliable and maintainable techno logi-ies in Hokkaido, Japan. Bulletin of the IndoPacific cal strategies in the Mesolithic of mainland Brit-Pre history Association 27, 114–121.

ain. In: Torrence, R. (Ed.), Time, Energy and Stone Kim, J.C., Kim, D.K., Youn, M., Yun, C.C., Park, G.,

Tools. Cam bridge University Press, Cambridge, UK, Woo, H.J., Hong, M., Lee, G.K., 2007. PIXE prov-pp. 78–91.

enancing of obsidian artifacts from Paleolithic sites

Pantukhina, I.E., 2006a. Stoyanka Moloderzhnaya 1 v
in Korea. IndoPacific Prehistory Association Bulletin Yugo-Zapadnom Primorye [The Moloderzhnaya

27, 122–128.

1 site in the southwestern part of Primorye]. In:

Kluyev, N., Sleptsov, I., 2007. Late Pleistocene and early Ruban, N.I., Goncharova, S.V. (Eds.), Pyatiye gro

Holocene uses of basaltic glass in Primorye, Far
deckovskiye chteniya (in Russian). HKKM im. N.I.

East Russia: A new perspective based on sites near

Grodeckova, Khabarovsk, pp. 7–94.

114 | OBSIDIAN AND GLASS PROVENANCE

Pantukhina, I.E., 2006b. Pamyatnik Shecklyayevo-6 v
i istochniki [Obsidian in archaeological sites of the

Centralnom Primorye: Kharakteristika i osobennosti
middle and lower basins of the Amur River: Geo-
mikroplastinchatogo komplexa [Shecklyayevo-6 site
chemical composition and sources]. In: Ruban, N.I.,
in the central part of Primorye: Characteristics and

Goncharova, S.V. (Eds.), Pyatiye Grodeckovskiye peculiarity of microblade complex]. In: Piskareva,

Chteniya (in Russian). HKKM im. N.I. Grodeckova, Y.E. (Ed.), Devyataya Dalnevostochnaya konferen

Khabarovsk, pp. 99–108.

cia molodikh istorikov (in Russian). DVO RAN, Summerhayes, G.R., Bird, J.R., Fullagar, R., Gosden, C., Vladivostok, pp. 315–323.

Specht, J., Torrence, R., 1998. Application of PIXE-

Pantukhina, I.E., 2007. The role of raw material in micro-PIGME to archaeological analysis of changing pat-
blade technology at three late Palaeolithic sites,
terns of obsidian use in West New Britain, Papua

Russian Far East. Bulletin of the IndoPacific Pre history New Guinea. In: Shackley, S. (Ed.), Archaeological Association 27, 144–153.

Obsidian Studies. Plenum, New York, pp. 129–158.

Popov, V.K., Kuzmin, Y.V., Shevkomud, I.Y., Greben-

Torrence, R., 1989. Re-tooling: Towards a behavioural
nickov, A.V., Glascock, M.D., Zaitsev, N.N., Petrov,
theory of stone tools. In: Torrence, R. (Ed.), Time, V.G., Naumchenko, B.V., Konopatsky, A.K., 2006.

Energy, and Stone Tools. Cambridge University Press, Obsidian v arkheologicheskikh pamyatnikakh Cred-Cambridge, UK, pp. 57–66.

nego i Nizhnego Priamurya: geokhimicheskii sostav

Chapter 9

Obsidian Provenance at Several Italian and

Corsican Archaeological Sites Using the Non-
destructive X-ray Fluorescence Method

Anna Maria De Francesco, Marco Bocci,

Gino Mirocle Crisci, and Vincenzo Francaviglia

Abstract

1. Introduction

The provenance of archaeological obsidian fragments

The geological sources of obsidian in the Mediter-
has been determined using the non-destructive X-ray
ranean area are located on the Italian islands of
fluorescence (XRF) analytical method, based on the

Lipari, Pantelleria, Sardinia, and Palmarola, and on
secondary X-ray intensity (Crisci et al. 1994). To estab-the Greek islands of Melos and Gyali. The ability to
lish this methodology, an analysis by classical XRF
determine their provenance comes from a long his-
method on powders (major elements and selected
tory of compositional studies around the globe where
trace element concentrations such as Nb, Y, Zr, Rb,
destructive or non-destructive analytical meth-
and Sr) was initially carried out on obsidian samples
ods have been implemented. Summaries of these
representative of all the geological outcrops in the
studies are presented in the following references:

Mediterranean area (De Francesco et al. 2008). The

Cann and Renfrew 1964 (OES); Hallam et al. 1976
provenance of archaeological obsidians was deter-

(INAA); Francaviglia 1984 (Powder XRF); Williams
mined by comparing their composition with that

Thorpe et al. 1984 (INAA); Biró et al. 1986 (SEM-
of the quarry obsidians in the entire Mediterranean

EDS); Bigazzi et al. 1993 (Fission Track Dating);
area. Five chemical elements (Nb, Y, Zr, Rb, and Sr)

Cirrincione et al. 1995 (Portable XRF); Williams
were sufficient to characterize the different places

Thorpe 1995 (various methodologies); Acquafredda
of origin, because they are particularly indicative of et al. 1996, 1999 (SEM-EDS); Kayani and McDonnel
the genetic processes that produced obsidian. With

1996 (BSE-SEM); Tykot and Young 1996 (ICP-MS);
the non-destructive XRF methodology, about 1398

Tykot 1997 (ICP-MS); Shackley 1998a, 1988b, 2002,
archaeological obsidian fragments have been ana-

2005 (Gamma rays, XRF, different methodologies);
lyzed, coming from numerous Italian Neolithic sites

Summerhayes et al. 1998 (PIXE-PIGE); Gratuze 1999
and from the island of Corsica. The provenance of

(LA-ICP-MS); Glascock and Neff 2003 (INAA);

97% of the archaeological obsidians was successful

Stewart et al. 2003 (Mossbauer Spectroscopy); Bellot-
determined. The provenance of 3% of the analyzed

Gurlet et al. 2004, 2005 (Raman micro-spectroscopy,
obsidian could not be established because of their

PIXE, and ICP); Liritzis 2007; Liritzis and Zacharias
small size. The results demonstrate that the non-

2011 (Portable ED-XRF).

destructive XRF method used, due to its sensitivity,

Since Mediterranean obsidians are easily distin-
low cost, and high speed, is an extremely valuable tool guishable from a compositional point of view, the
for the attribution of the provenance for archaeologi-
principal obstacle has for a long time been meth-
cal obsidian obtained from Neolithic sites.

odological. In fact, in this type of research it is very 115

116 | OBSIDIAN AND GLASS PROVENANCE
important to have a non-destructive and inexpensive
obsidian on these islands are very numerous, but not
analytical method of easy application, which allows
all of them have the technical properties necessary
the analysis of all finds recovered in excavations
for the production of artifacts.

without any numerical limitation, and which can

On Sardinia island, studies on the provenance
sometimes identify particularly meaningful patterns.

of archaeological obsidians, carried out by Hallam et

To answer such needs, a non-destructive analytical
al. (1976), and Mackey and Warren (1983), indicate
methodology using wavelength-dispersive X-ray flu-
three possible sources of obsidian: Conca Cannas
orescence (WDXRF) has been proposed by Crisci et al.

(SA), Santa Maria Zuarbara (SB), and Perdas Urias

(1994) and optimized by De Francesco et al. (2000,

(SC). Williams Thorpe et al. (1984), Tykot (1997),

2005, 2008). In the present work 1398 archaeological

Tykot et al. (1997), De Francesco and Crisci (1999,
obsidian fragments, collected from numerous Ital-

2003), and De Francesco et al. (2004, 2008) h

008) ave dis-
s-
ian Neolithic sites and from the island of Corsica,
tinguished, using different methodologies, five geo-
have been analyzed and the origin of archaeological
chemical groups in the obsidians of Monte Arci (SA,
obsidians attributed to their geological sources.

SB1, SB2, SC1, and SC2).

On Lipari there are several obsidian flows of

2. Geological sources of obsid ian
good quality, but the only one that was exploited in
in the Mediterranean area
the Neolithic period is that of the Vallone Gabellotto–

Fiume Bianco.

The obsidian sources in the Mediterranean area are

Palmarola is the westernmost of the Pontine
located on the Italian islands of Sardinia, Lipari,

Islands Archipelago in the Gulf of Gaeta. Two lithic

Palmarola, and Pantelleria and on the Greek islands
types are macroscopically distinguishable in the
of Melos and Gyali (figure 9.1). The outcrops of

Palmarola obsidian: the first is transparent with

Figure 9.1. Distribution of obsidian sources in the Mediterranean area exploitable in the Neolithic period.

Obsidian Provenance at Italian and Corsican Sites | 117
inclusions; the second is black and opaque. Tykot
preparation and without leaving any damage on the
et al. (2005) was able to distinguish three source
analyzed area. Fragments of obsidian, taken from
groups on Palmarola island using neutron activa-
the larger blocks collected from the geological out-
tion analysis.

crops (already analyzed as powders), but with a shape

In Pantelleria, it is possible to discriminate at
similar to workshop refuse usually found at archaeo-
least three geochemical groups of obsidian: Balata
logical sites, were analyzed by non-destructive XRF
dei Turchi, Salto La Vecchia, and Lago di Venere

(using the same Philips PW 1480 Spectrometer). The

(Fran
caviglia 1988). Their peralkaline character
non-destructive XRF analytical methodology con-
allows them to be distinguished from all other Med-
sists of irradiating the entire fragment of obsidian
iterranean obsidian.

with primary X-rays. As a result, the chemical ele-

Concerning the Greek islands, the obsidians of
ments present in the sample are excited and produce

Gyali are extremely homogeneous and easily distin-
secondary X-rays. In the traditional XRF method
guishable throughout chemical composition (Cann
the matrix effects must be considered (absorption
and Renfrew 1964; Renfrew et al. 1965; Francaviglia
effects, granulometric effects, and the surface effects); 1984), both from other Greek sources and those
but using the non-destructive XRF analytical meth-
throughout the rest of the Mediterranean. Melos
odology, the only theoretical obstacle to the use of
is the other island of the Aegean Archipelago with
the non-destructive XRF analysis for archaeological
obsidian of good quality. The obsidian is located
obsidians is related to the irregular surface that var-mainly in two principal outcrops, Aghia Nikia and
ies from sample to sample. Subsequently, the intensity Demenegakion. They are almost compositionally
ratios of such elements can be used in place of real
homogeneous but distinguishable by slight differ-
concentrations and employed to construct discrimi-
ences in Zr content (Francaviglia 1984; Liritzis 2007).

nating diagrams (De Francesco et al. 2008, 2011).

Only 5 elements, Nb, Y, Zr, Rb, and Sr, have

3. Non-destructive XRF
been selected, since they are more than sufficient
methodology on complete
to characterize the different areas. Such a choice
specimens
is fully justified by the particular sensitivity of the aforementioned chemical elements to the magmatic

The first stage of the work consisted of the charac-
processes that cause the formation of rhyolitic melts
terization of numerous samples of geological obsid-
that, once solidified, give rise to obsidians.

ian obtained directly from the principal obsidian

Table 9.1a reports the mean concentrations in ppm
sources in the Mediterranean area. A destructive
obtained on the powdered geological obsidians for the
analysis on powdered samples was first carried out.

5 selected trace elements (De Francesco et al. 2008).

Subsequently, a comparison was conducted between

Table 9.1b reports the secondary X-ray intensities for the classical XRF method on powders (major ele-the same chemical elements obtained on the geologi-
ments and selected trace element concentra tions
cal fragments using the non-destructive methodology.

such as Nb, Y, Zr, Rb, and Sr) and the non-destructive The X-rays intensities are always different because

XRF analytical methodology for fragments. These
they are influenced by the matrix effects, which are
analyses allowed an unambiguous characteriza-
undefined using the non-destructive methodology.

tion of the different obsidian sources (De Francesco

For this reason, it is necessary to reanalyze the
et al. 2008).

geological fragments together with the unknown

The non-destructive XRF analytical methodol-
arch aeological obsidian flakes. The attribution of
ogy, which has been optimized at the Dipartimento
the provenance to the archaeological unknown
di Scienze della Terra of the University of Calabria
fragments is based on a comparison with the geo-

(Crisci et al. 1994; De Francesco et al. 2000, 2008),
logical source material.

makes it possible to identify the areas of origin of

The diagrams in figure 9.2 compare the trace ele-
the obsidians used for the production of artifacts,
ment concentration ratios from the powder method-
by directly analyzing the entire artifact, without any ology (figure 9.2a) with the intensity ratios obtained

118 | OBSIDIAN AND GLASS PROVENANCE

Table 9.1a Concentrations in ppm obtained on the powdered geolog ical obsidians for five selected trace elements. The complete analysis of major elements and trace elements are reported in De Francesco et al. (2008) Source

No. of samples

Nb

Y

Rb

Zr

Sr

SA

15
mean 56 37 257 96 31

st.

dev. 1 1 2 1 1

SC

11
mean 30 24 175 213 134

st.

dev. 1 1 2 3 3

SB1

6
mean 45 30 245 132 68

st. dev.

7

5

2

17

13

SB2

3
mean 30 21 246 120 40

st.

dev. 1 1 1 9 4

Yali

4
mean 17 13 137 103 69

st.

dev. 1 1 5 3 1

Palmorola 8
mean 72 74 399 263 9

st. dev.

3

2

16

8

1

Lipari

4
mean 39 44 288 147 19

st. dev.

4

4

7

21

2

Pantelleria

6
mean

242

130

135

1252

7

st. dev.

76

72

40

419

1

Melos

8
mean

8 15 117 111 105

st. dev.

1

2

3

12

3
by the non-destructive methodology on the entire

The diagrams represent one of the possible bip-
fragments (figure 9.2b). In each case, the groups of
lots that show how a few trace elements (Zr, Sr, and
obsidians from the Mediterranean area (Lipari,

Nb) are enough to distinguish between the obsid-

Palm arola, Pantelleria, Sardinia–Monte Arci [SA,
ian sources of the whole Med iterranean area, using

SC, SB1, and SB2]) and those of the Greek islands
both the traditional XRF methodology and the non-
of Melos and Gyali are well separated, without any
destructive XRF approach. Other trace elements, such
possiblity of overlap between the groups, which are
as Rb, Y, Ba, Ti, Ce, and La, are also very useful for the perfectly distinct and comparable using the two
same purpose (Liritzis and Zacharias 2011). The same
methodologies.

results are obtained using ternary diagrams.

Figure 9.2. Comparison between the destructive and non-destructive XRF methodologies:

(a) Nb/Zr ppm versus Nb/Sr ppm on powders; (b) Nb/Zr versus Nb/Sr (X-rays intensity ratios) on entire fragments. Legend: PT: Pantelleria; PL: Palmarola; SA, SB1, SB2, SC: Sardinia–M. Arci; LP: Lipari; ML: Melos; YA: Gyali; + Archaeological Samples.

Obsidian Provenance at Italian and Corsican Sites | 119

Table 9.1b Secondary X-ray intensities for five selected trace elements obtained on the geological fragments using the non-destructive XRF methodology Sample

Nb

Y

Rb

Zr

Sr

Sample Nb Y Rb Zr Sr

SA-01

18250 6058 53002 22806 5185

YA05

4277 3602 18535 16742 6596

SA-02

16803

5662 50706

21248 4834

YA06

3852 3247 15784 15136 6431

SA-03

17930

5989 52064

22125 5181

YA07

4215 3726 19113 16841 7439

SA-04

14726

4431 44326

19177 4039

YA08

2971 2465 11890 11337 4967

SA-05

14946

4650 44850

18075 4245

YA09

3110 2652 12495 12311 5067

SA-06

14172

4277 42570

18027 4047

YA10

3347 2664 13014 13056 5213

SA-07

18084

5941 54042

24005 5333

PALM-01b 11272 9226 46214 38068 678

SA-08

14721

4478 45128

18525 4255

PALM-01c 14596 12271 59065 46582 770

SA-09

16814

5397 50208

20673 4643

PALM-01d 14174 11907 59619 48426 962

SA-10

13496

3730 40783

16258 3703

PALM-01e 12416 10430 50808 41093 590

SC-01

7734

3426 28871

46190 16863

PALM-01g 14706 12505 60814 48845 636

SC-02

8292

3668 30549

47909 18339

PALM-01h 14638 12203 59560 47741 815

SC-03

8739

3611 32318

53398 19906

PALM-01m 16163 13113 65035 52257 744

SC-04

7620

3402 28735

47242 17048

PALM-01n 16043 12792 64386 51346 834

SC-05

7561

3164 28369

46710 18668

PALM-01o 14564 11664 59039 47300 768

SC-06

9062

3881 33307

54042 20036

LIP-LC01

6840 7563 34712 26620 1697

SC-07

6565

2899 23769

39207 14285

LIP-LC02

8370 8827 40396 30955 2246

SC-08

9089

3915 34353

52776 20470

LIP-LCD01 8319 9367 40888 31806 2022

SC-09

10077

4322 34929

53912 20649

LIP-LCD02 8337 8943 40721 31755 1887

SC-10

9737

4189 34340

53824 20919

LIP-RIN01

8180 9383 40980 32539 1997

SB1-01

10722

3635 36128

25891 8405

LIP-RIN02

7558 8596 37689 29964 2028

SB1-02

15132

4944 50256

32030 12917

LIP-VL02

6331 6604 30746 25450 1606

SB1-03

13356

4322 45406

29348 10758

LIP-VL04

5540 5691 26550 21634 1321

SB1-04

12188

3922 37829

25235 11705

LIP-VL05

6880 7460 34477 27832 1734

SB1-05

12795

4922 42155

28245 9911

LIP-VL06

6082 6908 31585 25719 1504

SB1-06

11214

3781 38198

25825 10395

PANT-03 42767 9872 12461 149773 333

SB1-07

14983

4764 46276

28365 10599

PANT-04 41729 9361 11801 143908 383

SB1-08

10813

3946 36127

25250 8822

PANT-07

55071 12704 15612 189818 380

SB1-09

12281

4450 42305

27303 9264

PANT-BT01 62603 13376 17069 267110 492

SB1-10

13582

4619 44794

28924 10267

PANT-BT02 50962 11657 14244 175297 390

SB2-01

7372

2929 38973

21978 4389

PANT-BT03 57260 13174 16116 262745 421

SB2-02

7853

2784 40224

26036 7447

PANT-LV01 33095 7143 9786 109187 179

SB2-03

7881

3063 42107

22453 4656

PANT-LV02 34758 7572 10138 113666 195

SB2-04

8982

3445 46490

27643 6405

PANT-LV03 56937 13256 16313 197950 409

SB2-05

9105

3239 47177

28272 7856

MILOS-01

2191 3447 15855 20623 11701

SB2-06

10320

4138 53047

28422 5612

MILOS-03

2132 3345 15926 20212 11525

SB2-07

7037

2519 36074

21155 5273

MILOS-04

2366 3424 16173 20834 11976

SB2-08

7756

3036 40877

22259 4608

MILOS-05

2234 3369 15883 20118 11643

SB2-09

8625

3550 45968

29168 8200

MILOS-06

2068 2931 14275 17853 10484

YA01

4352

3980 19172

17345 8220

MILOS-07

2353 3526 16101 20237 11932

YA02

3517

3004 13720

13903 5535

MILOS-08

2161 3331 15265 19407 11171

YA03

3517

2942 13923

13951 5714

MILOS-09

2219 3413 15555 19946 11500

YA04

3150

2998 14815

12945 5324

MILOS-10

2342 3170 15295 19644 11035

120 | OBSIDIAN AND GLASS PROVENANCE

4. Archaeological sites
investigated

The obsidians analyzed in this study were selected
by the archaeologists. In some cases, the origin of
the entire group of artifacts discovered at a site has been determined, but in other cases only a few representative samples were selected after a macroscopic
analysis. In the application of the non-destructive
methodology, the attribution of origin to the archae-
ological artifacts occurred through a comparison of
intensity ratios obtained on fragments of known ori-
gin and those on the artifacts analyzed at the same
time. In addition, the fragments of known obsidians
can be used to identify possible drifting in the X-ray spectrometer (De Francesco et al. 2008).

For instance, in figure 9.3 the two diagrams
allow a distinction in provenance for the obsid-
ian artifacts discovered at different archaeological
sites. The diagrams refer to the intensity ratios of
the chemical elements and show that the sources
of obsidian of the Mediterranean area—Lipari, Pal-

Figure 9.4. Location of Neolithic archaeological sites marola, Pantelleria, Sardinia–Monte Arci (SA, SC,

(white dots) from where the obsidians were analyzed
and their determined obsidian source provenance.

SB1, and SB2)—and those of the Greek islands of

Melos and Gyali are well separated, without any
possibility of overlap between them. The unknown

Abruzzo),while the remaining material is located in
samples overlap on the areas corresponding with the

Southern Italy (Campania and Apulia), in Northern
geological obsidian sources.

Italy (Emilia Romagna and Lombardy), in Sar dinia,

The majority of the obsidians analyzed in the
and in Corsica (France). The locations of the Neo-
pre sent work originate from the archaeological sites
lithic archaeological sites, along with the provenances of Central Italy (Tuscany, Marches, Lazio, and

of the analyzed obsidians, are shown in figure 9.4.

Figure 9.3. Provenance of archaeological fragments from the Catignano site (a) and Torre Foghe (b) compared to the obsidian sources. Legend: PT: Pantelleria; PL: Palmarola; SA, SB1, SB2, SC: Sardinia–M. Arci; LP: Lipari; ML: Melos; YA: Gyali; + Archaeological Samples.

Obsidian Provenance at Italian and Corsican Sites | 121

Listed below is context information for each of

Central Italy
the main archaeological sites, from where the ana-

La Scola—Isola di Pianosa (Livorno)

lyzed obsidians originated. The number of the obsid-
ians analyzed and their provenance are outlined in

The rock cliff of La Scola is situated close to the east-tables 9.2, 9.3, and 9.4, and are separated according
ern coast of Pianosa. The islet has an almost circular to their geographical area.

shape and a flat summit. On the northeast side are

Table 9.2 Obsidian provenance from archaeological sites of Central Italy Nr

Site

Lipari

Palmarola

Pantelleria Sardinia

Unknown

Total

samples

1

Botteghino Pontedera (PI)

1

0

0

0

0

1

2

Cala Giovanna (LI)

1

9

0

162

4

176

3

Cala Giovanna Piano (LI)

2

1

0

38

1

42

4

Casa dell’Isola (LU)

0

0

0

6

0

6

5

Castiglione in Teverina (VT)

0

0

0

1

0

1

6

Catignano

(PE)

168

13 0 0 2 183

7

Chiarentana

(SI)

17 5 0 1 0 23

8

Colle Santo Stefano (AQ)

0

24

0

0

0

24

9

Collecera

29 4 0 0 2 35

10

Coppetella di Jesi (AN)

5

0

0

0

0

5

11

Donatelli di Genga (AN)

2

0

0

0

0

2

12

Fontenoce di Recanati (MC)

1

0

0

0

0

1

13

Gotta della Spinosa (GR)

0

0

0

6

0

6

14

Grotta all’Onda (LU)

0

0

0

34

1

35

15

La Scola (LI)

1

7

0

20

1

29

16

Maddalena di Muccia (MC)

6

2

0

0

0

8

17

Marche Mar 02

22

3

0

1

1

27

18

Marmotta (Roma)

55

338

0

0

12

405

19

Monte Frignone (LU)

0

0

0

0

2

2

20 M.te Tinello di Acquaviva Picena (AP)

1

0

0

0

0

1

21

Mulino 1 0 0 0 0 1

22

Neto Via Verga (FI)

21

0

0

4

0

25

23

Ripabianca di Monterado (AN)

5

0

0

0

0

5

24

Ripoli Fossecesia (CH)

36

5

1

0

2

44

25

Saline di Senigallia (AN)

2

0

0

0

0

2

26

Santa Maria in Selva (AN)

31

0

0

0

1

32

27

Settefonti

(AQ) 3 6 0 0 1 10

28

Spazzavento

(FI)

22 0 0 1 8 31

29

Villa Panezia di Ascoli (AP)

0

1

0

0

0

1

Total Central Italy

432

418

1

274

38

1163

122 | OBSIDIAN AND GLASS PROVENANCE
a number of shelters under the rock that functioned

Grotta all’Onda (Lucca)

in ancient times as real caves. With reference to the

The first excavations made at Grotta all’Onda started
lithic industry, nearly 1500 artifacts have been found, in 1867 and were performed by the researchers from
of which only 16% are tools. The most used raw mate-
the Committee for the Search of Human Palae ontol-
rial is quartz (69%), followed by obsidian (20%),
ogy of Florence, who reconstructed the principal
quartzite (7%), and flint (4%). All of the materials
stages of habitation in the cave. The most ancient
were imported to the site (Radi 2003; Ducci et al.

prehistoric finds are datable to around 40,000 BP

1999; De Francesco et al. 1999).

and are represented by a lithic industry with many

Cala Giovanna Piano—Isola Di Pianosa
flint tools. Small arrowheads and many small blades

(Livorno)

made of Sardinian obsidian have been recovered.

These finds result from exchange activities when

The lithic industry discovered at this site is made up navigation was actively practiced. The contacts with
of 1796 artifacts of which nearly 90% are made of

Sardinia are also testified by the forms and decora-
quartz and only 5% of obsidian. Altogether the obsid-
tion on ceramic artifacts (Campetti et al. 2001).

ian material constitutes artifacts manufactured either as tools, flakes, or blades; discards resulting from poor Marche Region
workmanship; and 3 nuclei. Due to the shortage of

In the sixth millennium BC the new “Neolithic”

available artifacts, it is difficult to establish if obsidian economy was everywhere, characterized by the
processing has been performed in place, even when
emergence of stable villages, animal breeding, agri-
the presence of discards of workmanship and nuclei
culture, and pottery manufacture. In this period, the
suggest this (Tozzi 2007; De Francesco et al. 1999).

Marche region shows peculiar aspects, which differ

Botteghino (Pisa)

between areas. The most ancient stage of the March-
igian Neolithic (settlement of Maddalena di Muccia)

The finds originate from Podere Casanuova, a Neo-
has been dated to within the sixth millennium BC.

lithic village that has been discovered thanks to the

A calibrated chronology for artifact types shows a
construction of a filling channel dug out in the 1980s difference in material culture with the latest phase of by the Superintendence of Archaeological Goods
the same period (e.g., the settlement of Ripabianca
in Tuscany. The numerous finds consist of ceramic
di Monterado), which is dated to between the end
vases, flint tools, obsidian, bone, and botanical
of the sixth and the beginning of the fifth millen-
remains, all documenting the daily life of an evolved
nium BC (Silvestrini 2003). A more advanced Neo-
community.

lithic stage in this region (e.g., the settlements of

Fontenoce di Recanati and Villa Panezia in Ascoli

Chiarentana (Siena)

Piceno) can be placed in the first half of the fifth

In this area, there are many remains of Bronze Age
millennium BC. It is characterized by the existence
and Iron Age activity. Noteworthy among these is the
of close relationships with neighboring regions as

Eneolithic settlement of Chiarentana, on the slopes of well as with those that are relatively distant. These

Cetona Mountain, where remains have been found.

relationships are demonstrated by the association of
typical pottery forms of the advanced stage of the

Grotta Della Spinosa (Grosseto)

culture of Ripoli (Abruzzo) with the peculiar forms

The excavations conducted by the Superintendence
like Serra D’Alto e Diana (Silvestrini 2003). In the
of Archaeological Goods in 2000–2002 brought to
first half of the fourth millennium BC, the peo-
light a level of occupation that refers to the Neolithic pling of the Marche is mostly concentrated in the
period. It dates according to the 14C method to
interior areas (e.g., the settlements of Coppetella di around the midpoint of the fifth millennium BC.

Jesi, Donatelli di Genga, S. Maria in Selva di Treia)

Nuclei, scrapers, and blades are made of flint. A por-
and along valleys of the principal rivers (e.g., Misa, tion of tools and flakes are made from obsidian.

Esino, Potenza), while occupation of the coastal

Obsidian Provenance at Italian and Corsican Sites | 123
areas is less frequent (Saline di Senigallia and Monte site between 5750 BC and 5260 BC and qualify the

Tinello di Acquaviva Picena). The lithic industry of

“La Marmotta” village as the most ancient Neolithic
the Marchigian Neolithic also contains obsidian and
bank settlement of western Europe known at pres-
smoothed greenstone (Antonelli et al. 2006).

ent. Particularly abundant is the lithic industry
expressed in stone, flint, and obsidian (Fugazzola

Colle Santo Stefano (L’Aquila)

Delfino et al. 2004).

This is a Neolithic site dated to between 6800 and

6600 BP. It has yielded over 1000 obsidian artifacts

Castiglione in Teverina (Viterbo)

(8% of the assemblage). The main source is Palmarola

The site attests to the habitation of the Masseto
followed by Lipari, and both glasses are of good qual-
region since utensils to tan skins have been found,
ity. At the site, the assemblage appears homogeneous
together with blades, arrowheads, chisels (30,000–
because of the similar macroscopic characteristics of

13,000 BC), pottery, and even an obsidian nucleus
the obsidian (Pessina and Radi 2006; De Francesco

(10,000–3000 BC).

et al. 2006).

The results on the provenance of the obsidians
from the sites of Central Italy are shown in table 9.2.

Catignano (Pescara)

Dated to between 6300 and 5900 BP, the site deposits

Northern Italy
have yielded 577 obsidian artifacts (8% of the lithic

Bazzarola (Reggio Emilia)

assemblage). The raw material arrived in prepared

The 2003 excavations yielded stratigraphic data of
cores and processing continued to be carried out on
national importance that are useful to outline some
site, as testified by the high number of nuclei (Tozzi of the scientific problems related to the agricul-and Zamagni 2003).

tural colonization of the Pianura Padana. The first
farmers arrived in Emilia from the coast. The lithic

Ripoli Fossecesia (Chieti)

industry is entirely made up of lithotypes coming

At the site of Fossecesia the obsidian quantity is
from the Appennine (flint pebbles). Lessinian flints
remarkable, and a definite change emerges in the use
are missing. The obsidian discards of workmanship
of this material in comparison to the preceding stages are frequent, and after this first appearance in the
for this area. The site, dated 5400 years BP, yielded

Pianura Padana, the other discards found originate

816 obsidian elements (9% of the lithic assemblage)

only from the Middle Neolithic.

(Pessina and Radi 2006).

Benefizio (Parma)

Settefonti (L’aquila)

The excavations performed in the rotunda of the

Set in the late culture of Ripoli and dated between
street named Via Spezia follow those already made in

5500 and 5300 years BP, the site has yielded 58 obsid-
the nearby area of Benefizio, which at the end of 2002
ian elements. The production is strongly laminar,
brought to light interesting finds from the Copper
and only a small part of the thin laminas has traces

Age (fourth and third millennium BC). Finds of the
of use on the borders or is turned into tools (Radi
same type have also been recovered in the subway of
and Danesi 2003).

Via Spezia. At a depth of about 3 m below the sur-
face, artifacts of Neolithic age have been discovered

La Marmotta—Anguillara (Roma)

(fourth millennium BC) that reveal the identity of

Excavations started in 1989 on the floor of Lake
the first farmers of Parma. Pieces of “Appen ninic

Bracciano in the place called “La Marmotta,” near
flint” and crocks of “engraved ceramics” show that

Anguillara Sabazia (Rome). The investigators of this
those who brought agriculture to Parma originated
site added much new information for the recon-
from the Ligurian coasts.

struction of the lifestyle of a Neolithic village. The The results on the provenance of the obsidians
calibrated radiocarbon dates place the use of the
from the sites of Northern Italy are shown in table 9.3.

124 | OBSIDIAN AND GLASS PROVENANCE

Table 9.3 Obsidian provenance from archaeological sites of Northern Italy Nr

Site

Lipari

Palmarola

Pantelleria

Sardinia

Unknown

Total

samples

1

Bazzarola (RE)

5

0

0

9

0

14

2

Benefizio (PR)

2

0

0

0

0

2

3

Gaione (PR)

4

0

0

0

0

4

4

Le Mose (PC)

2

0

0

0

0

2

5

Monte Covolo (BS)

0

0

0

5

0

5

6

Ponteraro (PR)

10

8

0

0

2

20

7

Travo (PC)

1

0

0

4

2

7

Total Northern Italy

24

8

0

18

4

54

Table 9.4 Obsidian provenance from archaeological sites of Southern Italy Nr

Site

Lipari

Palmarola Pantelleria Sardinia

Unknown

Total

samples

1

Ariano Irpino (AV)

0

1

0

0

0

1

2

Botteghelle

(NA) 4 1 0 0 0 5

3

Grotta della Serratura (SA)

5

0

0

0

0

5

4

Masseria di Gioia (BR)

0

0

0

12

0

12

5

Oria Sant’Anna (TA)

36

1

0

0

0

37

6

Ripatetta

(FG) 1 0 0 0 0 1

Total Southern Italy

46

3

0

12

0

61

Southern Italy

Superintendence of Archaeological Goods of the

Botteghelle (Napoli)

provinces of Avellino, Benevento, and Salerno, con-
ducted by F. Martini (University of Florence) and

During the archaeological investigations in the
by L. Sarti (University of Siena). The investigations

Napolitan urban territory, close to Viadotto Bottegh-
were made in two areas, one in the back of the cave
elle, a site rich in archaeological evidence has been
and one in the atrium. The stratigraphy of the first
discovered. In addition to remains of a Neolithic vil-
sector includes levels that are attributable to the
lage, in the deepest layers of the site artifacts from Neolithic, with dates ranging between 6300 ±130 BP
the fourth millennium BC have been recovered,
and 13,100 ±120 BP.

while in more superficial layers numerous materi-
als have emerged that lead us to hypothesize that a
sanctuary was present. Diagnostic artifacts suggest

Oria Sant’Anna (Taranto)

a date between the end of the fourth and the second

The first traces of a Neolithic population in this area century BC.

are dated to around the fifth millennium BC. The
most meaningful peopling of the region took place

Grotta della Serratura (Salerno)

only during the late Neolithic, as shown by the notable The entry of Grotta della Serratura is situated in the concentration of settlements on the hills of Sant’Anna.

oriental coastal area of Marina di Camerota in the

These settlements were located in Monte Papa lucio,
province of Salerno. The excavations made in Grotta
where the traces of an occupation consist only of a
della Serratura started in 1984 on behalf of the
few lithic fragments. This pattern occurs in the region

Obsidian Provenance at Italian and Corsican Sites | 125

Table 9-5 Obsidian provenance from archaeological sites in Sardinia and Corsica Nr

Site

Lipari

Palmarola

Pantelleri a Sardinia

Unknown

Total

samples

1

Costa di U Monte (Corsica)

0

0

0

50

0

50

2

Lumaca (Corsica)

0

0

0

21

0

21

3

Torre Foghe Tresnuraghes (OR)

0

0

0

49

0

49

Total Sardinia and Corsica

0

0

0

120

0

120
of Contrada Pappadà, close to San Giovanni lo Parete,
and sometimes with a smoky gray aspect (n = 15); (3)

with the recovery of obsidian tools; in the region of
opaque and with whitish parallel striations (n = 5);

Con trada Monti, with trapezoidal blades and again
and (4) transparent and bright (Lorenzi 1999). The
the presence of obsidian tools; and in the region of

XRF analysis was conducted on only 21 fragments

Contrada Fontane, where trapezoidal blades and

(De Francesco and Crisci 1999:2002a).

obsidian blades were found. Traces of a Neolithic
occupation have also been discovered in Madonna

Costa di U Monte
della Scala, of the Canale Reale, where blade frag-

The site is situated on the east coast of Corsica, on a ments and obsidian blades have been found.

hill with a flat summit at a height of 213 m and 2 km

The results on the provenance of the obsidians
from the coast. Occupational stages are known to
from the sites of Southern Italy are shown in table 9.4.

exist during and after the Neolithic period. Approx-
imately 800 obsidian elements have been found

Sardinia

(Marini et al. 2007).

Torre Foghe (Oristano)

The results on the provenance of the obsidians

The site is located on the western coast of Sardinia
from these two sites in Corsica and the previously
at the mouth of Rio Mannu. The lithic industry con-
mentioned sites in Sardinia are shown in table 9.5.

sists of rocks belonging to the fonolite group (10%),
flint created by hydrothermal processes (10%), and

5. Results and conclusions
obsidian (80%) (Dini 2007). The obsidian assem-

The results obtained show that for the archaeologi-
blage consists of 938 artifacts and 107 tools (De
cal sites of Central Italy, the majority of obsidian

Francesco and Bocci 2007; Dini 2007).

originates from Sardinia, Lipari, and Palmarola. In

Corsica

Northern Italy the majority of obsidians derive from

Lipari and from Monte Arci in Sardinia. In Southern

Lumaca

Italy obsidian provenance from Lipari, Sardinia, and

The site is situated on the crest of a hill at a height Palmarola prevails. Only Sardinian origins have
of 450 m, in the northwest extremity of Cap Corse.

been found for the sites of Lumaca and Costa di U

It consists of several adjoining terraces. A series of Monte in Corsica and Torre Foghe in Sardinia (fig-soil corings performed on two terraces revealed
ure 9.5). The results obtained indicate that for the
several levels of occupation starting from the early
entire group of samples, the majority of archaeologi-

Neolithic. The lithic materials discovered originated
cal obsidians come from Lipari (36%) and Palmarola
from drill holes 2, 3, and 4. Sixty-seven obsidian

(31%), and the remaining large portion is from
fragments came from drill hole 3. Obsidian consti-

Sardinia (30%).

tutes 60% of all the lithic materials discovered, thus The analyses of the archaeological obsidian frag-making it the most used of all lithic types. From
ments with the non-destructive WDXRF allowed the
the macroscopic analysis of the fragments, 4 vari-
attribution of the provenance for 1356 samples out of
eties of obsidian have been recognized: (1) opaque

1398. The percentage of the unassigned archaeologi-
black, more or less bright (n = 25); (2) translucent
cal samples is very low (around 3%) (figure 9.6), and

126 | OBSIDIAN AND GLASS PROVENANCE

Figure 9.5. Archaeological obsidian provenance according to geographical area.

References

Acquafredda, P., Adriani, T., Lorenzoni, S., Zanettin, E., 1996. Proposal of a non-destructive analytical method
by SEM-EDS to discriminate Mediterranean obsidian
sources. Advances in Clay Minerals, 269–271.

Acquafredda, P., Adriani, T., Lorenzoni, S., Zanettin, E., 1999. Chemical characterization of obsidian from
different Mediterranean sources by non-destructive

SEM-EDS analytical method. Journal of Archae ological Science 26, 315–325.

Antonelli, F., Crisci, G.M., De Francesco, A.M., Silvestrini, M., 2006. Le ossidiane degli insediamenti neolitici
delle Marche: Provenienza ed implicazioni. Pro ceedings of the V Convegno di Archeometria Inno vazioni Tecnologiche per i Beni Culturali in Italia. Patron Edi tore, Bologna, 301–309.

Figure 9.6. A pie diagram of the provenances for 1398

Bellot-Gurlet, L., Le Bourdonnec, F., Popeau, G.,
analyzed archaeological samples. The prov-

Dubernet, S., 2004. Raman micro-spectroscopy of
enance of only 3% could not be determined.

western Mediterranean obsidian glass: One step
towards provenance study? Journal of Raman Spectroscopy 35, 671–677.

in most cases this can be attributed to the extremely

Bellot-Gurlet, L., Popeau, G., Salomon, J., Calligaro, Th., small size of the fragment. Thus it can be concluded

Moignard, B., Barrat, J.-A., Pichon, L., 2005. Obsid-
ian provenance studies in archaeology: A compari-
that the non-destructive WDXRF methodology is a
son between PIXE and ICP. Nuclear Instruments and particularly effective instrument for the determina-Methods in Physics Research B 240, 583–588.

tion of origin for archaeological obsidian. This desir-Bigazzi, G., Yegingil, Z., Ercan, T., Oddone, M.,
ability is enhanced by the low cost and the high speed Ozdogan, M., 1993. Fission track dating obsidian
of analysis, especially when compared with other
in Central and Northern Anatolia. Bulletin of Vol
more sophisticated and expensive methodologies.

canology 55, 588–595.

Obsidian Provenance at Italian and Corsican Sites | 127

Biró, T.K., Pozsgai, I., Vlader, A., 1986. Electron beam supplemento italiano all’. European Journal of microanalyses of obsidian samples from geologi-Mineralogy 28, 137–138.

cal and archaeological sites. Acta Archaeologica De Francesco, A.M., Crisci, G.M., 2003. L’ossidiana. In: Academiae Scientiarum Hungaricae 38, 257–258.

Tozzi, C., Zamagni, B. (Eds.), Gli scavi nel villaggio Campetti, S., Dodaro, S., Ferrini, G., Crisci, G.M., De neolitico di Catignano (1971–1980). Origines, Studi Francesco, A.M., Montanari, C., Guido, M., Cozzani,
e materiali pubblicati a cura dell’Istituto Italiano di M., Perrini, L., Berton, A., Bigini, I., Turini, R., 2001.

Preistoria e Protostoria, Florence, pp. 239–240.

Risultati preliminari di nuove indagini nel deposito

De Francesco, A.M., Bocci, M., Crisci, G.M., 2004. Pro-preistorico di Grotta all’Onda, Camaiore (Lucca).

venienza dal Monte Arci per le ossidiane di alcuni siti Atti della XXXIV Riunione Scientifica dell’Istituto di archeologi dell’Italia Centrale e della Francia Mer-Storia e Protostoria, 349–366.

idionale. Proceeding of 2nd Convegno Inter na zionale

Cann, J.R., Renfrew, C., 1964. The characterisation of L’ossidiana del Monte Arci nel Medi terraneo. Pau
obsidian and its application to the Mediterranean

(Cagliari), 28–30 November. Ed. AV (CA), 303–309.

region. Proceeding of the Prehistoric Society 30, 111–133.

De Francesco, A.M., Bocci, M., Crisci, G.M., Lanzafame, Cirrincione, R., Di Martino, G., Lo Giudice, A.,

U., 2005. Caratterizzazione archeometrica delle

Pappalardo, G., Pappalardo, L., Pezzino, A., 1995.

ossidiane del Monte Arci: Confronto fra metodolo-

Analisi non distruttiva di Ca e Sr eseguita mediante
gia tradizionale in XRF e metodologia XRF non dis-
un sistema XRF portatile su diversi tipi di calcare
truttiva. Proceeding of 3rd Convegno Internazionale
provenienti da cave di Palazzolo e Monti Cli miti.

L’ossidiana del Monte Arci nel Mediterraneo, Ed.

Proceeding of 1st International Congress on Science PTM (OR), 117–128.

and Technology for the Safeguard of Cultural Heri

De Francesco, A.M., Bocci, M., Crisci, G.M., Martini,
tage in the Mediterranean Basin. 27 November–2

F., Tozzi, C., Radi, G., Sarti, L., Cuda, M.T., 2006.

December 1995. Catania, Siracusa, Italy.

Applicazione della metodologia analitica non dis-

Crisci, G.M., Ricq-De Bouard, M., Lanzafame, U., De
truttiva in Fluorescenza X per la determinazione

Francesco, A.M., 1994. Nouvelle méthode d’ana-
della provenienza delle ossidiane archeologiche
lyse et provenance de l’ensemble des obsidiennes
del progetto “Materie Prime” dell’I.I.P.P. Atti della neolith iques du Midi de la France. Gallia Préistoire XXXIX Riunione Scientifica dell’Istituto di Storia e 36, 299–327.

Protostoria. Vol. 1, 531–548.

De Francesco, A.M., Crisci, G.M., 1999. Provenienza

De Francesco, A.M., Bocci, M., 2007. Risultati dell’analisi delle ossidiane dei siti archeologici di Pianosa (Arci-non distruttiva in XRF sulle ossidiane dei siti archeo-pelago Toscano) e Lumaca (Corsica) con il metodo
logici di Cala Giovanna Piano (Arcipelago Toscano)

non distruttivo in Fluorescenza X. In: Tozzi, C.,
e Torre Foghe. In: Tozzi, C., Weiss, M.C. (Eds.), Pre

Weiss, M.C. (Eds.), Il primo popolamento Olocenico istoria e Protostoria dell’area Tirrenica. Ed. Felici, dell’area corsotoscana. Edizioni ETS, Pisa, pp. 253–258.

Pisa, p. 121.

De Francesco, A.M., Crisci, G.M., Lanzafame, U.,

De Francesco, A.M., Crisci, G.M., Bocci, M., 2008. Non-2000. Non-destructive analytical method by XRF
destructive analytical method by XRF for determina-
for provenancing archaeological obsidians from
tion of provenance of archaeological obsidians from

Mediterranean area. Bollettino dell’Accademia Gio
the Mediterranean Area: A comparison with tradi-
di-
enia di Scienze Naturali 357, 229–239.

tional XRF method. Archaeometry 50 (2), 337–350.

De Francesco, A.M., Crisci, G.M., Radi, G., Tozzi, C., De Francesco, A.M., Bocci, M., Crisci, G.M., 2011.

Perazzi, P., Ducci, S., 2002a. Provena
en nce o
e f t
of the o
e b
o si
bs d-
id-

Non-destructive applications of wavelength XRF
ians coming from Catignano (Abruzzo), Pianosa
in obsidian studies. In: Shackley, M.S. (Ed.), XRay (Tuscany Archipelago) and Lumaca (Corsica)

Fluor escence Spectrometry in Geoarchaeology. Natural neolithic sites with non-destructive X-ray fluores-Sciences in Archaeology series, Springer North Amer-
cence analytical method. 2nd Congresso Nazionale
ica, New York, pp. 81–107.

Scienza e Beni Culturali. Bologna 29 gennaio, 1

Dini, M., 2007. L’industria in ossidiana dei siti neolitici February 2002.

di S. Caterina Pittinuri e Torre Foghe sulla costa

De Francesco, A.M., Crisci, G.M., Bocci, M., Lanzafame, occidentale della Sardegna. In: Tozzi, C., Weiss, M.C.

U., 2002b. Provenienza delle ossidiane archeo-

(Eds.), Preistoria e Protostoria dell’area Tirrenica. Ed.

logiche di alcuni siti neolitici italiani. PLINIUS,

Felici, Pisa, pp. 195–202.

128 | OBSIDIAN AND GLASS PROVENANCE

Ducci, S., Guerrini, M.V., Perazzi, P., 1999. L’insediamento (Eds.), Il primo popolamento Olocenico dell’area de La Scola (Isola di Pianosa, Comune di Campo
corsotoscana. Edizioni ETS, Pisa, pp. 133–138.

nell’Elba, LI). In: Tozzi, C., Weiss, M.C. (Eds), Il primo Mackey, M.P., Warren, S.E., 1983. The identification of popolamento Olocenico dell’area corsotoscana. Edi-obsidian source in the M. Arci region of Sardinia.

zioni ETS, Pisa, pp. 83–90.

In: Aspinall, A., Warren, S.E. (Eds.), Proceedings of Francaviglia, V., 1984. Characterization of Mediterranean the 22nd Symposium on Archaeometry. University of obsidian sources by classical petrochemical meth-Bradford, England, pp. 420–431.

ods. Preistoria Alpina—Museo Tridentino di Scienze Marini, N., De Francesco, A.M., Bocci, M., Bressy, C., Naturali di Trento (Italy) 20, 311–332.

Gratuze, B., 2007. Costa di U Monte—du Néolithique

Francaviglia, V., 1988. Ancient obsidian sources on Pan-à l’âge du Fer sur la cote orientale corse: Résultats
telleria (Italy). Journal of Archaeological Science 15, de fouilles et provenance des vestiges. In: Tozzi, C., 109–122.

Weiss, M.C. (Eds.), Préhistoire et protohistoire de Fugazzola Delfino, M.A., Pessina, A., Tiné, V., 2004. Il l’aire tyrrhénienne. Ed. Felici, Pisa, pp. 35–42.

Neo litico in Italia. Ricognizione, catalogazione e pub

Pessina, A., Radi, G., 2006. La diffusione dell’ossidiana blicazione dei dati bibliografici, archivistici, materiali nell’Italia centro-settentrionale. Atti della XXXIX
e monumentali. Vol. 3. Istituto Italiano di Preistoria Riunione Scientifica dell’Istituto di Storia e Protostoria.

e Protostoria, Rome, Soprintendenza al Museo Pre-

Vol. 1, 435–460.

istorico Etnografico “L. Pigorini,” Florence.

Radi, G., Danesi, E., 2003. Il sito neolitico di Settefonti a Glascock, M.D., Neff, H., 2003. Neutron activation

Prata d’Ansidonia (AQ). Atti della XXXVI Riunione analysis and provenance research in archaeology.

Scientifica dell’Istituto di Storia e Protostoria, 163–179.

Measurement Science and Technology 14, 1516–1526.

Renfrew, C., Cann, J.R., Dixon, J.E., 1965. Obsidian in Gratuze, B., 1999. Obsidian characterization by laser
the Aegean. Annual of the British School at Athens 60, ablation ICP-MS and its application to prehistoric

225–247.

trade in the Mediterranean and the Near East:

Shackley, M.S. (Ed.), 1998a. Archaeological Obsidian Stud

Sources and distribution of obsidian within the
ies: Method and Theory. Kluwer Academic/Plenum Aegean and Anatolia. Journal of Archaeological Sci

Press, New York.

ence 26, 869–881.

Shackley, M.S., 1998b. Gamma rays, X-rays, and stone

Hallam, B.R., Warren, S.E., Renfrew, C., 1976. Obsidian tools: Some current advances in archaeological
in the western Mediterranean: Characterization by
neutron activation analysis and optical emission
geo chemistry. Journal of Archaeological Science 25, spectroscopy. Proceeding of the Prehistoric Society 259–270.

42, 85–110.

Shackley, M.S., 2002. Precision versus accuracy in the Kayani, P.I., McDonnel, G., 1996. An assessment of back-XRF analysis of archaeological obsidian: Some les-
scattered electron petrography as a method for dis-
sons for archaeometry and archaeology. In: Jerem,
tinguishing Mediterranean obsidians. Archaeometry

E., Biro, K.T. (Eds.), Proceedings of the 31st Sym

38, 43–58.

posium on Archaeometry, Budapest, Hungary. B.A.R.

Liritzis, I., 2007. Assessment of Aegean obsidian sources International Series 1043(II). Archaeopress, Oxford,
by a portable ED-XRF analyzer (grouping, prov-

UK, pp. 805–810.

enance and accuracy). In: Facorellis et al. (Eds.),

Shackley, M.S., 2005. Obsidian. Geology and Archaeology Proceedings of Hellenic Archaeometry Con ference in the North American Southwest. University of Ari-

(with international participation). B.A.R Inter na tional zona Press, Tucson.

Series, Archaeopress, Oxford, UK, pp. 399–406.

Silvestrini, M., 2003. Dal Paleolitico all’età del Bronzo.

Liritzis, I., Zacharias, N., 2011. Portable XRF of a
e XRF o rchaeo-
o-

In: Luni, M. (a cura di), Archeologia nelle Marche.

logical artefacts: Current research, potentials and lim-Nardini Editore, Florence, pp. 21–30.

itations. In: Shackley, M.S. (Ed.), XRay Fluor escence Stewart, S.J., Cernicchiaro, G., Scorzelli, R.B., Poupeau, Spectrometry in Geoarchaeology. Natural Sci ences in G., Acquafredda, P., De Francesco, A.M., 2003. Mag-Archaeology series, Springer North Amer ica, chapter
netic properties and 57 Fe Mossbauer spectroscopy

6, pp. 109–142.

of Mediterranean prehistoric obsidians for proven-

Lorenzi, F., 1999. Lumaca: un example de neolithisation ance studies. Journal of NonCrystalline Solids 323, au nord du Cap Corse. In: Tozzi, C., Weiss, M.C.

188–192.

Obsidian Provenance at Italian and Corsican Sites | 129

Summerhayes, G., Bird, J.R., Fullagar, R., Gosden, C., Series 625, Archaeological Chemistry. Washington, Specht, J., Torrence, R., 1998. Application of PIXED.C., pp. 116–130.

PIGME to obsidian characterization on west New

Tykot, R.H., 1997. Characterization of the Monte Arci

Britain, Papua New Guinea. In: Shackley, M.S. (Ed.),

(Sardinia) obsidian sources. Journal of Archaeological Archaeological Obsidian Studies: Method and Theory.

Science 24, 467–479.

Plenum Press, New York, pp. 129–158.

Tykot, R.H., Setzer, T., Glascock, M.D., Speakman, R.J., Tozzi, C., Zamagni, B., 2003. Gli scavi nel villaggio neo

2005. Identification and characterization of the
litico di Catignano (1971–1980). Origines, Studi e obsidian sources on the island of Palmarola, Italy.

materiali pubblicati a cura dell’Istituto Italiano di

Geoarchaeological and Bioarchaeological Studies 3, Preistoria e Protostoria, Florence, pp. 239–240.

107–111.

Tozzi, C., 2007. Considerazioni riassuntive sull’insed-Williams Thorpe, O., Warren, S.E., Courtin, J., 1984. The iamento di Cala Giovanna—Piano. In: Tozzi, C.,
distribution and sources of archaeological obsid-

Weiss, M.C. (Eds), Preistoria e Protostoria dell’area ian from Southern France. Journal of Archaeological Tirrenica. Felici, Pisa, pp. 167–168.

Science 11, 135–146.

Tykot, R.H., Young, S.M.M., 1996. Archaeological appli-Williams Thorpe, O., 1995. Obsidian in the Mediterranean cations of inductively coupled plasma-mass spec-and the Near East: A provenancing success story.

trometry. In: Orna, M.V. (Ed.), ACS Symposium Archaeometry 37, 217–248.

Chapter 10

Polynesian Volcanic Glass

Uses, Sourcing, and Distribution

Marshall Weisler

Abstract
is a subclass of high-silica rhyolitic volcanic glass

(Weisler and Clague 1998:104), and basaltic glass refers Volcanic glass has been used the world over for
to Hawaiian glasses that are more or less basaltic in
manufacturing a range of cutting tools used for utili-
composition and are correctly called trachylite, which tarian as well as ceremonial purposes. In Polynesia,
is commonly found as chilled margins of dikes (Gary
aside from the mata’a of Easter Island, few formal et al. 1972:721). Pitchstone, where the only Polynesian tools are made and routine artifact forms are simple
occurrence is on Pitcairn Island, forms by the deposi-
flakes and cores approximately 20 mm in size. Flakes
tion and consolidation of ash flows and has a waxy,
rarely exhibit retouch or use-wear and few flakes in
dull, resinous luster (Bates and Jackson 1984:254, 386).

a typical assemblage appear used. However, volca-
nic glass flakes and debitage are common artifacts in

2. Geologic settings of
early sites in Samoa and Tonga, often associated with
the first pottery-bearing deposits. Hawaiian volcanic
volcanic glass
glass artifacts are found throughout the sequence.

Volcanic glass is found in a range of geological

Obsidian is well attested in New Zealand archaeo-
contexts, both primary (in situ) and secondary or
logical sites, where it is found as flakes throughout
detrital accumulations. Dikes are the most numer-
all time periods and across all regions (Sheppard
ous sources of volcanic glass in Polynesia (Weisler

2004; Sheppard et al. 2011). Despite the presence of

1990:fig. 4). These are intrusive bodies, 1 m to more
a substantial source of large boulders and cobbles
than 10 m in width, that follow lines of weakness
on Mayor Island, New Zealand, formal tools were
through existing strata. The margins of the dikes
not made, while large and small flakes, some with
cool rapidly and solidify or quench before much
retouch, were common. This paper summarizes the
crystal formation, thus forming a glassy ground-
distribution of volcanic glass throughout Polynesia
mass. The thin selvages or borders are characteris-
except Easter Island and New Zealand and describes
tically about 20 mm thick (figure 10.1). At present,
the prehistoric uses as inferred from use-wear
there has been no recorded evidence of “quarrying”

studies and recent residue analyses. Volcanic glass
at these sources. However, the volcanic glass from
artifacts and source material have also been used
these selvages is cubelike in shape and was com-
effectively in documenting prehistoric interaction,
monly reduced by bipolar reduction.

and these initial pursuits are outlined.

Volcanic glass can also form as a thin “crust”

(<30 mm thick) on lava flows over an extensive area.

1. Definitions

These deposits are relatively uncommon and are
only found on the leeward slopes of Hawaii Island

In this paper the term volcanic glass is a general label where the lavas are geologically young and relatively
that indicates noncrystalline glasses where obsidian unweathered (Williams 2004).

130

Polynesian Volcanic Glass | 131

Figure 10.1. A volcanic glass
dike at Waiahewahewa, west

Moloka‘i, Hawaiian Islands. The
thin ~20 mm thick selvedges of
volcanic glass are located just
above the lines of white dots
added to the figure. The scale
is 50 cm long.

Volcanic cones form a third geologic context
tasks (Kirch 1979; Kirch and Kelly 1975; Rosendahl
in which rare deposits of volcanic glass have been

1972), although after a comprehensive study of 980
found. The best-known source of trachytic volca-
specimens, Schousboe et al. were “not prepared to
nic glass is the 1.6-km-diameter pumice and vol-
make any definitive statements on the functions of
canic glass cone at Pu‘u Wa‘awa‘a on Hawaii Island
the Waimea-Kawaihae [Hawaii Island] artifacts”

(Stearns and Macdonald 1946:205).

(1983:368). Some have speculated that volcanic glass

Detrital or secondary sources of volcanic glass
flakes may have been used for circumcision (Orliac
are characterized by pebbles and cobbles that accu-

1997:206). Morwood (1974) analyzed obsidian flakes
mulate in drainages downslope of in situ geologic
from several North Island, New Zealand, sites and
sources such as dikes, plugs, or other outcrops. The
suggested uses including woodworking, scraping,
cortex of detrital material is often pitted, rounded,
and cutting tasks. Microscopic edge damage, usu-
and smoothed during transport.

ally small flake scars along only one edge of the flake, was thought to result from cutting, scraping, or bor-3. Uses
ing tasks when scaling and gutting fish, butchering
dog and pig, scraping vegetables, and preparing fiber

Since the raw material is quite small, there is no tra-or bark. None of these explanations has been tied
dition of formal tool manufacture as in other parts
directly to empirical evidence of these inferred tasks.

of the world where obsidian is a preferred resource

However, residue studies are a significant avenue for
for manufacturing flake blades and a range of bifaces
unraveling the uses of volcanic glass in prehistory.

(e.g., arrow and spear points). Based on retouch,

A recent study examining a total of 29 Hawaiian
microscopic edge damage, step flake scars, and crush-
basaltic glass artifacts from Moloka‘i and pitchstone
ing, most researchers have assumed that small sharp
flakes from Henderson Island (Pitcairn Group) docu-
flakes were used for light or fine cutting and scraping mented residues suggestive of plant processing and

132 | OBSIDIAN AND GLASS PROVENANCE
shell incising (Weisler and Haslam 2005). Further
that Goat Island was not the source of the artifacts.

analysis on an expanded sample from a broader range

These and other studies show that volcanic glass is
of sites should elucidate further the functions of this often obtained from local sources.

nondescript artifact class.

From a collection of 51 volcanic glass artifacts

Volcanic glass has also been used by archaeolo-
from 12 archaeological sites spanning the culture-
gists in Polynesia to determine stratigraphic integ-
historical sequence from Tonga, Burley et al. (ms)

rity. Green (1974:148) assumed that volcanic glass
used the new portable X-ray fluorescence tech-
artifacts found in the European levels of a Western
nique (p-XRF) (Sheppard et al. 2010) to characterize

Samoan house site were displaced from the older,
sources and artifacts for examining inter-island voy-
pottery-bearing layer below.

aging and interaction between Tonga and Samoa.

Using a suite of 18 elements, rubidium (Rb) and

4. Sourcing or Interaction
strontium (Sr) were effective in separating sources.

Studies

Tonga and Samoa were considered an integrated
homeland region, yet the sourcing results document

In briefly reviewing interaction studies, or the geo-
little extra-archipelago interaction. The transfer of
chemical characterization of artifacts and geological
volcanic glass within Tonga occurred throughout
source material, it is necessary to separate obsid-
the sequence along a 600-km length of islands.

ian from volcanic glass since much work has been

Despite its proven efficacy more than 20 years
done with the former in New Zealand (e.g., Green
ago (Weisler 1990; Weisler and Clague 1998), geo-

1962; Ward 1974a; Leach 1978; Leach et al. 1986;
chemical characterization studies in Hawai‘i have

Leach and Warren 1981; Sheppard 2004; Sheppard
been slow to take hold (McCoy et al. 2011). From the
et al. 2011), and the demonstrated efficacy of geo-
electron microprobe analysis of volcanic glass arti-
chemical analysis with volcanic glass in Tonga and
facts from several habitation sites on Moloka‘i, 2 were Samoa (Clark and Michlovic 1996; Clark and Wright
assigned to a source on O‘ahu and 1 to the Mauna

1995; Sheppard et al. 1989; Ward 1974b), the Pitcairn

Kea adze quarry area on Hawaii Island (Weisler and

Group (Weisler 1995; Weisler and Clague 1998), and

Clague 1998:122), documenting the first inter-island

Hawai‘i (Weisler 1990; Weisler and Clague 1998) has
transport of this material. McCoy et al. (2011) ana-
only recently been pursued further by others (Burley
lyzed 3329 volcanic glass artifacts from 87 archaeo-
et al. ms; McCoy et al. 2011).

logical sites throughout the Hawaiian Islands and

Ward (1974b) used X-ray fluorescence (XRF)

the Pu‘u Wa‘awa‘a source using non-destructive
analysis of 23 volcanic glass artifacts—14 from Samoa

XRF and focusing on selected mid-Z elements (Sr,
excavated by Green (1974) and 9 from Tonga—to

Zr, and Y). The Pu‘u Wa‘awa‘a trachyte appears to be
determine if the geologic source was on Tafahi Island, the only Hawaiian volcanic glass that is distinctive

Tonga. Only 4 elements were analyzed in this early
macroscopically (Olson 1983). Using primarily arti-
study: zirconium (Zr), magnesium (Mn), rubidium
fact size and distance from Pu‘u Wa‘awa‘a, McCoy et

(Rb), and strontium (Sr), and only Tongan artifacts
al. (2011) developed a cost-surface model in which
were assigned to the Tafahi source. Sheppard et al.

it was possible to infer down-the-line exchange and

(1989) analyzed 7 volcanic glass artifacts from the
remote direct access to the source (see also Weisler
same assemblage with a non-destructive Instru-
and Green 2001:436–440 for defining interaction
mental Neutron Activation Analysis (INAA) using
spheres in East Polynesia based on travel time).

20 elements and XRF (analyzing 10 elements) to

The distinctive Pitcairn pitchstone can be
determine the source. Samples from a suspected
sourced in hand specimen due to its color, lus-
archaeological source on Goat Island, Pago Pago
ter, translucency, and opaqueness (Weisler and
harbor, Tutuila, were analyzed and compared to the

Clague 1998:105–109). However, energy-dispersive
artifacts suggesting a local Samoan provenance, but

X-ray fluorescence was also used to characterize
not Goat Island. Petrographic descriptions of the
the Pitcairn pitchstone (Weisler 1994:94, 1997:165).

artifacts and geological material also demonstrated

From habitation contexts dating as early as AD 900

Polynesian Volcanic Glass | 133
on Henderson Island (located approximately 100 km

Wright 1995:256) because TiO was removed from

2
north of Pitcairn Island), some 132 pieces of volca-
the magmas by early crystallization of titanium mag-
nic glass were recovered from five sites. This mate-
netite (Natland 1980). In other words, there are clear rial was part of a comprehensive suite of imported
petrogenetic reasons why Tutuila volcanic glass is
materials used to reconstruct an interaction sphere
geochemically distinctive.

operating for about six centuries that was ultimately
tied to the Mangareva group, about 400 km west

5. Distribution

(Weisler 1997).

One of the most thoughtful and interdisciplin-

From west to east, the archaeological evidence for
ary studies of volcanic glass underscores the benefit
volcanic glass in each of the Polynesian archipela-
of archaeologists working with geochemists (see also
goes is briefly summarized (figure 10.2). Where little Weisler 2008; Weisler and Clague 1998). Geochemist
evidence is available, it is presented in more detail.

Wright analyzed 14 volcanic glass artifacts from the

Conversely, the data for Hawai‘i is summarized and

‘Aoa site, Tutuila, using the scanning electron micro-
ample references provided for additional details.

scope energy-dispersive (EDAX) attachment for

It will be apparent from this review that actual
the standard suite of 10 elements from SiO to P O

“sources” are rare aside from the few basaltic glass

2

2 5

(Clark and Wright 1995). Rather than using statis-
dike sources on Moloka‘i and the Pu‘u Wa‘awa‘a tra-
tical clustering programs to assign these artifacts
chyte on west Hawaii Island, the undescribed source
to a source, a multistage, geochemically-informed
on Tafahi (Tonga) and Futuna (Wallis and Futuna
procedure was used. Tutuila and ‘Upolu rocks can
group), and secondary alluvial deposits in Samoa.

be separated from other Pacific volcanic glasses as
these Samoan rocks have higher aluminum/calcium

5.1 West Polynesia

(Al O /CaO) ratios. Alkalies (Na O + K O) were

Wallis and Futuna. Situated between Fiji and Samoa 2 3

2

2
plotted against silica (SiO ) to clearly demonstrate
in the extreme west of Polynesia, the two smaller

2
that Tutuila basalts are easily differentiated from
of the three islands of the Wallis and Futuna group,
those of ‘Upolu. Furthermore, low values for tita-

Futuna (80 km2) and Alofi (35 km2), are deeply weath-
nium (TiO ) are diagnostic for Tutuila (Clark and
ered volcanic islands. Kirch recovered 59 volcanic

2

Figure 10.2. A map of West and East Polynesia with the locations of archipelagoes and
islands mentioned in the text. The Andesite

Line separates Oceanic Island Basalt (OIB)

islands from those of continental origin,
which have a greater diversity of rock types.

134 | OBSIDIAN AND GLASS PROVENANCE
glass cores and flakes from excavations at site FU-19, A small core (13.3 mm maximum length) was
about 5 km south from the source on Futuna (1981:

reported from the To‘aga site, Manu‘a Islands, Amer-
fig. 1, 140). Similar to sites in Tonga and Samoa, many ican Samoa, that was “a reddish brown color, with
of the artifacts were from the pottery-bearing earliest black spots and banding” (Kirch 1993:165) and was
layers. The Futuna volcanic glass artifacts were quite likely to be an import.

opaque with numerous microfractures filled with an

Excavations at a 3000-year-old habitation site
orange-colored material (Kirch 1981:140). These arti-
at the mouth of ‘Aoa Valley, Tutuila Island, recov-
facts probably occurred as small nodules with the
ered 177 flakes (24 of which were used) and 98
average length of cores 14.2 mm. There was no evi-
cores from the deepest layers of the site (Clark and
dence of retouch, and the bipolar technique was prob-

Michlovic 1996:table 2). Most of the artifacts were
ably the reduction strategy. No details were provided

<10 mm in diameter, 31.5% had cortex, all were red-
on the source.

dish brown to black in color, and many exhibited

Samoa. Savai‘i, ‘Upolu, and Tutuila, ranging in the characteristics of the bipolar reduction strategy.

size from 1820 km2 to 124 km2, are the three major

Secondary deposits, such as streambeds, were prob-
islands of Samoa and probably reflect a hotspot ori-
able sources due to the partially weathered cortex
gin (Duncan 1985). Dikes with volcanic glass borders

(Clark and Michlovic 1996:161), or material may
and plugs with breccias containing volcanic glass
have originated from quenched magma exposed
exposed by erosion in steep drainages produced
near the base of plugs as chunks in breccias on
nodules that subsequently developed water-rounded

Tutuila (Clark and Wright 1995:256). Only 14 vol-
cortex that may be the source of artifacts found in
canic glass artifacts (5 cores and 9 flakes) have been several habitation sites. Terrell (1969:168–170) iden-reported from seven other Samoan sites (see Clark
tified one of the first occurrences of Samoan “obsid-
and Wright 1995:table 5).

ian” restricted primarily to pottery-bearing contexts

Tonga. Consisting of about 150 islands (the larg-at a habitation mound (SU-VA-4), Western Samoa.

est, Tongatapu, is 257 km2), this archipelago consists Like many researchers who first encounter volcanic
of three main subgroups with younger volcanic arc
glass artifacts in Polynesia, Terrell was surprised
islands west of the older limestone-covered islands.

by the small size of the artifacts. Of 74 specimens,

Although volcanic “country” rock is available on

23 cores were 10–23 mm long (mean = 15 mm), and
many of the islands, only one fine-grained basalt

50 flakes ranged from 5 to 17 mm (mean = 10 mm).

source on the southernmost island of ‘Ata (Weisler

Only one flake had obvious retouching and was prob-

2004) and one volcanic glass source on Tafahi are
ably used for “fine cutting” (Terrell 1969:169). Because currently known. Ten samples from Tafahi were
at least one of the cores had water-rounded cortex,
analyzed by X-ray fluorescence to characterize the
the source of the volcanic glass was assumed to be the source and were compared to nine artifacts col-nearby Falefa Valley where natural siliceous pebbles
lected by Rogers (1974) on Niuatoputapu 7 km away.

were found in the alluvium. The artifacts had a dull

Ward reported (1974c:345) that the artifacts from
black luster with fresh surfaces that were glassy and a Lapita contexts were most likely from Tafahi. The
few had reddish streaks (Terrell 1969:169).

Tafahi source is at Tefitomaka and consists of nod-

Green recovered 22 flakes and cores, primarily
ules of volcanic glass, up to the size of a “chicken
from pottery-bearing layers, at a Western Samoan
egg,” embedded in tuff (Dye 1988). Dye mentioned
house site; he commented that more artifacts could
similar tuff outcrops behind Viapoa village, but the
have been recovered if the matrix was not muddy

Tefitomaka source is more easily accessible. Dye

(1974:146–149). The average size of the flakes and

(1988:table 3) collected 97 pieces of volcanic glass
cores was 6–23 mm (mean = 12 mm). The flakes
from five surface and excavated Tafahi sites; no fur-
were produced by the bipolar reduction of cores. A
ther data were provided.

single, detrital local source of the volcanic glass was Only two pieces of unworked volcanic glass were
suggested by the water-rounded cortex and small
recovered from Poulson’s extensive excavations on
artifact size.

Tongatapu, Tonga, both coming from pottery-bearing

Polynesian Volcanic Glass | 135

(i.e., early) layers (Poulson 1987). This small amount weathered nature of most of the volcanic islands, no
is likely a reflection of the collection techniques
locally available volcanic glass artifacts have been
used during the 1960s when the excavations were
reported from Cook Island archaeological sites
conducted.

despite extensive research on several of the islands

From excavations on Niuatoputapu, Kirch recov-

(Allen 1992; Kirch et al. 1995; Walter 1998; Weisler et ered 11,457 volcanic glass flakes and cores primarily
al. 1994). It is likely that any volcanic glass artifacts associated with 3000 BP ceramic sites (Kirch 1988:

would be imported from outside the archipelago.

214–217). Less than 3 percent of the assemblage was

This may be the case for an approximately 35-mm-
analyzed for metrical attributes (length, width, thick-long “obsidian” retouched flake reported from a
ness, weight, striking platform thickness and width)

surface context from site AIT.3, ‘Are Karioi, Aitutaki and morphological attributes (presence/absence of

(Bellwood 1978:fig. 46c, 132).

cortex, dorsal ridges, bulb of percussion, and termin-

Society Islands. The Society Islands are a time-ation type). The typical flake was <23 mm in length, progressive hotspot-evolved archipelago much like
generally lacking cortex, with one or two dorsal

Hawai‘i. The large island of Tahiti has fine-grained
ridges; percussion bulbs were lacking or diffuse, and
basalt sources in Papeno‘o Valley, but no volcanic
a range of flake terminations were present. Hard
glass has been reported. Indeed, dikes are consid-
hammer and anvil were used for flake production.

ered rare on Tahiti and have been observed at only

Only occasional flakes had secondary retouch (Kirch
four localities on Mo‘orea (Williams 1933:29, 73).

1988:215).

The artifact class is rare in Society Islands sites with Burley recovered a varied assemblage of volcanic
only 6 pieces recovered from recent excavations in
glass artifacts from recent excavations on Vava‘u (per-

‘Opunohu Valley, Mo‘orea; these specimens ranged
sonal communication 2004). Connaughton (2007:

from about 11 mm to 28 mm long and all had cortex

209) recovered 4 “obsidian” flakes from later prehis-
suggesting they were reduced from small nodules
toric contexts on Falevai, suggesting a local source

(Kahn 2005:366–367). Rappaport et al. (1967:199)

(probably Tafahi). No further data were presented in
reported 3 “obsidian” flakes from their coastal exca-
his preliminary report.

vations at the Ta‘auroa site on Mo‘orea. Leach geo-

Niue. Situated approximately 400 km east of
chemically analyzed 2 of these reported flakes, and

Tonga, 700 km south of Samoa, and 500 km west of

1 of them (catalog number 85/2218) turned out to
the Cook Islands, isolated Niue (260 km2) is strategi-
be “English” chert, perhaps a gun flint. Another
cally situated for addressing issues of interaction and specimen (85/2232) reported as “obsidian” had only
isolation. As a raised limestone ( makatea) island, 12.8% silica, which is extremely low for any volca-there are no naturally occurring volcanics. Although
nic glass and it was assumed to be basaltic glass (B.F.

one polished basalt adze flake was recovered from

Leach, letter to the American Museum of Natural
recent archaeological excavations that might be from

History, 22 July 1981), although this assumption

Samoa (Walter and Anderson 2002:77–78), no vol-
seems unlikely as Hawaiian basaltic glass is approxi-
canic glass was recovered.

mately 48–52% silica (Weisler and Clague 1998:

table 5.2). Historic artifacts were found throughout

5.2 East Polynesia
the unstratified deposits (Rappaport et al. 1967:200)

Cook Islands. Only 6 of the 15 Cook Islands are vol-and it may be that all of the “obsidian” specimens
canic (Weisler and Sinton 1997:table 10.6), and geol-
were historic chert artifacts. However, this does not
ogists Wood and Hay lament that “volcanic rocks
discount the use of volcanic glass prior to European
are almost all weathered to a considerable degree
contact in the Society Islands, for Orliac reports

. . . and rock specimens can be obtained in a few

2 flakes of volcanic glass from the Putoa rockshelter
places” (Wood and Hay 1970:27). Dikes have been
in the Papeno‘o Valley, Tahiti (Orliac 1997:206; see
identified on four islands (Walter and Sheppard
also Kahn 2005) from presumably prehistoric con-

2001:table 29.1) without any mention of glassy sel-
texts. From work thus far, prehistoric volcanic glass
vages. Because of the eroded topography and highly
artifacts are extremely rare in the Society Islands.

136 | OBSIDIAN AND GLASS PROVENANCE

Australs. Geologically, the five Austral Islands and Kirch 2004; Green and Weisler 2000), no volca-form the southern extent of the Southern Cook
nic glass artifacts have been recovered.

Islands–Australs volcanic chain that shares geochem-

Pitcairn Group. Made famous by the Bounty ical and geochronological affinities (Woodhead
mutineers, the Pitcairn Group consists of four

1996:2, fig. 1). Archaeological field research in this islands: Pitcairn, a Pleistocene volcano about 4.5 km2
area of French Polynesia has been limited to late
in size and the only volcanic island of the group;
prehistoric settlement pattern surveys on Ra‘ivavae

Hen derson, a raised limestone makatea island some
where no suitable fine-grained basalt dikes were

37 km2 in area; and the diminutive atolls of Oeno
located (Edwards 2003:161) that could have con-
and Ducie. Hence, only Pitcairn has naturally
tained volcanic glass selvages. Test excavations by the occurring sources of fine-grained basalt and a

Norwegian Archaeological Expedition on Rapa did
highly siliceous volcanic glass or ignimbrite (also
not report any volcanic glass artifacts (Smith 1965),
known as pitchstone). The main source of volca-
nor did recent excavations there by Anderson recover
nic glass is located at the cliffs above Down Rope
any. Anderson did not locate any geological sources
where cobbles and pebbles of angular black, glassy
on the island (personal communication 2004). No
rock have eroded out of the tuff and accumulated
volcanic glass artifacts were reported by Vérin (1969) at the beach below (Carter 1967:28, fig. 1; Weisler
from Rurutu. Recent excavations on Tubuai (Bollt,

1995:fig. 2). In thin section the glass is pale brown
personal communication 2004) and on Rurutu (Bollt
with rare crystals of anorthoclase, scattered micro-

2008) did not recover any volcanic glass artifacts, but phenocrysts of fayalitic olivine, and augite together
fine-grained basalt debitage was common.

with numerous microlites of sodic feldspar (Carter

Tuamotus and other atoll archipelagoes. The 75

1967:28). It has characteristic black to gray patches
low coral atolls and 1 raised makatea island of the
in a glassy groundmass (Weisler and Clague 1998:

Tuamotus are dispersed over approximately 1000 km

106, fig. 5.3). This volcanic glass is easily identifi-between the Society Islands to the northwest and
able in hand specimen when compared to all the
southeast to Mangareva. There are no naturally
known glass sources in Polynesia. Flakes of this
occurring volcanic rocks and no volcanic glass has
ignimbrite are found in archaeological sites across
been reported to date (Emory 1975). The same is

Pitcairn (Gathercole 1964), and flakes and cores
true of the atoll archipelagoes of Tuvalu and Tokelau
were also transferred prehistorically to Henderson

(West Polynesia) and the Line Islands of East

(see above) approximately 100 km distant (Weisler

Polynesia, although imported basalt adze material

1994:94; 1997). Beginning as early as AD 900, Pit-
is known from many atolls throughout these groups
cairn volcanic glass appears in Henderson habita-

(e.g., Best et al. 1984; Collerson and Weisler 2007).

tion sites, where 132 artifacts weighing 110 g were

Mangareva. Mangareva is situated between the
found mostly at north coast sites (Weisler 1997:165,

Tuamotus to the northwest and the Pitcairn Group
table 9.1, figs. 9.41 and 9.4m).

to the southeast that together form the Pitcairn-

Marquesas. Thus far only one volcanic glass

Mangareva lineament that is time-progressive with
flake has been recovered from a Marquesan
increasing island age toward the northwest (Duncan
archaeo log ical site. No volcanic glass artifacts were and McDougall 1976). Mangareva consists of 4 main
reported from extensive excavations at Hanamiai,
volcanic islands and 22 smaller islands, coral islets, Tahuata (Rolett 1998) or other sites on Nuku Hiva
and sand cays. Dikes are found on all the volcanic

(Allen and McAlister 2010; Rolett and Conte 1995;
islands except Aukena (Brousse and Guille 1974:fig.

Suggs 1961). This is especially curious since the

1), but only a few personally observed have very

Marquesas are oceanic basalt islands with intru-
thin (<5 mm) selvages of volcanic glass, unusable
sive dikes. It is likely that the glassy selvages are
for flake production (Weisler and Green 2001:429).

too thin for stone-tool production, similar to the

Island-wide surveys (Weisler 1996) have failed to
situation in Mangareva. The only known volcanic
locate any useable volcanic glass sources. With more
glass flake is approximately 15 mm long, shiny, dark
than 100 m2 excavated throughout the group (Conte
brownish-black, and opaque (M.S. Allen, personal

Polynesian Volcanic Glass | 137
communication, 2011). It was recovered from layer
beginning to provide empirical evidence suggest-

IV at Teavau‘ua, Anaho, Nuku Hiva and dated to
ing plant processing and shell working (Weisler and

AD 1200–1400 (Allen 2009:fig. 5).

Haslam 2005).

Hawai‘i. Unlike at other Polynesian islands, volcanic glass artifacts are very common in Hawaiian

6. Conclusions
prehistoric habitation sites. The Hawaiian Islands
are the longest linear, time-progressive chain in the

Volcanic glass has a limited distribution in Polynesia Pacific, trending nearly 2500 km northwest from
as summarized in table 10.1. Outside of Easter Island, Hawaii Island positioned above the active hotspot
the only obsidian deposits are located on the North

(Clague and Hazlett 1989; Macdonald and Abbott

Island of New Zealand, where four major source

1970:fig. 1). The marked age gradient is reflected in
regions are known (Sheppard et al. 2011). Due to
the relatively pristine lava flows of west and south-
the quantity of volcanic glass-bearing dikes found
east Hawaii Island to the widespread, deeply dis-
across the Hawaiian Islands (Weisler 1990:fig. 1)

sected valleys and gulches toward the north of the
and widespread chill glass sources associated with
main islands as exemplified by O‘ahu and Kaua‘i.

flows on Hawaii Island (Williams 2004), flakes and

Hawaiian volcanic glass occurs in three geologic
cores are very common in prehistoric archaeologi-
formations: rare trachyte associated with volcanic
cal sites from all time periods. Indeed, the Hawaiian
cones (Cross 1904), most commonly as a glassy bor-

Islands may have more volcanic glass artifacts than
der or selvage along dikes (Weisler 1990), and occa-
any Polynesian archipelago. It is interesting to note
sionally as surface chills on lava flows (Williams
that volcanic glass artifacts in West Polynesian sites, 2004). Because of the erosional regime of the archi-however, are most often associated with the oldest
pelago, more dikes are found on the older islands of
pottery-bearing layers in Futuna, Alofi, Samoa, and

Kaua‘i and O‘ahu (Weisler 1990:table 1), but more

Tonga. Perhaps these colonists, coming from Lapita
useable, unweathered volcanic glass appears to be
settlements to the west, were trying to replicate their found on the younger islands. In this latter regard,
long tradition of obsidian use and trade so com-
only surface chill glass, of stone-tool quality, has
mon in Near Oceania (see Kirch 1997). The inferior
been found on the youngest Hawaii Island (Williams
sources of volcanic glass in West Polynesia proved to

2004). The biggest source of trachytic volcanic glass
be of limited utility and its use eventually declined
is at Pu‘u Wa‘awa‘a, a pumice and volcanic glass
or ended.

cone some 1.6 km in diameter, located on the north

Ironically, the diminutive island of Pitcairn
slope of Hualalai volcano (Stearns and Macdonald

(4.5 km2) has one of the largest volcanic glass sources 1946:205). The largest nodules of Hawaiian volcanic
in Polynesia, where nodules can exceed 100 mm, yet
glass are known from here (Macdonald and Abbott
artifacts are not abundant in habitation sites. Due

1970:109), yet only recently have volcanic glass arti-
to the differing age and weathering regimes of East
facts in distant habitation sites been geochemically

Polynesian archipelagoes, volcanic glass has a patchy
identified as coming from this source (McCoy et al.

distribution. Of the volcanic islands, no indigenous

2011). Clearly, more geochemical sourcing work in
volcanic glass artifacts are known from the Cook

Hawai‘i is warranted from successful early studies

Islands, Australs, Mangareva, and the Marquesas,

(Weisler 1990; Weisler and Clague 1998).

while they are extremely rare in the Society Islands,

Like non-obsidian volcanic glass artifacts found
where the few reported flakes may well be imports.

throughout Polynesia, flakes and cores are usually no

In this regard, it will be interesting to see if the
larger than 20 mm and few flakes exhibit any evidence
erosional regime of the main Hawaiian Islands is
of use-wear and/or retouch. Technological studies
mirrored by the average amount of volcanic glass
document a bipolar technique for reducing cores to
artifacts in archaeological sites; for example, we may flakes (Schousboe et al. 1983), and use-wear studies
expect to find more volcanic glass artifacts in Hawaii have not been very illuminating in determining solid

Island (0.6 million years old) sites as opposed to sites evidence of specific uses, although residue studies are on Kaua‘i (5.25 million years old).

138 | OBSIDIAN AND GLASS PROVENANCE

Table 10.1 Volcanic glass artifacts in Polynesia Wallis &

Cook

Society

Pitcairn

Marquesas

Hawaiian

Futuna

Samoa

Tonga

Islands

Islands

Australs

Mangareva

Group

Islands

Islands

Cores
x x x - - -

- x - x

metric
attributes
x x x - - -

- x - x

discrete
attributes - - x - - -

- x - x

Flakes
x x x x x -

- x x x
metric attributes
x
x
x

-
x

-

-
x
x
x

discrete
attributes x x x - x -

- x - x

Material Description

hand specimen
x
x

-

-

-

-

-
x
x
x
petrographic

-

-

-

-

-

-

-
x

-
x

geochemical

- x x - - -

- x - x

Relative Quantity
common
v. common
v. common
rare
rare
absent
absent
v. common
rare
v. common

Sourcing studies are the most developed in New
provided unpublished data on a volcanic glass flake

Zealand, with generally smaller successful applica-
from Nuku Hiva (Marquesas), and Mark McCoy
tions in Hawai‘i, Pitcairn, Tonga, and Samoa. Tech-
made an “in press” version of his 2011 paper avail-
nological studies are well developed, but have not
able. The Australian Research Council is acknowl-
been applied across Polynesia, where the most
edged for supporting this research. Thanks to all.

detailed studies have been in Hawai‘i (Schousboe et
al. 1983), in Tonga (Kirch 1988), and most recently in References

New Zealand (Holdaway 2004). Of primary concern
for future studies should be (1) the discovery, descrip-Allen, M.S., 1992. Dynamic Landscapes and Human Sub
tion, and geochemical characterization of new in situ
sistence: Archaeological Investigations on Aitutaki and secondary sources of volcanic glass; (2) increased Island, Southern Cook Islands. University Microfilms (UMI), Ann Arbor, MI.

emphasis on geochemical analysis of artifacts from

Allen, M.S. 2009. Morphological variability and tempo-
dated contexts for reconstructing patterns of inter-
ral patterning in Marquesan domestic architecture:

action; and (3) the more widespread documentation

Anaho Valley in regional context. Asian Perspectives of edge damage and use-wear to infer tool function,

48, 342–382.

including residue analysis for determining how small

Allen, M.S., McAlister, A.J., 2010. The Hakaea beach site, sharp flakes were utilized (Weisler and Haslam 2005).

Marquesan colonisation, and models of East Poly-

Although Polynesia does not garner worldwide atten-
nesian settlement. Archaeology in Oceania 45, 54–65.

tion for its volcanic glass artifacts, the subject merits Bates, R.L., Jackson, J.A. (Eds.), 1984. Dictionary of Geo
continued study for enhancing our understanding
logical Terms. Anchor Press, Garden City, NY.

of this nondescript material and its place in ancient

Bellwood, P.S., 1978. Archaeological Research in the Cook Polynesian societies.

Islands. Pacific Anthropological Records 27. Department of Anthropology, B.P. Bishop Museum, Honolulu.

Best, S., Sheppard, P., Green, R., Parker, R., 1984. Necro-Acknowledgments
mancing the stone: Archaeologists and adzes in

Samoa. Journal of the Polynesian Society 101, 45–85.

A version of this paper was delivered at the “Obsidian Bollt, R., 2008. Peva: The Archaeology of an Austral Island Summit” conference at Rikkyo University, Tokyo,

Settlement. Bishop Museum Bulletin in Anthro pology in 2004, and I thank the organizers for their efforts

12. Bishop Museum Press, Honolulu.

and memorable hospitality. Dave Burley provided a

Brousse, R., Guille, G., 1974. Réseau de dykes aux iles manuscript on his Tongan work, Melinda Suzy Allen

Gambier. Cahiers du Pacifique 18, 253–264.

Polynesian Volcanic Glass | 139

Table 10.1 Volcanic glass artifacts in Polynesia Duncan, R.A., 1985. Radiometric ages from volcanic
rocks along the New Hebrides–Samoa lineament.

Wallis &

Cook

Society

Pitcairn

Marquesas

Hawaiian

In: Brocher, T.M. (Ed.), Geological Investigations Futuna

Samoa

Tonga

Islands

Islands

Australs

Mangareva

Group

Islands

Islands
of the Northern Melanesian Borderland. Circum-Cores
x x x - - -

- x - x

Pacific Council for Energy and Mineral Resources,

metric
attributes
x x x - - -

- x - x

Houston, pp. 67–76.

discrete
attributes - - x - - -

- x - x

Duncan, R.A., McDougall, I., 1976. Linear volcanism in Flakes
x x x x x -

- x x x

French Polynesia. J. Volcanol. Geothermal Research metric attributes
x
x
x

-
x

-

-
x
x
x

1, 197–227.

discrete
attributes x x x - x -

- x - x

Dye, T.S., 1988. Appendix C. Archaeological investiga-

Material Description

tions on Tafahi Island. In: Kirch, P.V. (Ed.), Niuatoputapu: The Prehistory of a Polynesian Chiefdom.

hand specimen
x
x

-

-

-

-

-
x
x
x

Thomas Burke Memorial, Washington State Museum
petrographic

-

-

-

-

-

-

-
x

-
x

Monograph no. 5. Burke Museum, Seattle, pp. 278–287.

geochemical

- x x - - -

- x - x

Edwards, E., 2003. Ra‘ivavae, Archaeological Survey of Relative Quantity
common
v. common
v. common
rare
rare
absent
absent
v. common
rare
v. common

Ra‘ivavae, French Polynesia. Bearsville Press, Easter Island Foundation, Los Osos, CA.

Emory, K.P.E., 1975. Material Culture of the Tuamotu Burley, D.V., Sheppard, P.J., Simonin, M., ms. Tongan and Arch ipelago. Pacific Anthropological Records 22.

Samoan volcanic glass: pXRF analysis and implica-

Depart ment of Anthropology, B.P. Bishop Museum,
tions for constructs of ancestral Polynesian society.

Honolulu.

Carter, R.M., 1967. The Geology of Pitcairn Island, South Gary, M., McAfee Jr., R., Wolf, C.L., (Eds.), 1972. Gloss

Pacific Ocean. Bulletin 231. B.P. Bishop Museum, ary of Geology. American Geological Institute, Wash-Honolulu.

ington, D.C.

Clague, D.A., Hazlett, R.W., 1989. Geologic Field Guide Gathercole, P., 1964. Preliminary Report on Archa eo-to the Hawaiian Islands. 28th International Geologic logical Fieldwork on Pitcairn Island, January–March

Congress field trip guidebook T188/304. American

1964. Report on file, Library, University of Otago,

Geo physical Union, Washington, D.C.

Dunedin, New Zealand.

Clark, J.T., Michlovic, M.G., 1996. An early settlement in Green, R.C., 1962. Obsidian: Its application to archaeol-the Polynesian homeland: Excavations at ‘Aoa Valley,
ogy. New Zealand Archaeological Association News

Tutuila Island, American Samoa. Journal of Field letter 5, 8–16.

Archaeology 23, 151–167.

Green, R.C., 1974. Excavation of the prehistoric occupa-Clark, J.T., Wright, E., 1995. Volcanic glass in Samoa: A tions of SU-SA-3. In: Green R.C., Davidson, J.M.

technological and geochemical study. Journal of the (Eds.), Archaeology in Western Samoa. Vol. 2. Bulle tin Polynesian Society 104, 239–266.

of the Auckland Institute and Museum no. 6. Auck-

Collerson, K.D., Weisler, M.I., 2007. Stone adze compo-land Institute and Museum, Auckland, pp. 108–154.

sitions and the extent of ancient Polynesian voyag-

Green, R.C., Weisler, M.I., 2000. Mangarevan Archa
ing and trade. Science 317, 1907–1911.

eology: Interpretations Using New Data and 40 Year Connaughton, S.P., 2007. Can we dig it? Archaeology of Old Excavations to Establish a Sequence from 1200 to Ancestral Polynesian society in Tonga: A first look

1900 AD. University of Otago Studies in Prehistoric from Falevai. In: Bedford, S., Sand, C., Connaughton,

Archaeology no. 19. Department of Anthropology,

S.P. (Eds.), Oceanic Explorations: Lapita and Western Uni versity of Otago, Dunedin, New Zealand.

Pacific Settlement. Terra Australis 26. Australian Holdaway, S.J., 2004. The Kohika obsidian artifacts:

National University, Canberra, pp. 199–212.

Tech nology and distribution. In: Irwin, G. (Ed.),

Conte, E., Kirch, P.V. (Eds.), 2004. Archaeological Inves ti

Kohika, The Archaeology of a Late Maori Lake gations in the Mangareva Islands (Gambier Arch i pel

Village in the Ngati Awa Rohe, Bay of Plenty, New ago), French Polynesia. Contribution 62, Archaeo log -

Zealand. Auckland University Press, Auckland, pp.

ical Research Facility, University of Cali fornia, Berkeley.

177–197.

Cross, W., 1904. An occurrence of trachyte on the island Kahn, J.G., 2005. Household and community organiza-of Hawaii. Journal of Geology 12, 510–523.

tion in the Late Prehistoric Society Island chiefdoms

140 | OBSIDIAN AND GLASS PROVENANCE

(French Polynesia). Ph.D. dissertation, University of

Morwood, M., 1974. A functional analysis of obsid-

California, Berkeley.

ian flakes from three archaeological sites on Great

Kirch, P.V., 1979. Marine Exploitation in Prehistoric Hawaii.

Barrier Island and one at Tokoroa. Records of the Pacific Anthropological Records 29. Depart ment of

Auck land Institute Museum 11, 77–99.

Anthropology, B.P. Bishop Museum, Honolulu.

Natland, J.H., 1980. The progression of volcanism in the Kirch, P.V., 1981. Lapitoid settlements of Futuna and

Samoan linear volcanic chain. American Journal of Alofi, Western Polynesia. Archaeology in Oceania 16, Science 280-A, 709–735.

127–143.

Olson, L., 1983. Hawaiian volcanic glass applied to dating Kirch, P.V., 1988. Niuatoputapu: The Prehistory of a Poly
and “sourcing”: Archaeological context. In: Clark,
nesian Chiefdom. Thomas Burke Memorial Washing-J.T., Kirch, P.V. (Eds.), Archaeological Investigations ton State Museum Monograph no. 5. Burke Museum,
of the MudlandWaimeaKawaihae Road Corridor, Seattle.

Island of Hawai‘i: An Interdisciplinary Study of an Kirch, P.V., 1993. Non-ceramic portable artifacts from Environmental Transect. Departmental Report Series To’aga. In: Kirch, P.V., Hunt, T.L. (Eds.), The To’aga 83-1. B.P. Bishop Museum, Honolulu, pp. 325–340.

Site: Three Millennia of Polynesian Occupation in Orliac, M., 1997. Human occupation and environmen-the Manu’a Islands, American Samoa. Contributions tal modifications in the Papeno’o Valley, Tahiti. In:

of the University of California Archaeological

Kirch, P.V., Hunt, T.L. (Eds.), Historical Ecology in Research Facility no. 51. University of California,
the Pacific Islands, Prehistoric Environmental and Berkeley, pp. 157–165.

Land scape Change. Yale University Press, New Haven, Kirch, P.V., 1997. The Lapita Peoples: Ancestors of the CT, pp. 200–229.

Oceanic World. Blackwell, Oxford, UK.

Poulson, J., 1987. Early Tongan Prehistory. Terra Austra-Kirch, P.V., Kelly, M. (Eds.), 1975. Prehistory and Ecol
lis 12. Department of Prehistory, Research School
ogy in a Windward Hawaiian Valley. Pacific Anthro-of Pacific Studies, Australian National University,
pological Records 24. Department of Anthropology,

Canberra.

B.P. Bishop Museum, Honolulu.

Rappaport, R.A., Rappaport, A., Green, R.C., 1967. Des-Kirch, P.V., Steadman, D.W., Butler, V.L., Hather, J., criptive and comparative analysis of portable arti-Weisler, M.I., 1995. Prehistory and human ecology
facts recovered from coastal excavations. In: Green,
in Eastern Polynesia: Excavations at the Tangatatau

R.C., Green, K., Rappaport, R.A., Rappaport, A.,
rockshelter, Mangaia, Cook Islands. Archaeology in Davidson, J. (Eds.), Archaeology on the Island of Oceania 30, 47–65.

Mo’orea, French Polynesia. Anthropological Papers Leach, B.F., 1978. Four centuries of community interac-of the American Museum of Natural History 51 (2).

tion and trade in Cook Strait, New Zealand. Man

New York, pp. 184–200.

kind 11, 391–405.

Rogers, G., 1974. Archaeological discoveries on Niuato-Leach, B.F., Warren, S., 1981. Neutron activation anal ysis putapu Island, Tonga. Journal of the Polynesian Soc
of New Zealand and Oceanic obsidians: Towards a
i ety 83, 308–348.

simple screening technique. In: Leach, B., Davidson,

Rolett, B.V., 1998. Hanamiai: Prehistoric Colonization J. (Eds.), Archaeological Studies of Pacific Stone and Culture Change in the Marquesas Islands (East Resources. B.A.R. International Series 104. Archaeo-Polynesia). Yale University Publications in Anthro-press, Oxford, UK, pp. 151–166.

pology 81. Yale University, New Haven, CT.

Leach, B.F., Anderson, A., Sutton, D., Bird, R., Duerden, Rolett, B.V., Conte, E., 1995. Renewed investigation of P., Clayton, E., 1986. Origin of prehistoric obsidian
the Ha’atuatua dune (Nukuhiva, Marquesas Islands):

artefacts from the Chatham and Kermadec Islands.

A key site in Polynesian prehistory. Journal of the New Zealand Journal of Archaeology 8, 143–170.

Polynesian Society 104, 195–228.

Macdonald, G.A., Abbott, A.T., 1970. Volcanoes in the Rosendahl, P.H., 1972. Aboriginal agriculture and resi-Sea: The Geology of Hawaii. University of Hawaii dence patterns in Upland Lapakahi, Island of Hawaii.

Press, Honolulu.

Ph.D. dissertation, University of Hawai‘i, Honolulu.

McCoy, M.D., Mills, P.R., Lundblad, S., Rieth, T., Kahn, Schousboe, R., Riford, M., Kirch, P.V., 1983. Volcanic J.G., Gard, R., 2011. A cost surface model of volcanic glass flaked stone artifacts. In: Clark, J.T., Kirch, P.V.

glass quarrying and exchange in Hawai‘i. Journal of (Eds.), Archaeological Investigations of the Mudlane

Archaeological Science 38, 2547–2560.

WaimeaKawaihae Road Corridor, Island of Hawai‘i:

Polynesian Volcanic Glass | 141

An Interdisciplinary Study of an Environmental Tran

Walter, R., Sheppard, P., 2001. Cook Island basalt sourc-sect. Departmental Report Series 83-1. B.P. Bishop ing: Current issues and directions. In: Jones, M.,

Museum, Honolulu, pp. 348–370.

Sheppard, P. (Eds.), Australasian Connections and Sheppard, P.J., 2004. Moving stones: Comments on the

New Directions: Proceedings of the 7th Austral asian archaeology of spatial interaction in New Zealand.

Archaeometry Conference. Research in Anthr opology In: Furey, L., Holdaway, S. (Eds.), Change Through and Linguistics no. 5. Department of Anthropology,

Time: 50 Years of New Zealand Archaeology. New University of Auckland, Auckland, pp. 383–399.

Zea land Archaeological Association Monograph 26,

Ward, G.K., 1974a. A systematic approach to the defi-
pp. 147–168.

nition of sources of raw material. Archaeometry 16, Sheppard, P.J., Hancock, R.G.V., Pavlish, L.A., Parker, R., 41–53.

1989. Samoan volcanic glass. Archaeology in Oceania Ward, G.K., 1974b. An investigation of the source of the 24, 70–74.

obsidian flakes from two Samoan sites. In: Green,

Sheppard, P.J., Irwin, G.J., Lin, S.C., McCaffrey, C.P., 2011.

R.C., Davidson, J.M. (Eds.), Archaeology in Western Characterization of New Zealand obsidian using

Samoa. Vol. 2. Bulletin of the Auckland Institute and pXRF. Journal of Archaeological Science 38, 45–56.

Museum no. 6. Auckland Institute and Museum,

Sheppard, P.J., Trichereau, B., Milicich, C., 2010. Pacific Auckland, pp. 167–169.

obsidian sourcing by portable XRF. Archaeology in Ward, G.K., 1974c. Appendix 3: Source of obsidian from Oceania 45, 21–30.

Niuatoputapu sites. Journal of the Polynesian Society Smith, C.S., 1965. Report 5. Test excavations and surveys 83, 345.

of miscellaneous sites on the island of Rapa Iti. In:

Weisler, M.I., 1990. Sources and sourcing of volcanic

Heyerdahl, T., Ferdon Jr., E.N. (Eds.), Reports of the glass in Hawai’i: Implications for exchange studies.

Norwegian Archaeological Expedition to Easter Island Archaeology in Oceania 25, 16–23.

and the East Pacific. Vol. 2: Miscellaneous Papers.

Weisler, M.I., 1994. The settlement of marginal Polynesia: Mono graphs of the School of American Research and

New evidence from Henderson Island. Journal of the Kon-Tiki Museum no. 24, part 2. Rand McNally

Field Archaeology 21, 83–102.

and Co., Chicago, pp. 77–87.

Weisler, M.I., 1995. Henderson Island prehistory: Colo-ni zation and extinction on a remote Polynesian island.

Stearns, H.T., Macdonald, G.A., 1946. Geology and Biology Journal of the Linnean Society 56, 377–404.

GroundWater Resources of the Island of Hawaii. Bul-Weisler, M.I., 1996. An archaeological survey of Man-
letin 9. Division of Hydrography, Territory of Hawaii.

gareva: Implications for regional settlement models

Suggs, R.C., 1961. The Archaeology of Nuku Hiva, Mar
and interaction studies. Man and Culture in Oceania quesas Islands, French Polynesia. Anthropological 12, 61–85.

Papers of the American Museum of Natural History

Weisler, M.I., 1997. Prehistoric long-distance interaction 49 (1). New York.

at the margins of Oceania. In: Weisler, M.I. (Ed.),

Terrell, J., 1969. Excavations at SU-VA-4. In: Green,

Prehistoric LongDistance Interaction in Oceania: An R.C., Davidson, J.M. (Eds.), Archaeology in Western Interdisciplinary Approach. New Zealand Archae-Samoa. Vol. 1. Bulletin of the Auckland Institute and ological Association Monograph 21. New Zealand

Museum no. 6. Auckland Institute and Museum,

Arch aeological Association, Dunedin, New Zealand,

Auckland, pp. 158–176.

pp. 149–172.

Vérin, P., 1969. L’Ancienne Civilisation de Rurutu (îles Weisler, M.I., 2004. A stone tool basalt source on ‘Ata, AustralesPolynésie Française), La Periode Classique.

southern Tonga. New Zealand Journal of Archaeology Office de la Researche Scientifique et Technique

25 (2003), 113–120.

Outre-Mer, Orstom, Paris.

Weisler, M.I., 2008. Sourcing studies are best done in col-Walter, R., 1998. Anai’o: The Archaeology of a Fourteenth laboration with geochemists. Comment on Atholl

Century Polynesian Community in the Cook Islands.

Anderson’s “Traditionalism, Interaction and Long-

New Zealand Archaeological Association Mono-

Distance Seafaring in Polynesia.” Journal of Island graph 22.

Coastal Archaeology 3, 265–267.

Walter, R., Anderson, A., 2002. The Archaeology of Niue Weisler, M.I., Clague, D.A., 1998. Characterization of Island, West Polynesia. Bishop Museum Bulletin in archaeological volcanic glass from Oceania: The

Anthropology 10. Bishop Museum Press, Honolulu.

utility of three techniques. In: Shackley, M.S. (Ed.),

142 | OBSIDIAN AND GLASS PROVENANCE

Archaeological Obsidian Studies, Method and Theory.

interactions studies in the Cook Islands. Journal of the Advances in Archaeological and Museum Science 3.

Polynesian Society 103, 203–216.

Plenum Press, New York, pp. 103–128.

Williams, H., 1933. Geology of Tahiti, Moorea, and Maiao.

Weisler, M.I., Green, R.C., 2001. Holistic approaches to B.P. Bishop Museum Bulletin 105. Honolulu.

interaction studies: A Polynesian example. In: Jones,

Williams, S., 2004. The Pōhakuloa chill glass quarry

M., Sheppard, P. (Eds.) Australasian Connections and complex, U.S. Army Pohakuloa training area,

New Directions: Proceedings of the 7th Australasian Hawai‘i Island. Hawaiian Archaeology 9, 105–118.

Archaeometry Conference. Research in Anthropology Wood, B.L., Hay, R.F., 1970. Geology of the Cook Islands.

and Linguistics no. 5. Department of Anthropology,

New Zealand Geological Survey Bulletin n.s. 82. New

University of Auckland, pp. 413–453.

Zealand Department of Scientific and Industrial

Weisler, M.I., Haslam, M., 2005. Determining the func-

Research, Wellington.

tion of Polynesian volcanic glass artifacts: Pre lim-

Woodhead, J.D., 1996. Extreme HIMU in an oceanic
inary results of a residue study. Hawaiian Archa eology setting: The geochemistry of Mangaia Island (Poly-10, 1–17.

nesia), and temporal evolution of the Cook-Austral

Weisler, M.I., Kirch, P.V., Endicott, J.M., 1994. The
hotspot. Journal of Volcanology and Geothermal Mata’are basalt source: Implications for prehistoric

Research 72, 1–19.

Chapter 11

Glass Vessels in Sub-Saharan Africa

A Compositional Study of Samples from Mtwapa, Kenya

Laure Dussubieux and Chapurukha M. Kusimba

Abstract

1. Introduction

Archaeological evidence for ancient glass vessels

Archaeological excavations at the ancient urban
has been recovered in virtually all urban contexts
site of Mtwapa in Kenya, inhabited from the 10th to
in Africa. However, since no elemental and chemi-
the 18th century AD, yielded material in the form
cal analyses have been carried out on that type of
of glass beads and glass vessel fragments. In both
material, the making, distribution, and use of glass
cases the typological features of the artifacts were
vessels in Sub-Saharan Africa remain poorly known.

not distinctive enough to be easily provenanced

Provenancing of African glass has remained specu-

(Kusimba 1993, 1999). All the glass beads are small,
lative and provided fodder for controversy. From
monochrome, drawn beads that were part of the
whence, when, and how did ancient Sub-Saharan

Indo-Pacific Mono chrome Drawn Bead tradition,

Africans procure their glass? Archaeology suggests
a vast group of beads that were made and traded
a number of sources, but no clear regions predomi-
around the Indian Ocean and in Southeast Asia for
nate. We recently undertook a chemical analysis
more than 1500 years (Francis 1986). The majority
using laser ablation–inductively coupled plasma–
of Mtwapa glass vessels were extremely small, frag-
mass spectrometry (LA-ICP-MS) on a small but rep-
mented, and badly corroded. Compounded with
resentative sample of glass vessel fragments from the
this condition, most vessels had lost their original

Swahili town of Mtwapa in Kenya (about AD 900 to
shapes and even colors. These problems made com-

1750). We report and discuss the results of our study
parative macroscopic analyses with glass material
in light of what is known about contemporary glass
found elsewhere less than objective without the use
artifacts recovered from different regions known to
of chemical characterization.

have had relations with East Africa, including the

In order to discern more information about the

Middle East, India, and Southeast Asia. The results

Mtwapa glass material, elemental composition of both
provide invaluable data for sourcing and provenanc-
types of artifacts was undertaken using laser ablation–
ing ancient African glass vessels and take us beyond
inductively coupled plasma–mass spectrom
etry
the now thoroughly out-of-date conjectural and

(LA- ICP-MS). Results obtained for the glass beads
intuitive discourse so commonplace in discussions
have been reported elsewhere (Dussubieux et al.

of technology transfer in Sub-Saharan Africa.

2008), and the chemical analysis revealed that glass
beads were imported from the west coast of India.

In this chapter we only report the results obtained
for the glass vessel fragments. We also compare the
main composition at Mtwapa with compositions

143

144 | OBSIDIAN AND GLASS PROVENANCE
of contemporaneous glass artifacts recovered from
standing architecture. Between 1986 and 1997, C.M.

regions known to have had relationships with East

Kusimba surveyed and mapped the site in its entirety

Africa, including the Middle East, India, and South-
and excavated 15 trenches at 9 localities.

east Asia.

Archaeological excavations recovered large vol-
umes of artifacts typical of urban societies. The finds 2. Description of the site
included local and trade ceramics, iron and iron slag, rock crystal, spindle whorls, glass vessels, and beads Mtwapa is one of 400 settlements that emerged
of shell, stone, and glass. The local potteries are sty-along the eastern coast of Africa from Somalia to
listically diverse and appear to have been made and

Mozambique around AD 800. A nominally Islamic
traded along the coast and the immediate hinterland.

and literate society that included farmers, fishers,

Of the total pottery assemblage, about 8% comprise
traders, scribes, rulers, and enslaved persons is cred-foreign wares (Kusimba 1993; Oteyo 1999; Oka 2008;
ited for building this civilization. Mtwapa is located Oka et al. 2009). The majority of traded ceramics are
on the Mtwapa Creek some 15 km north of Mombasa,
from Chinese and Islamic kilns. The rest originated

Kenya (figure 11.1). The present site consists of aban-from Indian, Indonesian, and Japanese kilns. The
doned houses, collapsed walls, and dry water wells.

occurrence of Islamic and Chinese pottery and glass

The remains include 5 mosques, 64 houses, 2 work-
practically in all localities at Mtwapa indicates that it shops, and possible commercial houses (Kusimba
was an important port of regional and international

1993). The site has always been under a thick coastal
trade. The town served as an important link between
forest vegetation cover, and this cover possibly con-
the Kenyan hinterlands and the Indian Ocean world
tributed to its conservation. The site of Mtwapa covers system, between AD 800 and 1750 (Kusimba 1999;
approximately 8 hectares out of which 4 still contain

Kusimba and Kusimba 2000; Oka 2008). The wealth
drawn from this commerce made Mtwapa an attrac-
tive port with a small but highly diversified resident population who engaged in different but comple-mentary subsistence and economic activities.

3. Description of the glass
vessel fragments

Approximately 400 glass fragments were recov-
ered at Mtwapa (figure 11.2). The vast majority of
these glass fragments were excavated at Locality 6.

Excavations at Locality 6 revealed that it was a house that was abandoned while the city was still inhabited. As is typical for abandoned residences in any
town, the house was subsequently used as a refuse
site by nearby residents. Thus the uneven distribu-
tion of what was presumably a rare and valuable
article can be partly explained in these terms.

Since most glass fragments were small in size,
determination of the original nature, shape, and
color of the objects was onerous. Some fragments
were shards of bottlenecks or vials. Two types of
rims, unfinished rims and looped-out rims, were
predominant. Unfinished rims were of small diam-

Figure 11.1. Map of Kenya with Mtwapa.

eter and likely belonged to vials, while looped-out

Glass Vessels in Sub-Saharan Africa | 145

Figure 11.2. Fragments of glass from

Mtwapa (paper grid
squares are 5 x 5 mm).

rims similarly belonged to larger containers. Only
ent lack of diversity in shapes, and the absence of
kick-up bases with pontil marks, some of which were
decoration suggest that glass containers possibly
looped, could be identified. Except for one large base served a purely utilitarian role. It is probable that the with an approximate diameter of 15 cm, most bases
content of the glass containers was more valued than
had a diameter of approximately 5 cm. These bases
the containers itself.

may have belonged to either flasks or bowls. Owing

We tested 31 samples from Mtwapa (table 11.1).

to the fragmentary condition of the shards, it is con-

They were selected to be as representative as possible ceivable that other types of bases including flat bases of the different colors and shapes present at the site.

were unrecognizable (figure 11.2).

Color is often difficult to determine because

4. Analytical technique
corrosion affects the surfaces of most glass frag-
ments. Corrosion may appear as a more or less thick

All the glass beads and vessel fragments were ana-
opaque crust at the surface of the glass that acquired lyzed with a Varian ICP-MS connected to a New
a brownish to black color. Sometimes, lighter corro-

Wave UP213 laser at the Field Museum of Natural
sion only turned the surface of the glass iridescent.

History, Chicago, USA, in 2005 and 2006. Analytical

On some glass fragments, pitting is visible. Totally
protocol and calculation methods were adapted
noncorroded fragments are extremely rare. When
from Gratuze (1999). The isotope 29Si was used as
possible to identify their original color, the glass
an internal standard, and the standard reference
fragments may appear transparent and colorless,
materials 610 and 612 from the National Institute for
light bluish, light greenish, olive green, dark blue, or Standards and Technology were used for external
dark amber. The only opaque glass is red with some
standardization along with the Corning glasses B, D,
black veins.

and C (Brill 1999). Unlike other analytical devices,

No decoration of any kind was identified: neither
the LA-ICP-MS analysis requires no sample prepara-
ra-
molded nor cut nor enameled decorations could be
tion and the technique is virtually non-destructive,
observed, but here again the poor preservation of
leaving no visible damage to the sample. Fifty-five
the glass may have caused us to overlook that kind
major, minor, and trace elements were identified, but
of feature.

only 36 elements are reported (table 11.2). The detec-

The small volume of glass fragments, the appar -
tion limits range from 10 parts per billion (ppb) to

146 | OBSIDIAN AND GLASS PROVENANCE

Table 11.1 Description of the samples analyzed Reference

Color

Description

MTK050

Bluish transparent

Fragment

MTK051

Greenish transparent

Fragment

MTK052

Yellowish transparent

Fragment

MTK053

Colorless

Fragment

MTK054

Slightly yellowish transparent/iridescent

Flat thin fragment

MTK055

Slightly yellowish transparent/iridescent

Thin fragment

MTK056

Colorless with dark trace of corrosion

Thin fragment

MTK058

Dark transparent glass (brown) covered by a

Fragment

dark iridescent layer

MTK060

Bluish-greenish transparent glass pitted by golden

Thin-intermediate small fragment

corrosion mark

MTK061

Pristine transparent green (bottle green)

Rather thick fragment of a kick-up

base with pontil mark

MTK062

Pristine opaque red/black

Looped rim

MTK063

Corroded transparent green glass

Looped base of small diameter

MTK064

Pristine transparent green

Looped base

MTK065

Corroded transparent dark blue glass

Curved fragment from a small container

or neck

MTK068

Red/black

Thick fragment

MTK069

Red/black

Fragment

MTK070

Corroded greenish transparent

Unfinished rim

MTK071

Bluish transparent

Unfinished rim

MTK072

Bluish transparent

Base of a vial

MTK073

Colorless or yellowish but dark because of corrosion

Kick-up base with pontil mark

MTK074

Bluish or greenish with a crust of brown corrosion

Unfinished rim of a small container

MTK075

Dark green with a thick crust of brown corrosion

Curvy fragment

MTK076

Dark greenish glass with a thick layer of brown corrosion Looped base

MTK077

Red/black

Unfinished rim of a small container

MTK078

Colorless, slightly yellowish glass

Looped rim, thin glass

MTK079

Dark greenish glass with a thick layer of brown corrosion Fragment

MTK080

Heavily corroded greenish glass

Looped base

MTK081

Covered with a brown layer of corrosion

Small fragment

MTK082

Colorless with silvery corrosion layer

Neck with flaring, thick wall

MTK083

Transparent greenish

Unfinished rim

MTK084

Slightly corroded transparent dark blue

Fragment

Glass Vessels in Sub-Saharan Africa | 147

Table 11.2 Composition for oxides (weight percent) and elements (ppm) for the 31 samples from Mtwapa

MTK050 MTK051 MTK052 MTK053 MTK054 MTK055 MTK056 MTK058 MTK060

SiO 59.6% 62.1% 58.0% 60.0% 61.7% 60.8% 56.0% 58.6% 56.712%

2

Na O 18.8% 17.4% 20.1% 18.3% 18.4% 18.2% 21.2% 18.6% 20.885%

2

MgO 5.5% 5.0% 5.1% 5.4% 5.3% 5.2% 4.8% 5.9% 5.746%

Al O

5.7% 5.7% 6.2% 4.7% 5.4% 5.8% 6.2% 6.0% 5.899%

2 3

P O 0.5% 0.3% 0.4% 0.3% 0.2% 0.3% 0.5% 0.3% 0.433%

2 5

K O 3.1% 3.1% 2.5% 2.1% 2.7% 2.8% 2.8% 3.2% 2.755%

2

CaO 4.6% 4.5% 4.8% 5.5% 4.6% 5.0% 5.5% 5.4% 5.530%

MnO 0.11% 0.08% 0.07% 1.38% 0.07% 0.06% 0.96% 0.08% 0.08%

Fe O

1.5% 1.5% 2.2% 1.8% 1.5% 1.7% 1.7% 1.8% 1.441%

2 3

CuO 0.006% 0.003% 0.09% 0.006% 0.004% 0.004% 0.004% 0.004% 0.006%

SnO 0.001% 0.0001% 0.0002% 0.0001% 0.0002% 0.0002% 0.0002% 0.0002% 0.0002%

2

Be 2.3 1.4 1.7 1.6 1.2 1.7 2.1 1.3 1.7

B 207 168 159.8

161.2 193 183 187 184 194

Ti 1586 1579 1624.6

1583.5 1398 1610 1440 1729 1220

V 26 27 23.8

30.3 23 27 29 32 25

Cr 26 26 29.1

27.9 25 31 28 36 28

Ni 20 14 646.2

15.8 16 13 13 17 16

Co 23.46 4.28 529.3 4.9 4.42 5.52 4.55 5.12 5

Zn 61 42 61.3

63.1 42 50 61 48 58

As 55.72 <dl <dl <dl 24 <dl <dl <dl 15

Rb 33 36 34.4

25.5 37 32 33 34 36

Sr 306 331 373 525 329 379 444 434 458

Zr 92 102 112 101 110 110 124 120 107

Nb 9 10 12 9 9 10 13 11 12

Ag 0.1 0.1 0.7 0.1 0.1 0.1 0.1 0.1 0.03

Sn 8.5 1.0 1.3 0.9 1.1 1.1 1.2 1.3 1.6

Sb 0 0 0.4 0.1 0.1 0.1 0.2 0.1 0.1

Cs 0.1 0.2 0.2 0.1 0.1 0.1 0.2 0.1 0.2

Ba 246 238 235 1331 229 221 1994 278 266

La 13 13 15 15 13 13 19 15 15

Ce 25 26 31 26 26 26 33 30 29

Pr 3 3 4 4 3 3 5 4 3

Y 11 12 15 17 12 12 15 13 15

Pb 41 6 10 6 10 8 7 6 8

Bi 15 0.03 0.02 0.03 0.02 0.02 0.02 0.01 0.03

U 1.3 1.3 1.2 1.8 1.1 1.2 1.5 1.3 3.0

Continued on page 148

148 | OBSIDIAN AND GLASS PROVENANCE

Table 11.2 (continued from previous page) Composition for oxides (weight percent) and elements (ppm)

MTK061 MTK062 MTK063 MTK064 MTK065 MTK068 MTK069 MTK070 MTK071

SiO 58.845% 58.4% 61.75% 59.07% 60.62% 57.6% 57.3% 63.6% 59.5%

2

Na O

18.096% 19.0% 17.64% 18.31% 16.94% 18.8% 19.0% 16.7% 18.6%

2

MgO

5.669% 4.4% 5.34% 5.11% 6.41% 4.8% 5.1% 5.0% 5.4%

Al O

5.928% 6.9% 5.48% 6.16% 5.65% 7.3% 7.1% 5.5% 6.0%

2 3

P O

0.586% 0.2% 0.20% 0.22% 0.14% 0.5% 0.4% 0.4% 0.4%

2 5

K2O

2.670% 2.6% 2.61% 2.82% 2.18% 2.8% 2.8% 2.9% 2.5%

CaO

6.083% 4.8% 4.60% 5.02% 4.87% 5.0% 5.2% 4.0% 5.3%

MnO 0.09% 0.23% 0.07% 0.83% 0.13% 0.22% 0.27% 0.10% 0.18%

Fe O

1.620% 2.6% 1.51% 1.84% 2.08% 1.6% 1.6% 1.3% 1.7%

2 3

CuO 0.006% 0.8% 0.004% 0.005% 0.09% 0.7% 0.7% 0.005% 0.011%

SnO 0.0002% 0.0225% 0.0001% 0.0002% 0.0002% 0.0214% 0.0198% 0.0002% 0.0006%

2

Be 2.5 1.8 1.2 2.9 3.0 1.9 1.6 1.8 1.4

B 189 149 177 182 214 155 162 145 166

Ti 1355 1360 1482 1673 1577 1356 1296 1075 1420

V 27 24 23 30 25 27 28 28 33

Cr 32 27 25 23 24 32 32 29 37

Ni 16 14 14 15 731 18 18 16 18

Co 5 5 4 6 861 6 5 5 7

Zn 61 77 34 49 86 103 92 47 62

As 16 <dl <dl <dl <dl 31 24 14 11

Rb 30 35 37 37 24 44 41 47 33

Sr 473 443 302 360 412 480 470 320 451

Zr 127 110 100 128 101 114 118 105 114

Nb 12 11 9 13 12 13 13 9 11

Ag 0.1 5 0.1 0.1 1 7 5 0.1 0.1

Sn 1.3 147 0.8 1.2 1.0 153 141 2 5

Sb 0.1 40 0.1 0.3 1 43 37 0.3 0.2

Cs 0.1 0.1 0.1 0.2 0.2 0.3 0.2 0.5 0.2

Ba 249 414 210 787 332 462 529 249 424

La 16 14 12 18 14 16 17 13 14.7

Ce 32 28 23 39 29 33 33 29 29.9

Pr 4 3 3 5 3 4 4 4 3.7

Y 15 12 11 18 14 13 14 12 13.9

Pb 6 148 5 10 15 235 166 9 23

Bi 0.08 1.2 0.03 0.04 0.25 1.6 1.3 0.03 0.03

U 1.3 1.2 1.1 1.6 1.2 1.53 1.6 1.4 1.5

Continued on next page

Glass Vessels in Sub-Saharan Africa | 149

Table 11.2 (continued from previous page) Composition for oxides (weight percent) and elements (ppm)

MTK072 MTK073 MTK074 MTK075 MTK076 MTK077 MTK078 MTK079 MTK080

SiO 57.2% 61.9% 58.5% 58.6% 60.5% 57.8% 60.1% 57.0% 58.8%

2

Na O 20.3% 17.8% 18.8% 17.5% 19.5% 21.2% 17.1% 20.6% 19.3%

2

MgO 5.7% 5.5% 4.7% 5.2% 5.1% 5.1% 5.2% 6.0% 4.7%

Al O

5.5% 4.8% 5.6% 6.3% 5.1% 5.0% 5.1% 5.2% 4.6%

2 3

P O 0.4% 0.3% 0.4% 0.4% 0.2% 0.4% 0.4% 0.3% 0.3%

2 5

K O 3.2% 2.9% 2.4% 2.5% 2.8% 2.4% 3.0% 2.9% 2.4%

2

CaO 5.3% 4.7% 5.2% 6.0% 4.6% 5.2% 5.0% 5.6% 5.3%

MnO

0.08% 0.1% 2.0% 0.4% 0.1% 0.2% 1.7% 0.1% 1.9%

Fe O

1.9% 1.3% 1.6% 2.6% 1.4% 1.4% 1.5% 1.7% 1.8%

2 2

CuO 0.006% 0.004% 0.005% 0.011% 0.004% 0.5% 0.004% 0.006% 0.006%

SnO 0.0002% 0.0001% 0.0002% 0.0168% 0.0002% 0.0082% 0.0005% 0.0001% 0.0001%

2

Be 1.7 1.4 2.3 1.9 1.6 1.4 1.8 1.1 1.5

B 234 179 153 154 184 172 151 243 180

Ti 1625 1346 1574 2611 1499 1409 1466 1649 1826

V 35 25 29 46 24 23 30 29 34

Cr 33 28 29 43 27 25 27 33 33

Ni 19 18 19 24 15 18 15 21 16

Co 7 5 8 11 5 5 5 9 6

Zn 61 62 57 63 41 53 78 49 67

As 9 9 11 8 8 12 6 8 5

Rb 31 39 26 29 38 32 27 36 26

Sr 337 388 562 529 339 396 489 397 402

Zr 118 100 117 151 111 97 109 115 121

Nb 11 10 11 14 10 10 9 10 11

Ag 0.1 0.2 0.1 0.2 0.1 1 0.1 0.8 0.1

Sn 1.4 0.9 1.3 117 1.1 57 3.5 0.8 0.8

Sb 0.1 0.1 0.2 1 0.1 3 0.2 0.1 0.3

Cs 0.2 0.2 0.1 0.2 0.1 0.2 0.2 0.1 0.1

Ba 228.5 214 1989 533 233 330 2843 232 3042

La 14.6 13 14 17 14 13 21 14 17

Ce 28.6 26 27 35 26 26 46 28 36

Pr 3.5 3 4 4 3 3 5 3 4

Y 13.0 12 13 17 12 12 16 12 15

Pb 5 6 297 6 56 14 4 30 5

Bi 0.34 0.04 0.05 0.08 0.05 0.12 0.06 0.04 0.05

U 1.6 0.7 1.9 1.0 0.7 0.7 1.0 0.8 0.9

Continued on page 150

150 | OBSIDIAN AND GLASS PROVENANCE

Table 11.2 (continued from previous page) Composition for 1 part per million (ppm) for most of the elements.

oxides (weight percent) and elements (ppm)

Accuracy ranges from 5% to 10% depending on the

MTK081 MTK082 MTK083 MTK084
elements and their concentrations. More details on

SiO 59.9% 70.5% 62.6% 62.6%
the technique and its performance are described in

2

Dussubieux et al. (2009).

Na O 20.5% 10.8% 15.0% 12.5%

2

MgO 4.5% 3.5% 4.3% 3.9%

5. Description of the

Al O

5.0% 0.8% 6.5% 8.1%

2 3
compositions

P O 0.3% 0.3% 0.5% 0.6%

2 5

K O 2.5% 3.2% 2.3% 2.4%

Aside from one sample (MTK082), all the glass

2
artifacts in this study had the same composition

CaO 4.8% 8.7% 5.7% 6.6%

(table 11.2). Sample MTK082 was a soda-lime glass

MnO 0.1% 0.7% 0.1% 0.1%
made from low-alumina sand. Its alumina concen-

Fe O

1.6% 0.5% 2.5% 2.6%

2 3
tration was 0.8%. Concentrations of potash and

CuO 0.004% 0.002% 0.005% 0.008%
magnesia higher than 1.5% showed that the soda

SnO 0.0001% 0.0001% 0.0002% 0.0003%
source was quite likely halophytic plant ash rather

2
than mineral soda, a generally purer soda source.

Be 1.2 1.0 1.6 2.6

We identified a similar composition for the

B 185 110 158 227
remaining 30 samples from Mtwapa (table 11.3).

Ti 1702 525 1565 2477

Soda was the most abundant constituent in all the

V 29 12 23 30
glass samples after silica. The concentrations for

Cr 31 14 30 49
this oxide can be as high as 21.2%. As with sample

Ni 15 8 12 17

MTK082, potash and magnesia concentrations
were both higher than 1.5%, suggesting that soda

Co 5 3 4 6
plant ashes were likely used as flux. Alumina and

Zn 55 83 53 91
lime concentrations were nearly equivalent in mag-

As 5 12 16 10
nitude and slightly higher than 5%.

Rb 34 14 32 57

High concentrations of alumina (>5%) are gen-

Sr 390 458 624 572
erally associated with the use of granite sand that,

Zr 108 119 140 161
in addition of alumina, tends to have particularly
high concentrations of trace elements like titanium

Nb 11 2 13 15
and rare earth elements such as uranium. India and

Ag 0.2 0.1 0.1 1
possibly Southeast Asia are the most likely source

Sn 0.9 0.7 1.1 1.9
areas for alumina glass, with high concentrations of

Sb 0.1 0.1 0.1 0.3
impurities coming from granite sand (Dussubieux et

Cs 0.1 0.2 0.1 0.2
al. 2008; Dussubieux and Gratuze 2004). Therefore

Ba 274 81 234 314
the extremely low concentration of trace elements
in our sample would appear to exclude the use of

La 13 4 16 19
that kind of granite sand.

Ce 26 8 30 45

Coloring ingredients include cobalt and cop-

Pr 3 1 4 5
per. MTK052 and MTK065 were colored using

Y 13 4 15 16
cobalt (530 and 861 ppm respectively). In both

Pb 6 6 11 3
samples, significant concentrations of copper and

Bi 0.07 0.05 0.07 0.08
nickel were measured, while much lower con-
centrations were reported for the other glasses.

U 0.8 0.6 1.1 0.6

MTK062, MTK068, and MTK069 were opaque red

Glass Vessels in Sub-Saharan Africa | 151

Table 11.3 Average concentrations of the major dated from the 9th to 15th century AD (Robertshaw
elements (weight percent) in 30 Mtwapa
et al. 2006), Mtwapa glass beads had lower soda and
glass samples with the same composition.

magnesia concentrations (figure 11.3). Further com-

Oxide

Vessels
parisons with data published by Robertshaw et al.

SiO

59 ±2 %

(2006) showed lower concentrations for some trace

2
elements in the glass beads, confirming the differ-

Na O

19 ±2 %

2
ences. For example, zirconium had an average con-

MgO

5.2 ±0.5 %
centration of 111 ±10 ppm in the Mtwapa glass vessel

Al O

5.8 ±0.8 %

2 3
fragments compared to 87 ±33 ppm in African glass

K O

2.7 ±0.3 %
beads. Cerium is also lower in the glass beads, with

2
an average concentration of 16 ±8 ppm instead of 29

CaO

5.1 ±0.5 %

±4 ppm. These differences suggest that these types

Fe O

1.8 ±0.4 %

2 3
of glass were manufactured using two different reci-
pes and possibly two different sources of ingredients.

Further investigations are necessary to determine the
with small amount of black mixed in the red glass.

precise technical and geographical differences.

The samples contained 0.7% to 0.8% copper. All the

Turning to glass compositions for material recov-
samples contained from 1.3% to 2.6% iron that may
ered outside Sub-Saharan Africa, we were more suc-
be responsible for glasses with greenish, bluish, or
cessful in finding glass artifacts with similarities to yellowish to amber hues. Addition of manganese in
the high-alumina glass type at Mtwapa. In North
some cases and control of the furnace atmosphere

Africa, a relatively high-alumina glass composi-
may have been used to obtain a specific color.

tion was identified at Qsar es-Seghir, located on the

Moroccan coast of the Strait of Gibraltar (Brill 1999, 6. Regional comparisons

2001). This site was used as a strategic point to cross the Strait of Gibraltar to Spain by the Muslim armies

First, we should emphasize that since no serious ana-
as early as the 8th century AD and was abandoned by
lytical research has been conducted on ancient glass
the Portuguese during the 16th century AD (Redman
vessels recovered in Sub-Saharan Africa, any pio-
neering work such as reported here will suffer from
a lack of comparative analytical data. Typological
descriptions of glass inserted into archaeological
reports (e.g., Juma 2004; Chittick 1984) or glass-
oriented journals (Morrison 1987; Insoll 1998) pro-
vide little data for sourcing. In contrast, the scenario is changing for glass beads where recent analytical
studies have produced a large volume of compara-
tive compositional data for glass beads in the Sub-

Saharan region (Dussubieux et al. 2008; Popelka et al.

2005; Robertshaw et al. 2003, 2006).

Some glass beads in Sub-Saharan Africa feature
a composition quite similar to the dominant com-
position at Mtwapa, characterized by high alumina
concentrations in a glass manufactured with soda

Figure 11.3. Na O-MgO concentrations bi-plot for the 2
plant ash as a flux (Robertshaw et al. 2003, 2006;
dominant type of glass at Mtwapa and for

Popelka et al. 2005). However, there are some differ-
some beads from Madagascar, published by
ences. When compared to the Malagasy glass beads

Robertshaw et al. (2006).

152 | OBSIDIAN AND GLASS PROVENANCE
et al. 1979). Brill (2001) interprets the original compo-few kilometers away from Lobu Tua, is slightly more
sition of the glass samples from Qsar es-Seghir as “an recent. Prosperous during the 13th and 14th century
indication of regional manufacture.” This glass fea-

AD, this site was probably founded during the sec-
tures relatively high soda concentrations (19.4 ±1.3%), ond half of the 12th century (Daniel Perret, personal
and alumina concentrations can be as high as 5.2%.

communication). Kota Krueng (Samudra subdistrict,

Soda plant ashes were used in the recipe. However,

Aceh Utara district, Special Territory of Aceh) is the magnesia is slightly lower for this glass compared to
most recent site. Surface finds of ceramic shards indithe glass from Mtwapa, with concentrations from
cate a 15th- to beginning of 16th-century AD settle-

2.1% to 4.6% at Qsar es-Seghir compared to an average
ment, but it could be earlier (Daniel Perret, personal of 5.2% for Mtwapa. Comparing trace element con-communication). The combined data of McKinnon
centrations for these two locations would be useful to and Brill (1987) and Dussubieux (2009) suggest that
determine whether the glass from Qsar es-Seghir has
this type of glass was present on the island of Sumatra a truly distinctive composition or whether it is just a from the 9th to the 15th centuries AD. Relatively rare variation of the Mtwapa composition.

in early periods, this glass became more common

Data for glass vessels found in the Middle East
after the 11th century AD.

are quite abundant. Mtwapa shows important con-

It is interesting to note that Bernard Gratuze
nections with this region through the presence of

(ms) identified 6 samples with an identical composi-

Islamic pottery, and the typology of the glass vessels tion from a Chinese junk shipwreck located 22 nauti-is not incompatible with what was produced in the
cal miles off the Sultanate of Brunei. According to the Middle East (Kusimba 1993). However, no serious
ceramics found in the junk, it was dated from the end
evidence for the presence of the high-alumina
of the 15th to the beginning of the 16th century AD.

Mtwapa glass was found in this region. Henderson

All but one sample were blocks of different shades
et al. (2004) found at al-Raqqa in Syria a unique
of green. The last sample was a shard of yellow glass.

piece of bracelet dated from the 11th century AD

The glass quite likely came from India and China.

with a composition similar to the one identified

Chinese, Thai, and Vietnamese ceramics were recov-
at Mtwapa. Although glass is known to have been
ered in the junk, suggesting an interregional nature
manufactured at al-Raqqa, the sample in question
of the cargo (L’Hour 2001). Table 11.4 recapitulates
had such a unique compositional signature as to be
the reduced average compositions from Mtwapa and
considered an in-trusion (foreign) at this site.

different other areas.

An important assemblage of glass objects with a

The data available, although extremely sketchy,
composition identical to that of Mtwapa was identi-
show a significant presence for the glass found at
fied in Indonesia by McKinnon and Brill when they

Mtwapa in Southeast Asia. This means that this glass
investigated the site of Kota Cina dating from the
was traded over long distances. It is quite likely that 11th to the 14th century AD (Brill 1999; McKinnon
more compositional analysis in Sub-Saharan Africa

2003; McKinnon and Brill 1987). Indian and Chinese
and in South India would modify this picture and
merchants occupied this site. A more recent study
would give us a more accurate idea about the impor-

(Dussubieux 2009) identified more of this glass type
tance of this very specific glass production.

at Kota Cina. The combination of both studies reveals
that 59% of the glass samples from Kota Cina belong to 7. Provenance
this type of glass. Three other Sumatran sites yielded that type of glass: Lobu Tua, Bukit Hasang, and

Since no glass workshop with glass bearing a similar

Kota Krueng. Lobu Tua, located on the west coast of
compositional signature to the dominant glass type

Sumatra (Barus subdistrict, Tapanuli Central district, at Mtwapa has so far been identified, we cannot at

North Sumatra province) and dated from the 9th to
this stage of our analysis point to any one source
the 12th century AD, was excavated from 1995 to 2000
center. The wide repartition of this glass indicates

(Guillot 1998; Guillot et al. 2003). Chinese and Arab
that Mtwapa glass originated from an important
merchants occupied this site. Bukit Hasang, located a
trade center. The absence of known workshops

Glass Vessels in Sub-Saharan Africa | 153

Table 11.4 Comparison of the composition found at Mtwapa with similar compositions from different areas. Compositions are expressed in weight percentage of oxides.

Mtwapa

Indonesia

Kota Cina

Chinese Junk

Qsar es-Seghir
al-Raqqa

Dussubieux

Mc Kinnon

Gratuze (ms)

Brill 1999

Henderson

2009
and Brill 1987

et al. 2004

9th to 15th c.

11th to 14th c.

15th to 16th c.

8th to 16th c.

11th

AD

AD

AD

AD

AD

SiO

59.3 ±1.9

61.3 ±2.7

63.3 ±2.5

63.1 ±0.6

60.4 ±2.2

60.0

2

Na O

18.8 ±1.3

19.5 ±1.7

18.3 ±1.1

18.8 ±0.8

19.4 ±1.3

20.6

2

MgO

5.2 ±0.4

4.7 ±0.6

5.6 ±1.0

5.1 ±0.1

3.2 ±0.8

4.7

Al O

5.7 ±0.6

5.9 ±1.5

4.8 ±0.6

4.4 ±0.4

4.3 ±0.6

5.7

2 3

K O

2.7 ±0.3

2.6 ±0.5

2.9 ±0.4

2.3 ±0.1

3.3 ±0.6

2.2

2

CaO

5.1 +0.5

4.5 ±0.8

3.5 ±0.4

4.8 ±0.3

6.2 ±0.9

4.2

Fe O

1.7 ±0.3

1.5 ±0.6

1.2 ±0.2

1.6 ±0.1

2.0 ±1.0

1.2

2 3
producing glass vessels in Sub-Saharan Africa leads

South Asia has a long and productive glass-making
us to propose that Mtwapa glass was nonlocal and
tradition. The industries specializing in production of quite possibly originated outside East Africa. We
beads and small ornaments enjoyed prominence for
will review the different hypothesis available to us
centuries (Francis 1986). Ironically, the making and
in the next paragraphs.

selling of glass vessels in South Asia was not so signifi-As mentioned above, the lack of distinctive
cant. At earlier periods, glass vessels found in South stylistic attributes due to the fragmentary state of

Asia are clearly imported from the Mediterranean
the artifacts creates difficulties for comparing the
area (e.g., at the site of Taxila [Marshall 1951] or

Mtwapa material with Middle Eastern glass vessels.

Arikamedu [Casal 1949]), but for later sites little

Numerous Kenyan ports contemporary to Mtwapa
attention is paid to these kinds of artifacts.

(e.g., Manda, Malindi, Gedi, Dar es-Salaam, Mafia)

In spite of the close connections between South
were engaged in the Indian Ocean trade (Meyer

Asia and East Africa, recently exhibited in the com-

1992), and Middle Eastern glass goods were certainly
positional signature of glass beads from Chaul and
available in the area. The composition of MTK082

Mtwapa (Dussubieux et al. 2008), we emphasize
has an obvious Middle Eastern origin, and compar-
here that the ingredients used to manufacture the
ison with the Brill data (1999, 2001) shows a close

Mtwapa glass are quite unusual for South Asia. If
resemblance with compositions measured on some
alumina glass was used to manufacture glass orna-
material from Fustat dating from the 9th to the 13th
ments and maybe later glass containers, the alumina
century AD. All the Middle Eastern glass was cer-
sand that was selected by the glassmakers con-
tainly not produced by the same workshop, as shown
tained a lot of impurities and had some diagnostic
by the variability of the compositions found in this
high uranium concentrations that are absent from
area (Brill 2001). We cannot exclude the existence
the Mtwapa glass. Also, at earlier periods there is
of an undiscovered Middle Eastern workshop of
no record of soda plant ash use; mineral soda was
importance, with an access to a high-alumina sand
used instead. In sum, the hypothesis of a Southeast
source, selling its production for export only.

Asian origin for Mtwapa glass cannot as yet be ruled

Trade between the east coast of Africa and South
out. Indeed, high concentrations of this glass were

Asia is well attested (Kusimba 1999; Middleton 2004;
recorded in Sumatra but a local production seems

Mitchell 2005; Pearson 2003; Oka and Kusimba
unlikely, as no primary glass-producing workshop

2008), and glass beads were among the items traded
has been identified for this period in this area.

between the two regions (Dussubieux et al. 2008).

A third area must be explored: Central Asia is a

154 | OBSIDIAN AND GLASS PROVENANCE
region where the presence of alumina glass manu-
in India are largely understudied. Central Asia is
factured with soda taken from plant ashes is attested
a region where alumina glass with flux from soda
at any period. Brill (1999) reports compositions of
plant ashes exists and could be an area where that
glass vessels dated from the Roman or the Sasanian
type of glass was manufactured; however, the scar-
periods that were recovered in the Chinese province
city of the data available does not allow for a direct of Xinjiang. These artifacts are made of soda glass.

connection between the site of Mtwapa and a pro-

Potash and magnesia concentrations are respectively
ducing center located in this area.

4.8–7.4% and 2.8–5%, alumina concentrations are

Because glass vessels are a well-studied material

7–10%, and lime concentrations are approximately 7%.

only in the Mediterranean region and in the Middle

Abdurazakov (2009) analyzed 79 glass samples recov-

East, the area of dispersal for the alumina glass
ered in Uzbekistan dated from the 2nd millennium
identified at Mtwapa is poorly defined, especially in

BC to the 14th century AD. If different glass groups

Sub-Saharan Africa but also in the rest of the Indian
were identified, alumina glass with soda flux obtained Ocean area. We still have a long way to go before we
from plant ashes is quite common at any period and
can understand the making and selling of glass ves-
testifies to the existence of a long tradition for such a sels in the Indian Ocean region. We will devote our
recipe even if the provenance of this type of glass could effort to the analysis of glass vessels from the Indian not be identified. It is important to notice that glass in Ocean area to address this important question and

Central Asia has been greatly understudied and pub-
hope that archaeologists from the region will make
lications available in English are scarce. It seems that available these glass vessel artifacts for analysis.

this region cannot be ignored and could be a potential provenance area for the glass of Mtwapa even if at this Acknowledgments
stage it is difficult to imagine the exchange mecha-
nisms that could explain the circulation of some glass The LA-ICP-MS laboratory at the Field Museum was
vessels from Central Asia to East Africa and no precise built with funds from the National Science Foun-provenance site can be proposed.

dation (BCS-0320903), an anonymous donation, and
the Anthropology Alliance.

8. Conclusion

References

The analysis of 31 glass vessel fragments found at

Abdurazakov, A.A., 2009. Central Asian glassmaking

Mtwapa in Kenya revealed the existence of a compo-
dur ing the ancient and medieval periods. In: Fuxi, G., sition resulting from the mixing of alumina sand and

Brill, R., Shouyun, T. (Eds.), Ancient Glass Research soda plant ash. Our analysis points out the lack of
along the Silk Road. World Scientific, Singapore, appropriate comparative data for that type of glass.

pp. 201–219.

If a Middle Eastern origin cannot be ruled out due

Brill, R.H., 1999. Chemical Analyses of Early Glasses.

to the existence of Islamic trade routes that include

2 vols. Corning Museum of Glass, Corning, NY.

Kenyan coastal ports, the compositional data lead

Brill, R.H., 2001. Some thoughts on the chemistry and tech-us to consider a more mixed conclusion. As far as
nology of Islamic glass. In: Carboni, S., Whitehouse, D.

we know, no evidence of a similar composition has

(Eds.), Glass of the Sultans. Metro politan Museum of been identified in the Middle East. Glass similar

Art, New York, pp. 25–45.

to that recovered at Mtwapa is quite common in

Casal, J.M., 1949. Fouilles de Virampatnam-Arikamedu.

Publication de la Commission des fouilles archéol-

Sumatra, at sites dated from the 9th to the 15th cen-
ogiques. Fouilles de l’Inde, Paris.

turies AD, and was traded by Chinese merchants.

Chittick, N., 1984. Manda, Excavations at an Island Port The use of alumina sand supports the hypothesis of
on the Kenyan Coast, Nairobi. Memoir no. 9. British an Indian origin; however, no glass with such a com-Institute in Eastern Africa, Nairobi.

position has ever been identified in India. This lack

Dussubieux, L., Gratuze, B., 2004. Non-destructive char-of evidence may be due to the fact that glass vessels
acterization of glass beads: Application to the study

Glass Vessels in Sub-Saharan Africa | 155
of glass trade between India and Southeast Asia. In:

Kusimba, C.M., 1999. Material symbols among the pre-

Källén, A., Karlström, A. (Eds.), Fish Bones and Glit
colonial Swahili of the East African coast. In: Robb,

ter ing Symbols: Southeast Asian Archaeology 2002.

J. (Ed.), Material Symbols: Culture and Economy in Museum of Far Eastern Archaeology, Stockholm,

Pre history. Center for Archaeological Investigations, pp. 135–148.

Southern Illinois University, Carbondale, pp. 318–341.

Dussubieux, L., Kusimba, C.M., Gogte, V., Kusimba, S.B., Kusimba, C.M., Kusimba, S.B., 2000. Hinterlands and

Gratuze, B., Oka, R., 2008. The trading of ancient
cities: Archaeological investigations of economy and
glass beads: New analytical data from South Asian
trade in Tsavo, Southeastern Kenya. Nyame Akuma and East African soda-alumina glass beads. Archaeo

54, 13–24.

metry 50 (5), 797–821.

L’Hour, M. (Ed.), 2001. La Mémoire Engloutie de Brunei.

Dussubieux, L., Robertshaw, P., Glascock, M.D., 2009.

Précis Scientifique, Editions Textuel, Paris.

LA-ICP-MS analysis of African glass beads: Lab-

McKinnon, E.E., 2003. Historic period earthenware
oratory inter-comparison with an emphasis on the
from the island of Sumatra. In: Miksic, J.N. (Ed.),
impact of corrosion on data interpretation. Inter

Earthenware in Southeast Asia. Singapore University national Journal of Mass Spectrometry 254, 152–161.

Press, Singapore, pp. 162–172.

Dussubieux, L., 2009. Compositional analysis of ancient McKinnon, E.E., Brill, R.H., 1987. Chemical analyses of glass fragments from North Sumatra, Indonesia. In:

some glasses from Sumatra. In: Bhardwaj, H.C. (Ed.),

Perret, D., Surachman, H. (Eds.), Histoire de Barus Archaeometry of Glass—Proceedings of the Arch aeo

III: Regards sur une place marchande de l’océan Indien metry Session of the XIV International Con gress on (XIIemilieu du XVIIe s). Association Archipel/

Glass—1986 (part II). New Delhi, India. Indian Cer-EFEO, Paris, pp. 385–417.

amic Society, Calcutta, pp. 1–14.

Francis Jr., P., 1986. Bead report XVIII—The Asian bead Marshall, J., 1951. Taxila, an Illustrated Account of Arch
study tour IV—A little tube of glass. Ornament 10, aeological Excavations. 3 vols. Syndics of the Cam-54–74.

bridge University Press, Cambridge, UK.

Gratuze, B., 1999. Obsidian characterization by laser abla-Meyer, C., 1992. Glass from AlQadim and the Indian tion ICP-MS and its application to prehistoric trade in Ocean Trade. Studies in Ancient Oriental Civilization the Mediterranean and the Near East: Sources and dis-53. The Oriental Institute of the University of Chicago.

tribution of obsidian within the Aegean and Anatolia.

Middleton, J., 2004. African Merchants of the Indian Journal of Archaeological Science 26, 869–881.

Ocean, Swahili of the East African Coast. Waveland Gratuze, B., ms. Study of glass objects from the wrecked Press, Long Grove, IL.

junk of Brunei. Manuscript on file with the author.

Mitchell, P., 2005. African Connections: Archaeological Guillot, C. (Ed.), 1998. Histoire de Barus. Sumatra. Le site de Lobu Tua. I : Etudes et Documents. Cahiers Perspectives on Africa and the Wider World. Altamira d’Archipel, 30, Paris.

Press, Walnut Creek, CA.

Guillot, C., Surachman, H., Perret, D. et al., 2003. Histoire Morrison, H., 1987. Unpublished medieval glass from
de Barus. Le site de Lobu Tua. II: Etude archéologique the island of Mafia in East Africa. Annales du 10e et Documents. Cahiers d’Archipel, 30, Paris.

congrès de l’Association Internationale pour l’Histoire Henderson, J., McLoughlin, S.D., McPhail, D.S., 2004.

du Verre, MadridSegovie, 23–28 Septembre 1985, pp.

Radical changes in Islamic glass technology: Evi-

305–316.

dence for conservatism and experimentation with

Oka, R.C., 2008. Economic growth and port decline:

new glass recipes from early and middle Islamic

Adaptive resilience in western Indian Ocean trade

Raqqa, Syria. Archaeometry 46 (3), 439–468.

networks, 1500–1700 CE. Ph.D. dissertation, Univer-

Insoll, T., 1998. Islamic glass from Gao. Journal of Glass sity of Illinois at Chicago.

Studies 40, 77–88.

Oka, R.C., Kusimba, C.M., 2008. Siddi as mercenary or

Juma, A., 2004. Unguja Ukuu on Zanzibar. An archaeo-
as African success story on the west coast of India.

logical study of early urbanism. Uppsala University,

In: Hawley, J.C. (Ed.), India in Africa, Africa in India.

Uppsala, Sweden.

Indiana University Press, Bloomington, pp. 203–229.

Kusimba, C.M., 1993. The archaeology and ethnography

Oka, R.C., Kusimba, C.M., Gogte, V.D., 2009. Where
of iron metallurgy of the Kenya coast. Ph.D. disser-
others fear to trade: Modeling adaptive resilience
tation, Bryn Mawr College.

in ethnic trading networks to famines, maritime

156 | OBSIDIAN AND GLASS PROVENANCE
warfare and imperial stability in the growing Indian

New Mexico Press, Albuquerque, pp. 84–93.

Ocean economy, ca. 1500–1700 CE. In: Jones, E.C.,

Redman, C.L., Anzalone, P.R., Rubertone, P., 1979. Med-Murphy, A.D. (Eds.), Political Economy of Disaster, ieval Archaeology at Qsar es-Seghir, Morocco. Journal Monographs in Economic Anthropology. Altamira of Field Archaeology 6, 1–16.

Press, Walnut Creek, CA, pp. 201–240.

Robertshaw, P., Rasoarifetra, B., Wood, M., Melchiorre, E., Oteyo, G., 1999. The significance of Chinese pottery in Popelka-Filcoff, R.S., Glascock, M.D., 2006. Chem ical the archaeology of the East African coastal settle-analysis of glass beads from Madagascar. Journal of ments. MPhil thesis, University of Oxford, UK.

African Archaeology 4, 91–109.

Pearson, M.N., 2003. The Indian Ocean. Routledge, London.

Robertshaw, P., Glascock, M.D., Wood, M., Popelka,

Popelka, R.S., Glascock, M.D., Robertshaw, P., Wood, M., R.S., 2003. Chemical analysis of ancient African glass 2005. Laser ablation ICP-MS of African glass trade
beads: A very preliminary report. Journal of Afri can beads. In: Speakman, R.J., Neff, H. (Eds.), Laser Abla

Archaeology 1, 139–146.

tion ICPMS in Archaeological Research. Uni versity of

Chapter 12

On the Provenance of Roman Glasses

Caroline M. Jackson

Abstract
concerning the organization of glass production and
distribution in the Roman world is discussed.

Roman glass is known for its compositional homo-
geneity, a feature that has been related to the use of 1. Introduction
sand and an evaporite soda-rich alkali (natron or
trona) in production. Recent work has suggested

The products of the Roman glass industry are com-
that, at least for the fourth-century AD and later
monly found throughout the Roman world and

Roman glasses, a small number of discrete com-
beyond. The early Roman glass industry grew out
positional groups can be identified. These groups
of the Hellenistic glass industry, which was typified
have been interpreted in terms of mass produc-
by core formed and cast vessels in a range of bright
tion of raw glass at specific locations in the east-
colors. The use of blue, purple, and green glasses
ern Mediterranean, which was then distributed to
especially, less commonly found in other media
specialist glass-working centers elsewhere in the
such as metals and ceramics, dominated the early
empire. For earlier Roman glasses a clearer picture
assemblages. These early period glasses were luxury
relating to production location and organization is
goods (Grose 1991), although as early as the first
now beginning to emerge. This chapter examines the
century AD glass was a relatively common product
search for provenance and examines in more detail

(Price and Cotam 1998). By the mid second century,
first-century AD Roman glasses from consumption
and with the adoption of blowing as the main form
contexts in Britain and France to determine compo-
of production, glasses ceased to be used solely for
sitional patterns within the glasses. Initial findings luxury items and were used as container vessels and
suggest that discrete chemical groups can be identi-
other utilitarian forms such as tablewares and win-
fied relating to different glass colors but more specif-dow glasses, mainly because glass was impervious
ically to the use of very different glass-forming raw
to liquids, could be easily mass produced, and was
materials. This difference implies that as early as the transparent—a new concept that was brought about
first-century manufacturing sites specialized in pro-
through blowing. Its prevalence in the archaeologi-
ducing primary glass of differing colors. The archae-
cal record would suggest that, certainly by the mid
ological evidence from shipwrecks indicates that
second century AD, glass was a mass-produced
these glasses were mass produced and distributed
commodity and there was an extensive and complex
as chunk glass for reworking elsewhere, a model
glass industry. In contrast, few glass production sites that mimics that recently identified through com-have been identified in the archaeological record.

positional evidence for fourth-century AD glasses.

Those industrial areas that have been recorded are

The compositional characteristics of these glasses
small-scale installations that show glass melting
and their contribution to the continuing debate
for a local market rather than large-scale industrial

157

158 | OBSIDIAN AND GLASS PROVENANCE
glass production (e.g., Price and Cool 1991; Foy 1991; using trona (more commonly known as natron) as

Follmann-Schulz 1991; Price 2002). In the absence
the alkali source (Pliny 1952, Natural His tory 31).

of reliable archaeological evidence for produc-

Natron is mainly composed of sodium salts (carbon-
tion sites, and only tentative suggestions for puta-
ates, bicarbonates, sulphates) (Turner 1956b) and,
tive regional manufacturing locations based upon
like the silica sand, should contain few minor or trace distribution patterns of identified types of glasses,
components. Therefore, glasses produced from these
other avenues of exploration have been sought, such
two ingredients are likely to produce a homogeneous
as glass provenancing through chemical analysis.

composition over time and space (Sanderson et al.

The premise here, as in many other fields of analy-

1984). Additional factors contributing to this com-
sis within archaeology, is that glass produced from
positional stability could be production to a strict
the primary raw materials, at discrete centers, will
recipe (e.g., Lemke 1998) and precise control of man-
have a chemical “fingerprint” that will differentiate it ufacturing technology, notably furnace temperature
from glasses produced at other locations (assuming

(Rehren 2000).

it has been produced using standardized raw materi-

Thus, the use of chemical analysis to prove-
als and manufacturing techniques and that these are
nance glasses has proved problematic, and chemi-
different from those at other glass-making centers).

cal differences between groups could as easily be
explained as the use of different technologies of

2. Compositional studies of
manufacture (particularly recipes) as they could

Roman glasses
to different manufacturing locations. The chemi-
cal provenance of glasses had reached an impasse

While the styles and fashions seen in the con-
in the same way that metals provenance had some
sumption of Roman glasses throughout the empire
years before (although see discussion below on iso-
change, their composition over time is relatively
topic data, which may also be linked to the avenues
homogeneous through five to six hundred years.

of exploration with metals). Paradoxically, both

This homogeneity was noted as early as the 1950s
undergo similar processes in manufacture, trans-
by Turner (1956a) and Sayre and Smith (1961) and
forming geological materials (ores or sands) into
was still deemed a problem for understanding prov-
something that is physically and chemically quite
enance and technology of Roman glasses as late as
different. The added complication with glasses is
the end of the last century (Nenna et al. 1997). Thus
that they may also be produced using mixtures of
the analyses of consumption assemblages contain-
inorganic or inorganic and organic raw materials,
ing glasses of apparently different types and styles,
which change markedly geographically and with
which were thought to be produced at different cen-
organic materials through different growing sea-
ters, are generally indistinguishable chemically, or no sons and underlying geology (Henderson this vol
clear patterns relating to composition or style can be ume; Jackson and Smedley 2008). The latter, whilst identified. This compositional stability may in part
seeming unimportant for Roman glasses produced
be attributable to the raw materials used to manufac-
using geologically sourced raw materials, becomes
ture Roman glass.

relevant in the discussion below.

If, as might be implied from the low levels of

In summary, explanations relating to raw mate-
impurities in the glasses, sand was chosen for its
rial homogeneity and technological processes may
purity, the silica sand used for glass-making would be describe the composition of Roman glasses, but
predominantly composed of silica, with only minor
they do not shed light upon the provenance of the
or trace levels of other compounds that would not
glasses or the organization of the industry. More
significantly affect either the glass-forming ability
in-depth investigation of the data in conjunction
nor the broad compositional traits. This composition
with a systematic choice of glass types and colors,
makes the sand difficult to provenance. In contrast
an assimilation of current archaeological evidence,
to both earlier and later glasses that were produced
and the introduction of new scientific techniques
using plant ashes, Roman glasses were manufactured
such as isotopic analysis, is now beginning to reveal

On the Provenance of Roman Glasses | 159
potential glass production locations and shed light
manganese, and titanium than other earlier, similarly
upon organization and distribution of glass produc-
colored glasses, elemental profiles that had not been
tion and trade in the Roman world.

identified because of the lack of well-dated glasses
in earlier publications. Subsequent isotopic analysis, 3. A model for the organization
using ratios of lead and strontium isotopes matched
of Roman glass production
to isotopic mapping across geographical regions,
suggests that this glass may have been produced in

Traditional 20th-century models to explain Roman

Egypt (Freestone et al. 2005). The mixture of isoto-
glass production used the evidence from small-scale
pic signatures would suggest a location possibly at a
furnaces, located throughout the Roman world. In
delta where riverine sands are washed downstream
the same way that ceramic production was region-
and meet marine sands. A second glass composi-
alized, so was glass. However, more recent indica-
tion was also identified, which was more like that
tions—not from archaeological evidence but from
of earlier Roman periods (Foy et al. 2003; Freestone
trace element analysis and isotopic patterns within

2003). Trace element analysis and isotopic ratios
the glasses—suggest that large-scale production at
again revealed an eastern Mediterranean source
discrete industrial locations is responsible for the
for the sand, probably from around the Levantine
compositional homogeneity of late Roman glasses—
coast. These compositions appear to have originated
from the fourth century and later (for a review see
in the early fourth century and are found through-

Jackson et al. 2003). These large manufacturing instalout the Roman world in a wide range of different
lations are recognized in the seventh and eighth cen-
vessel forms (Foster and Jackson 2009). These find-
tury from locations along the eastern Mediterranean,
ings support the model of mass production of glass,
such as those from the Greco-Roman, Byzantine, and
which in this period was located in the eastern Med-
early Islamic periods found in Egypt and Israel (e.g., iter ranean. Subsequent forming and shaping of the

Nenna et al. 2000; Gorin-Rosen 2000; Freestone et
glass would then take place elsewhere at small-scale
al. 2002). Isotopic patterns can be very complex in
glass-working complexes.

multicomponent materials such as glass, especially

The compositional homogeneity of second- and
where isotopes are introduced from many different
third-century AD Roman glasses may be explained in
sources such as plant ashes and sands. However, for
a similar manner, where the majority of glasses were

Roman glasses produced using natron as a flux, the
blue-green, the natural color of glasses. The similar-
use of particular isotopes such as lead (Pb), stron-
ity in compositions of these glasses may indicate cen-
tium (Sr), and neodymium (Nd) is associated partic-
tralized production, at an as yet unknown location.

ularly with the sand. This provides a means whereby,

Initial work by Degryse and Schneider (2008) using
through isotopic mapping within the larger environ-
strontium and neodymium isotopes suggests some
ment, sand sources can be suggested within broad
of the naturally colored glasses from the first to third geographical areas and potential glass production
centuries may have been manufactured at locations
locations mapped (Freestone et al. 2005; Degryse and
in western Europe at primary production centers (in

Schneider 2008).

contrast to the later glasses where isotope analysis
points to an eastern production location).

4. The search for the provenance

This standardization of colors and forms of
of Roman glasses
glasses, with a predominance of blue-green and col-
orless glasses, is in contrast to early Roman glass

The analysis of isotopic ratios in glasses has shown
production, which grew from an earlier Hellenistic
some success for late Roman glasses. In 1994
tradition. At the turn of the first millennium glass

Mirti et al. (1993) demonstrated that some fourth-
was a luxury commodity, mainly brightly col-
century Roman glasses were of a different compo-
ored, using its reflective and refractive properties
sition from that accepted as typical of the Roman
to mimic and “improve” upon metal and ceramic
period. These green glasses were higher in iron,
wares (Fleming 1997). The use of color was novel,

160 | OBSIDIAN AND GLASS PROVENANCE
with the introduction of colors such as peacock blue
manufactured using plant ashes as their flux). The
and emerald green. The most vivid display of col-
ratios of iron to cobalt are similar to cobalt blue beads ors for these early wares included blue-green (as in
found, and thought to have been manufactured, in
later periods), amber, dark blue, purple, and emerald

Britain that date to the fourth to second century BC
green, as discussed below.

(Henderson 1991), which may support a western

Euro pean origin for the blue glasses. Degryse and

5. The organization of early

Schneider (2008) have also recently tentatively pro-

Roman glass production
posed a western Euro pean origin for some Roman
glasses. These glasses contain manganese at higher

Chemical analysis of early Roman cast and blown
levels than would be expected from the glass-making
vessels of the first century AD from the western
raw materials, which is typical of Roman cobalt blue

Roman Empire (Jackson et al. 2009) suggests, from
glasses. How ever, the source of the colorant is not
compositional data alone, that distinct groups can be
known (Henderson 1991). Published compositions
identified that relate to glass color but are not linked for blue cameo glasses and deep blue ribbed bowls
specifically to the elemental impurities introduced

(Bimson and Freestone 1983; Brill 1999:138) show the
by the use of different mineral colorants. More over,
same traits, implying that these blue glasses form a
the compositional profile is homogenous within each
very coherent compositional group.

color group. As with much later glasses, the major-

The amber, blue, and purple glasses share the
ity of these early Roman glasses are soda-lime-silica, same base composition, typical of glasses produced
typical of those produced using a mineral evaporite
using a mineral evaporite flux. Although composi-
as their flux.

tional differences lie with the use of specific colo-

The amber glasses are typically soda-lime-silica
rants, there is compositional consistency within
glasses with low levels of impurities, characteristic of each color group. This consistency would suggest a
the typical composition identified for Roman glasses.

common manufacturing center (or process) for each

These glasses appear to be colored naturally by the
color. This group-specific consistency is most pro-
use of a reducing atmosphere that, in conjunction
nounced with the emerald green glasses. The green
with the presence of sulfur, has produced the amber
color in these glasses is produced by copper, which
chromophore associated with iron ferri-sulfide. The
by its association with small quantities of tin sug-
purple glasses display a similar composition but one
gests the addition of bronze. However, this alone
that has been modified by the use of a manganese-
does not discriminate this group compositionally.

containing mineral to produce the purple hue. The
particular mineral source, in this case, has also con-
tributed iron to glass (figure 12.1). The deep blue
glasses, colored by cobalt, show similarly increased
iron concentrations compared to the amber glasses.

Cobalt sources for the production of deep blue
glasses have been studied by a number of authors
and there are specific patterns that discriminate dif-
ferent mineral sources, although the origin of the ore is not always easy to provenance (e.g., Farnsworth
and Richie 1938; Gratuze et al. 1992). The min-
eral used is dissimilar to that used for Bronze Age

Egyptian glasses (an alum thought to have originated
in the western oases in Egypt (Kaczmarczyk 1986))

as the glasses display different cobalt/iron ratios

Figure 12.1. Iron oxide and manganese oxide
that cannot be fully explained by the use of different concentrations for purple and blue
glass-forming raw materials (Egyptian glasses were
glasses from first-century contexts.

On the Provenance of Roman Glasses | 161

The emerald green glasses do not conform to a

The compositional consistency within these
typical soda-lime-silica glass produced using a min-
different compositional groups would indicate a
eral evaporite. They have higher concentrations of
pro duction location that is common for each color
magnesium, potassium, and phosphorus, indicative
and that these production locations produced pri-
of the use of a plant ash alkali flux (figure 12.2) (also mary glass for redistribution within the empire. This
seen in data from Henderson 1996; Liritzis et al.

hypothesis is supported by the incidence of vividly

1997). Moreover the ratios of soda:potash:magnesia
colored blue chunk glass, or raw glass, from first-
at approximately 10:1:1 suggest a halophytic plant
century contexts identified in the archaeological
such as Salicornia (Brill 1999:483). Such halophytic record (Foy et al. 2000). Because these raw glasses
plants are typically associated with Bronze Age glass
already display the characteristic deep blue color
production in Egypt and the Middle East, rather
seen in fully formed glasses, it is likely these glass than with Roman glasses. Also, these emerald green
chunks were colored during manufacture at a pri-
glasses contain slightly enhanced concentrations of
mary location. Therefore, it might be suggested that,
iron that cannot be linked to a plant ash flux alone,
as with fourth-century Roman glasses, as early as
but rather to the use of sands that have a different
the first century AD Roman glasses were produced
mineral component from those used for other early
in large manufacturing centers and then exported

Roman glasses. This very distinctive composition
for reworking elsewhere. Primary glass production
for the emerald green glasses has recently also been
probably took place near raw material resources,
reported for early Roman red glasses in mosaic ves-
with specific colorants chosen from discrete loca-
sels (Nenna and Gratuze 2009). Red glasses are sim-
tions. The use of plant ashes in the production of
ilarly colored with copper.

emerald green and red glass may indicate a produc-

Do these compositional patterns in early Roman
tion complex with different traditions of manufac-
glasses suggest that the centralized production model
ture, such as that presented by Rehren (2000) for Late proposed for late Roman glasses was already in place

Bronze Age glasses from Egypt.

in the first century? Certainly these patterns, which
do conform to broad color groups in the glasses, can-

6. A color-centered model?

not be wholly explained in terms of the use of dif-
ferent colorants. In the case of the emerald green

The Egyptian model of color-centered complexes has
and red glasses, where completely different alka -
been suggested from different compositional groups
lis have been used, different glass-making traditions
of glasses seen in the Egyptian Bronze Age glass
are indicated.

repertoire and from archaeological evidence in the
form of glass ingots recovered from the Uluburun
wreck. It has recently been supported by the pub-
lication of primary red glass production at Qantir

(Rehren and Pusch 2005; Jackson 2005a). Rehren

(2000) suggests copper blue glasses, which have a
relatively heterogeneous composition, could have
been produced at many centers, because copper is
widely available as a colorant. Cobalt blue glasses,
which are compositionally more internally homoge-
neous, were produced with a more exotic coloring
raw material that may have been more tightly con-
trolled (Rehren 2001). Red glass production would
also have been produced at “specialist sites” because

Figure 12.2. Major element concentrations for it required a certain degree of technical expertise.

amber, purple, and green glasses from

Thus the pattern emerging is one that in the
first-century contexts.

early Roman period seems to be similar to the model

162 | OBSIDIAN AND GLASS PROVENANCE
proposed by Rehren (2001) for Late Bronze Age glass
forms a significant proportion of many Roman glass
production in Egypt: that of large centers producing
assemblages from the first century AD. It is con-
glass of different colors that was reworked elsewhere.

sidered to be a high-status material, and changes

By the late Roman period, the mass production of
in stylistic fashions mean that particular forms
glass at large installations still appears to be occur-have discrete and often short life spans that can be
ring. However there is a fundamental difference
firmly dated. The raw materials used in its manu-
in what is being produced. By the fourth century,
facture would need to be pure in order to produce a
the compositional patterns seen in the glasses do
good quality colorless glass, and it is likely recycling not appear to relate to color-specific primary glass-would be limited. This makes this group one where
producing complexes, but to large complexes mass-
compositional patterns can be studied in relation to
producing common blue-green glasses. This may be
fashion and change in styles over time.

explained by the changing nature of glass throughout

Compositional analysis of these colorless glasses
the Roman period. During the early Roman period
indicates in many cases that pure sand had been used
when glass color was still one of the main attractions in manufacture (Jackson 2005b), which set this glass
of this material, the expertise needed for the produc-
color apart from the naturally colored blue-green
tion of glass of specific colors may have meant that
glasses (Jackson et al. 1991). It also shows that, within different colors of glasses needed specialist color
this broad glass category, different compositional
centers with the right technical expertise (as in the
groups could be identified that were not based on the

Egyptian model). However, by the late Roman period
addition of decolorizers such as antimony or manga-
it is likely that expertise in glass production, and glass nese. Nevertheless, it has proved difficult to link these technology, was less related to primary glass manu-compositional groups to archaeologically defined
facture and the production of a specific color than to criteria such as style, date, or context (Jackson et al.

the exotic and complex forms manufactured, such as

2003). The color-centered model used to describe the
dietrata and cameo vessels, which combined glasses
organization of production for these glasses has some
with very differing compositions and hence rates of
subtleties in composition that would require further
thermal expansion. By the fourth century the major-
investigation, which is work in progress.

ity of commonly found utilitarian vessels and window

These compositional features identified in Roman
glass was made of either naturally colored blue-green
glasses relate to specific manufacturing practices
or colorless glass. Only the production of very spe-
and the organization of primary glass production
cialized pieces required high levels of skill. This may in the Roman world, and explain only part of the
account for the model in the fourth century whereby

Roman glass industry. Archaeologically, our great-
large centers were mass-producing green glass for
est resource for understanding the production and
working elsewhere. It must be noted, however, that
distributive network of glasses is the analysis of conthese hypotheses do not take into account the pro-
sumption assemblages. The redistributive model of
nounced political changes that took place in the late
primary glass production indicates that, throughout
fourth century.

the Roman Empire, artifact fabrication took place
on a much smaller scale, in a larger number of small

7. Extension of the production
glass-working centers potentially near the point of
model—the elucidation of
consumption. The archaeological evidence for small
glass assemblages
glass-working centers is attested (e.g., see Price and Cool 1991). To understand compositional patterns

Compositional analysis of colorless glasses have not
within consumption assemblages may be more dif-
always produced easily interpretable results, and
ficult. Each secondary fabrication center may have
an understanding of their production has proved
been supplied with glass from either a few or many
more problematic (Jackson et al. 2003; Baxter et al.

different primary glass producers, and each producer

2005; Jackson 2005b; Paynter 2006). Colorless glass
could have produced a very few object types for

On the Provenance of Roman Glasses | 163
local consumption and export, or alternatively could
groups in the first century indicate a common loca-
have produced a wide variety of objects to furnish
tion of manufacture for each group that as yet needs
a local market. Thus these different compositional
to be identified.

groups within and between vessel types identified,

It is these first-century Roman glasses that are
for example, in fourth-century glasses may be due to
perhaps the most intriguing. It has long been accepted this mixing of different primary glasses at secondary
that Roman glasses were produced using natron as the
centers (Foster and Jackson 2009). This mixing may
primary alkali, and that plant ash glasses had ceased
go some way to explaining the compositional pro-
to be produced around the Medi terranean at this
files seen in colorless glass. The potential combina-
time. This may represent a continuation of a much
tions are many and would explain why some Roman
older tradition of glass production that had become
glass vessel types are more or less easily defined
assimilated into the Roman repertoire. Alternatively,
compositionally than others, with specialist vessels
this occurrence of plant ash–based production could
perhaps having the most easily definable and com-
be specifically related to technology whereby red and
positionally coherent composition (e.g., see Baxter
emerald green glasses represent a tradition or exper-
et al. 2005 for compositional patterns relating to col-tise that was exclusive to a particular culture. An
orless facet-cut beakers).

investigation of trace element and isotopic signatures is underway to help us understand the potential prov-8. Continuity or change?

enances of these early glasses.

It is now possible to distinguish, within the Roman

9. The missing link?

period, glasses with varying compositions, although
all are of the soda-lime-silica tradition. It seems

Research on Roman glass has narrowed with the
that these differences appear to change subtly over
development of interpretative methods that look
time and relate to primary glass production, a well-
in more depth at compositional patterns in Roman
developed production process, and a sophisticated
glass, initially based on major and minor elemental
industry and distributive system in the Roman
evidence and now more recently assigned on the
world. In the fourth century two generic composi-
basis of trace elements with the introduction of iso-
tions are dominant and can be related to different
tope analysis to determine provenance. The search
sand sources and two primary glass production
for provenance is not just about the use of more
loci in Egypt and the Levant. This scientific evi-
sophisticated methods and the analysis of increas-
dence, which suggests that some late Roman glass
ing amounts of material; it is about searching in the
was being manufactured in large complexes located
right area and asking the right questions. Perhaps
somewhere off the coast of Egypt, can be linked to
one of the keys to understanding early Roman glass
supporting new archaeological evidence (Nenna et
production is to understand its roots. As the Roman
al. 2005) for the production of some Roman glass in

Empire grew in the early years, it assimilated many
specialist primary locations such as Egypt. Colorless
different cultures. Most notably for Roman glasses,

Roman glass of the second and third centuries indi-
this assimilation included the Hellenistic world,
cates that this too is specialized production of a sin-which brought to the Romans a successful, highly
gle color using different, purer sands than the more
developed, and sophisticated glass industry. By trac-
common blue-green glass (Jackson et al. 1991). In
ing the compositional trends apparent in Hellenistic
the first century, blue, purple, amber, and emerald
glasses, a more detailed picture of the early Roman
green glasses are compositionally different depend-
glass industry may emerge. It may be that the model
ing upon the addition of typical colorizing elements
seen in the Bronze Age for color-centered complexes
such as cobalt ores with similar trace element pat-
is one that is carried through, albeit in a different
terning or on the use of distinctly different alkali
form, into and beyond the Roman world. To sug-
sources. The compositional similarities within color
gest this pattern over as considerable a time period

164 | OBSIDIAN AND GLASS PROVENANCE
as 1000+ years is perhaps controversial, but through

Foy, D., Vichy, M., Picon, M., 2000. Lingots de verre
the analysis of Hellenistic and earlier glasses we may en Méditerranée (IIIe s. av. J.-C.-VIIe s. ap. J.-C.), be able to explore the missing link.

approvisionnement et mise en œuvre; les don-
nées archéologiques et les données de laboratoire.

References

Annales du 14e congrès de l’Association Internationale pour l’Histoire du Verre (Venise-Milan, October Baxter, M.J., Cool, H.E.M., Jackson, C.M., 2005. Further 1998). AIHV, Lochem, pp. 51–57.

studies in the compositional variability of colourless Freestone, I.C., 2003. Primary glass sources in the

Romano-British vessel glass. Archaeometry 47 (1), mid first millennium AD. Annales du 15e Congrès 47–68.

de l’Asso ciation Internationale pour l’Histoire du Bimson, M., Freestone, I.C., 1983. An analytical study Verre. Corning, NY, 2001. AIHV, Nottingham, UK, of the relationship between the Portland vase and
pp. 111–115.

other Roman cameo glasses. Journal of Glass Studies Freestone, I.C., Greenwood, R., Gorin-Rosen, Y., 2002.

25, 55–64.

Byzantine and early Islamic glassmaking in the east-

Brill, R.H., 1999. Chemical Analyses of Early Glasses.

ern Mediterranean: Production and distri bu tion of

Corn ing Museum of Glass, Corning, NY.

primary glass. In: Kordas, G. (Ed.), Hyalos= Vitrum=

Degryse, P., Schneider, J., 2008. Pliny the Elder and

Glass: History, Technology and Con ser vation of Glass.

Sr-Nd isotopes: Tracing the provenance of raw mate-

Proceedings of the First Balkan Con ference, Rhodes, rials for Roman glass production. Journal of Archa2001. Glasnet Publications, Athens, pp. 167–174.

eological Science 35, 1993–2000.

Freestone, I.C., Wolf, S., Thirlwall, M., 2005. The pro-Farnsworth, M., Ritchie, P.D., 1938. Spectrographic
duction of HIMT glass: Elemental and isotopic
studies on ancient glass: Egyptian glass, mainly of
evidence. Annales du 16e congrès d l’association inter
the eighteenth dynasty, with special reference to its
nationale pour l’histoire du verre, London, 2003. J.W.

cobalt content. Technical Studies in the Field of Fine Arrowsmith, Bristol, UK, pp. 153–157.

Arts 6 (3), 155–173.

Gorin-Rosen, Y., 2000. The ancient glass industry in

Fleming, S.J., 1997. Roman Glass, Reflections of Everyday Life. University of Pennsylvania Museum of Archa-Israel: Summary of the finds and new discoveries.

eology and Anthropology, Philadelphia.

In: Nenna., M.-D. (Ed.), La Route du Verre: Ateliers Follmann-Schulz, A.B., 1991. Fours de verriers romains primaire et secondaires de verriers du second milli
dans la province de Germanie inferiéure. In: Foy, D.,
nire av. J.C. au Moyen age. Travaux de la Maison de Sennequier, G. (Eds.), Ateliers de Verriers de l’Antiquité l’Orient Méditerranéen no 33. Lyon, pp. 49–64.

à la Période PréIndustrielle. Association Française Grose, D.F., 1991. Early Imperial Roman cast glass:

pour l’Archéologie du Verre, Rouen, pp. 35–40.

The translucent coloured and fine colourless fine

Foster, H.E., Jackson, C.M., 2009. The composition of
wares. In: Newby, M.S., Painter, K. (Eds.), Roman

“naturally colored” late Roman vessel glass from

Glass: Two Centuries of Art and Invention. Society of Britain and the implications for models of glass pro-Antiquaries London Occasional Paper 13, 1–19.

duction and supply. Journal of Archaeological Science Gratuze, B., Soulier, I., Barrandon, J-N., Foy, D., 1992. De 36, 189–204.

l’origie du cobalt dans les verres. Revue d’Archaeo

Foy, D., 1991. Ateliers de veriers de l’Antiquité et du metrie 16, 97–108.

haut Moyen Age en France. In : Foy, D., Sennequier,

Henderson, J., 1991. Industrial specialization in late Iron G. (Eds.), Ateliers de Verriers de l’Antiquité à la Age Britain and Europe. Archaeological Journal 148, Période PréIndustrielle. Association Française pour 104–148.

l’Archéologie du Verre, Rouen, pp. 55–72.

Henderson, J., 1996. Scientific analysis of selected Fish-Foy, D., Picon, M., Vichy, M., Thirion-Merle, V., 2003.

bourne vessel glass and its archaeological interpre-

Car actérisation des verres de la fin de l’Antiquité en tation. In: Cunliffe, B.W., Down, A.G., Rudkin, D.J.

Méditerranée occidentale: L’émergence de nouveaux

(Eds.), Chichester Excavations IX, Excavations at courants commerciaux. In: Foy, D., Nenna, M.-D.

Fishbourne 1969–1988. Chichester District Council, (Eds.), Échanges et Commerce Du Verre dans le Monde Chichester, UK, pp. 189–192.

Antique. Instrumentum 24, Éditions Monique Mergoil, Jackson, C.M., Hunter, J.R., Warren, S.E., Cool, H.E.M., Montagnac, pp. 41–85.

1991. The analysis of blue-green glass and glassy

On the Provenance of Roman Glasses | 165
waste from two Romano-British glass working sites.

vases mosaïqués antiques: Résultats préliminaries.

Archaeometry 90, 295–304.

Annales de 17e Congrès de l’Association Internationale Jackson, C., Baxter, M.J., Cool, H.E.M., 2003. Identifying pour l’Histoire du Verre. September 2006, Antwerp.

group and meaning: An investigation of Roman

AIHV, Nottingham, UK, pp. 199–205.

colourless glass. In: Foy, D., Nenna, M.-D. (Eds.),

Nenna, M.-D., Picon, M., Thirion-Merle, V., Vichy, M., Échanges et commerce du verre dans le monde 2005. Primary workshops in Wadi Natrun: New
antique. Actes du colloque de l’AIHV, AixenProvence discoveries. Annales du 16e Congrès de l’Associaet Marseille, juin 2001. Monographies Instrumentum tion Internationale pour l’Histoire du Verre. AIHV, 24. Monique Mergoil, Montagnac, pp. 33–39.

London, pp. 59–63.

Jackson, C.M., 2005a. Glassmaking in Bronze Age Egypt.

Paynter, S., 2006. Analyses of colourless Roman glass

Science 308, 1750–1752.

from Binchester, County Durham. Journal of Archa

Jackson, C.M., 2005b. Making colourless glass in the
eological Science 33 (8), 1037–1057.

Roman period. Archaeometry 47 (4), 763–780.

Pliny, 1952. Natural History. English translation by Jackson, C.M., Smedley, J.W., 2008. Medieval and post-H. Rackham. Loeb Classical Library ed. Harvard
medieval glass technology: The chemical composition

Uni ver sity Press, Cambridge, MA.

of bracken from different habitats through a growing

Price, A.J., Cottam, S., 1998. RomanoBritish Glass Vessels: season. Glass Technology: European Journal of Glass A Handbook. Practical Handbook in Archaeology Science and Technology Part A 49 (5), 240–245.

14. Council for British Archaeology, York, UK.

Jackson, C.M., Price, J., Lemke, C., 2009. Glass pro-

Price, J., Cool, H.E.M., 1991. The evidence for the produc-duction in the 1st century AD: Insights into glass
tion of glass in Roman Britain. In: Foy, D., Sennequier, technology. Annales de 17e Congrès de l’Association G. (Eds.), Ateliers de Verriers de l’Antiquité à la Période Internationale pour l’Histoire du Verre. Antwerp, Sep-PréIndustrielle. Actes des Journées d’etude Congrès tember 2006. AIHV, Nottingham, UK, pp. 150–156.

d’AFAV. November 1989, Rouen, pp. 23–31.

Kaczmarczyk, A., 1986. The source of cobalt in ancient Price, J., 2002. Broken bottles and quartz-sand: Glass Egyptian pigments. In: Olin, J.S., Blackman, M.J.

production in Yorkshire and the North in the Roman

(Eds.), Proceedings of the 24th Archaeometry sympo
period. In: Wilson, P., Price, J. (Eds.), Aspects of sium, Washington D.C. , 14–18 May 1984. Smithsonian Industry in Roman Yorkshire and the North. Oxbow Institution Press, Washington, D.C., pp. 369–376.

Liritzis Y., Salter, C., Hatcher, H., 1997. Chemical compo-Books, Oxford, UK, pp. 81–93.

sition of some Greco-Roman glass fragments from

Rehren, Th., 2000. New aspects of ancient Egyptian

Patras, Greece. European Journal of PACT, no. 45, glass making. Journal of Glass Studies 42, 13–24.

I2, 25–34.

Rehren, Th., 2001. Aspects of the production of cobalt Lemke, C., 1998. Reflections of the Roman Empire: First blue glass in Egypt. Archaeometry 43 (4), 483–489.

century glass manufacture as seen through tradi-

Rehren, Th., Pusch, E., 2005. Late Bronze Age glass pro-tions of manufacture. In: McCray, P., Kingery, W.D.

duction at Qantir-Pirameses, Egypt. Science 308, (Eds.), The Prehistory and History of Glassmaking 1756–1758.

Technology. Ceramics and Civilisation. Vol. 8. Ameri-Sanderson, D.C.W., Hunter, J.R., Warren, S.E., 1984.

can Ceramics Society, Cincinnati, pp. 269–291.

Energy dispersive X-ray fluorescence analysis of 1st

Mirti, P., Casoli, A., Appolonia, L., 1993. Scientific analy-millennium AD glass from Britain. Journal of Archa
sis of Roman glass from Augusta Praetoria. Archaeological Science 11, 53–69.

eometry 35, 225–240.

Sayre, E.V., Smith, R.W., 1961. Compositional categories Nenna, M.-D., Vichy, M., Picon, M., 1997. L’atelier de ver-of ancient glass. Science 133, 1824–1826.

rier de Lyon du 1er siècle après J.-C., et l’origine des Turner, W.E.S., 1956a. Studies in ancient glasses and
verre “Romains.” Revue d’Archaéométrie 21, 81–87.

glassmaking processes, part IV: The chemical com-

Nenna, M.-D., Picon, M., Vichy, M., 2000. Ateliers pri-position of ancient glasses. Journal of the Society of maries et secondaires en Égypte à l’époque Greco-Glass Technology 40, 162–186.

romaine. In: Nenna, M.-D. (Ed.), La Route du Verre.

Turner, W.E.S., 1956b. Studies in ancient glasses and

Maison de l’Orient Méditerranéen, Lyon, pp. 97–112.

glassmaking processes, part V: Raw materials and

Nenna, M.-D., Gratuze, B., 2009. Étude diacrhonique
melting processes. Journal of the Society of Glass Tech
des compositions de verres employés dans les
nology 40, 277T–300T.

Chapter 13

Characterization and Provenance of Archaeological

Glass Artifacts from Mainland and Aegean Greece

Konstantinos G. Beltsios, Artemios Oikonomou,

Nikolaos Zacharias, Pavlos Triantafyllidis

Abstract
addressed on the basis of past materials concepts
and statements scattered in ancient sources.

SEM-EDS analysis was used for the compositional
characterization of two ancient glass beads collec-

1. Introduction
tions, a late seventh-century BC Archaic collection
from Rhodes Island and an Archaic to Hellenistic

In the Middle East and East Mediterranean (ME-
collection from mainland Greece (Thebes). The

EM) world, early glass history is somewhat obscure.

inclusion of additional literature data from fourth-

Major glass-technology achievements and the
to second-century BC Rhodian glasses allows for
spread of glass artifacts start during the 16th to 12th a comparison of glass compositions over a sub-century BC (Henderson 2000), and the advances
stantial portion of antiquity for a mainland Greece
appear to originate mostly from the Mesopotamian
and an Aegean location. Compositional patterning
region and Egypt. Portions of the “glass materials
is explored on the basis of selected bivariate plots
map” for several MEEM subareas and time peri-
involving K O, MgO, CaO, Fe O , and Al O frac-
ods, such as the Late Bronze Age and later, remain

2

2 3

2 3
tional contents. The bulk of the seventh-century BC
rather sketchy with respect to the technological

Rhodian samples are found to correspond to plant
history of glass. This is true for Greece of histori-
ash–based material, while the samples from Thebes
cal times through the Hellenistic period,1 and this
are natron-based glasses that exhibit compositional
work focuses on the compositional makeup of
trends persisting for some centuries. Both CaO and
glasses from this region over time. Glasses from the

MgO can contribute substantially as alkaline earth

Greek mainland (Thebes) and an Aegean (Rhodes)

oxide components for the bulk of Rhodian sam-
location are investigated in this analysis. Some other ples, but the corresponding CaO/MgO ratio varies
issues, such as the connection between composition
widely (from <1 to >1). The samples from Thebes rely and processing temperatures and the presence of
largely on CaO, while MgO is a minor and, appar-
undissolved particles, pertinent to the related sam-
ently, accidental component. Fe O is present as an
ples, have been recently considered in other publica-

2 3
impurity for the bulk of the samples although the
tions (Zacharias et al. 2008; Oikonomou et al. 2008).

use of an iron oxide as a coloring agent is possible

Glass artifacts from within the Greek-speaking
in a few cases. Al O occurs as an impurity in the
world occur sporadically from the 15th century BC,

2 3
case of the samples from Rhodes, while the bulk of
more extensively from the seventh century BC, and

Al O present in the samples from Thebes appears to
abundantly during Hellenistic times. The island of

2 3
result from a deliberate addition of small amounts

Rhodes during the eighth to sixth century BC and
of alum-type materials. The broader issue of unusual
also in the Hellenistic Period was one of the most
raw materials in the ancient glass industry is also
important glass-making and glass-working centers in

166

Characterization and Provenance of Glass Artifacts | 167
the eastern Mediterranean (Rehren et al. 2003). An

6 samples from Rhodes and 6 samples from Thebes
impressive total of 10,000 glass objects was found in
are presented in figures 13.1 and 13.2.

the Geometric (eighth–seventh century BC) and early

The present study focuses on the presence of

Archaic tombs (late seventh–sixth century BC) of
oxide components found in common glasses at mod-

Ialysos and Kamiros and also in the sacred deposits of erate levels, that is, K O, MgO, CaO, Fe O , and Al O , 2

2 3

2 3
the large sanctuaries in Ialysos, Kamiros, and Lindos
all in the 0.1–10% range. SO and chlorine are also

3

(Triantafyllidis 2006). The Rhodian beads considered
found at concentrations at the low end of the specified here come from the ancient city of Kamiros, which
range but processing temperature effects and solubil-
blossomed mainly during the Archaic period (680–
ity limitations prevent simple correlations of the type 480 BC). The contents of graves and artifacts from
to be applied to the other oxides. Following a cursory the depository in the temple of Athena testify to the
examination of all possible two-component plots, and
fact that during the seventh and the sixth century BC
in order to avoid redundancy, we selected for presen-
commercial relations existed between Kamiros and
tation and discussion five plots that were found to be mainland Greece, along with Asia Minor and the
the most illuminating and informative with respect
southeast Mediter ranean. Indications of small-scale
to local glass-making trends. The chosen plots empha-
industries for ivory, gold, faience, and glass-making
size MgO and Al O contents but all five oxides appear 2 3
have also been reported (Filimonos et al. 2006). The
in at least one plot. The following compositional
explicit reference of Pliny to high-quality Rhodian issues are addressed on the basis of the bivariate plots: versions of verdigris and cerussa (Pliny, XXXIV:112,

(a) the type of alkaline source used (section 3.1.1),

175–176 respectively), two pigments widely and easily

(b) the relationship between alkaline-earth compo-
prepared during antiquity, is an indication of long-nents (section 3.2), (c) the amount of Al O present in 2 3
flourishing material
l p
reparation/p
n/ r
n/p

/pp ocessing
g in
i d
n us-
dus-
relation to MgO and Fe O (section 3.3), and (d) the

2 3
tries in ancient Rhodes.

proportions of Al O in relation to K O (section 3.4.2).

2 3

2

A large number of glass ornaments, mainly

Issues (a) and (b) pertain to key types of raw materi-
necklace beads (n = 6000), were excavated from the
als, while (c) pertains to two oxides (Fe O and Al O ) 2 3

2 3
acropolis during the Italian occupation of Rhodes
that may occur either as impurities or as deliberate

(1912–1943). A total of 70 samples that date to the
minor additions. Item (d) clarifies the origin of Al O

2 3
late seventh century (ca. 640–600 BC) is considered
as a deliberate addition of alum-type materials in the here. They were excavated from within an oinohoe
samples from Thebes.

( oenokhoē, wine vessel) of the wild goat style, which To broaden the analysis, additional data from
dates back to the Late Archaic period.

other sources are used for comparative purposes in

The second group of glass artifacts examined
some cases. In particular, published data from the
in this analysis originates from mainland Greece
fourth century BC (Triantafyllidis 2000) and from
and, in particular, from the City of Thebes. During
the third to second century BC (Brill 1999), both
the construction of a bridge for the Greek National
from Rhodes, are included in some comparisons

Railway in the outskirts of Thebes, a cemetery was
so that the time spans for Rhodes and Thebes are
identified during excavations conducted by the 9th
approximately matched.

Ephorate of Prehistoric and Classical Antiquities.

Section 3.4.1 reviews ancient literature references

The cemetery included dozens of graves dated from
pertinent to the employment of unusual raw materi-

Archaic to Hellenistic times. The recovered glass
als in glass-making. This issue has not received suf-
artifacts were assigned ages by the excavators on the
ficient attention before and therefore it is presented in basis of burial findings datable on stylistic grounds
some detail. This section should be of interest to those (Aravantinos in press). The 29 Thebian samples to
working on ancient glasses of various eras and areas,
be analyzed in this study have been dated as fol-
while at the same time providing a framework for the
lows: Archaic (n = 16), Late Archaic (n = 2), Late
proper evaluation of the findings in section 3.4.2. An Archaic/Classical (n = 1), Classical (n = 6), Classical/
additional issue addressed in the paper is the false

Hellenistic (n = 3), and Hellenistic (n = 1). Images of positive correlations in the grouping of glass samples

168 | OBSIDIAN AND GLASS PROVENANCE

Figure 13.1. Six samples from the Rhodes
collection. The composition of these
samples appears in appendix A.

Figure 13.2. Six samples from the Thebes
collection. The composition of these
samples appears in appendix A.

from multiple regions and time periods. This is a fre-
almost impossible to disentangle. Informed judg-
quent problem in the literature on ancient glass, and
ment can be more important than least-squares fit-
our detailed K O versus MgO data allow for a perti-
ting in deciding how glasses were made. Frequently,

2
nent demonstration (section 3.1.2).

the latter might yield a less than optimum eye-guide.

A word of warning is necessary in the use of

Also, as an example explored herein indicates, it is
bivariate plots. Bivariate plots that display compo-
possible that apparently meaningful correlations can
sitional data for ancient artificial glasses constitute a turn out to be largely misleading ones (section 3.1.2).

nightmarish experience for the purist. Component

It is hardly surprising that discussions of glass com-
complexity, substantial spatial and even seasonal
position trends are frequently based on bivariate
variability of raw materials, melt inhomogeneity,
plots where only a few compositional islands can be
recycling, and impurities from processing equipment
identified within the scatter of data points (see, for frequently generate a compositional situation that is
example, Henderson 2000).

Characterization and Provenance of Glass Artifacts | 169

2. Experimental Method

Table 13.1 Synopsis of EDS compositional analysis of key oxides in glass beads from

Compositional analyses were performed using a scan-
seventh-century BC Rhodes.

ning electron microscope (FEI-INSPECT) equipped

Rhodes Glass

Minimum

Maximum

Mean
with an energy-dispersive spectrometer (EDS), with

Beads

(wt. %)

(wt. %)

(wt. %)

an SUTW detector. All analyses were performed at

SiO 57.7 75.1 67.7

2

25 kV, with a take-off angle of 350. The accuracy of

Na O 10.4 23.5 18.4

2
oxide content determined by EDS drops gradually

K O 0.11 4.5 1.63

2
for components present at levels below 0.5% and only

CaO

2.9

9.0

5.4
components with a determined level of ≥0.1% are
considered. All values are averages obtained from a

MgO

0.62

7.1

3.93
minimum of 3 measurements per sample.

Al O 0.5 3.1 1.1

2 3

The surface for most of the analyzed glass beads

Fe O 0.1 1.2 0.5

2 3
and other glass objects exhibited a heavy corrosion

Notes:

layer. The selected surface area was polished by means 1. For 67 out of 70 artifacts: K2O ≥0.8 %.

of a hand-drill equipped with a silicon carbide head.

2. For 65 out of 70 artifacts: MgO ≥2.4 %.

Every abraded glass surface was further polished with

3. Mean for all 70 samples.

garnet paper of various grits (1000, 1200, and 1500
grit). Finally, the samples were cleaned with acetone.

Table 13.2 Synopsis of EDS compositional analysis The above treatment resulted in very clean, flat, and
of key oxides in glass beads from Thebes.

corrosion-free spots suitable for SEM-EDS analysis.

Thebes Glass

Minimum

Maximum

Mean

Glass samples were mounted on stamps with carbon

Beads

(wt. %)

(wt. %)

(wt. %)

glue to achieve better conductivity.

SiO 65.2 73.4 69.9

2

Na O 13.7 22.5 17.4

2

K O 0.1 0.9 0.4

3. Results and discussion

2

CaO

4.4

8.8

6.6

In tables 13.1 and 13.2 the results from SEM-EDS

MgO

0.4

1.1

0.7
examination are summarized in the form of com-

Al O 0.7 3.7 2.3

2 3
positional ranges and averages for the two groups

Fe O 0.2 2.81 0.82

2 3
of samples. Full compositional data are presented in

Notes:

appendix A.

1. For 24 out of 29 samples: Fe2O3 ≤ 1.1 %.

2. Mean for all 29 samples.

.

3.1. K O versus MgO

2

3.1.1. The Alkali Sources
based on natron ((Na CO .10H O) and/or trona

2

3

2

The alkali component of ancient glasses was derived

(Na H(CO ) .2H O) and having NaCl and Na SO

3

3 2

2

2

4
primarily from two types of sources: (a) plant ash
as primary impurities) contributes low K O and MgO

2
and (b) minerals of the natron family. The compo-
levels to the final glass. The connection between alkali sition of plant ashes vary substantially with plant
sources and composition of final glasses is described
species, area of growth, season of collection, firing
in some detail in standard works on ancient glass
conditions, and post-firing processing. Despite vari-

(e.g., Henderson 2000), while compositions of raw
ability in the specifics, when the alkali source is a
materials and final glasses from various eras and areas plant ash, it can be detected by the elevated levels of have been gathered by Brill (1999).

K O and MgO. Only rarely would plant ashes from

The K O and MgO contents of our glasses can

2

2
unique types of plants contribute low K O and/or low
be assessed from tables 13.1 and 13.2, and full compo-

2

MgO levels to glass composition. On the other hand,
sitional profiles are presented in appendix A. Figures the natron family of alkali sources (raw materials

13.3a and 13.3b provide bivariate plots of the K O and 2

170 | OBSIDIAN AND GLASS PROVENANCE

MgO concentration contents for our samples, as well
ian samples are largely plant ash–based ones, and
as for the additional literature data for Rhodes.

they were assigned to the 640–600 BC period.

The bulk of the new samples from Rhodes

Even if they were made on the average a genera-
exhibit a relatively high K O content (≥0.8%, except
tion before the time of deposition, they are still

2
for 3 samples) and a relatively high MgO content
seventh-century BC glasses and, hence, they are

(≥2.4%, except for 5 samples), while all samples
compatible with the estimated time period of Sayre
from Thebes exhibit relatively low K O (0.1–0.9%)

and Smith (1961). As a matter of fact, there is no

2
and MgO (0.4–1.1%) contents. Roughly speaking,
need to choose between the two temporal periods if
the differentiation reflects the fact that the bulk of we accept a transition period of some generations,
the samples from Rhodes corresponds to the tempo-
especially when all glass-making centers are con-
ral end of a compositional plant ash–using MEEM
sidered collectively. Local adoption of the natron
tradition originating from Late Bronze Age, while
route can vary, and variations can be related to
the samples from Thebes come from the follow-up,
the accessibility of natron and the composition of
natron-based, compositional tradition (Sayre and
plant ash used previously; the latter can vary widely

Smith 1961; Henderson 2000).

(Barkoudah an
h a d He
d H nderson 2006). A

6
s

). A hes compo-
o-

Out of the 70 samples from Rhodes, there are
sitionally closer to natron might make the transi-

3 (R33, R53, and R69) that originate clearly from a
tion easier. In MEEM lands, natron was available
batch that was exclusively, or at least largely, based primarily through Egypt, but various other poten-on natron-type material. In addition, a largely mixed
tial ancient sources are known. If the somewhat
batch might have been the source of the low mag-
obscure “natron foam” ( aphronitron, Greek/ spuma nesium and slightly elevated potassium found in
nitri, Latin) is included, it should be noted that at samples R11 and R29. Sample R42 might also reflect
least 10 good natron sources are listed in ancient
substantial contributions from both types of alkali
literature (Pliny, XXXI:106–122; Dioscurides, E.113,
sources, and a more strict screening will undoubt-

Strab0,11, C 529/8). Th e use of natron p
n persists dur
ts d -
edly reveal some more cases with a traceable natron
ing Roman (Liritzis et al. 1997) and Early Medieval
contribution. Still, it remains clear that our R1–R70
times, while plant ashes are reintroduced around
group of samples is predominantly glass-based on
the eighth–ninth century AD (Henderson 2000).

a plant ash alkali source. As a matter of fact, the

In the case of Rhodes, it is possible that glass-
group’s mean MgO and K O contents (table 13.1) are
working does not shift to a natron-based alkali raw

2
somewhat higher than the mean MgO and K O con-
material until Rhodians gained routine access to

2
tents (3.6% and 1.13%, respectively) offered originally Egyptian natron. The access might have been first
as crude guidelines (Sayre and Smith 1961) for pre-
ensured in the late seventh century BC, beginning
natron glass.

with the unobstructed operation of Naucratis, a

The limited amount of natron-based material

Greek trade station founded in Egypt by Rhodians
present in the seventh-century BC Rhodian ensem-
and others.

ble could reflect contributions either from a different It should be noted that our maximum K O con-2
glass-making center already employing a natron-
centration for Thebes exceeds the minimum K O

2
based alkali source or from the same glass-making
levels for Rhodes (0.9% versus 0.8%). The small
center at its early stage of handling a natron-based
difference alone is hardly an important one, but it
alkali source. Whatever the case might be, dim sig-
might be significant that almost one-third of our 29
nals for the new glass-composition era are captured
samples from Thebes exhibit a K O content higher

2
in the analyzed samples.

than the maximum value of 0.47% that Sayre and

The replacement of a plant ash alkali source by

Smith (1961) had found upon examination of 34
natron for the eastern Mediterranean is currently
samples from the post-600 BC natron-based tradi-
placed around 800 BC (Henderson 2000), while a
tion. The K O maximum for the natron-based tra-

2
later occurrence in the seventh–sixth century BC
dition was raised in later works to 1.0%, in order
was suggested by Sayre and Smith (1961). Our Rhod-
to encompass special cases. We believe that our

Characterization and Provenance of Glass Artifacts | 171

Figure 13.3a. K O versus MgO for glass

2
artifacts from Rhodes (seventh, fourth,
third–second centuries BC) and from

Thebes (Archaic to Hellenistic times).

A deceptive generalized trend for a
coarse proportionality (and a reason-
able scattering) between K O and

2

MgO contents might be considered
for mainland and Aegean Greece from

Archaic to Hellenistic times.

Figure 13.3b. K O versus MgO. Same

2
data as in Figure 3a but the contours

(approximated by ellipses) for the data
of four groups are indicated. For addi-
tional precision, two compositional
distinct subgroups of the Rhodian
group are traced separately. Th: Glass
from Thebes (Archaic to Hellenistic);

Rh 3/2: Glass from Rhodes (third–
second century BC); Rh 4: Glass from

Rhodes (fourth century BC); Rh 7a,b:

Glass from Rhodes (seventh century BC).

If the long axis of each ellipse is taken
as indicative of the overall direction
of the data of the corresponding
group, only Rh 7a exhibits a direction
comp arable to that of all data taken
together.

172 | OBSIDIAN AND GLASS PROVENANCE
samples from Thebes originate from a special ver-
found as rocks or pebbles. In some cases certain shells sion of the natron-based tradition with decipher-and ashes from specific land plants and algae might
able specifics; as suggested in a later section (3.4.2), also serve as major MgO contributors. The latter
the K O of our samples from Thebes largely derives
materials also contribute CaO, usually at comparable

2
from deliberate additions of small amounts of
or larger levels on a weight basis. Metal oxide (MO)

alum-type material.

sources might be either distinct raw materials or parts of other raw materials, sand (a potential prime source 3.1.2. Demonstration of a common
of the SiO glass-component), and secondarily plant
type of correlation pitfall

2
ash alkali sources. Compositions of raw materials

We now plot K O versus MgO data in two ways
gathered by Brill (1999) allow for a detailed consider-2

(figures 13.3a and 13.3b) and use our detailed prove-
ation of all alternatives.

nance knowledge in order to demonstrate a type of

A plot of MgO versus CaO for our samples
common pitfall associated with correlation studies
appears in figure 13.4. In the case of samples from
of ancient glasses that have appeared in the litera-

Thebes, it is apparent that the sources of CaO and
ture. Our data for Rhodes and Thebes, and the pub-

MgO are largely unrelated, that is, the two compo-
lished data from Rhodes, are plotted in the same
nents come neither from the same raw material nor
graph (figure 13.3a). All the data are considered to
from interchangeable raw material sources. These
be a representative sample of mainland and Aegean

Thebian glasses have CaO as the main alkaline earth

Greek glasses from the Archaic to Hellenistic
oxide, while MgO is a minor component. The MgO
times. Their distribution suggests a coarse positive
range (0.4–1.1%) and average (0.7%) compare well
correlation of K O and MgO contents. A trend line
with the Sayre and Smith (1961) values (0.60–1.24%

2
with a (0.0, 0.3) intercept appears to be an objective and 0.86%, respectively) found for a broad selection
choice that reflects the positive correlation. This
of natron-based glasses.

choice would reflect a low impurity-background

In the case of samples from seventh-century BC
for K O. Yet, when more distinct temporal and

Rhodes (figure 13.4), the situation is more compli-

2
geographic parts of the data set are grouped sepa-
a-
cated, but a weak correlation with a negative slope
rately (figure 13.3b), the correlation is largely lost; can be detected. The negative slope of the band is
for example, if there is any correlation within the
compatible with the scenario that includes the inter-

K O versus MgO data from Thebes, it possesses a
change of compositionally differing MO sources,

2
negative slope.

but the substantial breadth of the latter band implies A conclusion of broad interest to workers study-a considerable complexity as regards the origin of
ing ancient glass composition can be drawn. A weak
all important MO contributions. MO components
correlation found for a loosely related (in terms of
might be present in more than one type of raw mate-
era and area) group of samples does not necessarily
rial, and/or substantial contributions from glass
imply a stronger correlation of the same type for all, material made at different locations (and using dif-or most, of the more closely related (in terms of era
ferent recipes) can be reflected.

and area) subgroups of samples.

It might be noted that the data for Rhodes can
be split into (a) a main subgroup, characterized by a

3.2. CaO versus MgO and
minimum CaO of about 2.9% and a minimum MgO
alkaline-earth sources
of approximately 2.4%, and (b) a minor subgroup

Calcium oxide (CaO) and magnesia (MgO) are the

(5 samples) with a MgO maximum of 1.0%. The gen-
two alkaline-earth oxides (MO) found in ancient
eral comments pertinent to the negatively sloped
glasses. Calcium oxide originates primarily from
band traced in figure 13.4 are applicable to subgroup

CaCO sources such as bulk limestone, marble, and

(a). The exceptional case of the (b) subgroup (R11,

3
seashells. Magnesia originates primarily from magne-

R29, R33, R53, R69) has already been considered in
tite (MgCO ) or dolomite sources (MgCO . CaCO )

section 3.2.1.

3

3

3

Characterization and Provenance of Glass Artifacts | 173

Figure 13.4. MgO versus CaO for seventh-
century BC Rhodian artifacts (triangles)

and Thebian artifacts (squares). A low
level of MgO and a variable higher level
of CaO are seen in the case of samples
from Thebes. On the other hand, data
for samples from seventh-century BC

Rhodes fall largely within a band having
a negative slope.

Figure 13.5. Al O versus MgO for glass

2 3
artifacts from Rhodes (triangles: seventh
century BC; circles: fourth century BC;
diamonds: third–second century BC)

and from Thebes (squares).

3.3. Al O content in relation to
century BC data from Rhodes also fall within the

2 3

MgO and Fe O contents
ellipse defined by the samples from Thebes, but a sub-

2 3
stantially narrower range of Al O content is span-

3.3.1 Al O versus MgO

2 3

2 3
ned by these samples.

Two key patterns are evident in the data: one group

In view of this finding of a wide alumina range
has a nearly fixed Al O concentration and variable
for Thebian glasses, a less controlled production

2 3

MgO, and the second reflects the inverse situation
might be hypothesized. Yet the study of the Al O ver-

2 3

(figure 13.5). The first pattern pertains to the majorsus K O plot (see below) for the glasses from Thebes

2
ity (65 out of 70) of the seventh-century BC samples
suggests that Al O is largely due to intentional addi-2 3
from Rhodes and the second grouping includes all
tions of a minor component and not a reflection
samples from Thebes. The fourth- through second-
of an impurity. Also, there are no obvious traces of

174 | OBSIDIAN AND GLASS PROVENANCE
the practice for alumina addition in the case of the

However, there are a number of outliers pres-
fourth- through second-century BC Rhodian sam-
ent on this bivariate plot. A group of 4 samples (R35, ples. While the glass samples from Thebes and those

R36, R46, R63) has a 1.0 ±0.2% Fe O content that is

2 3
from fourth- through second-century BC Rhodes
significantly higher than that of the other samples.

share certain general features, ultimately a reflection The 4 samples in discussion are green, with a hue
of the natron-based character of the MEEM glasses, a
more intense than the usual lemon-green of unin-
sufficiently distinct character of the glass recipes for tentionally colored ancient glasses but less intense
samples from Thebes appears possible. This suggests
than what might be called a standard green. Thus
that a usable compositional marker may be present,
it is difficult to decide between clumsiness and
but this requires a nonmixed population of samples
intention. In this case, part of the iron oxide might
in order to be safely detected. Samples originating
originate from an intentional addition in the form
from different areas or massive local employment of
of a color-affecting substance that does not contain
recycled glass from different areas can easily obscure alumina. Alternatively, it might result from a low-markers based on special multicomponent raw mate-
alumina batch where an iron oxide impurity was
rials added in restricted amounts.

accidentally introduced. There are also 2 samples

(R11 and R29) with an alumina content of about

3.3.2. Fe O versus Al O

2 3

2 3

3.1%, which is much higher than that of any other

In the case of the artifacts from seventh-century BC

Rhodian samples; samples R11 and R29 will not be

Rhodes, the most telling correlation is that between
considered any further.

Al O and Fe O content (figure 13.6). For the vast

The Fe O versus Al O plot (figure 13.7) for

2 3

2 3

2 3

2 3
majority of the seventh-century BC samples from
the samples from Thebes demonstrates a situa-

Rhodes, the Al O and Fe O contents are weakly
tion markedly different from that for the seventh-

2 3

2 3
correlated. The relationship suggests that, in the case century BC Rhodian samples. There are two main
of Rhodian samples, Al O and Fe O are largely
populations. The first one exhibits an impurity level

2 3

2 3
associated impurities that may be found in the
of iron oxide of 0.40 ±0.20% coupled with a vary-
silica sources employed or originating from clay-
ing but always large range of Al O ; this is possible

2 3
based processing utensils. The correlation is not
if Al O present is largely non-impurity associated.

2 3
strong as this may reflect more than one impurity

The second has a roughly fixed amount of alumina
source characterized by different Al O /Fe O ratios
that reflects the combined contributions of impuri-

2 3

2 3
and contributing to different samples to a different
ties and the addition of a fixed amount of an alum-
extent. Generally, there is no sign of a systematic and type compound plus intentional additions of iron
intentional addition serving as a source of Al O .

oxide for the purpose of color control. Taking into

2 3

Figure 13.6. Fe O versus Al O for the

2 3

2 3

Rhodian artifacts. Al O and Fe O

2 3

2 3
contents for most of the artifacts
are coarsely correlated by a line that
can be extrapolated to a (0.0, 0.0)

composition.

Characterization and Provenance of Glass Artifacts | 175

Figure 13.7. Fe O versus Al O for

2 3

2 3
the samples from Thebes. Two main
subgroups are seen: one exhibiting an
impurity level of iron oxide and various
amounts of Al O (horizontal ellipse)

2 3
and another one with a roughly fixed
amount of alumina (vertical ellipse)

and variable but high Fe O contents.

2 3

In the latter case, the Fe O content

2 3
enhancement (over the level defined
by the reference compositional regime, R)

reflects intentional additions for the
purpose of color modification.

account information extracted from the Al O ver-
by Dioscurides in De Materia Medica (Books A–E) 2 3
sus K O plot (see below), a compositional regime for
provide a hint as regards the ancient tendency for

2
a reference glass (R) for Thebes, one without inten-
component blending, it might be hypothesized that
tional additions of either an alum-type compound
almost any material that does not interfere with glass-or iron oxide, can be suggested. There is no actual
making (e.g., by causing crystallization and/or crack-
sample falling within the R compositional regime,
ing, or excessive bubbling) may have been added to
because no samples were prepared without an alum-
certain glass recipes. Such raw material additions, if type addition.

traceable, might serve as additional origin markers
for ancient glasses.

3.4. Unusual raw materials

Pliny describes, somewhat confusingly, a stage
of glass manufacturing involving experiments with

3.4.1. Unusual raw materials for ancient
glass—potential choices
additives (XXXVI:192). However, he refers largely to
the empirical choice of sources and adjustments of

Before examining a final compositional plot (Al O
the level of key components (SiO + MO) and, over-

2 3

2
versus K O; see section 3.4.2), we will consider, in
all, offers nothing close to a detailed survey of ancient 2
general terms, some issues that are pertinent to com-
glass recipes. The only ancient source close to that of positional markers and have not received sufficient
the desired kind is a group of Mesopotamian recipes
literature attention so far. This is a subject of broad (Oppenheim et al. 1970). Unfortunately, the practical
interest; the case of glass manufacturing in Thebes
significance of these recipes remains limited because
will offer a specific example.

of the uncertainty surrounding the exact meaning of

It is known today that glass types produced by
several key terms and also because of the fact that
ancient glass-makers were achieved through the
the texts preserved are frequently adaptations of ear-
incorporation of typically two to four raw material
lier texts by Mesopotamian scholars without techni-
types: a source of silica that is also possibly a source cal training (Moorey 1999). In view of the deficiency
of MO (unknown metal oxide), a source of M O, a
of sources, we can attempt to complete the picture

2
possible separate source of MO, and, in some cases
through a list of materials that might have attracted
a simple or mixed colorizing agent (or a decoloriz-
past interest as potential additional raw materials
ing agent). However, it is far from certain that only
and refer to the list whenever compositional pecu-
the minimum necessary raw materials were involved
liarities are detected by chemical analysis.

in all cases of ancient glass production. If the late

What might correspond to “reasonable” devi-
first-century AD recipes for medicines described
ant raw materials for ancient glass? While “almost

176 | OBSIDIAN AND GLASS PROVENANCE
anything” is a good and safe answer, especially for
for glass ( vitrumque esse creditur). It might a period in which technology relied heavily on
be worth examining the potential use of

“massive trial and error,” it is not a very useful one.

certain hydrous sulfates as alternative

Hence, we will focus chiefly on candidates (whether
sources of Fe O (occasionally an inten-

2 3
ultimately successful, insignificant, or disastrous
tional glass colorant) or CuO (frequently
ones) that deserve more attention than others based
an intentional glass colorant) in ancient
upon the logic of the time.

glasses.

Certain materials having a glassy appearance

(2) Certain materials of the alum family. Alum-might have been considered, on the basis of the ill-
type materials are already known and used
founded (on the basis of current materials science
in the Helladic region from the Late Bronze
understanding) yet reasonable idea (on the basis

Age. Turuptereja in Linear B documents
of antiquity material concepts) that such additions

(Chadwick 1973) has been identified as
might favor the “nucleation of a good glass.” A pos-
equivalent to struptēria, an earlier form
sible example is the hyaloides ( hyaloeidēs = glass-of classical stuptēria (rarely struptēria) like; possibly a peridot [Mg, Fe] SiO ), which, as

= alum. Herodotus (II:180) refers to

2

4
reported by Theophrastus ( De Lapid. :30), “reflects 1000 talents of alum presented by
images as well as being transparent.” The use of Pharaoh Amasis (sixth century BC) to
items visually similar to clear glass such as chunks
the Delphians. Theophrastus (370–287 BC)

of rock crystal, as a silica alternative to sand (Pliny, had authored a lost work titled “On salts,

XXXVI:192) might not surprise us today, because it
natron and alum.” Finally, extensive refer-
is viewed as a chemically sound replacement. Yet the
ences to alum can be found in the first-
replacement was not obvious to the ancients since
century AD encyclopedias by Celsus,
sand and rock crystal were not considered closely

Dioscurides, and Pliny ( De Medicina,
related materials. As a matter of fact, Pliny, in a dif-De Materia Medica, and Naturalis ferent part of his work (XXXVII:25–26), repeats the

Historiae, respectively).

widely accepted view of the time, that rock crys-

In brief, alum is a material (actually,
tal was a form of ice. However, it is an elementary
a range of materials) well known and
empirical fact that ice has no ability whatsoever to
extensively used throughout Greco-
yield a useful glass product upon mixing with MO

Roman antiquity. The materials covered
and M O sources. Thus the incorporation of rock
under the ancient name stuptēria (Greek)/

2
crystal might have been triggered by some alternative
alumen (Latin) are rather diverse and can-
vague notion, say one that we might call “nucleation
not always be identified with certainty.

of clarity.” From a current materials science perspec-

Some might not even belong to the alum
tive, the latter notion is an overly simplistic one and family, as the latter is perceived today
in various glass-manufacturing cases it would lead
on the basis of structure and chemi-
to a processing disaster. Yet it happens to work in the cal composition. Conversely, some true
case of rock-crystal use and would also work if, say,
alum-type materials might bear unrec-
amethyst chunks were employed instead.

ognizable names during antiquity. This

Some interesting additional examples of materi-
is considered possible in the case of the
als having a glassy appearance are:

“Phrygian stone” discussed in some detail
by Dioscurides (E.123). Regardless of dis-

(1) Certain vitriols. “Vitriol” is a later but puted details, it can be stated with near
suggestive name as regards the common
certainty that various materials of the
impression created by certain hydrous
present alum family were known and used
sulfates. For example, Pliny describes
during antiquity and that their K O/Al O

2

2 3

(XXXIV:123) a form of a blue hydrous
mole ratio (see below) covered a substan-
copper sulfate that is frequently mistaken
tial range of values.

Characterization and Provenance of Glass Artifacts | 177

(3) Obsidian. This is a natural material iden-been involved in glass recipes and, regard-
tified as a form of glass during antiquity
less of its originally assumed role, might

(e.g., Pliny, XXXVI:196); thus, pieces of it
have contributed to the making of glasses
constitute a reasonable choice for a glass
upon sufficient experimentation.

additive. Yet, difficult-to-tame foaming
problems leading to pumice-type formations

Finally, we consider the type of products that
might discourage the occasional practitio-
could be obtained upon a strong heating of various
ner. Theophrastus, in De Lapidibus, 14–16, natural materials. Some materials will simply melt,
provides a dense and somewhat confusing
and upon cooling, recrystallize to their original
discussion that includes the comparison of
structures; this is the fully reversible behavior famil-a Melian stone and a black Liparaean stone
iar from metals and several salts. On the other hand,
that foams and whitens upon heating. While
there are various natural crystalline materials that

Melos and Liparae are key obsidian locations
undergo irreversible restructuring upon heating. In
exploited from Neolithic times, the identifi-
most cases the end result is a cracked, porous, or fully cation of Theophrastus stones with obsidian
incoherent mass such as CaCO and related carbon-

3
is frequently questioned. This stems, at least
ates that include dolomite and magnetite. In a few
in part, from the fact that modern commen-
cases a castable glass can be obtained. Lapis-lazuli
tators are unaware of the capacity of some
is a material whose glass-forming ability was likely
obsidian to foam substantially upon heat-
realized several times in antiquity. However, a color-
ing at temperatures easily accessible during
less glass end product hardly justifies the systematic antiquity. It should also be kept in mind that
processing of this extremely expensive deep-blue

Theophrastus in De lapidibus is not a plain starting material, or even the small-chunk byprod-reporter of facts but, largely, a theoretician
ucts of its usual mechanical processing for ornamen-
presenting data in a manner reasonably
tal purposes. The preparation of a primitive version
compatible with theoretical views of his
of ultramarine pigment by plain grinding exemplifies
own. Generally, there is no reason to doubt
a more attractive alternative use of leftover chunks.

that there was ancient probing of the behav-

Still, we can be certain that various minerals were
ior of obsidian upon heating; pertinent glass
used during antiquity in, at least, one case. Pliny
formulation experiments can be viewed as a

(XXXVI:62–63) provides information on a practice
possible extension.

applied to the Alabandicus stone (possibly almandine An alternative to obsidian is ground

[Fe Al Si O ] or another garnate): “idem liquatur 3

2 3 12
rhyolitic pumice. It is a released-gas rela-
igni funditurque ad usum vitri.” While this probably tive of obsidian. Pumice is amorphous
never became a practice of broad significance, occa-
and it visually resembles blocks of plant
sional ancient glass samples of unusual composition
ash or aphronitron (natron foam) rather
deserve examination from the perspective of stone
than glass. As a matter of fact, pumice
vitrification following thermal restructuring.

and ash are grouped together in one case

It should be noted that crystalline silica such as

(Theophrastus, De lapidibus:19), although that found in rock-crystal, amethyst, and sand can
in another case ( De lapiibus:21) a similar-also exhibit the same behavior, but the required pro-
ity between a certain pumice and sand is
cessing temperatures were not achieved until approx-
noted. In addition, a connection between
imately a century ago. Yet a qualitatively similar
pumice and obsidian can be deduced from
end-result is possible upon addition of fluxes such as the reading of the full sequence o
f p
o ara-
ra-
sodium carbonate, while stability is ensured through
graphs in De Lapidibus:14–22. Overall, the incorporation of additional compounds such as
pumice (viewed as a plant ash or natron

MO oxides. The final product is nothing else but stan-
or sand or ammonitron [= sand + natron,
dard man-made silica-based inorganic glass, known

Pliny, XXXVI:194] alternative) might have
for more than 4000 years.

178 | OBSIDIAN AND GLASS PROVENANCE

3.4.2. Al O versus K O
examined Fe O versus Al O plots (section 3.3.2) and

2 3

2

2 3

2 3

The occurrence of aluminum oxide in ancient glasses
found a weak positive correlation for the bulk of our
remains a puzzle. Alumina in ancient glasses is often

Rhodian samples, while markedly different trends
found at levels comparable to those found in com-
were revealed in the case of the samples from Thebes;
mon modern glasses (Zarzycki 1991), but a wider
the latter situation will become clearer upon consid-
range (0.2–4.0+%) is encountered in antiquity. While
eration of the corresponding Al O versus K O plot.

2 3

2
alumina in modern glasses reflects an intentionally

In the case of the artifacts from Thebes, most
added minor component that enhances durabil-
of the Al O and K O data (27 out of 29 analyzed

2 3

2
ity, intentional addition of an alumina-source com-
samples) appear to fall on lines that exhibit positive ponent in ancient glasses has not received adequate
but differing slopes (figure 13.8). These compositions attention, with the exception of the possibility of
form a triangular envelope where the low values for
minute amounts of colorants based on mixed cobalt

Al O and K O extrapolate to 0.45±0.15% and 0.0%,

2 3

2
oxide/alumina sources. An accidental presence of
respectively.

Al O might originate from minor components found

In reality, more than one potassium source is

2 3
in certain raw materials such as sands and ashes (Brill possible, but our findings can be approximated as

1999) or from ceramic glass-processing equipment.

resulting from the intentional addition of a substance The possibility of intentional Al O additions
or substances containing both Al O and K O, while

2 3

2

2 3
might be probed through the study of compositional
some additional Al O (at a typical level of about 0.45

2 3
data of interrelated artifacts from a single area. So far,

±0.15%) is part of the impurity load of the glasses.

we have examined Al O versus MgO plots (section

Our data suggest that the Al O /K O mole ratio of

2 3

2

2 3

3.3.1) and found fixed alumina versus variable mag-
the added compound (or compound mixture) is pos-
nesia, and vice versa, for two groups. We have also
sibly in the range of 5.5 ±2.5. Compounds contain-
ing both Al O and K O and widely used for

2 3

2
various purposes during antiquity belong to the
alum family (alum-proper, alunite, etc.). Alum-
proper (KAl(SO ) 12H O) exhibits a molar

4 2

2
ratio of 1, alunite ((KAl (SO ) (OH) )) a molar

3

4 2

6
ratio of 3, mixed (K/Na)-alunite ((Κ Na )

0.5

0.5

Al (OH) (SO ) ) a molar ratio of 6, while

3

6

4 2
natroalunite ((NaAl (SO ) (OH) )) and men-

3

4 2

6
dozite (NaAl(SO ) 12H O) contain only sodium

4 2

2
as an alkali (hence, the molar ratio of interest
equals “∞”). In addition, certain intermediate
compounds and compound mixtures, as well
as changes in molar ratio either upon individ-
ual firing or upon firing after inclusion in raw
glass (e.g., K O losses are enhanced when higher

2
melt temperatures are employed), allow for the
coverage of the full potential estimated range of

Al O /K O mole ratio.

2 3

2

The Aegean Cycladic Islands are known

Figure 13.8. Al O versus K O for the glass artifacts from Thebes.

2 3

2

The 16 filled squares represent the 16 Archaic samples, while from antiquity to have been a major source for
empty squares correspond to samples from subsequent
compounds of the alum family (e.g., Dioscurides,
periods. A bisection line has been drawn, and nearly half of De Materia Medica E.106; and Pliny, Nat. Hist. , the data fall on or close to this line, which might be thought 35:183–189) and might also have provided the
of as representative of a typical alum-type additive for the additives under consideration. While it is not safe
glasses from Thebes.

to specify the exact compound (or compound

Characterization and Provenance of Glass Artifacts | 179
mixture) employed (either as-collected or following
that we recover good local glasses with persistent
certain processing), our data suggest the possibility
features over some centuries practically rules out the that material of the alum family was purposely added
simple feldspar scenario.

as a minor component in glasses recovered from

Let us now consider a more complicated scenario

Thebes. We have examined geological maps of the
that involves feldspar impurities: the artifacts from
areas around Thebes and have not been able to locate

Thebes are the result of blending, at different ratios, sources of alum-type materials. Thus, the alum-type
of two glass batches, one batch containing little
materials employed in Thebes were probably sup-

Al O (ca. 0.4%) and no K O and a second batch

2 3

2
plied from elsewhere (e.g., from the Cyclades). This

(more precisely, a compositional family) character-
could result in an insufficient control of the compo-
ized by a high Al O content (ca. 3.0% or more) and

2 3
sition of the employed material. We know about the
some K O (ca. 0.4% to 0.9%), with the latter oxides

2
variability of the product, as the ancient authorities originating largely from feldspar impurities. Then,
refer specifically to different alum-type products, to the second family of batches might correspond
variability in product processing, and to frequent

(or, at least, lie close) to the side of the triangular adulteration. Of course, both Al O and K O can be
envelope that does not include the (Al O , K O) =

2 3

2

2 3

2
found in final glasses by being present as minor acci-

(0.4, 0.0) point. The latter side of the envelope is
dental components in the alkali and silica sources
defined by 6 points that appear to follow a line with
involved, but their wide range of correlated values
a negative slope. In order of increasing K O content,

2
can be best attributed to an intentional addition of
the 6 points reflect the K O and Al O contents of

2

2 3
varying amounts of material(s) of the alum family.

artifacts T13, T28, T20, T18, T25, and T17. Even if

The only other serious simple alternative to
the near-linerarity is only an accidental one, a nega-
a deliberate addition of alum-type product(s) is a
tive correlation remains. The significance of the lat-
correlation of Al O and K O stemming from the
ter correlation can be questioned only in the case

2 3

2
accidental incorporation of alkali feldspars such as
of T28, T20, T18, and T25 artifacts, which exhibit

K-feldspar (KAlSi O ) and albite (NaAlSi O ) in the
contents of certain oxides (such as CaO, MgO, and

3 8

3 8
form of mixture or mixed-phases. Feldspars can be

Na O) that lie between the corresponding contents

2
present as an impurity in certain sands (Brill 1999;
of the T13 and T17 artifacts. Artifact composi-

Henderson 2000). Feldspars do not contribute SO
tions (see appendix A) show that at least T20 and

3
to glasses while alum-type materials do, and our

T25 do not follow the latter pattern, and, taking
samples include SO . However, the latter component
also into account artifact dating, we conclude that

3
might also result from other sources such as a sulfate there are at least 4 independent samples (T13, T20,
impurity in natron, and for reasons explained below

T25, T17) for which there is a negative correlation
it is not possible to probe the potential connection
between Al O and K O; that is, it is probable that

2 3

2
between alum addition and presence of SO .

the observed negative trend is of some significance.

3

The case for Al O and K O content correlation

The latter trend is hardly compatible with a family

2 3

2
largely through feldspar impurities is weakened
of alumina-rich batches containing Al O and K O

2 3

2
substantially upon consideration of the implications
originating from similar sources (feldspar impuri-
for sand (i.e., the key raw material of glass indus-
ties) and, hence, the blending scenario considered
try). Feldspars are water-insoluble and hence a large
in this paragraph appears to be an improbable one.

variation (seasonal) of their level is quite unusual for It is also of interest to consider a different blend-a single sand source; thus strikingly different sands
ing scenario: the first batch is of the same charac-
are necessary. Therefore, we are left with the possi-
ter as before, while the second family of batches is
bility of a “systematically” haphazard selection of the characterized by the intentional addition of mate-key raw material as an explanation. This is a rather
rials of the alum-type. Here, a negative correlation
unusual practice that would have undermined glass
of K O and Al O contents of the second family of

2

2 3
production as the choice of widely different sands
batches is possible. Alum-type materials added are
would also seriously affect the MO balance. The fact
characterized by various K O/Al O ratios and, for

2

2 3

180 | OBSIDIAN AND GLASS PROVENANCE
appropriate subgroups of such materials, the addi-

The first of the two Archaic Period islands corre-
tion of a fixed total amount of them can lead to a
sponds to the 8 samples (T1, T2, T6–T8, T14–T16)

negative, and in special cases near-linear correlation exhibiting the lowest Al O and K O contents. While

2 3

2
of the K O and Al O contents of the glass batches.

island-type segregation might largely result from

2

2 3

Instead of going through the tedious details of all
the limited variety of available samples, the alterna-
possible subcases, it suffices to note here that a sective observed is compatible with a single persisting
ond batch characterized by the intentional addition
local tradition.

of alum-type materials remains, at least in principle, SO is also present in various antiquity glasses

3
a possible scenario, which, nevertheless, is just an
and might originate from various sources, with an
elaborate version of our basic claim: the artifacts
alum-type compound being just one of the possible
from Thebes are characterized by the intentional
sources. In addition, maximum processing tem-
addition of alum-type materials.

perature and corresponding solubility limitations

In Oppenheim’s presentation of glass formula-
affect SO content and prevent simple correlations

3
tion recipes from Mesopotamia, alum-type additions
with other potential alum-related markers. Hence,
have been identified in two instances (Oppenheim
we will not pursue the potential connection between
et al. 1970:41, 56). Thus, alum materials are potential SO content and alum-type additions.

3
minor raw materials in ancient glass-working. Alum
is also found in the Medieval work Mappae Clavicula 4. Conclusions

(Smith and Hawthorne 1974) in two glass-related rec-
ipes. Recipe no. 155 refers to a Cu2+-based green glass A comparison of glass artifacts from Rhodes and
and includes Egyptian alum, and recipe no. 281 per-

Thebes suggests that:

tains to a SnO -based white glaze and calls for Asian

2

(1) A group of 70 artifacts from Rhodes (an
alum. Most important is the former recipe, where a

Aegean Greek site) of the 640–600 BC
variation is found in the so-called Lucca Manuscript period is based largely on the plant ash

(ca. AD 750–800) that is considered to be a Latin ren-
tradition with fewer than 10% of the samples
dering of Greek recipes descending from late antiq-
exhibiting suffi ciently strong signs of the
uity workshops in Alexandria, Egypt. Recipe no. 281
subsequent natron-based tradition. The
is of lesser present interest as it is only found in the transition between the two traditions
enhanced 12th-century AD version (Phillips manu-
occurs in Rhodes at a date that is rela-
script) of Mappae Clavicula. In brief, while we lack tively late for Middle East and East Med-recipes from the period of interest, we do find a few
iterranean glass manufacturing.

cases of alum additions in recipes related to glass-

(2) A group of 29 artifacts from the mainland
making and coming from periods preceding and fol-

Greek site of Thebes that date from Archaic
lowing the manufacture of our samples.

to Hellenistic times is found compatible

The potential observable benefit from the addi-
with the natron-based tradition and dis-
tion of alumina-based compounds is a glass of addi-
plays more coherent compositional trends
tional durability under high moisture conditions.

than those of the Rhodes group.

This has been empirically documented in recent
times but there is no reason to exclude the same

As regards alkaline-earth components, the bulk of
empirical finding in the labor-intensive ancient glass the samples from Rhodes are mixed-MO glasses
technological practice. After all, the full composition with a minimum MgO of 2.4% and a minimum
range of ancient glass is frequently very close to the CaO of 2.9%.

full composition range of modern common glasses.

In the case of the samples from Thebes, the

As regards to the distribution of samples in the
sources of CaO and MgO are largely unrelated. CaO

Al O versus K O plot for Thebes, the Archaic Per-
is the key MO component, while MgO, with an aver-

2 3

2
iod samples form two islands that roughly alternate
age content of 0.7%, is a typical impurity of natron-
with islands corresponding to more recent samples.

based glass and a minor MO contributor.

Characterization and Provenance of Glass Artifacts | 181

As regards the Fe O –Al O pair, the bulk of the
were conceived of at the time and can explain the

2 3

2 3

Rhodian samples exhibit a weak positive correla-
peculiarities of the Al O versus K O plot for our

2 3

2
tion, while the two oxides are largely unrelated in
samples from Thebes. Deliberate additions of small
the case of samples from Thebes.

amounts of alum-type material were added to

As regards the Al O –MgO pair, the bulk of our

Thebian glasses and these may serve as a potential

2 3
samples from Rhodes and Thebes can be distin-
provenance marker.

guished rather clearly using a simple biviariate plot.

The employment of unusual raw materials in
glass is hinted at in the ancient literature. Their use Appendix A: Sample compositions
can be understood on the basis of how materials
as determined by SEM-EDS

Appendix A Table

Na O MgO Al O SiO SO Cl K O CaO Fe O

2

2 3

2

3

2

2 3

R.1 19.00 6.16 1.06 64.01 0.51 0.78 2.33 5.36 0.42

R.2 16.91 3.65 0.79 68.19 0.28 1.04 1.95 6.11 0.55

R.3 17.26 4.00 1.52 67.48 0.82 0.77 1.88 5.52 0.75

R.4 14.23 4.50 1.15 68.19 0.55 0.96 1.70 6.95 0.66

R.5 20.12 4.36 1.03 64.71 0.37 0.97 2.46 4.71 0.42

R.6 18.70 3.91 1.03 66.79 0.63 1.00 1.65 5.66 0.45

R.7 18.71 4.40 1.42 66.58 0.58 0.78 2.09 4.90 0.54

R.8 16.14 3.67 1.40 72.53 0.66 0.62 0.90 3.84 0.26

R.9 21.05 4.64 0.93 66.54 0.40 0.75 1.71 3.71 0.29

R.10 18.77 3.36 1.31 65.60 0.82 0.94 2.24 5.19 0.76

R.11 13.40 0.55 3.04 70.99 0.36 0.89 1.21 9.00 0.55

R.12 18.19 3.26 0.75 70.27 0.57 0.63 1.13 4.95 0.23

R.13 23.50 7.00 0.92 62.73 0.39 0.62 0.94 3.25 0.26

R.14 16.88 3.01 0.84 69.72 0.51 0.69 1.32 5.90 0.46

R.15 15.76 2.67 1.04 72.89 0.71 0.88 1.08 5.20 0.44

R.16 17.19 3.63 1.15 70.49 0.52 0.76 1.10 4.79 0.38

R.17 19.09 4.72 0.76 67.83 0.45 0.83 1.38 4.63 0.31

R.18 18.39 2.89 0.96 68.63 0.88 0.90 1.85 4.92 0.58

R.19 16.89 2.62 0.79 70.60 0.39 1.15 1.48 5.98 0.49

R.20 19.87 5.04 0.91 64.01 0.58 0.82 2.44 5.91 0.42

R.21 18.81 3.88 1.24 68.37 0.43 0.72 1.83 4.30 0.42

R.22 16.28 2.43 1.04 69.63 0.48 0.96 1.89 6.67 0.62

R.23 10.42 6.65 1.65 75.09 0.44 0.69 1.06 3.51 0.49

R.24 21.32 6.76 1.26 61.29 0.89 0.85 2.11 4.82 0.31

R.25 18.60 3.59 1.10 67.60 0.52 0.87 1.56 5.86 0.29

R.26 15.87 2.68 0.61 70.68 0.49 0.78 1.37 7.17 0.37

R.27 18.98 4.01 1.42 68.02 0.54 0.69 1.54 4.42 0.38

R.28 18.69 2.61 0.71 69.82 0.61 0.93 1.02 5.20 0.42

R.29 16.90 0.88 3.09 68.48 0.96 0.98 1.13 6.25 0.80

Continued on page 182

182 | OBSIDIAN AND GLASS PROVENANCE

Appendix A Table (continued)

Na O MgO Al O SiO SO Cl K O CaO Fe O

2

2 3

2

3

2

2 3

R.30

21.37 6.18 0.67 64.91 0.52 0.56 1.60 3.89 0.29

R.31

14.93 4.02 1.20 70.87 0.94 0.98 1.86 4.53 0.67

R.32

17.77 4.88 0.98 69.31 0.53 0.73 1.58 3.89 0.32

R.33

20.87 0.63 0.87 70.38 0.39 0.85 0.14 5.56 0.32

R.34

15.97 2.75 1.15 69.20 0.51 0.89 1.35 7.62 0.55

R.35

16.20 4.89 1.09 62.65 1.00 1.77 3.64 7.60 1.16

R.36

19.07 4.87 1.08 57.68 0.92 1.92 4.52 8.92 1.04

R.37

16.59 3.71 1.09 66.96 1.25 1.14 1.65 6.93 0.67

R.38

16.52 3.86 0.74 69.86 0.57 1.01 1.75 4.79 0.47

R.39

17.32 4.47 0.88 67.23 0.50 0.72 2.51 5.94 0.42

R.40

20.80 4.43 1.39 66.60 0.45 0.63 1.36 3.88 0.34

R.41

19.64 3.38 0.66 68.55 0.55 0.71 1.10 5.19 0.22

R.42

19.43 2.50 0.51 70.84 0.52 0.86 0.82 4.15 0.37

R.43

21.26 3.26 0.77 66.55 0.46 0.94 0.89 5.59 0.28

R.44

20.70 4.35 1.31 66.41 0.55 0.67 1.48 4.16 0.37

R.45

19.48 3.93 1.06 66.38 0.51 0.77 1.19 6.36 0.33

R.46

18.20 5.00 0.91 59.36 0.79 1.65 4.52 8.77 0.80

R.47

23.24 6.10 1.37 63.82 0.57 0.52 1.23 2.92 0.23

R.48

18.00 2.84 0.97 69.35 0.78 0.72 1.26 5.66 0.43

R.49

19.09 4.71 0.90 66.78 0.56 0.65 1.52 5.19 0.32

R.50

17.73 3.18 1.41 67.66 0.74 0.85 1.53 6.40 0.71

R.51

19.43 3.36 1.10 68.27 0.50 0.89 0.97 5.14 0.34

R.52

19.54 3.95 1.26 67.10 0.47 0.75 1.67 4.79 0.47

R.53

18.46 1.00 1.20 72.59 0.67 0.85 0.25 4.56 0.42

R.54

20.19 2.88 1.15 67.82 0.35 0.44 1.02 5.79 0.36

R.55

20.28 7.08 0.65 62.17 0.41 0.67 2.86 5.57 0.30

R.56

16.44 3.95 0.97 68.63 0.56 0.78 2.12 5.95 0.59

R.57

22.34 4.34 1.55 64.22 0.54 0.68 1.73 4.23 0.37

R.58

14.98 2.95 1.76 69.67 0.61 1.06 1.84 6.41 0.74

R.59

18.19 2.69 1.31 69.50 0.43 0.55 1.10 5.83 0.40

R.60

17.56 5.33 1.95 66.44 0.67 0.58 1.94 5.45 0.08

R.61 20.60 6.01 0.91 62.10 0.75 0.88 2.70 5.71 0.34

R.62 18.39 4.05 0.92 68.15 0.48 1.01 1.57 5.04 0.40

R.63 13.55 2.41 1.12 71.60 0.49 1.23 1.79 6.94

0.90

R.64 20.36 6.92 0.93 63.94 0.44 0.75 1.45 4.92 0.29

R.65 20.15 3.20 0.76 68.51 0.47 0.92 0.96 4.75 0.28

R.66 17.53 3.00 0.95 71.26 0.51 0.83 0.92 4.70 0.30

R.67 20.56 5.14 0.84 65.76 0.39 0.75 1.22 5.09 0.26

Continued on next page

Characterization and Provenance of Glass Artifacts | 183

Appendix A Table (continued)

Na O MgO Al O SiO SO Cl K O CaO Fe O

2

2 3

2

3

2

2 3

R.68 20.28 3.61 0.96 67.94 0.65 0.64 0.79 4.83 0.33

R.69 19.57 0.86 0.52 72.40 0.73 0.66 0.29 4.82 0.15

R.70 20.08 3.93 0.88 67.35 0.49 0.84 1.39 4.78 0.26

T.1 15.19 0.59 0.82 72.60 0.22 1.03 0.10 8.52 0.92

T.2 15.03 0.60 0.92 72.38 0.21 1.01 0.08 8.81 0.97

T.3 16.28 1.11 2.65 70.31 0.47 1.66 0.53 6.66 0.33

T.4 16.22 0.60 2.28 70.23 0.34 1.55 0.41 7.98 0.40

T.5 19.82 0.62 2.31 68.70 0.29 1.37 0.33 6.25 0.30

T.6 22.53 0.82 0.73 65.56 0.44 1.53 0.12 8.08 0.19

T.7 17.50 0.85 1.05 67.99 0.57 1.61 0.17 7.49 2.77

T.8 21.54 0.80 0.90 65.21 0.55 1.29 0.20 7.39 2.11

T.9 18.09 0.65 3.00 70.03 0.48 1.25 0.34 5.51 0.52

T.19 19.07 0.67 2.96 69.86 0.49 1.14 0.23 5.07 0.41

T.10 15.95 0.54 2.58 70.33 0.51 1.05 0.46 7.80 0.65

T.11 18.65 0.52 2.90 70.34 0.44 1.06 0.40 5.45 0.25

T.12 17.29 0.57 2.53 69.31 0.32 1.51 0.47 7.45 0.37

T.13 15.08 0.68 3.67 70.33 0.32 1.48 0.39 7.69 0.36

T.14 21.32 0.76 1.07 67.48 0.58 1.12 0.15 5.95 1.44

T.18 15.60 0.50 3.29 71.56 0.21 1.15 0.69 6.74 0.25

T.15 15.92 0.66 1.07 70.44 0.63 1.40 0.19 7.76 1.92

T.16 17.98 0.86 1.19 68.88 0.56 1.17 0.17 7.09 2.10

T.17 15.58 0.47 2.97 70.99 0.31 1.20 0.88 7.27 0.34

T.20 16.86 0.82 3.29 70.54 0.59 1.03 0.61 5.20 0.38

T.21 14.23 0.68 2.77 70.91 0.77 1.11 0.84 7.26 1.11

T.22 14.17 0.40 2.32 72.04 0.81 1.36 0.53 6.76 0.41

T.23 13.69 0.62 2.76 73.43 0.76 1.10 0.52 6.68 0.46

T.24 19.65 0.84 2.76 69.23 0.43 1.15 0.52 5.04 0.38

T.25 19.86 0.85 3.08 67.83 0.79 0.63 0.73 4.97

0.68

T.26 19.86 0.78 2.07 68.16 0.43 1.46 0.29 4.67

0.94

T.27 20.12 0.95 2.05 68.73 0.48 1.19 0.24 4.35

0.89

T.28 14.39 0.72 3.59 71.41 0.70 0.94 0.51 7.34

0.39

T.29 17.68 0.70 1.82 71.03 0.39 1.41 0.29 4.74

1.03

Notes

Acknowledgments

1. By literature convention and for Greece, “historical”

The authors wish to thank the director, Dr. V.

means from the eighth century BC. “Hellenistic

Aravantinos, and the staff of the 9th Ephorate of Pre-
times” correspond to the 323–31 BC period.

historic and Classical Antiquities of Thebes, Greece,
for permission to study the beads analyzed herein.

We would like to thank Professor K. Ioannides,

184 | OBSIDIAN AND GLASS PROVENANCE

Department of Physics, University of Ioannina, for

Oikonomou, A., Triantafyllidis, P., Beltsios, K., Zacharias, useful discussions. All analytical measurements

N., Karakassides, M., 2008. Raman structural study
were carried out at the SEM laboratory based at the
of ancient glass artifacts from the island of Rhodes.

Institute of Materials, National Centre of Scientific

Journal of NonCrystalline Solids 354, 768–772.

Research, Demokritos, Greece. Finally, Artemios

Oppenheim, A.L., Brill, R.H., Barag, D., von Saldern, A., Oikonomou expresses his gratitude to the American

1970. Glass and Glassmaking in Ancient Mesopotamia.

School of Classical Studies (Wiener Laboratory,

Corning Museum of Glass Press, Corning, NY.

Pliny, 1952. Natural History (Naturalis Historiae). Vol. 9, Athens) for the support of his contribution through

Books 33–35. Rackham, H. (Ed.). Loeb Classical
a geoarchaeology fellowship award. We thank

Library, Harvard University Press, Cambridge, MA.

C. Stevenson and I. Liritzis for useful comments.

Pliny, 1962. Natural History (Naturalis Historiae). Vol. 10, Books 36–37. Eichholz, D.E. (Ed.). Loeb Classical

References

Library, Harvard University Press, Cambridge, MA.

Pliny, 1963. Natural History (Naturalis Historiae). Vol.

Aravantinos, V. (in press). From the silent earth of

8, Books 28–32. Jones, W.H.S. (Ed.). Loeb Classical
ancient Thebes: The significance of recent archaeo-

Library, Harvard University Press, Cambridge, MA.

logical data. Chronica, Archaeologico Deltio, 56–59.

Sayre, E.V., Smith, R.W., 1961. Compositional categories Barkoudah Y., Henderson, J., 2006. Plant ashes from
of ancient glass. Science 133, 1824–1826.

Syria and the manufacture of a glass: Ethnographic

Smith, C.S., Hawthorne, J.G., 1974. “Mappae Clavicula.”

and scientific aspects. Journal of Glass Studies 48, Transactions of the American Philosophical Society 297–321.

64 (4), 3–128.

Brill, R.H., 1999. Chemical Analyses of Early Glass. Vols. 1

Theophrastus, 1965. De Lapidibus. Eichholz, D.E. (Ed.).

and 2. Corning Museum of Glass Press, Corning, NY.

Clarendon Press, Oxford, UK.

Chadwick, J., 1973. Documents in Mycenaean Greek. 2nd Triantafyllidis, P., 2000. Rhodian GlassWare I (in Greek, ed. Cambridge University Press, Cambridge, UK.

with an English synopsis). Ministry of the Aegean

Dioscurides, 2000. De Materia Medica. Books A–E.

Sea, Athens.

Kak tos Translation Team (Trans., Eds.). Kaktos Pub-

Triantafyllidis, P., 2006. Pre-Roman and Roman glass-
li ca tions, Athens.

making: The Helladic region. In: Kazazi, Y., Tassios,

Filimonos, M., Marketou, S., Patsiada, V., Dreliossi,

T.P., Palyvou, C. (Eds.), Proceedings of the 2nd Inter

A., Kaninia, E., Kasdagli, A.-M., Triantafyllidis, P., national Conference of Ancient Greek Tech nology.

2006. The Archaeologial Museum of Rhodes. Archa-Technical Chamber of Greece, Athens, pp. 254–260.

eological Receipt Funds, Athens.

Rehren, Th., Spencer, L., Triantafyllidis, P., 2003. The Henderson, J., 2000. Science and Archaeology of Mater
primary production of glass at Hellenistic Rhodes.

ials. Routledge, London.

In: Cool, H.E.M. (Ed.), Annales du 16e Congrès de l’

Herodotus, 1920. The Persian Wars. Vol. 1, Books 1–2.

Association Internationale pour l’ Histoire du Verre.

Godley, A.D. (Ed.). Loeb Classical Library, Harvard

London, pp. 39–43.

University Press, Cambridge, MA.

Zacharias, N., Beltsios, K., Oikonomou, A., Karydas, A., Liritzis, Y., Salter, C., Hatcher, H., 1997. Chemical compo-Bassiakos, Y., Michael, C., Zarkadas, Ch., 2008.

sition of some Greco-Roman glass fragments from

Solid-state luminescence for the optical examina-

Patras, Greece. European Journal of PACT, no. 45, tion of archaeological glass beads. Optical Materials I2, 25–34.

30, 1127–1133.

Moorey, P.R.S., 1999. Ancient Mesopotamian Materials Zarzycki, J., 1991. Glasses and the Vitreous State. Chap-and Industries. Eisenbrauns, Winona Lake, IN.

ter 17. Cambridge University Press, Cambridge, UK.

Chapter 14

The Provenance of Ancient Man-made Glass

Raw Materials and the Use of Chemical and

Isotopic Analytical Techniques

Julian Henderson

Abstract
contexts. In each ancient period glass production
was affected by social, political, and economic fac-

The differentiation of glass-making traditions be-
tors in different ways. The occurrence of glass in
tween primary production centers in the ancient
well-defined archaeological contexts provides us

Middle East based upon chemical differences is a
with an important basis on which to interpret its
difficult process because the complexities of glass
use, value, and significance to ancient societies; his-manufacture can change the composition of distinc-
torical evidence can also provide us with glimpses of
tive original raw materials. However, when used in
how glass was perceived as a material, where it was
conjunction with the measurement of radiogenic
produced, and how it was used.

isotopes, chemical analyses can provide an improved

The scientific analysis of glass offers a different
assignment of geological provenance for plant ash
means of investigation. It generates “objective” data
glasses based upon differences in strontium (Sr) and
that reflect the decisions made by those involved in
neodymium (Nd) isotopic ratios. The 87Sr/86Sr ratio
glass-making. How scientific data can be linked to
found within semidesert halophytic plants reflects
various social groups involved in the chaîne opéra
the relative geological age of the lime present in the toire for glass production is difficult to assess, but it soil in which the plants grow, and the 143Nd/144Nd
is nevertheless very worthwhile attempting to create
ratio in silica also reflects its relative geological age.

such links. Even if we are unable to provide insights

Each of these ratios is maintained throughout glass
in each (archaeological) case by doing this analysis,
production and provides a measure of provenance.

the very process should make us focus in a useful

The ability of isotopic analysis to characterize glass way and “stretch” the interpretation of the data as far from a primary production center, and to distinas possible, creating links between archaeology and
guish it from imported items, is illustrated with
science. The use of different scientific techniques to a case study on the primary glass-making site of
examine glass provides a means of measuring dif-

Al-Raqqa, Syria.

ferent characteristics of glass and the raw materials
used to make it. However, the chemical character-

1. Introduction: A context for
istics of glass raw materials are not necessarily car-glass provenance; scientific
ried through to the glass unaltered. Nevertheless, if
analysis and glass production
at least some of these remain unaltered during the
process of glass production, then it becomes pos-

Man-made glass is a complex and potentially valu-
sible to build up knowledge about production tradi-
able material. In the past it was used in a wide
tions used, and the information can be applied to
range of ritual, functional, political, and economic
provenance the glass.

185

186 | OBSIDIAN AND GLASS PROVENANCE

Glasses produced at different times in differ-

Henderson 2006; Boulogne and Henderson 2009). So
ent places can have distinctive elemental character-
in combination the techniques have the potential to
istics. As far back as the mid 19th century, scientists contribute to the study of ancient glass technology in initially using destructive wet-chemical techniques
crucial ways. However, the application of thermal ion
defined compositional characteristics that tied glasses mass spectrometry in the determination of radiogenic
to a particular area or period of production (Turner
isotopes in ancient glass raw materials and ancient

1956a; Sayre and Smith 1961). Later, clear distinc-
glasses is starting to provide data that add new infortions between, for example, Bronze Age plant ash and
mation about glass provenance (Degryse et al. 2009).

mixed alkali glasses and between these and (later)

For many years one of the “golden eggs” of this

Iron Age, Hellenistic, Roman, and Byzantine natron
research area has been the underlying attempt to
glasses became apparent (Henderson 2000:36–51).

provide a provenance for ancient glass. In this case

Glass with high alumina contents has been found in
the word provenance refers to the geographical loca-India, Africa, and the Far East from at least as early tion in which the raw materials were fused to make
as the fourth century BC (Robertshaw et al. 2006;
the glass and not, for example, the location where

Dussubieux et al. 2008), and occasionally in the
glass vessels were discovered (Henderson et al. 2009).

Middle East (Boulogne and Henderson 2009). From

Primary glass production is a very different process
the fourth century BC (Han dynasty), high-barium
from that of glassblowing to make vessels, involving
glasses were produced in China, and in this same area
different knowledge of temperature control and how
some of the first high-potassium glasses are found
to manipulate the glass when hot (see secondary

(Gan 2005). Later, in the medieval West, wood ash
glass-making below). If primary glass-making can
glasses of a different high-potassium composition
be shown to have occurred, it shows that artisans in
are to be found (Sanderson and Hunter 1981; Jackson
that particular place and at that time had the knowl-
and Smedley 2004). These are a selection of glasses
edge and skills involved.

with diagnostic elemental compositions that relate

The reasons for establishing a geological prov-to different times and, in a general way, to places
enance using isotopes, in addition to the more gen-
of production. So these results might be thought of
eral geographical provenance provided by chemical
as conferring a provenance on the glasses, but for
analysis, are as follows:

archaeological scientists attempting to address some

1. It relates the isotopic characteristics of glass
of the issues listed above in detail, these basic compo-raw materials to the glasses made from
sitional characteristics provide a starting point.

them, thus providing provenance;

Determining the trace element signatures of glass

2. It can provide evidence for the exploitation
microsamples, using laser-ablation ICP (inductively
of the source and type of primary glass raw
coupled plasma) spectroscopy (Gratuze et al. 2001)

materials;
conducted under appropriately controlled laboratory

3. It can provide evidence of the import of
conditions, can provide accurate and precise trace
raw materials and whether they were drawn
data, down to parts-per-billion levels for a range of ele-from the local environment;
ments important to the study of glass. Such data can,

4. It can provide evidence for trade and
for example, distinguish between the uses of different exchange in raw and vessel glass within pro-silica sources in glasses (Saitowitz et al. 1996; Freestone duction zones (even without archaeological
et al. 2000; Robertshaw et al. 2006; Shortland et al.

evidence for production);

2007). The same samples can be analyzed using elec-

5. It can provide evidence for specialized
tron probe microanalysis, providing accurate results
production centers for specific vessel forms
for major and minor components and establishing
and/or decorative types.

evidence for the use of particular raw materials such
as plant ash or mineral alkali sources and colorants.

The rest of this chapter will describe glass produc-

The technique can also provide evidence of mix-
tion and to what extent the chemical compositions
ing fully fused glasses (Andreescu-Treadgold and
of glass raw materials are characteristic of the place

The Provenance of Ancient Man-made Glass | 187
in which they occur. Second, by means of a case
materials to decompose, thereby helping gases such
study, the provenance of plant ash glass will be con-
as CO, CO SO , and SO to evolve. The solid state

2,

2

3
sidered using elemental and isotopic analysis.

reaction is carried out in fritting ovens at relatively low temperatures of about 600 ºC (Turner 1954).

2. Glass-making and glass raw

The procedure is to heat the mixture but to avoid
materials
the formation of a vitreous phase, to throw the hot
gray granular material into cold water so that it dis-

2.1 Glass production and glass
aggregates, to grind it up, and then to repeat the pro-technology
cess several times. The ground-up material is then

Two principal types of glass were manufactured
added to the batch. The batch would usually include
in the ancient (Western) world, one made from an
scrap glass to improve the melting conditions: the
organic alkali source (plant ash) and the other from
glass produced would have been relatively bubble-
a mineral alkali source (natron). Both alkali types
free. If fritting was not carried out, and glass produc-were used to make soda-lime glasses. The “lime”

tion occurred at relatively low temperatures, bubbly
present in such glass is a network stabiliser and
glass would be produced. Another reason for fritting
derived from either shell fragments in sand or the
the glass raw materials is to promote their complete
plant ashes used. Batches of glass raw materials were
fusion (Henderson 2000:38–39). Whether fritting
melted in specially constructed furnaces discussed
occurred prior to the fusion of the batch in tank fur-
in more detail below.

naces is an interesting question. Fritting occurred

Currently there is no definite archaeological evi-
at the early Islamic glass-making site of al-Raqqa
dence for the kind of glass furnace that was used to
in northern Syria (Henderson 1995:99) where pri-
fuse Bronze Age glass raw materials to make plant
mary glass-making occurred (see below). Whether
ash glass. Excavations of the 14th-century BC site of
fritting occurred prior to the full fusion of plant ash Tell el Amarna in Egypt have produced evidence for
glass raw materials in all periods and in all locations a possible glass-making furnace but this is not certain is difficult to prove. There is historical evidence, in (Nicholson 2007:127). Excavations at the 13th-century
the form of cuneiform texts, which suggests that

BC site of Qantir, also in Egypt, have revealed that the fritting occurred as part of glass production during
fusion of the relatively small volumes of plant ash and the Bronze Age in Mesopotamia (Oppenheim 1970:

silica to make glass occurred in crucibles (Rehren and 19, 75). Other evidence that it occurred, in 16th-Pusch 2005; Pusch and Rehren 2007). On the other
century AD Europe, is a description by Georgius
hand, by the late Hellenistic–early Roman period,

Agricola in his De re Metallica, published in 1556.

fusion of natron glass apparently occurred in large

In the production of plant ash or wood ash glass,
tank furnaces (Nenna et al. 2005; Kowatli et al. 2008), fritting would have reduced the overall volume
and there is increasing evidence for the use of these
of the batch considerably. Plant ashes have quite a
furnaces in the Byzantine period for the fusion of
low density and a high volume; following the solid
natron glass (Gorin-Rosen 2000).

state reaction that forms part of the relatively low-

At the time when the change from natron back
temperature process of fritting, the volume would be
to plant ash glass production occurred in about the
reduced and the density increased. No fritting ovens
ninth century AD (Gratuze and Barrandon 1990;
have been found at excavated tank furnace sites

Brill 2001; Henderson 2002; Henderson et al. 2004),
where natron glasses were made. Therefore, it seems
enormous tank furnaces were still in use, with the
likely that fritting was mainly carried out during the best preserved found at the 10th to 12th century
manufacture of plant ash and wood ash glasses.

AD site at Tyre in Lebanon. It was thought to have
produced some 16 tons of raw glass with each firing

2.2 Raw materials

(Aldsworth et al. 2002).

There has been a tacit assumption that a primary

The process of fritting glass raw materials
production site used the same source of raw mate-
purifies them by allowing various salts in the raw
rials over time and that this could/would lead to

188 | OBSIDIAN AND GLASS PROVENANCE
the elusive chemical characterization of the glasses
arenaceous (sedimentary) strata, which are rocks
made there (a “workshop composition”). Such an
composed of sand. If the latter are reworked, min-
assumption, especially by some archaeologists,
erals like feldspars can be removed, producing a
should be modified: the chemical composition of
purer sand deposit. The depositional environment is
the glass batch (including recycled glass) and the
therefore also important in determining the compo-
added colorants and decolorants (the melt) are
sition of sands.

directly related to the combination of raw materi-

A variety of mineralogical impurities can occur
als used and the melting conditions at that specific
in sands, including iron oxide (e.g., magnetite), oliv-time and in that particular place for the manufac-
ine ((Mg, Fe) SiO ), chromite (FeCr O ), epidote

2

4

2 4
ture of glass. The quality of sand used (particle size (Ca (Al,Fe) (SiO ) OH), ilmenite (FeTiO ), sphene

2

3

4 3

3
and purity) would be a reason to continue to use the
or titanite (CaTiSiO ), mica, calcite (CaCO ), and

5

3
same source, but this does not necessarily guarantee
zircons (ZrSiO ). These minerals can therefore be

4
that, once a source has been found, the same source
sources of iron, chromium, titanium, alumina, and
was used during the course of a generation. The sup-
calcium oxide impurities in glasses made from the
ply of natron would tend to be from the same source
sands containing them. Rare earth elements (REEs)

because of its relatively limited occurrence. How-
and yttrium can be found in zircons, and specific
ever, the sources and species of ashed plants and
phases such as monazites occur (Patyk-Karar et al.

trees could vary far more during the life of a glass

1999). Hoskin and Ireland (2000) are skeptical that
furnace. Such a variation would be expected to lead

REEs in zircons can be used as a (geological) prov-
to variations in glass compositions made from them.

enance indicator and by extension indicate this

Silica is a polymorph that has three principal approach may have a limited archaeological appli-crystalline forms (with the same chemical composi-
cation. However, given sufficient geological contrast
tion): quartz, tridymite, and cristobalite. Quartz is
between silica sources, there is a place for their charfar more abundant than the others, forming 12% of
acterization using neutron activation or LA-ICP-MS
the earth’s crust. Tridymite and cristobalite are high-

(laser ablation–inductively coupled plasma–mass
temperature forms of silica that occur rarely, in cer-
spectrometry). The concentrations of europium (Eu)

tain volcanic rocks, but can be produced by heating
and cerium (Ce) relative to other REEs are thought to
quartz to high temperatures. Quartz exists as its α
reflect the particular parameters of the chemical sys-
form at room temperature, but is converted to its β
tem in which minerals containing REEs were formed
form at 573 °C. Above 1470 °C quartz slowly forms

(Loveland 1989) and are known as the europium and cristobalite, which if heated at temperatures between
cerium anomalies.

870 °C and 1470 °C slowly converts to tridymite.

These anomalies are produced by fractiona-

The sources of silica for glass-making could be
tion during various geological processes. Europium
quartz pebbles, riverine and coastal sand deposits,
variation results from fractionation during igneous
or inland/coastal geological deposits. High-purity
processes (with minimal cerium variation). These
quartz can either occur as vein quartz or can fill
processes produce basaltic and gabbroic rocks
cavities as a result of the precipitation of silica-
with REE signatures enriched in heavier elements,
rich (hydrothermal) groundwater. The weathering
while rhyolitic and granitic rocks will be enriched
of quartz-rich deposits leads to deposits of quartz
in lighter elements. Cerium fractionation (with
pebbles and gravel along the courses of rivers and to
limited europium variation) occurs during a range
quartz-rich sands on the coast. The purity of sand is
of processes leading to cerium variations. These
greatly influenced by the type of rock from which it
processes are cementation (the formation of sand-
is derived and the distance over which the material
stone), lithification (formation of deep-sea clays),
has been transported before deposition. Sediments
and precipitation (such as the formation of carbon-
containing sand that derive from the weathering
ates), all occurring in marine environments. These
of crystalline rocks tend to have a higher feldspar

REE anomalies will be reflected in the compositions
and heavy mineral content than those derived from
of different sand sources used in glass-making. For

The Provenance of Ancient Man-made Glass | 189
example, the chemical analysis of 10th- to 13th-
and Jackson et al. (2005) have outlined the composi-
century AD Egyptian and South African glass beads
tional variability of tree and bracken ash and the dif-indicates that REE determinations could provide a
ficulties that such variability produces in attempting means of distinguishing between silica sources and
to link the sources of ashes using compositions to the help to source glasses (Saitowitz et al. 1996). The
glasses made from them. Rehren (2008) has outlined
relative levels of zirconium and titanium, thought to
some of the compositional changes that can occur in
be associated (only) with the sand used, have been
glass melts as a result of melting conditions.

used as a means of characterizing its sources in 16th-

Here discussion will focus on semidesert halo-
and 17th-century AD European glasses (Aerts et al.

phytic plants because they were used in the manu-

2003). Other impurities that occur in sand include
facture of plant ash glass that is used as an example
shell fragments that introduce the calcium-bearing
of glass provenance below. Halophytic plants occupy
mineral aragonite (CaCO ) to a glass melt (Lucas
an ecological niche in semidesert, evaporitic, and

3

1948), providing the essential network stabilizer in
maritime environments where they are able to with-
glass. Feldspars, which are often high in alumina,
stand very high alkali concentrations in the soil.

can otherwise have variable compositions. They

Their alkali tolerance has its limits, and they have
can be potassium- or sodium-rich. Sodium-rich
developed various means of shedding excessive
feldspars are also rich in calcium, and barium can
alkali concentrations (Batanouny 2001). Examples
occur in alkaline feldspars. Another potential impu-
of such plants that grow in the Middle East are those
rity in silica is clay. Aluminum levels in ancient glass of the genera Salsola, Arthrocnemum, Halopeptis, have, in the past, mainly been considered as having
and Anabasis (Ashtor and Cividalli 1983; Barkoudah derived from feldspars in the silica used. This is cer-and Henderson 2006). When the use of plants for
tainly true, but for plant ash glasses alumina can also glass-making is being investigated, it is important
be introduced in the plant ash, and there is a possi-
that botanists identify them in the field rather than
ble contribution at the edges of melts from the walls
attempting the more difficult task of identifying
of crucibles in which glasses were melted (Merchant
plant samples taken out of their context.

et al. 1997). The mineralogical and chemical analy-

In the past those involved in the investigation of
ses of nine sand samples from beaches by the Belus
ancient glasses made from plant ashes have assumed

River, Akko and Caesarea, Israel, published by Brill
that different plant species have quite distinct chem-

(1999a:208–209, 1999b:478–479) provide clear evi-
ical compositions and that these distinctions will be
dence for the variable but significant levels of shell, carried through into the glasses made from them.

feldspars, and bone fragments mixed in with the

For example, this has been an explanation for the
quartz sand. This evidence provides the expected
distinctively low potassium levels found in some
explanation for the high calcium oxide levels found

14th-century BC Egyptian glasses (Lilyquist et al.

in the natron glasses made on the Levantine coast.

1993). However, the results of chemically analyzing

Plants, including trees, draw up water from soils halophytic plant ashes of various plant species (figure as part of the process of transpiration in which nutri-14.1) and from a variety of geological environments
ents are distributed to different parts of the plant, lead-show that the situation is much more complex than
ing to growth. The ashes of plants are a reflection of this explanation (Barkoudah and Henderson 2006).

the chemical and mineralogical characteristics of the

The variations in concentrations in the ashes of
soil in which the plant grows. Ashes of both trees and plants (determined using LA-ICP-AES [laser abla-shrubs can introduce calcium and alkalis to the glass
tion–inductively-coupled plasma–atomic emission
melt. In the context of this chapter, the question is
spectroscopy]) shown in figure 14.1 underline the
whether it might be possible to relate geological con-
ways in which plants of the same genus respond to
trasts of the soils in which the plants grew to the com-the underlying geochemistry of the soil. It can be
position of the plant ash produced and to the glasses
seen that, apart from sodium, each sample of halo-
made from the plants. Sanderson and Hunter (1981),
phytic plant responds to the geology in the same way.

Smedley et al. (1998), Jackson and Smedley (2004),

If these constant ratios of elements in plant ashes

190 | OBSIDIAN AND GLASS PROVENANCE

Figure 14.1. Variations in the
concentrations of element
oxides (log weight % oxide)

of ashed plants of the genus

Salsola growing in four locations
along a 30-km transect in the

Balikh valley, northern Syria

(data taken from Barkoudah
and Henderson 2006:table 14.2).

are carried through to the glasses made from them,
sample 8a with 28.7% soda might be. The extent to
then this represents locational information deriving which the sodium forms compounds with elements,
directly from the local geology. The same patterns
such as Na CO , that flux silica is critical here (Turner 2

3
are to be found for trace levels of Ba (barium), Cu

1956b). So it cannot be guaranteed that samples of the (copper), and Sr for these plant ash samples (based
same species of halophytic plant growing in different
on data published in Barkoudah and Henderson
locations would contain the appropriate levels of soda 2006:table 2). Since the methodology used to ash
for glass-making. Initially, the selection of plants for each plant sample was precisely the same, the results
glass-making must have been carried out as a result of must be due to the variations in the soil geochemis-trial and error, and once suitable geological locations try in which the plants were growing.

and plant communities were identified, the glass-

In figure 14.1 the concentrations of sodium vary
maker, or groups providing him with plant ashes,
inversely to the rest because the plant physiognomy
would presumably have returned there repeatedly to
dictates that the correct balance of sodium and
harvest the plants.

potassium is needed in order for the plant to pro-

In spite of the fact that the melting conditions
duce the appropriate osmotic pressure within the
can affect the relative levels of some compounds
cell walls, crucial for the movement of liquids into
introduced in the glass batch, such as potassium in
and out of cells. Therefore the sodium levels do not
the presence of high chlorine levels, it may eventually reflect variations in the soil geochemistry.

be possible to be more confident that a specific plant Figure 14.2 shows how the absolute levels of sod-genus (such as Salsola) was used in glass produc-ium and potassium oxides vary for Salsola jordanicola tion, as long as the elemental ratios are unaffected
ashes from three geological locations over a distance
by processes of ash preparation and glass produc-
of 29 km from al-Raqqa northward up the Balikh val-
tion. If sufficiently detailed geographical surveys of ley (Barkoudah and Henderson 2006). S. jordanicola plant compositions are carried out, they could help
is very likely to have been used for making ancient
to provide locational information, but these surveys
glass. It can be seen that their relative levels vary
would need to be carried out on an intensive level in
inversely to each other, as would be expected from
known glass production zones.

figure 14.1. Moreover, soda levels occur at levels of

Primary glass production is the fusion of raw between 19.4% and 28.7% and potassium oxide lev-materials to produce raw glass, possibly involving
els between 11.9% and 25.5%. Sample 5a with 19.4%
fritting. One should never forget that different groups Na O would not be suitable for making glass whereas
of people may have been responsible for different

2

The Provenance of Ancient Man-made Glass | 191

Figure 14.2. Relative levels of Na and K in 3 samples of Salsola jordanicola from three geologically contrasting areas of northern Syria (based on data published in Barkoudah and Henderson 2006:table 14.2).

aspects of primary glass production. These may have
specialized in primary glass production and sites
consisted of different groups involved in collecting
that have specialized in secondary glass production
fuel, building the furnace, assembling the raw materi-

(Henderson 1989:39; Freestone et al. 2000). However,
als (including colorants), preparing the raw materi-
fitting this rather simple model into what was a range als, mixing the raw materials in the right proportions, of processes, which included all kinds of variations
overseeing the temperature rise, and (possibly) mak-
around a theme, may not always stand up to scrutiny.

ing sure that the right kinds of fuel were used at the Time and money would be saved, and it would be
right time in order to determine the desired glass
more practicable (including shared fuel supplies), to
color(s). Each of these activities may have involved a fuse and blow glass vessels in close proximity.

(different) range of contacts and skills. By using scientific analysis it is possible to investigate aspects of 3. Case study: Scientific
each process.

analysis and provenance of

Secondary glass production involves the working Islamic (plant ash) glass
of ready-made glass in various ways at lower temper-
atures than those involved in primary glass-making

3.1 Archaeological and

(around 950–1050 ºC rather than around 1250 ºC).

technological background

The processes include glass molding, slump ing, and

The glass vessels used by Muslims from the sev-
blowing. Different furnaces from those involved
enth century AD were initially made out of natron
in primary glass-making were used (Henderson
glass. Such glass was melted in the large tank fur-

2000:39–47). Again, a different range of skills from
naces noted above, such as those on the Levantine
primary glass-making, quite possibly involving dif-
coast at seventh–eighth-century Hadera/Bet Eli’ezer
ferent groups of people, is involved. Distinc tions have (Gorin-Rosen 1995:42–43, 2000:52–53; Freestone et
been made between sites that are thought to have
al. 2000:67) where the foundation courses of 17 such

192 | OBSIDIAN AND GLASS PROVENANCE
tank furnaces were found. At Hadera each furnace is
the same site. However, with plant ash glass produc-
thought to have produced about 8 tons of raw glass
tion there is at least one example (Henderson et al.

when it was fired. The ethnicity of those who were

2004) where both primary and secondary glass pro-
involved in all aspects of making glass at Bet Eli’ezer duction occurred on the same site. This is not simply
is important as they could have been Christian,
to say that natron glass production was associated

Jewish, or Muslim. The raw glass produced would
with split primary and secondary production centers
have been remelted and used to make glass vessels
before the Medieval period and that plant ash glass
used in Byzantine, Jewish, and Muslim communities.

production saw both processes occurring on the

Excavations of early ninth-century and later
same site in the Medieval period. For example, both

Middle Eastern Islamic sites have produced vessels
primary and secondary glass production occurred at
made from both natron and plant ashes. However,
ninth-century al-Raqqa, and this early Islamic site is at this time environmental (Foy and Nenna 2001:26)

not Medieval in date. Whether primary and second-
and perhaps political factors caused natron to be
ary glass-making occurred on the same site is there-
replaced by plant ash as the principal alkali source
fore likely to be governed by the availability/proximity (Gratuze and Barandon 1990; Henderson 2002), and
of the alkali source. Both may well have occurred on,
it must have been the Muslims who were instrumen-
for example, Sasanian (plant ash) glass-making sites
tal in reintroducing plant ash glass across large parts in the second–sixth centuries.

of the Middle East (Henderson et al. 2004). Thus, by
the 10th–12th centuries at Tyre on the Lebanese coast, 4. Al-Raqqa, Syria
plant ash glass rather than natron was used to make
glass (Freestone 2002). Nevertheless, plant ash glass

The best archaeological evidence for the primary
was apparently being made between the second and
and secondary production of early Islamic plant ash
sixth centuries AD in inland locations of the Middle
glass at an inland location is at al-Raqqa, northern

East and Iran under Sasanian auspices. Both natron

Syria (figure 14.3), where deeply stratified ninth-
and plant ash glasses were found at the Sasanian sites century deposits of primary and secondary glass
of Seleucia and Veh Ardašīr. The natron glass prob-
production evidence, as well as the bases of beehive-
ably had a Mediterranean source and the plant ash
shaped furnaces in two workshops, have been found.

glass is likely to have come from an inland production The ninth century was a period of innovation
center yet to be determined (Mirti et al. 2008:443).

and experiment in the Islamic world, especially under

Suitable halophytic plants for the manufacture
the caliphs Harun al-Rashid and his son al-Mamun.

of glass grew (and still grow) commonly in semides-

Between AD 796 and AD 808 Harun al-Rashid
ert environments (see above). Assuming that silica
resided in al-Raqqa. His presence would have influ-
and fuel sources were available, glass production
enced the activities on the industrial complex at al-
could potentially have been established in many

Raqqa, including experimentation with technology
places across the Middle Eastern landscape.

(Henderson et al. 2005a).

As the Muslim caliphate founded urban cen-

At al-Raqqa, the furnaces were located in an
ters and expanded them, with an especially thriving
industrial complex 2 km in length, where glass man-
period beginning from AD 750 under the Abassid
ufacture occurred alongside glazed and unglazed
caliphate, industrial activities and industrial estates pottery production (Henderson et al. 2005a). Some
were increasingly associated with urban foci. In

10 metric tons of destroyed tank furnaces associ-
industrial estates both the primary manufacture of
ated with raw glass were found during excavations
glass in large tank furnaces and secondary produc-
on sites dating to the 8th–9th, 11th, and 12th centu-
tion (glassblowing) could have occurred. One model
ries, so the manufacture of raw glass occurred over
of production, for natron glass, is the split between
a period of about 400 years. There is some evidence
primary and secondary glass production (Henderson
that fritting of the raw materials, as described by

1989:39; Freestone et al. 2000). This split does not rule Abd’ul Q’asim (Allan 1973:114) occurred in al-Raqqa
out completely the possibility that both occurred on

(Henderson 1995).

The Provenance of Ancient Man-made Glass | 193

Figure 14.3. The location of al-Raqqa, Syria.

In addition to tank furnace remains, excavations
its presence in combination with iron provided a
at al-Raqqa also revealed the existence of beehive-
range of colors depending on the gaseous atmosphere
shaped glass furnaces. Beehive-shaped furnaces are
in the furnace at different times during glass melt-
associated with glassblowing. The use of scrap glass
ing. Apart from the use of manganese, the colors of

(cullet) to aid glass melting in tank furnaces prob-
raw glass from the site were produced as a result of
ably occurred, and the concept is supported by eth-
the melting conditions and the presence of iron and
nographic evidence based on research in India (Sode
manganese oxides; no cobalt was detected in the raw
and Kock 2001). In this case, only the top half of the blue glass from al-Raqqa. Although fragments of
melt in a tank furnace was used; the lower half of
many different vessel types were found at al-Raqqa,
the melt was considered unusable and added to the
it is very difficult to establish which vessel types were succeeding melt. During secondary glass produc-manufactured on the site and which might have been
tion there is a likelihood that glass made in different imported. Only by using chemical and isotopic analy-locations was mixed in the crucibles in which glasses
sis can we hope to answer this important question.

were reheated in beehive-shaped furnaces. It would
be at this stage that colorant-rich materials, including deeply colored glass, would be added to the glass melt 5. Scientific analysis
prior to blowing.

Scientific analysis of glass from al-Raqqa has so far

The colors of raw glass made at al-Raqqa, found
involved the use of two principal techniques: elec-
attached to furnace remains, were blue, a range of
tron probe microanalysis (EPMA) and thermal ion
green hues, purple, and colorless. Manganese was
mass spectrometry (TIMS). EPMA was used to
added deliberately, presumably in the batch because
determine major, minor, and some trace-level oxide

194 | OBSIDIAN AND GLASS PROVENANCE
concentrations in glass; TIMS was used to determine
furnace and vessel glass found on sites of all periods the ratios of 143Nd/144Nd and 87Sr/86Sr in glasses,
when plant ash glasses were made (e.g., Bronze Age,
plants, and silica along with the concentrations of Sr Sasanian, and Islamic in the West and the Middle
and Nd. Inductively-coupled plasma–atomic emis-

East). The concentration of strontium varies accord-
sion spectroscopy (ICP-AES) was used to chemi-
ing to a range of factors but is independent of the
cally analyze a range of halophytic plant species
isotope ratios (Henderson et al. 2005b). If alkalis
from the local environment and from farther afield
from different geological zones are mixed during
that were potentially used in glass production. The
the process of manufacturing glass, this will result
principles of EPMA, including the analytical errors
in an isotopic mixing line, because the result will fall involved, are described elsewhere (Henderson 1988).

between the results for unmixed glasses (the “end

Because TIMS is a relatively new technique applied
members”) (Henderson et al 2005b:669; Degryse et
to ancient glass, it is worth summarizing the prin-
al. 2006).

ciples involved.

Neodymium (143Nd/144Nd) is a second radio-
genic isotope that helps to provenance plant ash

5.1 Thermal ion mass spectrometry
glass. Neodymium can be concentrated in minerals

The isotopic (87Sr/86Sr) composition of the plant ash
such as feldspars, which are a common impurity in
used to make Islamic glass reflects the (geological)

sands. The 143Nd/144Nd ratio of a mineral/rock reflects age and rubidium content of the bedrock on which
the formation age of the silica and the concentration
the plants grew (Freestone et al. 2003; Montgomery
of the parent element, samarium. The sand depos-
et al. 2006). Strontium substitutes for the calcium
its used may have been quarries, river sand, or sand
that is taken into plants by transpiration, calcium
from evaporite deposits; the Levant has a number of
being a major component of plant ash. No isotopic
sandy beaches including those referred to by Pliny
fractionation occurs when the glass is made, as is
and Strabo. The composition of inland deposits of
clear by comparing the 87Sr/86Sr signatures in glass
sand, such as that from the Euphrates, would be
made in al-Raqqa with those in plant ashes found
dominated by contributions from its source in the
at al-Raqqa (Henderson et al. 2005b; Henderson
mountains of Turkey. It should therefore be possi-
et al. 2009). All plant species growing in a specific
ble to discriminate between the use of sand derived
geological location will have the same 87Sr/86Sr iso-
from the erosion of old, metamorphic rocks and one
tope value. Therefore, by determining the strontium
derived from the erosion of a younger rock, such as
isotope signatures of glasses and plants, we have a
granite. The concentration of Nd within glass can
means of linking the geological origin of the lime (in also help to indicate the type of silica used, since
the plant) to the (origin of the) glass made from it.

the purer the silica, the lower the Nd concentration.

Assuming local plants were used, this determination

The neodymium levels detected in halophytic plants
constitutes a means of provenancing glass.

have been found to be negligible (Barkoudah and

Therefore, contrasting geological ages of the cal-

Henderson 2006:table 2) so are unlikely to contrib-
cium sources used across the landscape are essen-
ute to the isotopic signature significantly.

tial if this technique is to be successful. To select a simple example, old marine limestones found across

5.2 The approach to sampling
the Middle Eastern steppe can be distinguished

Because of artifact diversity it was difficult to select isotopically from seashells (in sand) that take in
a range of glass samples considered to be represen-

“modern” (Holocene) water. By sampling plants that
tative of color, production process, and vessel form
grow on contrasting geologies such as those in the
from the several thousand glass artifacts excavated at Middle East (Beydoun 1977), and by determining
the production site of ninth-century Tell Zujaj on the their 87Sr/86Sr isotope signatures, an index of sig-excavated industrial complex at al-Raqqa. However,
natures reflecting variations in the geology across
samples from the assemblage of raw furnace glasses,
the landscape can be established. This index can
vessel glass, melted vessel glass, and threads of glass of then be compared with 87Sr/86Sr signatures of raw
a variety of colors were selected for chemical analysis.

The Provenance of Ancient Man-made Glass | 195

A second, smaller set of samples from an early 11th-
of raw materials or of raw glasses. In this case it is century site on the same industrial complex in al-likely that, in the absence of magnesium-rich min-

Raqqa (Tell Fukhkhar) was taken for comparison.

erals in sands, the magnesia was introduced in the

The total number of samples analyzed was 244. Raw
plant ash (Barkoudah and Henderson 2006:fig. 4,
glass was found on this second site but not attached
table 2), and that the alumina was mainly intro-
to furnace remains. This study represented the first
duced as an impurity in the silica source used, there
detailed set of glass chemical analyses from an Islamic being a minimal aluminum contribution from plant
primary glass-making site (Henderson et al. 2004).

ashes (Barkoudah and Henderson 2006:table 2). The
kinds of silica sources used could potentially include 5.3 The chemical results
sand of a range of purities or crushed quartz pebbles.

The results can be investigated by using a series of

Assuming that there was no alumina enrichment
bivariate plots. The first important result provides
from crucibles when glasses were reheated for glass-
evidence for the presence of both plant ash glass
blowing, the alumina levels detected in the glasses
and natron glass (figure 14.4). None of the natron
made from these silica sources would be a reflec-
glass was attached to furnace fragments, so it was
tion of these silica types. In figure 14.5, the Type 4
assumed that raw natron glass was imported from a
plant ash glasses with the highest alumina contents
production zone elsewhere, probably the Levantine

(about 4.2%) would have been made with sand con-
coast where there is evidence for its manufacture.

taining a relatively high proportion of feldspars that The chemical composition of natron samples was
introduced the alumina. Purer sand would have
significantly more constrained than that of plant ash
introduced the alumina levels at the lower end of the
glasses as can be seen by referring to figures 14.4 and correlation (about 1%). Therefore glasses with high

14.5. This constraint is an indication that plant ashes alumina and low magnesia levels (A in figure 14.5)

introduced a far wider and more variable range of
were mixed with glasses with low alumina and high
elements due to the physiognomies of the plants.

magnesia levels (B in figure 14.5) to produce glasses

The discovery of this wide compositional varia-
with the range of MgO and Al O compositions (A

2 3
tion between individual samples was unexpected, and

+ B in figure 14.2) in between. To be able to suggest
it was unexpected that it was actually possible to dis-why there is such a range in magnesia values in al-
tinguish between the three types of plant ash glasses

Raqqa glasses is more difficult, given the range of
shown in figure 14.5. The existence of three dis-
tinct compositional groups of plant ash glasses
also indicates they were not mixed. The plant ash
glass labelled Raqqa Type 1 is of a type that can be characterized further in two ways: it has lower
compositional variation when compared to the
other main plant ash glass type (Type 4), and it
continued to be manufactured and used in the

Islamic world until the 15th century AD, includ-
ing its use to make mosque lamps.

The other main plant ash type, Raqqa Type 4, has a much wider compositional range. Unlike

Type 1, available evidence suggests that it was no
longer made after the 10th–11th centuries AD.

Figure 14.5 shows that the relative levels of mag-
nesia and alumina in Type 4 form a negatively
correlated spread of data points. Correlations

Figure 14.4. Relative concentrations of weight % MgO
between oxides of this kind can be interpreted
and K O in 9th- and 11th-century AD glass samples

2
from al-Raqqa, Syria.

as the result of mixing different proportions

196 | OBSIDIAN AND GLASS PROVENANCE
conditions in tank furnaces), does suggest strongly
that mixing of raw glass occurred there.

In figure 14.6 it is notable that the lowest P O

2 5
levels are to be found in some natron glass samples
and that the use of a plant ash alkali has introduced
higher levels in Type 1 and some samples of types 2
and 4. Some Type 4 glasses contain P O levels that

2 5
are comparable with those found in natron glasses.

Not only does this finding underline the distinctions
between the compositional types, it also hints at the
possibility that natron glass was mixed with plant
ash glass at this period of technological transition
between the two to produce Type 4 (and this would
help to explain the high alumina levels normally

Figure 14.5. Relative concentrations of weight % MgO
associated with the manufacture of natron glass on
and Al O in 9th- and 11th-century AD glass samples

2 3
the Levantine coast). However, the Type 4 samples
from al-Raqqa, Syria.

with high alumina levels also contain relatively high
phosphorus pentoxide levels, assumed to be associ-
ated with the use of plant ashes (e.g., Henderson et
al. 2004:table 1, samples 1 and 12). One would expect
the P O levels to be somewhat reduced if indeed a

2 5
proportion of natron glass was added. However, in
this case an increase in the level of phosphorus has
been interpreted as the possible use of bone ash as a
calcium source instead (Henderson et al. 2004:459).

Chemical analyses of eight “raw” glasses from
two tank furnaces in Tyre (Freestone 2002:table 1)

show that two compositions from Furnace 2 are
similar to the raw glasses from 11th-century AD Tell

Fukhkhar from the industrial estate at al-Raqqa;
those from Furnace 1, with characteristically high
calcium oxide contents, are closest composi tionally

Figure 14.6. Relative concentrations of weight % P O

2 5
to some Fustat glasses. Indeed the Tyre furnaces
and CaO in 9th- and 11th-century AD glass samples
may be the source for the Fustat glasses and possibly
from al-Raqqa, Syria.

for the al-Raqqa glasses. A comparison of al-Raqqa
glasses with those published by Brill (1999b:table

VII, 1) for the glasses (including raw and vessel)

factors that would affect the magnesia levels, includ-
found on the 11th-century AD shipwreck of Serç
ing the geological contexts in which the plants

Limani shows that they are quite distinct from al-
grew (Barkoudah and Henderson 2006:315–316, fig.

Raqqa glasses (Henderson et al. 2004).

8). Moreover, the melting conditions in furnaces

(and crucibles) can change the relative levels of com-
ponents from those found in the raw materials to

5.4 The isotopic results
those in the glasses (Rehren 2008). Nevertheless, the

The determination of radiogenic isotopes in raw fur-
unusually wide compositional variation of Type 4
nace plant ash glass from a primary glass-making site
glass at al-Raqqa, especially in the alumina lev-
provides a basis against which to (1) compare isotopic els (which are unlikely to be affected by melting
results of glass from other regions and (2) compare

The Provenance of Ancient Man-made Glass | 197
from various geological contexts, provides the best
means of being confident about a geological prov-
enance for glass (Henderson et al. 2009).

The Nd isotope results for Raqqa glasses are
plotted in figure 14.7. The reason why there are rela-
tively few data points compared to the number of
chemical analyses that can be carried out is because
the technique is very expensive. First, it is worth
noting that many of the Type 1 glasses were made
with sand of a relatively consistent purity contain-
ing Nd concentrations of around 6 ppm. The Type

4 glasses, on the other hand, are less consistent in

Figure 14.7. A plot of neodymium isotope values against terms of Nd levels, and a set of 5 plotted points (indi-neodymium concentration in 9th- and 11th-century
cated by a line in figure 14.4) confirms the mixing

AD glass from al-Raqqa by chemical type.

of silica sources (of contrasting geological ages and
purities), also suggested on the basis of relative alumina and magnesia levels (figure 14.5). There is a
further group of four other Type 4 samples with Nd
isotope values of between 0.51220 and 0.51225.

If we examine how these Nd isotopic results
relate to artifact type (figure 14.8), we see that the group of four Type 4 glasses are the only bangles and
window glass samples for which we have results, all
of which are highly colored. The bangles are of an

11th-century AD date and the window glass is of an
early ninth-century date. It can be suggested that glass with 143Nd/144Nd values of around 0.5122 was made
with a different (geologically younger) silica source

Figure 14.8. A plot of neodymium isotope values against from that used to make raw glass in al-Raqqa: apart
neodymium concentration in 9th- and 11th-century
from one, the raw glasses have 143Nd/144Nd values of

AD glass from al-Raqqa by artifact type.

below around 0.5121. Furthermore, the site(s) that
produced the bangles and the window glass appear to
have partly specialized in the manufacture of highly
the isotopic results from locally growing plants, to
colored glasses. No archaeological evidence for the
provide a scientific provenance for it.

manufacture of highly colored glass was found in

Samples of raw furnace glass provide an essential
al-Raqqa, so this finding supports further the inter-
starting point for such a study because the likelihood pretation that the four samples were made elsewhere.

of mixing of different glass compositional/isotopic

The results for both 143Nd/144Nd and 87Sr/86Sr
types made at some distance from the production
plotted in figure 14.9 for artifact types underline that site is minimized. The association of contrasting
raw furnace glass produced in al-Raqqa was mainly

143Nd/144Nd values with contrasting geological ages
manufactured using plants from a constrained geo-
of silica, and contrasting 87Sr/86Sr values with con-
logical context (with 87Sr/86Sr values of between
trasting geological ages of calcium sources, provides

0.708090 and 0.708204). The results also show that
a basis for provenancing ancient glass using radio-
one sample of raw glass (with a strontium value of
genic isotopes. The determination of isotopic values

0.7076) was imported to the site. This result indi-
for silica and plants (containing calcium), the main
cates that although the import of raw glass occurred,
raw materials used to make plant ash glass, taken
it was rare and gives us further confidence in the

198 | OBSIDIAN AND GLASS PROVENANCE
of different geological ages were used to make the
glasses. However, without an estimate of the varia-
tion in isotopic results for raw materials across the
landscape, the locational/provenance information
for the imported glass leaves the question of its
provenance open. Trace element analysis of glass
raw materials and glasses can also provide a degree
of provenance, especially if related to the investi-
gation of primary glass-making sites. However, a
range of complex factors may affect the direct trans-
fer of the trace element characteristics of the raw
materials into fully formed glasses that can reduce
their use as a provenance tool. It is not always easy

Figure 14.9. A plot of neodymium isotope values against to explain why different groups are obtained using
strontium isotope values in 9th- and 11th-century AD
glass from al-Raqqa by artifact type.

chemical analysis of plant ash glasses. This difficulty may be partly due to the geological origin of the
raw materials used and partly due to the produc-
provenancing methodology. Two vessel samples
tion processes that can affect the relative levels of

(flasks) were clearly made in al-Raqqa from the raw
components (Rehren 2008). The social, economic,
glass manufacturing process. They sit squarely on
and political complexities associated with each case
the core values for raw glass. Moreover, one vessel
study need to be taken into account. For example,
fragment with the highest 87Sr/86Sr value of 0.7094
the historical and archaeological evidence for pri-
is an import and must have been made from plants
mary production sites, evidence of craft special-
growing on geologically young soil. Three samples of
ization, the scale of production, associations with
vessel glass and the two each of window and bangle
other industries, trade, and exchange can all help
glass discussed above were clearly made using silica
to influence the interpretation. The determination
of a younger geological age than that used for fusing
of radiogenic isotopes (Sr, Nd) cuts through some
glass at al-Raqqa: this is very strong evidence for the of the complexities (Henderson et al. 2010). For
import of the vessel window and armlet fragments
example, it is possible to define separate composi-
to al-Raqqa. The window glass was used in one of
tional groups of Islamic glass vessels with distinc-
the early ninth-century AD palaces constructed by
tive designs such as scratch- and cameo-decorated

Harun-al-Rashid at al-Raqqa.

vessels (Henderson et al. 2009:424–425, fig. 7), but
currently we cannot be sure whether one or more

6. Conclusions
sites were involved in their production, so we are
unable to make a case for specialized production

It is apparent that the interdependence of the chem-
centers. Isotopic investigations could at least help to ical and isotopic analyses of ancient glass informs
shed light on where the raw glasses for such vessels
us about ancient glass production in slightly differ-
were made.

ent and overlapping ways. Furthermore, the use of

The trade in raw and vessel glass certainly
the two techniques, set in the archaeological and
occurred in the Islamic period; witness the vast
environmental context of al-Raqqa, northern Syria,
quantities of raw glass, vessel glass, and cullet that has provided scientific proof of glass provenance,
were found on the 11th-century AD Serç Limani
the mixing of glass, and the importation of glass.

shipwreck off the Turkish coast (Bass 1984; Bass et

It is possible to produce quite distinct differences
al. 2009). Even when such discoveries are made, iso-
in strontium and neodymium isotope values for
topic results could help to define the origin of the
glasses from primary glass-making sites and glasses
glass and identify whether the raw and vessel glass
made elsewhere, showing that raw material sources
found was made from mixed glasses deriving from

The Provenance of Ancient Man-made Glass | 199
different sources. Trade in plant ash also apparently

Bass, G.F., Lledo, B., Matthews, S., 2009. Serce Limani.

occurred (Ashtor 1992:482), so trade could generate

Vol. 2: The Glass of an Eleventh Century Shipwreck.

misleading isotopic results. However, as long as the

Texas A&M University Press, College Station, TX.

interpretation is set within an environmental con-

Batanouny, K.H., 2001. Plants in the Deserts of the Middle text, including primary production sites, this poten-East. Springer-Verlag, Berlin.

tial problem can be overcome.

Beydoun, Z.R., 1977. The Levantine countries: The geology of Syria and Lebanon (maritime regions). In:

In contrast to the provenance of plant ash glasses,

Nairn, A.E.M., Kanes, W.H., Stehli, F.G. (Eds.), The the provenance of natron glasses is different because

Ocean Basins and Margins. Vol. 4A: The Eastern Med
the compositional variability of the glasses is more
iterranean. Plenum Press, New York, pp. 319–353.

constrained. Such work relies more on the isotopic

Boulogne, S., Henderson, J., 2009. Indian glass in the characteristics of the silica source, and the first evi-Middle East? Medieval and Ottoman glass bangles
dence for a non-Levantine source of Roman natron
from central Jordan. Journal of Glass Studies 51, 53–75.

glass is an exciting result (Degryse and Schneider

Brill, R.H., 1999a. Chemical Analyses of Early Glasses.

2008; Degryse, Schneider et al. 2009). The compo-

Vol. 1: Catalogue of Samples. Corning Museum of sitional groups produced by the isotopic and chemi-Glass, Corning, NY.

cal signatures of some of these samples show that

Brill, R.H., 1999b. Chemical Analyses of Early Glasses.

both sets of results are important but can provide

Vol. 2: Tables of Analyses. Corning Museum of Glass, Corning, NY.

different information about glass production. In this

Brill, R.H., 2001. Some thoughts on the chemistry
case the chemical composition of the glass suggests a
and technology of Islamic glass. In: Carboni, S.,

Levantine source but the isotopic composition con-

Whitehouse, D. (Eds.), Glass of the Sultans. Metro-firms a non-Levantine, probably Western source.

pol itan Museum of Art, New York, pp. 25–46.

Degryse, P., Schneider, J., Haack, U., Lauwers, V.,

Poblome, J., Waelkens, M., Muchez, P.H., 2006. Evi-

References
dence for glass “recycling” using Pb and Sr isotopic
ratios and Sr-mixing lines: The case for early Byzan-

Aerts, A., Velde, B., Janssens, K., Dijkman, W., 2003.

tine Sagalassos. Journal of Archaeological Sci ence Change in silica sources in Roman and post-Roman

33, 494–501.

glass. Spectrochimica Acta B58, 659–667.

Degryse, P., Schneider, J., 2008. Pliny the Elder and

Aldsworth, F., Haggerty, G., Jennings, S., Whitehouse, D., Sr-Nd isotopes: Tracing the provenance of raw mate-2002. Medieval glassmaking at Tyre, Lebanon. Jour
rials for Roman glass production. Journal of Archanal of Glass Studies 44, 49–66.

eological Science 35, 1993–2000.

Allan, J.W., 1973. Abd_ul Q’_asim’s treatise on ceramics.

Degryse, P., Henderson, J., Hodgin, G., 2009. Isotopes Iran 11, 111–120.

and Vitreous Materials. Studies in Archaeological Sci-Andreescu-Tradgold, I., Henderson, J., 2006. Glass from ences 1. Leuven University Press, Leuven, Belgium.

the mosaics on the west wall of Torcello’s Basilica.

Degryse, P., Schneider, J., Lauwers, V., Henderson, J., Arte Medievale 2, 87–140.

Van Daele, B., Martens, M., Huisman, H.D.J.,

Ashtor, E., 1992. Levantine alkali ashes and European

De Muynck, D., Muchez, P., 2009. Neodymium and
industries. In: Kedar, B.Z. (Ed.), Technology, Industry strontium isotopes in the provenance determina-and Trade: The Levant versus Europe, 1250–1500. Var-tions of primary glass production. In: Degryse et al.

i orum, Hampshire, Vermont, pp. 475–522.

(Eds.), Isotopes and Vitreous Materials. Studies in Arch-Ashtor, E., Cividalli, G., 1983. Levantine alkali ashes and aeological Sciences 1. Leuven University Press, Leuven, European industries. Journal of European Economic Belgium, pp. 53–72.

History 12 (3), 487–491.

Dussubieux, L., Kusimba, C.M., Gogte, V., Kusimba, S.B., Barkoudah, Y., Henderson, J., 2006. Plant ashes from

Gratuze, B., Oka, R., 2008. The trading of ancient

Syria and the manufacture of ancient glass: Ethno-
glass beads: New analytical data from south Asian
graphic and scientific aspects. Journal of Glass Stud ies and east African soda-alumina glass beads. Archaeo

48, 297–321.

metry 50 (5), 797–821.

Bass, G.F., 1984. The nature of the Serç Limani glass.

Foy, D., Nenna, M.-D., 2001. Tout Feu tout Sable. Musée Jour nal of Glass Studies 26, 64–69.

d’Histoire de Marseille, Aix-en-Provence.

200 | OBSIDIAN AND GLASS PROVENANCE

Freestone, I.C., 2002. Composition and affinities of glass Henderson, J., 2009. The provenance of archaeologi-from the furnaces on the island site, Tyre. Journal of cal plant ash glasses. In: Shortland, A.J., Freestone, Glass Studies 44, 67–77.

I.C., Rehren, Th. (Eds.), From Mine to Microscope, Freestone, I.C., Gorin-Rosen, Y., Hughes, M.J., 2000. Pri-Advances in the Study of Ancient Technology. Oxbow mary glass from Israel and the production of glass in

Books, Oxford, UK, pp. 129–138.

late antiquity and the early Islamic period. In: Nenna, Henderson, J., McLoughlin, S., McPhail, D., 2004. Radi-M.-D. (Ed.), La Route du Verre. Maison de l’Orient cal changes in Islamic glass technology: Evidence for

Méditerraneéan-Jean Pouilloux, Lyon, pp. 65–84.

conservatism and experimentation with new glass

Freestone, I.C., Leslie, K.A., Thirlwell, M., Gorin-Rosen, recipes from early and middle Islamic Raqqa, Syria.

Y., 2003. Strontium isotopes in the investigation of

Archaeometry 46, 439–468.

early glass production: Byzantine and Early Islamic

Henderson, J., Evans, J.A., Sloane, H.J., Leng, M.J.,
glass from the Near East. Archaeometry 45, 19–32.

Doherty, C., 2005a. The use of oxygen, strontium

Gan, F., 2005. Development of Chinese Ancient Glass.

and lead isotopes to provenance ancient glasses in

Fudan University, Shanghai.

the Middle East. Journal of Archaeological Science 32

Gorin-Rosen, Y., 1995. Hadera Bet Eli’ezer. Excavations (5), 665–673.

and Surveys in Israel 13, 42–43.

Henderson, J., Challis, K., O’Hara, S., McLoughlin, S., Gorin-Rosen, Y., 2000. The ancient glass industry in

Gardner, A., Priestnall, G., 2005b. Experiment and

Israel: Summary of the finds and new discoveries.

innovation: Early Islamic industry at al-Raqqa, Syria.

In: Nenna, M.-D. (Ed.), La Route du Verre. Maison Antiquity 79, 130–145.

de l’Orient Méditerraneéan-Jean Pouilloux, Lyon,

Henderson, J., Evans, J., Barkoudah, Y., 2009. The roots pp. 49–64.

of provenance: Glass, plants and isotopes in the

Gratuze, B., Barrandon, J.-N., 1990. Islamic glass weights Islamic Middle East. Antiquity 83, 414–429.

and stamps: Analysis using nuclear techniques.

Henderson, J., Evans, J., Nikita, K., 2010. Isotopic evi-Archaeo metry 32 (2), 155–162.

dence for the primary production, provenance and

Gratuze, B., Blet-Lemarquand, B., Barrandon, J.-N.,
trade of late Bronze Age glass in the Mediterranean.

2001. Mass spectrometry with laser sampling: A new

Journal of Mediterranean Archaeology and Archa
tool to characterize archaeological materials. Journal eometry 10 (1), 1–24.

of Radio analytical and Nuclear Chemistry 247 (3), Hoskin, P.W.O., Ireland, T.R., 2000. Rare earth element 645–656.

chemistry of zircon and its use as a provenance indi-

Henderson, J., 1988. Electron probe microanalysis of
cator. Geology 28, 627–630.

mixed-alkali glasses. Archaeometry 30, 77–91.

Jackson, C.M., Smedley, J.W., 2004. Medieval and post-

Henderson, J., 1989. The scientific analysis of ancient glass medieval glass technology: Melting characteristics
and its archaeological interpretation. In: Henderson,
of some glasses melted from vegetable ash and sand

J. (Ed.), Scientific Analysis in Archaeology and Its mixtures. Glass Technology 45, 36–42.

Inter pretation. Oxford University Committee on Jackson, C.M., Booth, C.A., Smedley, J.W., 2005. Glass Archaeology Monograph no. 19, UCLA Institute of
by design? Raw materials, recipes and compositional

Archaeology Research Tools 5. Oxford Books,
data. Archaeometry 47, 781–795.

Oxford, UK, pp. 30–62.

Kowatli, I., Curvers, H.H., Stuart, B., Sablerolles, Y., Henderson, J., 1995. An investigation of early Islamic glass Henderson, J., Reynolds, P., 2008 [2006]. A pot-production at Raqqa, Syria. In: Vandiver, P., Druzik,
tery and glass production site in Beirut (BEY 015).

J., Madrid, J.L.G., Freestone, I.C., Wheeler, G.S. (Eds.), Bulletin s’Archéologie et d’Architecture Libanaises 10, Proceedings of the Materials Research Society Confer

103–120.

ence, Issues in Art and Archaeology IV. 16–21 May, Lilyquist, C., Brill, R.H., Wypyski, M.T., Koestler, R.J., Cancun, Mexico. MRS, Warrendale, PA, pp. 433–444.

1993. Part 2. Glass. In: Lilyquist, C., Brill, R.H.,

Henderson, J., 2000. The Science and Archaeology of Wypyski, M.T. (Eds.), Studies in Early Egyptian Glass.

Materials. Routledge, London.

Metropolitan Museum of Art, New York, pp. 23–58.

Henderson, J., 2002. Tradition and experiment in 1st

Loveland, W., 1989. Environmental sciences. In: Bunzli, millennium AD glass production—the emergence

J., Choppin, G. (Eds.), Lanthanide Probes in Life, of early Islamic glass technology in late antiquity.

Chem ical, and Earth Sciences. Elsevier, New York, Accounts of Chemical Research 35, 594–602.

pp. 391–411.

The Provenance of Ancient Man-made Glass | 201

Lucas, A., 1948. Ancient Egyptian Materials and Indust

Robertshaw, P., Rasoarifetra, B., Wood, M., Melchiorre, E., ries. Edward Arnold and Co., London.

Popelka-Filcoff, R.S., Glascock, M.D., 2006. Chem ical Merchant, I., Henderson, J., Crossley, D., Cable, M., 1997.

analysis of glass beads from Madagascar. Jour nal of An examination of the chemical interaction of glass

African Archaeology 4 (1), 91–109.

and ceramics in medieval glass technology. Pro ceed

Saitowitz, S.J., Reid, D.L., van der Merwe, N.J., 1996.

ings of the Liverpool Archaeometry Con ference, Uni ver

Glass bead trade from Islamic Egypt to South Africa,
sity of Liverpool 1997. Oxbow Mono graph 64. Oxbow c. AD 900–1250. South African Journal of Science 92, Books, Oxford, UK, pp. 31–37.

101–104.

Mirti, P., Pace, M., Negro Ponzi, M.M., Aceto, M., 2008.

Sanderson, D.C.W., Hunter, J.R., 1981. Compositional

ICP-MS analysis of glass fragments of Parthian and
variability in vegetable ash. Science and Archaeology Sasanian epoch from Seleucia and Veh Ardašīr (cen-23, 27–30.

tral Iraq). Archaeometry 50 (3), 429–450.

Sayre, E.V., Smith, R.W., 1961. Compositional categories Montgomery, J., Evans, J.A., Wildman, G., 2006. Sr-87/
of ancient glass. Science 133, 1824–1826.

Sr-86 isotope composition of bottled British mineral

Shortland, A.J., Rogers, N., Eremin, K., 2007. Trace
waters for environmental and forensic purposes.

element discriminants between Egyptian and Mes o -

Applied Geochemistry 21 (10), 1626–1634.

po tamian Late Bronze Age glasses. Journal of Archa

Nenna, M.-D., Picon, M., Thirion-Merle, V., Vichy, M., eological Science 34, 781–789.

2005. Ateliers primaires du Wadi Natrun: Nou velles

Smedley, J., Jackson, C.M., Booth, A., 1998. Back to the découvertes. In: Annales du 16e Congrès de l’Asso
roots: The raw materials, glass recipes and glass-
ciation Internationale pour l’Histoire du Verre. AIHV, making practices of Theophilus. In: McCray, P.,

London, pp. 59–63.

Kingery, W.D. (Eds.), The Prehistory and History of Nicholson, P.T., 2007. Brilliant Things for Akhenaten, The Glass and Glassmaking Technology. Ceramics and Production of Glass, Vitreous Materials and Pottery Civilisation 8. American Ceramic Society, Wester-at Amarna Site 04.125. EES Excavation Memoir 80.

ville, OH, pp. 145–65.

Egypt Exploration Society, London.

Sode, T., Kock, J., 2001. Traditional raw glass production Oppenheim, L., 1970. Glass and Glassmaking in Ancient in northern India: The final stage of an ancient tech-Mesopotamia. Corning Museum of Glass, Corning,NY.

nology. Journal of Glass Studies 43, 155–169.

Patyk-Karar, N.G., Bardeeva, E.G., Sjevelev, A.G., 1999.

Turner, W.E.S., 1954. Studies of ancient glass and glass-Titano-zirconium placers in the sedimentary cover
making processes. Part I: Crucibles and melting
platforms. Episodes 22, 89–97.

temperatures employed in ancient Egypt at about

Pusch, E.B., Rehren, Th., 2007. Hochtemperatur-

1370 BC. Journal of the Society of Glass Technology Tech nologie in der Ramses-Stadt. Rubinglas für

38, 436–444.

den Pharao, Forschungen in der Ramses-Stadt 6.

Turner, W.E.S., 1956a. Studies of ancient glass and glass-Gerstenberg-Verlag, Hildesheim.

making processes. Part III: The chronology of glass-

Rehren, Th., 2008. A review of factors affecting the com-making constituents. Journal of the Society of Glass position of early Egyptian glasses and faience: Alkali Technology 40, 39–52.

and alkali earth oxides. Journal of Archaeological Sci

Turner, W.E.S., 1956b. Studies of ancient glass and glass-ence 35, 1345–1354.

making processes. Part V: Raw materials and melting

Rehren, Th., Pusch, E.B., 2005. Late Bronze Age glass
processes. Journal of the Society of Glass Technology pro duction at Qantir-Piramesses, Egypt. Science 308, 40, 277–300.

1756–1758.

Chapter 15

Thoughts on Natural and Manufactured Glass

Studies in a 21st-Century Archaeology

M. Steven Shackley

The major development in world archaeology
discipline (Green 1998; Joyce 2011; Goldberg 1988;
over the past decade has in fact been the astound-

Killick 2008; Killick and Goldberg 2009; Pollard and
ing expansion of archaeological science.

Bray 2007). So, in an effort to support and defend

—Killick and Goldberg, “A quiet crisis
the application of glass studies to an ever-expanding
in American archaeology”

theoretical archaeology, I’ll take a rather larger view, returning to more specifics at the end.

It is an exciting moment in social archaeology
and archaeological materials science, specialties
that are growing so close that it probably is time

2. A personal background
to stop worrying about their differences and start
perspective
building on their shared engagements.

—Joyce, “Is there a future for XRF in

Taking the lead from a mentor and friend, the late
a 21st century archaeology?”

New Mexico–born Roger C. Green (1998), I’ll inter-
ject a bit about my own experience in the volcanic
glass field and 21 years of teaching at a major research 1. Introduction
university in an anthropology department that hasn’t
always been that supportive of science in archaeology.

It is rather axiomatic that “this is the only book of

In my own region of interest, the North Ameri-
its kind,” which all publishers and authors note in
can Southwest, the use of obsidian source prov-
publishing today, but this volume on the range of
enance to solve methodological and theoretical
glass studies in a 21st-century archaeology is truly
issues in prehistory was rejected 25 years ago, or
the only volume of its kind. In 1998 when many of
at least ignored by most archaeologists. Ceramics
the authors here collaborated on the volume Arch
were seen as the most important data set to solve
aeological Obsid ian Studies: Method and Theory, few these problems, of course overlooking the first
could imagine the hold that glass studies would have

12,000+ years of prehistory in this part of the world.

on the archaeological world (Shackley 1998). I’m not

Slowly, as obsidian studies began to illuminate issues here only to be prescient, but to outline what I think of social identity, gender relations, and more pro-glass studies, and indeed archaeological science, has
cessual areas of procurement and exchange that
done, and will do, for archaeological method and
could not be addressed with ceramic data, obsidian
theory. Of course, I’m not the only one who has tack-
studies became more “normative” in the Southwest
led this issue, and if one looks at the few attempts

(Shackley 2005). Now, few large research or cultural
to examine the relationship between archaeology
resource management projects are designed without
and the natural and physical sciences that wholly
an obsidian provenance and sometimes a hydration
underpin it, the ideology is rather obscured in the
component. Indeed, a recent multimillion-dollar

202

Thoughts on Natural and Manufactured Glass Studies | 203

U.S. National Science Foundation–funded project
of obsidian in Late and Terminal Classic Honduras
focusing on migration and social networks during
to argue that rather than pursuing a sitewide strat-
the Classic period, awarded to both the University
egy of minimizing cost, or creating a single monop-
of Arizona and the Center for Desert Archaeology,
olistic relationship with a single site providing all
is primarily based on obsidian source provenance
the obsidian used at the site, the people of Cerro
in concert with ceramic studies to elucidate migra-

Palenque obtained obsidian in small quantities from
tion and social relations during this controver-
a wide range of sources, many of them quite distant.

sial period. This very evolution of recognition by

She [Hendon] argues that for the people of Cerro
archaeologists of the exemplary utility of obsidian

Palenque, this cosmopolitanism of social relations,
studies with ceramic analyses has transformed our mediated through exchange of obsidian, was what
concept of prehistory in the Southwest. This proj-
was of greater social value:

ect might be considered “post-processual” by many

Based on a variety of analyses, we found

Southwestern archaeologists, but like Rosemary
that people in the Ulua Valley oriented their

Joyce, I prefer the label social archaeology to define ritual actions toward geographic points
this kind of work. I’ll return to this idea shortly.

on the horizon, mountains that were also

This philosophical change in the attitude toward
sources of valued stone resources. In a situ-
glass studies in Southwestern archaeology can be
ation where stones used for items of daily
mirrored in many of the regions focused on by the
use indexically signified their places of ori-
authors in this volume.

gin, the gathering together of obsidian from
many sources transformed Cerro Palenque

3. Archaeological science and
into a place containing many places . . . This
social archaeology
is the kind of richness that XRF promises

Interestingly, one of the reviewers for this volume
archaeology of the twenty-first century, and
was concerned that there was not enough “theo-
is already delivering. It is a way of interro-
retical” foundation for the chapters. I found that an
gating materiality that can open windows
interesting critique given that the volume is directed into past social experiences that are limited
toward explaining the character of these techniques
only by our ability to imagine how materials
rather than their application, which is rather com-
that XRF can be applied to mediate the lives
mon elsewhere in the literature while the under-
of people across space and over time. (Joyce
standing of the techniques themselves is not. Many

2011:200–201)

in archaeology would characterize me as a “scien-

In Hendon and Joyce’s case, these avowed social
tific” or “processual” archaeologist, labels they are
archaeologists recognize that to address the under-
happy to apply but that mean little to me. True, I
standing of prehistory with a 21st-century perspec-
have degrees in geology and anthropology, so both
tive, it could very well be that only techniques of could be thrown my way. In a recent volume I pub-archaeological science can truly illuminate them.

lished in a university press when applying obsidian

In the early 1990s when I arrived at Berkeley, the
provenance studies to social and gender identity
boundaries between processual and post-processual
in the pre-Classic Hohokam Southwest, one of the
archaeology were being sharply drawn, particularly
reviewers took exception: “Come on Shackley, you
by the typically energized graduate students. Emble-
don’t do that stuff.” Was I being untrue to my physi-
matic during shifts in perspective, the old is seen
cal science heritage by rallying scientific evidence
as less useful, even useless, and the new as the only
to understand and explain the social differences
way to go. My archaeological science courses were
among men and the technological and social dif-
seen as the old stuff, while visiting lecturers Alyson ferences between men and women in that society?

Wylie and Ian Hodder as the new, exciting stuff,

Recently, Rosemary Joyce and Julie Hendon
even though these colleagues did not necessarily see
have used the XRF analysis and source provenance
it that way.

204 | OBSIDIAN AND GLASS PROVENANCE

Archaeology really has never generated its own
part due to the ability to calibrate with 14C (radio-
body of theory. During my career we have borrowed
carbon) dates from the same sediments (Novak
theoretical views from the natural sciences (cul-
and Stevenson, chapter 1; see also Liritzis 2006; and
tural ecology, optimal foraging, historical ecology,

Liritzis and Laskaris, chapter 3 in this volume, for
behavioral ecology), from sociology (much of what’s
a detailed look at the method). Solving the inter-
called post-processualism), and from mathematics
observer issue is a major advance, but others are
and statistics. This is not the place to argue whether just as concerned with time and environmental fac-borrowing theory from other disciplines has been
tors. Ambrose and Novak in chapter 2 and Rogers in
good or bad for archaeology. However, as we move
chapter 4 are concerned about time and temperature
into the 21st century, methods and theory in the
and are using both SIMS and optical measurements
archaeological sciences will form the discipline, not
comparatively.

only because the techniques will focus the problems,

While SIMS has excited the obsidian hydration
but because they are becoming normative.

sphere in archaeology, it hasn’t necessarily “con-
verted” the masses, as shown at the recent Society

4. The studies in this volume
for American Archaeology meetings in Sacramento,

California (Anovitz et al. 2011; Rogers and Steffen

The volume editors have introduced the authors and

2011). These two papers, presented in the same
their chapters, and I won’t repeat that here. I do want session on the state of play in obsidian studies,
to examine the areas covered in the volume within
trumpeted the value of direct observation and deni-
the context of archaeological science and what could
grated the SIMS approach. This is not an unusual
be the future of these methods and technologies.

methodological and philosophical circumstance in
archaeology. While the correlation, or should I say

4.1 Obsidian hydration dating

“calibration,” of SIMS analyses of obsidian hydra-

As might be expected of the editors, much of the
tion and 14C dates has markedly improved the tech-
volume is devoted to obsidian hydration as a dating
nique and dates as ably demonstrated by Liritzis and
method. In my 30+ years in archaeology, obsidian

Laskaris in this volume, it hasn’t converted some
hydration dating has moved from direct observation
archaeologists, including many in my home state of
to a number of techniques that attempt to remove

California (see also Anovitz et al. 2011 for a similar interobserver error from direct reading of hydra-argument). As I’ve discussed elsewhere here, this is
tion rims and to deal with some of the environmen-
symptomatic of a larger issue in scientific applica-
tal and chronometric issues. Not every archaeologist
tion and relevance in modern archaeology.

who works in a region where obsidian artifacts occur

Wal Ambrose and Steven Novak (chapter 2)

is enamored with obsidian hydration as a dating
continue the career-long work of Wal on environ-
method. In Southwestern North America where I
mental issues in hydration, and in this case use SIMS
work, it is rather a last resort method behind radio-
for measurement. Wal Ambrose has never given up
carbon and archaeomagnetic dating. This is not to say
the very real concern for environmental effects, and
that no one has attempted it, but between the above
this is one of the more interesting empirical studies
chronometric techniques and ceramic cross-dating
in the group (see Ambrose 1998).

that still dominate the Southwest, obsidian hydration

Stanley Ambrose provides a mainly applica-
dating is not at the forefront of scholars’ tool kits.

tion chapter devoted to using both hydration and

In this volume the promising secondary ion
provenance studies of obsidian in Africa (chapter
mass spectrometric (SIMS) technique is the domi-

5). This study shows the potential utility of both
nating technology today (see Novak and Stevenson,
techniques in solving both chronological and social
chapter 1 in this volume, for a short review; Anovitz
problems, the former an important area of study
et al. 1999, 2004; Anovitz et al. 2008). The major
in East Africa. This is certainly a new amalgam of
utility of SIMS is that it “offers a significant increase research in Africa and promises much. Unlike other
in accuracy over the standard optical method,” in
regions of the world, Fission-Track and 40Ar/39Ar

Thoughts on Natural and Manufactured Glass Studies | 205
dating of volcanic sediments, some of which contain
studies. The newer digital detectors, smaller targets, quenched glass (obsidian), are beginning to estab-small-aperture X-ray tube collimators, and Windows-
lish a well-detailed chronology (see Morgan and
driven software have immeasurably improved the

Renne 2008). Perhaps most important, these refined
efficiency of this technique (Glascock and Ferguson
chronologies are shedding light on human evolution

2011; Shackley 2011a). There is also a fortuity in the and the shifts in technology from the Early to Late
elements in the mid-Z region that are analyzed with

Stone Age.

great precision by XRF and in those elements in that
region that are sensitive incompatible elements in

4.2 Obsidian and glass provenance
discriminating volcanic rocks (Cann 1983; Shackley

As in obsidian hydration studies, the technology,

2005, 2011a). However, XRF, while sensitive down to
methodology, and theoretical perspective on obsid-
about 8 mm in minimum sample diameter, cannot
ian and artificial glass provenance have expanded
measure small debitage at all. Why is this important?

exponentially in the latter half of the 20th century

Eerkens et al. (2007) and Shackley (1990) note that

(Shackley 2005, 2008). Gone are the days when
when analyzing small debitage smaller than 10 mm

NAA (neutron activation analysis) and XRF (X-ray
in various Great Basin archaeological contexts, both
fluorescence) were the dominant instrumental tech-
the distance to source and the diversity of sources
niques used to determine elemental composition
detected were greater. This is probably because these
of obsidian and glass. Now LA-ICP-MS (laser abla-
hunter-gatherers are rejuvenating cutting and scrap-
tion–inductively coupled plasma–mass spectrome-
ing tools and in-haft projectile points while traveling try) and portable XRF (p-XRF) are allowing scholars
over the landscape, and the resulting debitage is quite to analyze much smaller sizes non-destructively and
small. However, recent experiments at Berkeley with
to move the laboratory to the field. This shift will
the ThermoScientific Quant’X EDXRF instrument
irrevocably change glass studies for the foreseeable
using a 3.5-mm tube collimator suggest that obsidian
future, and mainly for the better.

down to at least that size can be reliably analyzed (see Part 2, “Obsidian and Glass Provenance,” begins
also Hughes 2010). With the advances in digital tech-
with an important study comparing the results of
nology and software, XRF will remain one of the best
three techniques on Wari obsidian from Peru: INAA
non-destructive options for the analysis of obsidian

(instrumental neutron activation analysis), LA-
and glass (Shackley 2011b).

ICP-MS, and p-XRF by Williams, Dussubieux, and

Portable XRF (p-XRF) has literally taken archae-

Nash (chapter 6). This is one of some recent com-
ology by storm (see Liritzis and Zacharias 2011).

parative studies on obsidian by a number of schol-

Promised are the portability of an instrument less
ars, and very necessary in my opinion (Glascock
expensive than a desktop model by 40% to 50% and

2011; Johnson 2011; Nazaroff and Shackley 2009). All
no need to calibrate! As Williams et al. note in chap-
three of the most utilized techniques have strengths
ter 6, “the use of p-XRF in the field of archaeology
and weaknesses. While NAA can acquire nearly
is still new and the reliability of the quantitative data every element in the periodic table, a number of
obtained using fundamental parameters and unpre-
incompatible elements that are sensitive discrimi-
pared samples is often questioned.” Unfortunately,
nating elements between silicic melts are beyond
many archaeologists are not trained in XRF theory
the capability of NAA or measured poorly, includ-
and apply the instrument essentially right out of
ing strontium, yttrium, zirconium, and barium, and
the case (see Speakman et al. 2010). Nazaroff and
of course NAA is essentially destructive. However,

Shackley (2009) found that an empirical calibration
the wide range of rare earth elements acquired and
using 17 international standards provided a much
the great precision, down to parts per billion in
better fit and accuracy than fundamental parameters.

some cases, more than makes up for the deficiency

Some of the earlier p-XRF instruments were difficult

(Glascock 2011).

or impossible to calibrate empirically, but most have

For nearly three decades, XRF has remained the
caught up to the necessity of providing that utility.

dominant non-destructive technology for obsidian

Nazaroff and Shackley’s (2009) size study found that

206 | OBSIDIAN AND GLASS PROVENANCE
with empirical calibration, obsidian debitage down
been a concern for those doing provenance analyses
to about 10 mm could be reliable derived for the ele-
in the Pacific Basin (Kirch 1997; Weisler 1990, 1997).

ments of interest, but like the Williams et al. study

Here Weisler deals with volcanic glass, including
here, some elements were off up to 20% or more.

both the rather rare mafic glasses that are formed

The p-XRF size study suggests that this is similar to
in small bodies and rhyolite glasses known as obsid-
desktop precision in most cases (Davis et al. 2011). I ian, as well as vitrophyres (see Weisler and Clague
suspect that the issues of instrumental precision with 1998). In the former case the raw material is so small p-XRF have more to do with user inexperience and
that there are no real formal tools; however, the glass training than the instruments themselves. This issue
was found to be so useful that where present it was
will be rectified over time, and with advances in XRF
used for cutting and scraping tools, and it provides
technology some form of handheld/transportable
an opportunity to explore group interaction and the

XRF will be the norm at some point in the future.

social dimension of volcanic glass use in prehistory.

Perhaps coming from applications in ceramic

Weisler’s study exhibits the longest distance trans-
studies, LA-ICP-MS promises to provide another ana-
port of glass in this volume, so the issues explored
lytical technique that is in essence non-destructive,
here are relevant for anyone dealing with long-
although some museum staff will have to be con-
distance transport.

vinced. The range of elements detected is great, and

The other obsidian provenance studies in this
the most advantageous attribute is the ability to ana-
volume are more “traditional” in a sense. Glascock
lyze very small areas down to the micron (Speakman
and Giesso (chapter 7) present some new perspec-
and Neff 2005). P-XRF will probably not get below
tives on procurement and exchange at Tiwanaku,
about 10-mm sample sizes given the low voltage

Bolivia. Andean scholars have begun to look at
push, but LA-ICP-MS will not be hampered by
obsidian source provenance in some depth in the last
sample size. While the instrument cost is high for
decade, and the archaeological issues explored have

ICP-MS, it is becoming more readily available at uni-
begun to expand. In this study using NAA and XRF,
versities worldwide.

the authors focused on elite production and distribu-

A final note about the Williams et al. study. We
tion of obsidian artifacts and found that while obsid-
talk about sample size constantly in archaeology,
ian was acquired from great distances (i.e., Chivay),
and the authors found that with p-XRF compared
much of the material came to non-elite areas. They
to INAA and LA-ICP-MS, a version of sampling
examine the potential issues of elite versus non-elite became an issue: “This study also shows that a larger
distribution and what that may represent socially,
sample is best to get a representative picture. The reli-similar to a Classic period Hohokam study in the
ability of p-XRF is dependent on the limited num-

1990s (Peterson et al. 1997). Similar to the Hohokam
ber of sources present at the site and their chemical
case, elites and non-elites obtained obsidian through
distinction on a few element pairs.” As distance to
somewhat different networks, signaling differing kin
source increases, the potential for source misassign-
or social networks within society. This is a very 21stment increases. This is the shortcoming of p-XRF
century application of obsidian source provenance
right now. Given that the elemental concentration
studies and can be applied with a number of facets
differences between the INAA and LA-ICP-MS ver-
of current archaeological theory.

sus p-XRF were rather great in some cases, p-XRF

In chapter 8, Doelman et al. focus on a very dif-
will be of more limited utility in regions or time peri-ferent set of issues in the Late Paleolithic of Far East ods where distance to source and source diversity

Russia. The hunter-gatherers in this region expended
are great. We found the same problem with p-XRF
much effort in producing obsidian and basaltic glass
compared to lab EDXRF (energy-dispersive X-ray
microblades, in some cases from distant sources. The
fluorescence) (Nazaroff and Shackley 2009). This
production of these blades is quite time consuming
problem may be resolved as the technology evolves.

and signals both the level of expertise required and an Skipping to Weisler’s chapter 10 on Polynesian
adaptation to small cobble sizes with abundant cor-
glass artifacts, great distance to source has always
tex. This was scheduling at its best, involving obvious

Thoughts on Natural and Manufactured Glass Studies | 207
planning to acquire and transport these valuable raw
region and thus mainly provides comparative data
materials sometimes great distances over their land-
for later and larger studies.

scape. Perhaps just as important here is the deliberate Caroline Jackson’s provenance of Roman
comparison between megascopic source determina-
glasses in chapter 12 is the opposite of the Sub-
tions and PIXE-PIGE (proton-induced X-ray emis-

Saharan African study in that Roman glass has
sion–proton-induced gamma-ray emission) analyses
been studied for many years using many different
to determine the reliability of the macroscopic attri-
techniques. As with so much in Roman society,
bute selection.

Roman glass is known for its compositional homo-

The De Francesco et al. study in chapter 9
geneity. Indeed, analyses of shipwrecks suggest that
discusses a method using non-destructive second-

“chunk” glass was produced at a limited number of
ary X-ray wavelength-dispersive XRF (WDXRF).

Roman glassworks and distributed throughout the

This method, discussed in detail in other places,
empire for final production. Given the evolution of
allows one to use the crystal wavelength XRF non-

Roman glass studies, more specific and regionally
destructively and thereby analyze much larger

oriented problems are possible. Methodologically,
samples (De Francesco et al. 2008). Non-destructive
a number of techniques have been applied to

WDXRF through elemental ratioing was common

Roman glass, most recently isotopic analyses, while
in the 1970s, but did not provide the accuracy neces-
destructive techniques appear to provide the great-
sary when a large number of sources was possible in
est resolution (see chapter 14).

a region or the distances were great (Hughes 1984,

Jackson’s and Henderson’s chapters should be

2010; Shackley 1990). The De Francesco et al. study
read in tandem. Both are dealing with similar issues as here goes beyond these limitations and provides
well as the raw material. A short comment about iso-
greater accuracy when WDXRF is available.

tope analyses is worthwhile. It is quite apparent now
that radiogenic isotopic analyses of artificial glasses 4.3 Artificial glass studies
are increasing in the field and for many good reasons.

Human-made glasses offer specific analytical prob-

While isotopic data on these glasses are extremely
lems not encountered with natural glasses. Obsidian
useful, in general these techniques are destructive—
and other volcanic glasses are produced by nature at
not always possible with museum specimens. I think
very high melt temperatures, and the range of vari-

Henderson is correct that a combination of tech-
ability possible from mantle and crustal raw materials niques will be increasingly necessary in a 21st-century is by definition limited. Humans experiment con-archaeology as the questions we are asking become
stantly in the production of beads and glassware, and
more theoretically sophisticated. Nevertheless, radio-
while many of the issues inherent in natural glasses
genic isotopic studies can provide
are still present with artificial glass, a whole batch of problems arises due to human intervention, as

1. the isotopic characteristics of glass raw
discussed by Beltsios et al. in chapter 13. This is also materials to compare with the glasses made
discussed for the particular problems in Sub-Saharan
from them, thus providing provenance;

Africa in chapter 11 by Dussubieux and Kusimba.

2. evidence for the exploitation of the source

The four papers in this volume dealing with artificial and type of primary glass raw materials;
glasses tackle these problems in various ways.

3. evidence of the import of raw materials and

In chapter 11, the authors employ an LA-ICP-MS
whether they were drawn from the local
study of a small sample for a site in Kenya inhabited
environment;
between the 10th and 18th centuries and conclude

4. evidence for trade and exchange in raw
that the sample was made from a soda-lime glass
and vessel glass within production zones
with some alumina sand. While the sample is small,

(even without archaeological evidence for
it appeared that India or Southeast Asia was the best
production);
candidate for the raw materials. As the authors note,

5. evidence for specialized production centers for
this is nearly the only study of this kind from the
specific vessel forms and/or decorative types.

208 | OBSIDIAN AND GLASS PROVENANCE

As with any new approach to an old problem, the

Cann, J.R., 1983. Petrology of obsidian artefacts. In
protocols will correspondingly change. Henderson

Kempe, D.R.C., Harvey, A.P. (Eds.), The Petrology of and Jackson provide a direction for glass analysis in

Archaeological Artefacts. Clarendon Press, Oxford, the future.

UK, pp. 227–255.

Davis, M.K., Jackson, T.L., Shackley, M.S., Teague, T., 5. Conclusions

Hampel, J.H., 2011. Factors affecting the energy-
dispersive x-ray fluorescence (EDXRF) analysis of

Given the premise I discussed in the beginning,
archaeological obsidian. In Shackley, M.S. (Ed.),

“conclusion” is not the proper term. All these papers

XRay Fluorescence Spectrometry (XRF) in Geoarch
indicate a process. Glass studies have been around
aeology. Springer, New York, pp. 45–64.

archaeology for a very long time, but the way we

De Francesco, A.M., Crisci, G.M., Bocci, M., 2008. Non-are approaching them is changing as rapidly as
destructive analytical method by XRF for determina-
tion of provenance of archaeological obsidians from
the discipline. As I noted earlier, in my program at
the Mediterranean area. A comparison with tradi-

Berkeley, graduate student projects are just as driven tional XRF method. Archaeometry 50 (2), 337–350.

by archaeological science technology as by current

Eerkens, J.W., Ferguson, J.R., Glascock, M.D., Skinner, archaeological theory. We, as archaeological scienC.E., Waechter, S.A., 2007. Reduction strategies and
tists, are providing techniques and technology that
geochemical characterization of lithic assemblages:

these young minds are morphing into ways we never

A comparison of three case studies from Western
conceived. Instead of science’s being the enemy, it is North America. American Antiquity 72, 585–597.

the guiding hand that is in synergistic cooperation

Glascock, M.D., 2011. Comparison and contrast between
with the way we look at the human condition. The

XRF and NAA used for characterization of obsid-
chapters in this volume move us a bit further toward
ian sources in Central Mexico. In Shackley, M.S.

that understanding.

(Ed.), XRay Fluorescence Spectrometry (XRF) in Geoarchaeology. Springer, New York, pp. 161–192.

References

Glascock, M.D., Ferguson, J.R., 2011. Obsidian charac-
terization by elemental analysis: The state of play.

Ambrose, W.R., 1998. Obsidian hydration dating at

Paper presented at the 76th Annual Meeting of the
a recent age obsidian mining site in Papua New

Society for American Archaeology, 30 March–3

Guinea. In Shackley, M.S. (Ed.), Archaeological

April, Sacramento, CA.

Obsidian Studies: Method and Theory. Advances in Goldberg, P., 1988. The archaeologist as viewed by the Archaeological and Museum Science 3. Springer
geologist. Biblical Archaeologist 51, 197–202.

Publishing/Plenum Press, New York, pp. 205–222.

Green, R.C., 1998. A 1990s perspective on method and

Anovitz, L.M., Elam, J.M., Riciputi, L.R., Cole, D.R., theory in archaeological volcanic glass studies. In

1999. The failure of obsidian hydration dating:

Shackley, M.S. (Ed.), Archaeological Volcanic Glass Sources, implications and new directions. Journal of Studies: Method and Theory. Springer Publishing/

Archaeological Science 26, 735–752.

Plenum Press, New York, pp. 223–236.

Anovitz, L.M., Elam, M., Riciputi, L., Cole, D., 2004.

Hughes, R.E., 1984. Obsidian sourcing studies in the Great Isothermal time-series determination of the rate of

Basin: Problems and prospects. In Hughes, R.E. (Ed.),
diffusion of water in Pachuca obsidian. Archaeometry Obsidian Studies in the Great Basin. Con tributions of 46, 301–326.

the University of California Archaeolog ical Research

Anovitz, L.M., Cole, D., Fayek, M., 2008. Mechanisms of Facility 45. UCARF, Berkeley, pp. 1–20.

rhyolitic glass hydration below the glass transition.

Hughes, R.E., 2010. Determining the geologic provenance American Mineralogist 93, 1166–1178.

of tiny obsidian flakes in archaeology using nonde-

Anovitz, L.M., Fayek, M., Cole, D., Carter, T., 2011.

structive EDXRF. American Laboratory 42, 27–31.

Analysis of obsidian hydration: The current state of

Johnson, P.R., 2011. Elemental analysis of fine-grained the art. Paper presented at the 76th Annual Meet ing
basalt sources from the Samoan Island of Tutuila:

of the Society for American Archaeology, 30 March–3

Applications of energy dispersive X-ray fluores-

April, Sacramento, CA.

cence (EDXRF) and instrumental neutron activation

Thoughts on Natural and Manufactured Glass Studies | 209
analysis (INAA) towards an intra-island provenance

Shackley, M.S., 1990. Early hunter-gatherer procurement study. In Shackley, M.S. (Ed.), XRay Fluorescence ranges in the Southwest: Evidence from obsidian

Spec tro metry (XRF) in Geoarchaeology. Springer, geochemistry and lithic technology. Ph.D. disserta-New York, pp. 143–160.

tion, Arizona State University, Tempe.

Joyce, R.A., 2011. Is there a future for XRF in a 21st cen-Shackley, M.S. (Ed.), 1998. Archaeological Obsidian Stud
tury archaeology? In Shackley, M.S. (Ed.), XRay
ies: Method and Theory. Advances in Archaeological Fluorescence Spectrometry (XRF) in Geoarchaeology.

and Museum Science 3. Springer Publishing/Plenum

Springer, New York, pp. 193–202.

Press, New York.

Killick, D., 2008. Archaeological science in the USA and Shackley, M.S., 2005. Obsidian: Geology and Archaeology Britain. In Sullivan, A. (Ed.), Archaeological Concepts in the North American Southwest. University of Ari-for the Study of the Cultural Past. University of Utah zona Press, Tucson.

Press, Salt Lake City, pp. 40–64.

Shackley, M.S., 2008. Archaeological petrology and the Killick, D., Goldberg, P., 2009. A quiet crisis in American archaeometry of lithic materials. Archaeometry 50, archaeology. The SAA Archaeological Record 9 (1), 194–215.

6–10, 40.

Shackley, M.S., 2011a. An introduction to X-ray fluores-Kirch, P.V., 1997. The Lapita Peoples: Ancestors of the Oce
cence spectrometry for archaeologists. In Shackley,
anic World. Blackwell, Oxford.

M.S. (Ed.), XRay Fluorescence Spectrometry (XRF) Liritzis, I., 2006. SIMS-SS, a new obsidian hydration
in Geoarchaeology. Springer, New York, pp. 7–44.

dating method: Analysis and theoretical principles.

Shackley, M.S. (Ed.), 2011b. XRay Fluorescence Spec

Archaeometry 48 (3), 533–547.

trom etry (XRF) in Geoarchaeology. Springer, New York.

Liritzis, I., Zacharias, N., 2011. Portable XRF of a
e XRF o rchaeo-
o-

Speakman, R.J., Neff, H., 2005. Laser Ablation–ICPMS
logical artifacts: Current research, potentials and lim-in Archaeological Research. University of New Mex-itations. In Shackley, M.S. (Ed.), XRay Fluores cence ico Press, Albuquerque.

Spectrometry (XRF) in Geoarchaeology. Springer, Speakman, R.J., Phillips, S.C., Florey, V., Little, N., New York, pp. 109–142.

Iñañez, J.G., 2010. Approaches to micro-XRF anal-

Morgan, L.E., Renne, P.R., 2008. Diachronous dawn of
ysis of obsidian. Paper presented at the 38th Inter-

Africa’s Middle Stone Age: New 40Ar/39Ar ages from
national Symposium on Archaeometry, 10–14 May,
the Ethiopian Rift. Geology 36, 967–970.

Tampa Bay, FL.

Nazaroff, A., Shackley, M.S., 2009. Testing the size dimen-Weisler, M.I., 1990. Sources and sourcing of volcanic
sion limitation of portable XRF instrumentation for
glass in Hawai‘i: Implications for exchange studies.

obsidian provenance. Poster presentation, Geological

Archaeology in Oceania 25, 16–23.

Society of America Annual Meeting, Port land, OR.

Weisler, M.I., 1997. Prehistoric long-distance interaction Peterson, J., Mitchell, D.R., and Shackley, M.S., 1997.

at the margins of Oceania. In: Weisler, M.I. (Ed.),

The social and economic contexts of lithic procure-

Pre historic LongDistance Interaction in Oceania: ment: Obsidian from Classic period Hohokam sites.

An Interdisciplinary Approach. Monograph 21. New American Antiquity 62, 231–259.

Zea
land Archaeological Association, Dunedin,

Pollard, A.M., Bray, P., 2007. A bicycle made for two? The pp. 149–172.

integration of scientific techniques into archaeologi-

Weisler, M.I., Clague, D.A., 1998. Characterization of cal interpretation. Annual Review of Anthropology archaeological volcanic glass from Oceania: The

36, 245–259.

utility of three techniques. In: Shackley, M.S. (Ed.), Rogers, A., Steffen, A., 2011. How in the world does

Archaeological Obsidian Studies: Method and Theory.

obsidian hydration work? Paper presented at the

Advances in Archaeological and Museum Science 3.

76th Annual Meeting of the Society for American

Plenum Press, New York, pp. 103–128.

Archaeo logy, 30 March–3 April, Sacramento, CA.

Contributors

Stanley H. Ambrose: Department of Anthropology,

Michael D. Glascock: Research Reactor Center,

Uni versity of Illinois, Urbana, USA

Uni ver sity of Missouri-Columbia, Columbia,

Wallace Ambrose: Archaeology and Natural

Missouri, USA

History, School of Culture, History and Language,

Julian Henderson: Department of Archaeology,

ANU College of Asia and the Pacific, Australian

Univer sity of Nottingham, Nottingham, UK

National University, Canberra, Australia

Caroline M. Jackson: Department of Archaeology,

Konstantinos G. Beltsios: Department of Materials

Un i ver sity of Sheffield, Sheffield, UK

Sci ence and Engineering, University of Ioannina,

Nikolai Kluyev: Institute of History, Archaeology

Ioannina, Greece
and Ethnography, Russian Academy of Sciences,

Marco Bocci: Department of Earth Sciences,

Vladi vos tok, Russia

University of Calabria, Rende, Italy

Chapurukha M. Kusimba: Department of

Gino Mirocle Crisci: Department of Earth

Anthropology, The Field Museum, Chicago,

Sciences, Uni versity of Calabria, Rende, Italy

Illinois, USA

Trudy Doelman: Department of Archaeology,

Nikolaos Laskaris: Department of Mediterranean

University of Sydney, Sydney, Australia

Stud ies, Laboratory of Archaeometry, University of

Laure Dussubieux: Department of Anthropology,
the Aegean, Rhodes, Greece

The Field Museum, Chicago, Illinois, USA

Ioannis Liritzis: Department of Mediterranean

Vincenzo Francaviglia: Institute for Applied

Studies, Laboratory of Archaeometry, University

Technol o gies to Cultural Heritage–National
of the Aegean, Rhodes, Greece

Council of Research, Rome, Italy

Donna J. Nash: Department of Anthropology,

Anna Maria De Francesco: Department of Earth

University of North Carolina at Greensboro,

Sci ences, University of Calabria, Rende, Italy

Greensboro, North Carolina, USA

Martin Giesso: Department of Anthropology,

Steven W. Novak: College of Nanoscale Science

North eastern Illinois University, Chicago,
and Engineering, State University of New York,

Illinois, USA

Albany, New York, USA

Artemios Oikonomou: Laboratory of

Archaeometry, Ins t itute of Materials Science,

Attiki, Greece

211

212 | CONTRIBUTORS

Vladimir Popov: Petrology of Volcanic

Robin Torrence: Anthropology, Australian

Formations, Far East Geological Institute,

Museum, Sydney, Australia

Vladivostok, Russia

Pavlos Triantafyllidis: 22nd Archaeological

Alexander K. Rogers: Maturango Museum,

Ephorate of Prehistorical and Classical Antiquities,

Ridgecrest, California, USA

Rhodes, Greece

M. Steven Shackley: X-Ray Fluorescence

Marshall Weisler: School of Social Science, The

Laboratory, Uni versity of California-Berkeley,

Univer sity of Queensland, Brisbane, Australia

Berkeley, Califor nia, USA

Patrick Ryan Williams: Department of

Igor Sleptsov: Institute of History, Archaeology

Anthro pology, The Field Museum, Chicago,
and Ethno graphy, Russian Academy of Sciences,

Illinois, USA

Vladivos tok, Russia

Nikolaos Zacharias: Department of History,

Christopher M. Stevenson: Richard Bland College,

Archaeol ogy, and Cultural Resources Management,

The College of William and Mary, Petersburg,

University of Peloponnese, Kalamata, Greece

Virginia, USA

About the Editors

Ioannis Liritzis: Professor of Archaeometry, Direc-Christopher M. Stevenson: Archaeologist, Richard tor (and Founder) of the Laboratory of Archa-Bland College, The College of William and Mary,
eom etry, Depart ment of Mediterranean Studies,

Peters burg, Virginia, USA.

University of the Aegean, Rhodes, Greece.

Current Research Interests: Obsidian hydration

Current Research Interests: Dating by luminescence
dating, hydrothermal experimentation with glass,
and obsidian hydration, analytical techniques in
arch aeol ogy of Polynesia, hunter-gather adaptations, archaeology, archaeoastronomy, geophysical pros-ancient farming practices.

pection and isotopic dating of archaeomaterials

Regions of Interest: Easter Island, Chile, Eastern
during the Holocene.

United States, Europe.

Regions of Interest: Greece, Sardinia, Egypt, Asia

.

Minor, Near East, Bavaria.

213

Index

African archaeological sites: Abeke rock

Early (Earlier) Stone Age, 56, 57, 63–64

Lipari (Liparae), 115–16, 118, 120–21,
shelter, 58; Aduma site complex, 64;
effective hydration temperature (EHT),

123–25, 177; Palmarola, 115–18, 120–21,

Enkapune Ya Muto rock shelter, 62,

46–50, 53–54, 61–62

123–25; Pantelleria, 115–18, 120;

65; FwJj4, 67; Gadeb, 63; Gamble’s

Egypt, 21, 56, 68, 159–63, 166, 170, 180, 187,

Sardinia, 115–16, 118, 120–22,

Cave, 60; Garba IV, 63; Gombore 1B2,

189, 211

124–25, 128

63; HWKE, Olduvai Gorge, 60, 63;
electron probe microanalysis (EPMA), 193

Italian obsidian distributions, 125–26

Isenya, 63; Kaptabuya, 63; Kapthurin,
experimentally hydrated obsidian,

63; Kariandusi, 63–64; Kilombe, 63;

19–20, 27
laser ablation-inductively coupled plasma-

Kisima Farm KFR-AR 1/2, 67; Lake
mass spectrometry (LA-ICP-MS), xvii,

Besaka (FeJx4), 65; Lowasera, 67;
fission track dating, 56, 60, 63
xix, 15, 75–84, 115, 143, 145, 188, 205–7

Lukenya Hill (site GvJm16), 64; Melka

Later Stone Age, 57–62, 65–68

Konture, 60, 63; Muguruk, 64; Mumba
geological provenance, 186

Lee’s equation, 46
rock shelter, 64, 66–67; Naisiusiu,
glass beads, 68, 143, 151, 153, 160, 166–69,

Olduvai Gorge, 66; Nasera rock shel-

189, 207
magnetic sector SIMS instrument, 3, 5–7, 12
ter, 64; Ngamuriak, 62; Norikiushin
glass chemical composition, 143, 150–52,

Mejia Ladera, Peru, 76, 79, 81–82, 84

(GvJh12, Nyuka River 4), 65; Ntumot

158, 167–69, 172–80, 193–94, 195–96
microblade technology, 97–112

(GvJh11, Ntuka River 3), 65–66;
glass corrosion, 76, 145–46, 169

Middle Stone Age, 56–66, 68

Oldorotua, 62; Olorgesailie, 63; Porc
glass furnaces, 151, 158–59, 187–88, 191–97

Monochrome Drawn Bead tradition, 143

Epic Cave, 60, 63–64; Prolonged Drift,
glass production, 157, 159–62, 190–91

Mtwapa, Kenya, 143–45, 150–54

65; Prospect Farm, 61, 64–65; Shum
glass provenance, 152–54, 159–60, 162–63,

Lake rock shelter, 58

180–81, 185–86, 198
natron glass, 160, 163, 166, 169–70, 172,

African Obsidian Source Regions: Ethopia
glass raw materials, 187

174, 176, 177, 179–80, 186–89, 191–92,
and Eritrea, 60; Kenya and Tanzania,
glass unusual raw materials, 175–77

195–96, 199

58–60; West Africa, 58

Greek islands: Gyali, 115–18, 120; Melos,

Neolithic, 40, 56–58, 60–62, 65–68
al-Raqqa, Syria, 152–53, 187, 190, 192–98

40, 115–18, 120, 177; Rhodes, 166–74,
neutron activation analysis (INAA, NAA),
analytical precision and error, 77–79

180–81
xvii–ix, 13, 40, 75–76, 83–84, 86–87,
analytical reference standards, 76, 90

89–93, 115, 117, 132, 188, 205–6
argon isotope dating, 62–63

Hawaiian volcanic glass, 131–32, 137–39

Arrhenius equation, 21, 47
hydration age calculation, 22–24, 39–41
obsidian density, 4, 9, 17

Atomic Force Microscopy (AFM), 3–4,
hydration process, 3, 26–28, 47–48
obsidian initial water, 12, 28

10–12, 19, 28, 30–31, 42–43
hydrogen profile, xviii, 4, 6, 19, 27, 29, 37,
obsidian internal fissure, 21–23, 61

42–43
obsidian sources: Alca, Peru, 79–84, 88;

Basaltic glass sources: Arsenievka, Russia,
hydration rate, 15–16, 19–21, 24, 27, 29,

Arafali, Eritrea, 68; Balchitt, Ethopia,

98, 101; Falefa Valley, Samoa, 133–34;

46–47, 50, 53–54, 60–61

60, 63; Charana, Bolivia, 92–94;

Goat Island, Tutuila, 132; Ilystaya,
hydration rate development, 16–17, 26, 60

Chivay, Peru, 9, 79, 82–84, 86, 88, 90,

Russia, 101–3; Obrivisti, Russia, 98,
hydration rim measurement: digital

92–94; Fantale, Ethopia, 67; Gyali,

103, 106; Poperechnaya, Russia, 98,
microscopy, 16, 18; optical microscopy,

Greece, 115–18, 120; Igwageta, Papua

103, 106; Tafahi Island, Tonga, 132–35;

4, 16–17, 46; photoacoustic, 9–10;

New Guinea, 16–20, 41; Kedong Valley,

Wallis and Futuna Islands, 133–34, 137
resonant nuclear reaction, 4, 18; SIMS,

Kenya, 59, 63; Kone, Ethopia, 63, 65;

4–7, 18, 204

Lipari, Italy, 115–16, 118, 120–21, 123–25;

Cerro Baúl, Peru, 76, 79–84

Little Glass Buttes, Oregon, 76–79;

Cerro Mejia, Peru, 76, 79, 81–82, 84
impacts on hydration rate: composition 16,

Manengouba Mountain, Cameroon,
chaîne opératoire, 185

28; temperature, 16, 46, 48–49, 56–57;

58; Melos, Greece, 115–18, 177; Modjio,
vapor pressure, 16

Ethopia, 60, 64; Mount Arci, Sardinia,
depth profiling, 3, 6, 9, 11, 28
isotopic analysis, 196–98

Italy, 116, 118, 120–21, 125; Mount Bao,
digital hydration rim measurement, 23

Italian archaeological sites, 120–26

Papua New Guinea, 16–17, 19–20,

Dioscurides, 170, 175–76, 178

Italian islands: Corsica, 115–16, 120, 125;

41; Mount Eburu, Keyna, 59, 61, 65,

215

216 | INDEX

67; Mount Hicks, Nevada, 9; Mount

Molokai, Oahu), 130–32, 137–39;

SEM EDS, 15, 166, 169, 181

Suswa, Kenya, 59; Njorowa Gorge,

Marquesas, 136–37, 139; Pitcairn Island

SEM EDX, 17, 20

Kenya, 59; Paektusan, North Korea/

Group (Ducie, Henderson, Oeno),

Shkotovo Plateau, Russia, 98–101, 106–7

China, 106–10, 112; Palmarola, Italy,

136, 139; Samoa (Ata, Goat, Savai’i,

SIMS crater, 3, 4, 6–8, 10–12, 28, 35, 44

115–18, 120–21, 123–25; Pantelleria,

Tafahi, Tutuila, Upolu), 132–34, 138;

SIMS distorted profiles, 42

Italy, 115–18, 120–21; Queen, Nevada,

Society Islands (Mo’orea, Tahiti),

SIMS-SS, xviii, 19, 26–44

9; Quispisisa, Peru, 79–84; Rio Hondo,

135, 138; Tonga (Niuatoputapu, Niue,

SIMS-SS software, 37–39

Columbia, 9; Sierra Pachuca, Hidalgo,

Tongatapu), 134–35, 138; Tuamotus
surface roughness, 3–4, 10–12, 30–31

Mexico, 76–79; Sonachi, Kenya, 59, 65,
and Atoll Archipeligoes (Line Islands,

66; Sopocachi, Bolivia, 92–94; Sora

Mangareva, Tokelau, Tuvalu), 136, 139
territorial organization, 57–58, 67–68,

Sora, Bolivia, 92–94; Suregei, Kenya,
polynomial fitting, 27–29, 32, 35–36

111–12

67; Umleang, Papua New Guinea,
portable XRF (p-XRF), xviii, 75–84, 115,

Thebian glass, 167, 172–73, 181

16–17, 19–20, 22–23; Wekwok, Papua

132, 205–6

Theophrastus, 176–77

New Guinea, 16–17, 20, 41; Zapaleri,
thermal ion mass spectrometry (TIMS),

Argentina, 92–94

Qsar es-Seghir, Morocco, 151–53

193–94
obsidian surface weathering, 16, 21–22, 40,
quadrupole SIMS instrument, 3, 5–8, 12

Tiwanaku, Bolivia, 75, 82–84, 86–88, 90,

56, 61, 204

92–93
radiocarbon dating, 15, 18–19, 21–22, 24, 26,
trachytic glass sources: Pu‘u Wa‘awa‘a,
paleoclimatic change, 50–53

39, 41, 46, 62, 66, 82, 100, 123

Hawai‘i, 131–33, 137

Papua New Guinea, 15–17, 22
regional glass industries: Egyptian, 166;
pitchstone sources: Pitcairn Island, 130–32,

Hellenistic/Greek, 157, 166; Iranian,
volcanic glass definitions, 130

136, 139

192; Islamic, 192; Lebanese, 192;
volcanic glass geology, 130–31
plant ash glass, 150–54, 158–61, 163, 166–70,

Roman, 157–63; Syrian, 192–98
volcanic glass use patterns, 63–68, 82–84,

172, 177, 180, 185–87, 189–92, 194–99

Rhodian glass, 166–67, 170, 171, 173–74,

93–94, 104–10, 125–26, 131–32, 137–38,

Pliny, 158, 167, 170, 175–78, 194

178, 181

205–6
polarized light microscopy (PLM), 30–31,

RimBuster software, 18

42–43

Roman colored glasses, 157, 159–62

Wari culture, Peru, 75, 79, 82–84

Polynesia, 130–39

Roman glass production, 157, 159–62

Polynesian Islands: Austral Islands

X-ray fluorescence (XRF), xvii–xix, 15, 40,

(Ra’ivavae, Rapa, Rurutu, Tubuai),

Salsola jordanicola, 190–91

59–60, 65, 75–84, 87–91, 93, 115–19,

136, 138; Cook Islands (Aitutoki), 135,
sampling before analysis, 75, 89, 120–21,

125–26, 132, 202–3, 205–7

138; Hawaiian Islands (Hawai’i, Kaua’i,

144–45

Document Outline

- Front Cover
- Title Page
- Copyright
- Contents
- Figures and Tables
- Preface
- Editors’ Introduction

- PART I: OBSIDIAN HYDRATION DATING

- 1: Aspects of Secondary Ion Mass Spectrometry (SIMS) Depth Profiling for Obsidian Hydration Dating

- 2: Obsidian Hydration Chronometrics Using SIMS and Optical Methods from 26-year Temperature-controlled Exposures

- 3: The SIMS-SS Obsidian Hydration Dating Method

- 4: Temperature Correction for Obsidian Hydration Dating

- 5: Obsidian Dating and Source Exploitation Studies in Africa: Implications for the Evolution of Human Behavior

- PART II: OBSIDIAN AND GLASS PROVENANCE

- 6: Provenance of Peruvian Wari Obsidian: Comparing INAA, LA-ICP-MS, and Portable XRF

- 7: New Perspectives on Obsidian Procurement and Exchange at Tiwanaku, Bolivia

- 8: Volcanic Glass Procurement and Use in the Late Paleolithic, Central Primorye, Far East Russia

- 9: Obsidian Provenance at Several Italian and Corsican Archaeological Sites Using the Non-destructive X-ray Fluorescence Method

- 10: Polynesian Volcanic Glass: Uses, Sourcing, and Distribution

- 11: Glass Vessels in Sub-Saharan Africa: A Compositional Study of Samples from Mtwapa, Kenya

- 12: On the Provenance of Roman Glasses

- 13: Characterization and Provenance of Archaeological Glass Artifacts from Mainland and Aegean Greece

- 14: The Provenance of Ancient Man-made Glass: Raw Materials and the Use of Chemical and Isotopic Analytical Techniques

- 15: Thoughts on Natural and Manufactured Glass Studies in a 21st-Century Archaeology

- Contributors
- About the Editors
- Index

Table of Contents

- Front Cover
- Title Page
- Copyright
- Contents
- Figures and Tables
- Preface
- Editors’ Introduction

- PART I: OBSIDIAN HYDRATION DATING

- 1: Aspects of Secondary Ion Mass Spectrometry (SIMS) Depth Profiling for Obsidian Hydration Dating

- 2: Obsidian Hydration Chronometrics Using SIMS and Optical Methods from 26-year Temperature-controlled Exposures

- 3: The SIMS-SS Obsidian Hydration Dating Method

- 4: Temperature Correction for Obsidian Hydration Dating

- 5: Obsidian Dating and Source Exploitation Studies in Africa: Implications for the Evolution of Human Behavior

- PART II: OBSIDIAN AND GLASS PROVENANCE

- 6: Provenance of Peruvian Wari Obsidian: Comparing INAA, LA-ICP-MS, and Portable XRF

- 7: New Perspectives on Obsidian Procurement and Exchange at Tiwanaku, Bolivia

- 8: Volcanic Glass Procurement and Use in the Late Paleolithic, Central Primorye, Far East Russia

- 9: Obsidian Provenance at Several Italian and Corsican Archaeological Sites Using the Non-destructive X-ray Fluorescence Method

- 10: Polynesian Volcanic Glass: Uses, Sourcing, and Distribution

- 11: Glass Vessels in Sub-Saharan Africa: A Compositional Study of Samples from Mtwapa, Kenya

- 12: On the Provenance of Roman Glasses

- 13: Characterization and Provenance of Archaeological Glass Artifacts from Mainland and Aegean Greece

- 14: The Provenance of Ancient Man-made Glass: Raw Materials and the Use of Chemical and Isotopic Analytical Techniques

- 15: Thoughts on Natural and Manufactured Glass Studies in a 21st-Century Archaeology

- Contributors
- About the Editors
- Index