IAOS
International Association for Obsidian Studies

Bulletin
ISSN: 2310-5097

Number 62

Winter 2019

CONTENTSInternational Association for Obsidian Studies

News and Information ………………………… 1
Notes from the President……....……….………. 2
Candidate Statements…………………….……...4
Role of Minimal Analytical Nodules in OH…….8
Application of Modern OHD to Old Data Sets…16
Instructions for Authors …..……………………29
About the IAOS………………………………...30
Membership Application ………………………31

President
President-Elect
Secretary-Treasurer
Bulletin Editor
Webmaster

Kyle Freund
Sean Dolan
Matt Boulanger
Carolyn Dillian
Craig Skinner

Web Site: http://www.deschutesmeridian.com/IAOS/

NEWS AND INFORMATIONNEWS AND NOTES
Have news or announcements to share?
Send them to IAOS.Editor@gmail.com forthe next issue of the IAOS Bulletin.

CONSIDER PUBLISHING IN THE
IAOS BULLETIN
The Bulletin is a twice-yearly publication that reaches
a wide audience in the obsidian community. Please
review your research notes and consider submitting anarticle, research update, news, or lab report for
publication in the IAOS Bulletin. Articles andinquiries can be sent to IAOS.Editor@gmail.com
Thank you for your help and support!

IAOS AT THE SAA IN AUSTIN
The annual IAOS business meeting will be held during the SAA conference in Austin, Texas,
on Saturday, April 25, 2020 from 12-1pm. Please see your conference program for meeting
location. All IAOS members are invited to attend.
This year’s meeting will include a vote on changes to the IAOS By-Laws as outlined in the Notes
from the President on the next page. Please attend and participate.
Please watch your email and the IAOS webpage for additional announcements about
IAOS events, meetings, and trips in Austin. If you have items for the meeting agenda, please
send them to Kyle Freund at kylepfreund@gmail.com.

NOTES FROM THE PRESIDENT
Another year has flown by, and this will be
my last introduction in the Bulletin as IAOS
President. There will be a couple of changes tothe IAOS Executive Board next year as new
officers are instated, and I look forward toseeing how they implement their new ideas andvisions. Sean Dolan will take over from me at
the upcoming SAA Annual Meeting in Austin,and IAOS will hold an election for a new
Secretary/Treasurer in the upcoming months;
the candidate statement from Lucas Martindale
Johnson is included below. I would like to be
the first to thank Matt Boulanger for his service
as Secretary/Treasurer since 2015. His
contribution to the organization has been
considerable, and I hope that he continues tostay active in IAOS business.
This summer, the International Obsidian
Conference (IOC) took place in Sárospatak,
Hungary, and I was fortunate enough to attend
this well-organized event. One of the highlightsof the conference was the excursions to all
three of the major obsidian sources in theregion, one of which was (conveniently)
located in a Tokaj wine cellar. I am including aphoto from our trip to the Ukrainian source ofRokosovo, also known as Carpathian 3.
The next IOC meeting will be held at UC
Berkeley in 2021, being organized by Lucas
Martindale Johnson, Nico Tripcevich, andmyself. IOC 2021 will take place immediately
preceding the SAA Annual meeting that year in
San Francisco, and IAOS members will receivea discount for registration. The IOC is an
obvious fit with our members’ interests andexpertise, and I hope that we will be well
represented at the next conference. I also hopethat IAOS can continue to provide logisticaland financial support for this venue moving
forward. Note that the following IOC will be inJapan in 2023, being organized by long-timemember Dr. Akira Ono.
One last issue that the IAOS board has
been discussing relates to our policies on
sexual harassment and misconduct. This is of

critical importance, and we are working to
update our by-laws. We plan to send themembership our proposed changes for review
and potential ratification at least 30 days prior
to our annual business meeting, in compliancewith the procedures outlined in Article 13 of
the IAOS Bylaws, which state:“1. The By‐laws may be amended by a two‐
thirds vote of the members present at a businessmeeting of the Annual Meeting or at a Special
Meeting called in accordance with Article 10,paragraph 3. The By‐laws may also be
amended by mail or email ballot provided thata proposed amendment is approved by two‐
thirds vote of the votes cast.
2. Amendments may be proposed by the
Executive Board or by any ten (10) members of
the IAOS. The proposed amendments shall bemailed or emailed to the members of the IAOS
by the Secretary at least thirty (30) days before
an Annual Meeting or Special Meeting. In thecase of a mail ballot upon an amendment,
members shall address ballots to the Secretaryand place them in the mail and postmarked not
more than thirty (30) days from the date they
were mailed out and postmarked by the
Secretary. An amendment shall go into effectimmediately upon approval unless otherwise
specially provided.”
Don’t forget to renew your IAOS membershipfor 2020.
Happy Holidays!
Kyle Freund, IAOS President
Department of Anthropology
Indian River State College
kfreund@irsc.edu

IAOS Bulletin No. 62, Winter 2019
Pg. 2

IOC 2019 excursion to the Rokosovo obsidian source, Ukraine

Twenty-Five Years on the Cutting Edge of ObsidianStudies: Selected Readings from the IAOS Bulletin
Edited volume available for purchase online!
As part of our celebration of the 25th anniversary of the IAOS,
we published an edited volume highlighting important
contributions from the IAOS Bulletin. Articles were selectedthat trace the history of the IAOS, present new or innovative
methods of analysis, and cover a range of geographic areas andtopics. The volume is now available for sale on the IAOS
website for $10 (plus $4 shipping to U.S. addresses).
http://www.deschutesmeridian.com/IAOS/iaos_publications.html

International addresses, please contact us directly at
IAOS.Editor@gmail.com for shipping information.

IAOS Bulletin No. 62, Winter 2019
Pg. 3

CANDIDATE STATEMENT: IAOS SECRETARY/TREASURER
Please email your vote for the next IAOS President directly to Kyle Freund, kfreund@irsc.edu
Lucas R. M. Johnson, Ph.D., Far Western Anthropological Research Group, Inc.
Personal Background:
My current role at Far Western Anthropological Research Group, Inc. is as a seniorarchaeologist responsible for lithic technological and XRF geochemical analysis. Through thiscompliance and research role I have learned much about indigenous trade economies and crafting
strategies in California and the Great Basin. These two essential research topics are just as complex
as those I studied at Caracol, Belize for my master’s and doctoral research at the University ofCentral Florida and the University of Florida respectively. Before my research at Caracol, little
was known about the chert and obsidian industries practiced there during the ancient Maya period(~ AD 100-950. My dissertation research emphasized the “itinerant” and socially embedded
nature of obsidian through sourcing more than 2,000 artifacts using handheld XRF, analyzing thevaried reduction sequences (i.e., crafting, recording macro-scale use-wear patterns, mapping the
distributional nature of depositional context (both ritualized and quotidian, and understanding themarket and non-market mechanisms for intra-city circulation. During this research I developed
critical networks with scholars at MURR, University of Pennsylvania, University of Central
Florida and others who helped facilitate important aspects for this research. This network included
members of the IAOS. Since then I have submitted two publications to the IAOS on obsidian
imaging techniques and sourcing a unique artifact from Belize.
Statement of Interest:
Although my participation in the IAOS has been as a recent member and contributor,
I understand the breadth of its impact and its part in archaeological research andprofessional networking. My perspective on the role of the Secretary/Treasurer is to
document the IAOS meetings, track its financial transactions, and aid in recruitment. As aco-organizer of the forthcoming 2021 International Obsidian Conference (IOC) in Berkeley,
CA, I aim continue documenting and managing transactions within the IAOS through thisimportant meeting. The role of Secretary/Treasurer fulfils an essential function for any
organization. The next two years will be an important time for the IAOS and its members
because of its participation in the 2021 IOC. This meeting should allow expanded
international participation and enable a climate for recruitment of new members.
Thank you for considering electing me as your next Secretary/Treasurer.

IAOS Bulletin No. 62, Winter 2019
Pg. 4

International Obsidian Conference 2021
1st Circular – IOC 2021
Venue: University of California, Berkeley Campus
Hosted by Far Western Anthropological Research Group, Inc. (FWARG), International
Association of Obsidian Studies (IAOS), and the Archaeological Research Facility (ARF)
April 10-13, 2021
(Preceding the Society for American Archaeology Annual Meeting)

Dear Friends and Colleagues,
We invite you to participate or attend the International Obsidian Conference to be heldon the UC Berkeley Campus between April 10-13, 2021.
As before, our aim is to invite specialists in all aspects of obsidian studies extending
from natural sciences to anthropology. Following prior meetings, we hope that the conference
will be global in scope, yet highlight obsidian studies in the Americas. Because the geologies
of North America are so diverse, we also aim to include semi-glassy fine-grained volcanics(FGV) used by Amerindians in the Great Basin and other regions in the Americas.
Suggestions for conference sessions and themes:
●
●
●
●
●
●

Formation and geology of obsidian and FGV
Sources and their characterization
Analytical and methodological aspects
Archaeological obsidian and FGV by chronological periods
Lithic technology and use wear
Theoretical and cultural concerns

Local Organizing Committee● Lucas R. M. Johnson – Far Western Anthropological Research Group, Inc.
● Lisa Maher - University of California, Berkeley● Nicholas Tripcevich – University of California, Berkeley Archaeological Research
Facility
Scientific Committee● Biró, Katalin - Hungarian National Museum, Budapest, Hungary● Glascock, Michael - University of Missouri, Columbia, MO, USA● Kuzmin, Yaroslav - Institute of Geology & Mineralogy, Siberian Branch of the Russian
Academy of Sciences, Novosibirsk, Russia● Le Bourdonnec, François-Xavier - Université Bordeaux Montaigne, Pessac, France● Lexa, Jaroslav - Earth Sciences Institute of the Slovak Academy of Sciences,
Bratislava, Slovakia● Markó, András - Hungarian National Museum, Budapest, Hungary● Ono, Akira - Meiji University, Tokyo, Japan● Torrence, Robin - Australian Museum, Sydney, Australia● Tykot, Robert - University of South Florida, Tampa, FL, USA● Vianello, Andrea - University of South Florida, Tampa, FL, USA
Partnering Institutions
UC Berkeley
Contact Persons
Kyle Freund, kfreund@irsc.edu
Lucas R. M. Johnson, lucas@farwestern.com
Nicholas (Nico) Tripcevich, tripcevich@berkeley.edu
Technical Information
Duration and Dates: 3 days, April 10-12, 2021
Post Conference Excursion: 1 day, April 13, 2021
Location: UC Berkeley campus (building and room TBA)
Oral Contributions: Oral contributions will be 15 minutes, followed by 5-minute discussion.
Please prepare them in common presentation format (e.g., PPT). Video conference will likely
be a possibility for registered participants, but we would prefer you present in person.
Poster Presentations: The posters should be planned as standing (portrait) orientation andtheir size must not exceed A0 (841 x 1189 mm).
Abstracts: must not exceed 300 words (including author’s details and institutional
affiliation).

Language: The official language of the conference is English.
Deadline for submitting abstracts: December 1, 2020
Deadline for registration: December 1, 2020 for presenters (April 1, 2021 for attendees notpresenting a poster or paper)
Registration Fee:
Full registration
Early-bird registration (before July 1, 2020)
Distance participants$100 USD$80 USD$50 USD

Students and accompanying persons
Early-bird registration (before July 1, 2020)$50 USD$40 USD*A discount will be offered to members of the International Association for Obsidian Studies (IAOS)

Other costs:
Conference dinner$50 USD

Conference excursion:
Visit to Napa Valley winery and obsidian quarry location of Napa Valley obsidian. Price TBA
Accommodations:
UC Berkeley is located in the center of town with many hotel options. Accommodations canalso be found in the Oakland, Emeryville, and San Francisco. Mass transit or ride-shares areeasily accessible no matter where you stay. In you stay in downtown Berkeley, mosteverything is just a short walk away including restaurants and grocery.
Transportation:
UC Berkeley is located in the center of town near to Bay Area Rapid Transit (BART) stops.
The campus can be reach in about 30 minutes from the Oakland International Airport andabout 1.5 hours from the San Francisco airports if by BART. Taxi and rideshare services are
faster but more expensive. Via BART the cost is about $10-12 USD.
Homepage:
http://arf.berkeley.edu/projects/ioc2021
On-line registration will be open from June 1, 2020 at the conference web page.
Please forward this circular to anybody who may be interested.
We look forward to seeing you in 2021!
Lucas, Kyle, and Nico

ROLE OF MINIMUM ANALYTICAL NODULES IN OBSIDIAN HYDRATIONMEASUREMENT: INSIGHT FROM KYU-SHIRATAKI 3 IN HOKKAIDO, JAPANYuichi Nakazawaa, Kyohei Sanob, Yasuo Naoec, Naofumi Sakamotoc, Masami Izuhod,
Hidehiko NomuraeaFaculty of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo 060-8638, Japan;
ynakazawa@med.hokudai.ac.jpbGraduate School of Regional Resource Management, University of Hyogo, Futagadani 128,
Shounji, Toyooka 668-0814, Japanc
Hokkaido Archaeological Operation Center, 685-1, Nishinopporo, Ebetsu, Hokkaido 069-0832,
JapandFaculty of Social Sciences and Humanities, Tokyo Metropolitan University, 1-1, Minami Osawa,
Hachioji City, Tokyo 192-0397, JapaneThin Section Laboratory, Graduate School of Science, Hokkaido University, Kita 10, Nishi 8,
Kita-ku, Sapporo, 066-0810, Japan
Abstract
To obtain reliable dates for multiple assemblages from a single site, measurements of obsidian
hydration rim thicknesses from the flakes of Kyu-Shirataki 3 (northeastern Hokkaido, Japan), a
large prehistoric open-air site, are evaluated using Minimum Analytical Nodules (MAN).
Variations in measured rim thicknesses within the unit of MAN are minimal and less than thoseof samples from artifact assemblages without considering MAN. This suggests MAN is aneffective method to increase the reliability of obsidian hydration dating, particularly for its
application to prehistoric sites that are potentially palimpsests of long-term human exploitation of
obsidian.
Introduction
It is a challenge for archaeologists toprovide reliable dates for artifacts thatencompassmultiple
assemblages
that
potentially experienced various formation
histories. This situation is often brought tomind when needing to analyze large-scale sites
such as quarries and workshops in and aroundobsidian outcrops. Here, we report the
preliminary results of a study on obsidian
hydration dating (OHD) from Kyu-Shirataki 3(northeastern Hokkaido, Japan), an extensive
and deeply-buried open-air site characterized
by dense obsidian scatters. The study site of
Kyu-Shirataki 3, excavated in 2009, ischaracterized by various lithic assemblages
that were techno-typologically distinguishedthrough three years of intensive laboratory
work in 2010–2012 (Hokkaido Archaeological

Operation Center 2015). Based on the lithic
typology of the study region, it is estimated thatthe assemblages are mostly attributed to thelate Upper Paleolithic age (ca. 25,000-11,000
BP). Furthermore, they are hypotheticallyordered in the timeframe between ca. 30,000
and 10,000 BP (Hokkaido Archaeological
Operation Center 2015, Izuho et al. 2012, Naoe
2015). However, the extent to which temporal
differences are present between typologicallydistinctive assemblages that are hypothetical in
local cultural chronologies remains unclear.
Given this situation, we employed OHD to thestudy assemblages to evaluate the temporal
relationships of late Upper Paleolithic
assemblages.

IAOS Bulletin No. 62, Winter 2019
Pg. 8

Materials and Methods
Although establishing dates for multiple
assemblages is a challenge, the Kyu-Shirataki
3 site provides an ideal setting for using OHD.
Kyu-Shirataki 3 is located on the western riverterrace along the Yubetsu River, which flows
from the high mountain range (1,500–1,800 masl.) known as the Daisetsu Mountains(Daisetsuzan-kei) to the Sea of Okhotsk innortheastern Hokkaido (Figure 1). In 2009,

Figure 1. Location of the KyuShirataki 3 site in northeastern
Hokkaido (A), and locations ofsampling units 1 and 2 within the
distribution of lithic scatters andfeatures of the Kyu-Shirataki 3 site
(B). The map of B is from Hokkaido
Archaeological Operation Center(2015).

IAOS Bulletin No. 62, Winter 2019
Pg. 9

Figure 1. Location of the KyuShirataki 3 site in northeastern
Hokkaido (A), and locations ofsampling units 1 and 2 within the
distribution of lithic scatters andfeatures of the Kyu-Shirataki 3 site
(B). The map of B is from Hokkaido
Archaeological Operation Center(2015).

Table 1. Summary of the measurements of hydration rim thicknesses (μm) (means, standard deviations,and coefficient variations) shown by Minimum Analytical Nodules (MAN) from Kyu-Shirataki 3.

archaeologists of the Hokkaido Archaeological
Operation Center conducted a salvage
excavation for compliance with cultural
resource laws in Japan, yielding 147,000
obsidian artifacts (Hokkaido Archaeological
Operation Center 2015). Recovering this large
number of obsidian artifacts is not unusual in
the upper stream of the Yubetsu River, because
large obsidian outcrops are located in the
Akaishi Mountain just 5 km north of the river.
Approximately 100 open-air sites are clusteredin the upper stream of the Yubetsu River(named the Shirataki district after the local
village of Shirataki). All of these sites have alarge number of obsidian artifacts left by theintensive prehistoric human exploitation of
obsidian. Based on the lack of Jomon pottery
from most of these clustered sites, 90% were
dominated by human activities during the Late
Glacial to early Holocene periods (ca. 25,000 –10,000 BP), culturally comparable to the Upper
Paleolithic and Incipient Jomon eras.

Taking advantage of the regional
abundance of prehistoric obsidian, we obtained
samples for OHD from study units B25/26(Sampling unit 1 measuring 4 by 8 m) andCD25 (Sampling unit 2 measuring 4 by 8 m) at
the study site, namely Kyu-Shirataki 3 (Figure
1, Table 1), because these units have groups ofartifacts with different temporal periods basedon technological and typological criteria(Hokkaido Archaeological Operation Center
2015, Naoe 2014).
OHD is a dating method using thehydration rim developed over time since theobsidian surface was exposed at the time ofknapping. Because obsidian was used to makean artifact, OHD has the advantage over othermethods (e.g., radiocarbon dating, opticallystimulated luminescent dating) of a time lag
betweennon-artifact
formation(e.g.,
generation of charcoal, accumulation of
sediment) and obsidian artifact deposition.
In addition, obsidian artifacts can be sorted
into analytical units known as the “minimum
IAOS Bulletin No. 62, Winter 2019
Pg. 10Figure 2. The schematic relationshipsof excavated artifacts, typologicalgroups (assemblages), analyticalnodules, refitted specimens, and unrefitted specimens from which OHD
samples were taken.

analytical nodule” (MAN) based on visualcharacteristics (e.g., color, texture) (Larson andKornfeld 1997: 4). Because Japanese
Paleolithic archaeologists have routinely
employed artifact sorting using analytical units
comparable to MAN, along with lithicrefitting, analysis since the 1970’s (e.g., Anbiru
1992, see Bleed 2002, Takakura 2011),
obsidian artifacts from the Kyu-Shirataki 3 sitewere also sorted into numerous MANs, themajority of which have artifacts that refit.
To make thin sections to observe hydration
rims, we took samples of obsidian flakes that
do not refit, but are sorted into an identical
MAN (Figure 2). To evaluate the hydration rim
thicknesses, we chose six MANs from whichappropriate samples were collected (Table 1).
Based on the tool typology, the six MANs fromwhich samples for the OHD were taken are
attributable to four techno-typological groupsof assemblages consisting of groups of small
boat-shaped tools, Hirosato-type microblade
cores, bifacial points associated with Hirosatotype microblade cores, and stemmed points.
For the purpose of comparison, samples from
Shirataki Group I, characterized by small

amorphous flakes, were collected without
controlling MAN.
All thin sections were made by the lastauthor using the facility at the Thin Section
Laboratory of the Graduate School of Scienceat Hokkaido University. The obsidian
hydration rim was observed under a polarized
light microscope (MT9300, Meiji Techno Co.,
LTD.) at a magnification of 400–500×.
Following the standard recording system(Nakazawa 2015, Origer 1989), the thicknessesof the hydration rims were taken by threemeasurements on the exterior and interior
surfaces of a single obsidian sample in μm
using a computer-assisted measuring device(Art Measure, Artray Inc.). To nullify interobserver error, only the first author took themeasurements. The fifth author measured thegeochemistry of the sampled obsidian using a
portable ED-XRF, following the method of
Izuho et al. (2017).
Results
Table 1 summarizes all measured
thicknesses. The measured rim thicknesses
among the MAN have small deviations andcoefficient of variations (CV), mostly within
IAOS Bulletin No. 62, Winter 2019
Pg. 11

Figure 3. Illustrations of refitted bifacial-thinning flakes of Minimum Analytical Nodules (MAN) No.
33 and No. 35.

the range of 0.1–0.3 and less than 0.06,
respectively. The largest set of deviations andCV was observed for Shirataki Group I, which
consists of samples without regard to MAN.
While measurement errors are minimized
within the unit of MAN, differences inhydration rim thicknesses in the sameassemblage were observed. In the group ofstemmed-point assemblages, MAN #33 and#35 have significant differences in the meansof the hydration thicknesses: the mean
thickness for MAN #33 is 3.57 μm, and that of
MAN #35 is 4.42 μm, a difference of 0.9 μm.
This is 10 times larger than the difference
between MAN #46 and #52 (i.e., 0.09 μm).
Discussion
The small deviations in the observed
measurements of hydration rim thicknesses
suggest that choosing samples from MAN
gives reliable measurements for OHD.
However, the difference in mean rim
thicknesses between two MANs (#33 and #35)
in the stemmed point assemblage needs
explanation. Because these two MANs arederived from the same geochemical group of

obsidian sources (Akaishiyama), the hydration
rates likely differed even in nodules from thesame source.
Differences in hydration rates necessarily
relate to differential rates of water diffusion,
because hydration is the process of water
diffusion into the glass. Besides ambient
temperature (Ambrose 1976, Friedman andSmith 1960), rate of water diffusion into
obsidian glass is affected by endogenous
factors, notably obsidian geochemistry(Friedman and Long 1976, Kimberlin 1976,
Suzuki 1973) and intrinsic water content of
obsidian (Rogers 2008, Steffen 2005,
Stevenson et al. 1993, Stevenson et al. 2019).
In particular, systematic studies of water
diffusion in silicate melts and glasses havesuggested that water diffusion increases withincreasing water content, and molecular water(H2Om) reacts with the silicate structure ofglass (e.g., Behrens and Zang 2009, Schmidt etal. 2013, Zhang et al. 1991). According to Ni
and Zhang (2018), the molecular water (H2Om)
increases exponentially with water content, butdiffusivity of hydroxyl groups (OH) is
independent of water content at high
IAOS Bulletin No. 62, Winter 2019
Pg. 12

temperatures (403－1629 ). Mechanistic
relationships between water diffusion andwater content have been modeled based on
experimental studies in high pressure and hightemperature conditions (>400 ), whereas themechanism of water diffusion in low
temperature conditions (<100 ), in which
obsidian hydration normally occurs, is still
unclear (but see Yokoyama et al. 2008).
Given the complex processes of water
diffusion in obsidian, we present three potential
factors to explain the difference in rim
thicknesses between analytical nodules
typologically classified into the same group.
First, the difference simply shows the time theartifacts were manufactured. MAN #33 and#35 are both bifacial-thinning flakes (Figure 3).
Most of these flakes are refitted to shapephantom bifaces, implying that manufactured
bifaces were transported from the site. Because
the precise shapes of the bifaces, whether they
have stems or not, are undetermined based on
the refitted bifacial-thinning flakes of MAN#33 and #35, either of these bifaces is indeed
from an older assemblage than the terminal
Pleistocene stemmed-point assemblage (e.g.,
Naoe 2014). Second, the rim thicknesses
between the two nodules validly reflect the
duration of site occupation. Since the site was
occupied multiple times over an extensive
duration, likely for thousands of years withoutchanging tool morphologies, the remaining
artifacts differ greatly in age. This is the effectof the palimpsest of human activities (e.g.,
Nakazawa et al. 2009, Stern 1993, Straus
1979), and large quarries are generally
expected to demonstrate this situation. Third,
the difference in rim thicknesses is the effect of
the intrinsic water content of obsidian. Since
the geochemically identified obsidian sourcefor MAN #33 and #35 is identical (Akaishi
Mountain) and the measured samples wereburied under the same conditions and same
chronological period, the difference in rim
thicknesses may be explained by intrinsic watercontent. The slight difference in water content

between the nodules may have affected thehydration rates, resulting in the difference in
rim thicknesses.
Conclusion
An implication of the results of this study
is that sampling obsidian while taking into
account MAN will lead reliable measurementsof obsidian hydration rim thicknesses, which
will enable a good estimation of hydration
dates. Specifically, employing MAN is also
effective in studying palimpsest sites
potentially created by long-term humanoccupation. Archaeologists are struggling tounderstand site formation processes andestablish a temporal order of technotypologically distinguished stone tool
assemblages. Since this is the preliminary
report, we will continue to build a data set toevaluate the role of OHD in identifying
patterns of prehistoric exploitation of obsidian.
Acknowledgements
This paper is based on a presentation in the
symposium “An advancement of obsidianstudies in the Old and New Worlds” held at the84th annual meeting of the Society for
American Archaeology in Albuquerque, New
Mexico in 2019. We thank IAOS for
supporting the symposium, Phyllis Johnson forher enthusiasm and consistency in organizing
the session, and Robert Tykot for serving as thediscussant. Ana Steffen and Kyle Freund also
provided support to enable the session. In thesampling of obsidian artifacts at the Shirataki
GeoPark in Engaru Town, we thank Yoshifumi
Matsumura and Naoto Seshimo for theirgenerous help.
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Pg. 13

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Obsidian Flakes Produced by Ishi During
the Historic Period. In Contributions of
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edited by Richard E. Hughes and MarkBasgall, pp. 69-77. ArchaeologicalResearch Facility, Department of
IAOS Bulletin No. 62, Winter 2019
Pg. 14

Anthropology, University of California,
Berkeley.
Rogers, A.K. (2008) Obsidian Hydration
Dating: Accuracy and Resolution
Limitations Imposed by Intrinsic Water
Variability. Journal of Archaeological
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Schmidt, B.C., N. Blum-Oeste, and J.
Flagmeier (2013) Water Diffusion in
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Cosmochimica Acta 107: 220-230.
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Investigating the Interaction of Heat,
Hydration, and Glass Geochemistry. PhD
dissertation, Department of
Anthropology, The University of New
Mexico, Albuquerque.
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Pleistocene Archaeological Record.
Current Anthropology 34: 201-225.
Stevenson, C.M., E. Knauss, J.J. Mazer, andJ.K. Bates (1993) Homogeneity of Water
Content in Obsidian from the Coso
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Hydration Dating. Geoarchaeology 8:
371-384.

Suzuki, M. (1973) Chronology of Prehistoric
Human Activity in Kanto, Japan, Part I:
Framework for Reconstructing
Prehistoric Human Activity in Obsidian.
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Tokyo Section V Anthropology IV-1:
241–317.
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Sequence Among the Microblade
Assemblages: A View from the
Okushirataki-1 Site, Hokkaido, Northern
Japan. Asian Perspectives 49(2): 332347.
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Nakashima (2008) Hydration of Rhyolitic
Glass During Weathering as
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117-125.
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Glasses. Geochimica et Cosmochimica
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Stevenson, Christopher M., Alexander K.
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IAOS Bulletin No. 62, Winter 2019
Pg. 15APPLICATION OF MODERN OBSIDIAN HYDRATION DATING (OHD) METHODSTO OLD DATA SETS: A CASE STUDY BASED ON DATA FROM THE INDIAN HILLSROCKSHELTER (CCA-SDI-2537), ANZA-BORREGO STATE PARK, CALIFORNIA
Alexander K. Rogers1 and Robert M. Yohe II2
12

Maturango Museum, Ridgecrest, California, USA
California State University, Bakersfield, California, USA

Abstract
This paper describes an obsidian hydration analysis for Indian Hills Rockshelter (CA-SDI2537) in Anza-Borrego State Park, which was excavated in 1984 - 1987. The data set is from a
PhD dissertation from 1992. The assemblage included significant quantities of obsidian, but
unfortunately, the state of the OHD art at the time did not permit a cogent OHD analysis. Advancesin the last decade now make this possible, but the question remains as to whether application ofnewer mathematical methods to an old (and previously intractable) data set can provide useful
results. In this case study we apply modern methods to the obsidian specimens from Indian Hills
Rockshelter, focusing on those which were sourced to Obsidian Butte. The age computations are
based on modeling the hydration process by temperature-dependent diffusion theory, using a flowspecific hydration rate and with corrections for local temperature, artifact burial depth, and site
formation processes. Ages are computed for each class of artifact: preforms, projectile points,
bifaces, and flakes; ages thus determined are compared with radiocarbon data. The ages
determined for temporally-sensitive projectile points are as expected for those morphologicaltypes, which suggests the temperature parameters for the site are valid, as is the hydration rate for
Obsidian Butte. We find the site experienced a sequence of three occupation or use episodes: 6000
– 5000 BP, 3800 – 3800 BP, and less than 1000 BP, all of which agree reasonably well withradiocarbon ages. This analysis shows the potential of applying modern methods to previouslyintractable data sets.
Introduction
This study describes an obsidian hydration
dating (OHD) analysis for Indian Hills
Rockshelter (CA-SDI-2537) in Anza-Borrego
State Park. The data set is from the Ph.D.
dissertation of Alison M. MacDonald, who
excavated the site in 1984-1987 for the
UniversityofCalifornia,
Riverside(MacDonald 1992). A considerable quantity ofobsidian was recovered, the majority from
Obsidian Butte near ancient Lake Cahuilla.
However, the state of the art in OHD was not
sufficiently advanced at the time to do a cogent
OHD analysis. Advances in the physics,
chemistry, and mathematics of OHD since2007 now permit such an analysis. The current
age computations are based on modeling thehydration process by temperature-dependent
diffusion theory, using flow-specific hydration
rates and with corrections for local
temperature, artifact burial depth, and site
formation processes.
This analysis focuses only on the specimens
which were sourced to Obsidian Butte. A set oftemperature parameters for the site isestablished based on meteorological data andon known properties of rockshelters; since
specimens were collected both inside andoutside the shelter, the temperature parameters
take this into account. A hydration rate for
Obsidian Butte was derived from obsidianradiocarbon data at the shelter. Ages werecomputed for each class of artifact: preforms,
projectile points, bifaces, and flakes. Ages
IAOS Bulletin No. 62, Winter 2019
Pg. 16

derived from OHD were compared withradiocarbon, and with the expected ages fordiagnostic artifacts.
Obsidian Butte is an outcrop of rhyolitic
lava, which is part of the Salton Buttes
formation. Geochronologic studies have shownthat the buttes erupted in late Holocene times(Schmitt et al. 2013, Wright et al. 2015).
Recently published research, based on infraredstimulated luminescence dating of feldspar
from a geothermal exploration well havedetermined an age of 490 ± 230 BC, 1-sigma,
or approximately 2500 cal BP (Schmitt et al.
2019). Prior to that time the obsidian source did
not exist.
A major caveat is that the site has beenheavily disturbed over the years, both bynatural processes and by looters, which places
a limit on what can be determined.
Obsidian Hydration
Hydration of obsidian is known as adiffusion-reaction process (Doremus 1994,
2000, 2002). The basis of chronometricanalysis using obsidian hydration is theequationt = r2/k(1)

where t is age in calendar years, r is rim
thickness in microns, and k is the hydration
rate. Although other equations have been
proposed (e.g., Basgall 1991, Pearson 1994),
equation 1 is the only form with boththeoretical (Ebert et al. 1991, Doremus 2002)

and laboratory (Doremus 1994; Stevenson etal. 1998, 2000) support.
The hydration rate is affected by fiveparameters:
ground-waterchemistry(Morgenstein et al. 1999), obsidian anhydrous
chemistry (Friedman et al. 1966), obsidian
intrinsic water content (Zhang 2008, Zhang etal. 1991, Zhang and Behrens 2000), humidity(Mazer et al. 1991); and temperature (Rogers
2007). Ground-water chemistry is only aproblem in cases where potassium content isvery high, as in some desert playas, otherwise
it can be ignored. Obsidian anhydrous
chemistry is controlled by sourcing theobsidian. Intrinsic water concentration can vary
within an obsidian source (Stevenson et al.
1993), and can affect hydration rate
significantly (Zhang 2008, Zhang et al. 1991,
Zhang and Behrens 2000). There are noarchaeologically appropriate techniques formeasuring intrinsic water at present, so its
effects must be controlled statistically bysample size. Humidity is a small effect which
can generally be ignored.
It is now known that temperature is the
major environmental effect which needs to becontrolled for in performing an OHD analysis,
and techniques for doing so have beendeveloped and published (Rogers 2007, 2012).
Effective hydration temperature (EHT) is
defined as a constant temperature which yields
the same hydration results as the actual timevarying temperature over the same period oftime. The exact solution for EHT requires
integration of the temperature-dependent

Table 1. Temperature data.
IAOS Bulletin No. 62, Winter 2019
Pg. 17

hydration rate over a time span in which thetemperature varies diurnally and annually
about an annual mean temperature (Rogers
2007, 2018). The temperature is modeled as thesum of a mean temperature and two sinusoids,
one with 24-hour period and the other with a
12-month period. The amplitudes of the mean
and the two sinusoids were estimated frommeteorological records downloaded from theWestern Regional Climate Center website.
Table 1 summarizes the temperature data for
Borrego Desert Park, Station 040983, for theperiod July 1, 1942 – June 10, 2016.
The presence of a rockshelter also affects
the magnitude of the temperature variation
terms (although it has no effect on annual mean
temperature). Measurements at Ray Cave (CAINY-444) in the Coso Range of eastern
California showed that the annual variation
inside the cave is approximately 75% of thevariation outside the cave; further, publisheddata show that the mean diurnal variation
seldom exceeds 5C (Curran-Everett et al.
1991: 113). The surface EHT is computed fromthe equation

correction, on the average, gives a better age
estimate.
Burial depth is often a function of site
formation processes, such that an artifact isdiscarded on the surface and is gradually
covered with soil over time. Equally, a buried
artifact may be exposed by erosion ordeliberately recovered and reused or
repurposed. Thus, the depth at which theartifact was recovered archaeologically is may
not be characteristic of its entire life. To
account for this uncertainty, the computer code
assumes the artifact was buried at the recovery
depth for half its life, and on the surface theother half, which affects the uncertainty in age.
Finally, EHT should in principle also beaffected by paleotemperature shifts (West et al.
2007), however analysis shows the effect in thenorth temperate zone is negligible for ages lessthan about 13000 cal BP, so they are notincluded here (Rogers 2015a).
Once EHT has been computed, themeasured rim thickness is multiplied by a rim
correction factor (RCF) to adjust the rims to becomparable to conditions at a reference site:

EHT = Ta + 0.0062*(Va2 + Vd2)

RCF = exp{[(E/EHT) - (E/EHTr)]/2}

(2)

(4)

From these data the temperature parameters forthe site were computed (Table 2).
For buried artifacts, Va and Vd represent thetemperature variations at the artifact burial
depth, which are related to surface conditions
bywhere EHTr is effective hydration temperature
for the hydration rate (20C here) and E is theactivation energy of the obsidian. The EHTcorrected rim value rc is thenVa = Va0exp(-0.44z)

There are always errors, or uncertainties, inthe parameters used for age computation,
which in turn lead to errors in the computed
age. The primary error sources are: obsidian
rim measurement, errors in the hydration rateascribed to a geochemical source (Rogers
2010), intra-source rate variability due touncontrolled intrinsic water in the obsidian(Ambrose and Stevenson 2004; Rogers 2008;
Stevenson et al. 1993, 2000; Zhang 2008;
Zhang et al. 1991; Zhang and Behrens 2000),

(3a)

and
Vd = Vd0exp(-8.5z)(3b)where Va0 and Vd0 represent nominal surface
conditions and z is burial depth in meters(Carslaw and Jaeger 1959:81). Depth
correction for EHT is desirable, even in thepresence of site turbation, because the depthrc = RCF  r(5)

IAOS Bulletin No. 62, Winter 2019
Pg. 18

Table 2. SDI-2537 Temperature parameters.

errors in reconstructing the temperature history(Rogers 2007, 2012), and association errors
caused by site formation processes (Schiffer
1987). The effects of these errors have been
examined in detail, with the analysis is
documented in Rogers 2010.
Sample standard deviation is generally not agood estimate of age accuracy because
obsidian sample sizes are generally relatively
small due to cost constraints, while theuncertainty sources introduce at least fivedegrees of freedom in the errors. The optimal
strategy for estimating age accuracy is to use apriori information about the individual error
sources, and infer the accuracy of the age
estimate. With this method, the coefficient ofvariation of the age estimate, CVt, can beshown to be
CVt2=4[(σr/r)2+(0.06σEHT)2+(CVks/2)2+CVke2] (6)where the variables are defined as follows: σr isthe standard deviation of the hydration rim
measurement, and is ~0.1µ; r is the mean
hydration rim; σEHT is the uncertainty in EHT
post-correction, and is ~1.0C; CVke is thecoefficient of variation of the hydration rateascribed to the obsidian source, and is typically~0.05; and CVks is the coefficient of variationof the intra-source rate variations, which aresource-specific.
Once age t is computed from equation (1)and CVt is computed from equation (6), thestandard deviation of the uncertainty in the age
estimate isσt = CVt × t(7)

This is the accuracy figure quoted in thecomputer program output in Tables 3 - 5.
A hydration rate for Obsidian Butte wasdeveloped from the data at SDI-2537, based on
obsidian-radiocarbon
association.
Theradiocarbon data point is UCR-1927D, on bone
collagen at a level of 48-57 inches, with an ageof 4070  100 rcybp; the median calibrated age
is 4676 cyb2k (= cal BP + 50). The obsidian
specimen chosen for association was Cat. No.
C4-259, from the 45-48 inch level; thehydration rim is 8.4. The resulting rate is
8.42/4.676 = 15.09 2/1000 years at an EHT of
24.45C inside the rockshelter.
Age computation is based on a standard
EHT of 20C, so it is necessary to modify therate to this temperature by multiplying it by acorrection factor:
Correction factor=exp[(E/EHT)-(E/EHTr)](8)

Most computations of EHT corrections employ
an approximate value for the activation energy
E of 10000K (e.g. Rogers 2007, 2012), a value
derived from Friedman and Long (1976). The
accuracy is improved, however, if a value
specific to the obsidian source is used. Thisvalue is a function of the intrinsic water content
of the obsidian, but not of temperature. The
hydration rate at archaeological temperatures
has been shown to be related to temperature
and water content by the equation
k=exp(37.76–2.289*w–10433/T+1023*w/T)(9)

where k is rate in 2/1000 yrs, w is total watercontent in wt%, and T is temperature in K
IAOS Bulletin No. 62, Winter 2019
Pg. 19

Table 3. Obsidian Butte Cottonwood Triangular Points, inside Rockshelter.

(Rogers 2015b). Knowing k and T, w can becomputed, and activation energy is thenE = 10433 – 1023*w(10)

For Obsidian Butte obsidian, w = 0.30 wt%,
and E = 10402K. Using this value in equation(8) yields a hydration rate of 9.09 2/1000 years
at an EHT of 20C. This value was used in theage computations.
Analysis of Obsidian Hydration Ages
Projectile points:
A total of 8 Cottonwood Triangular points
was recovered from inside the rockshelter(Table 3). Remarkably, all fall within the

expected range of ages for this point type, withno outliers (Justice 2002). The mean age is 401
cyb2k, standard deviation 211 years, CV =0.53, and N = 8. Probable error of the mean is
75 years.
A single Cottonwood Triangular point was
found on the surface outside the rockshelter(Cat. No. S84-7). Its age is 346 cyb2k, with astandard deviation of 79 years.
Three Desert Side-Notched points wererecovered from inside the shelter. All fallwithin the expected age range, with a mean ageof 145 cyb2k, a standard deviation of 97 years,
and a CV of 0.67.
Four Dos Cabezas Serrated points were
found inside the shelter. The mean age is 446

Figure 1. OHD ages on Obsidian Butte glass from CA-SDI-2537, showing points excluded
from summary statistics.
IAOS Bulletin No. 62, Winter 2019
Pg. 20Table 4. Obsidian Butte flakes from inside the shelter.

cyb2k with a standard deviation of 174 years,
CV = 0.39. The probable error of the mean is
87 years. These ages do not conform to
expectations, and are discussed further below.

197 years and a probable error of the mean of
88 years; CV = 0.47. Assuming these are
preforms for Desert Series points, the ages
again fall in the correct region.

Projectile Point Preforms:
Five projectile point preforms wererecovered from inside the shelter. The mean
age is 422 cyb2k, with a standard deviation of

Bifaces:A single biface was recovered (Cat. No.
B4-99), with an age of 221  54 cyb2k.
IAOS Bulletin No. 62, Winter 2019
Pg. 21

Figure 2. OHD ages on Obsidian Butte material from CA-SDI-2537, showing two plateaus
indicating sustained site use.

Projectile Point Blank:
A single blank was recovered from inside
the shelter, with an age of 572  131 cyb2k.
Flakes:Obsidian Butte flakes recovered frominside the shelter are listed in Table 4. Figure 1

shows a plot of the ages vs. catalog numbers(Cat. Nos.), and clearly shows that the five data
points marked "Exclude" in Table 4 areanomalous. They may reflect reuse of very oldtoolstone, or they may have been read on ageologic surface. They are not included in thestatistics. The age statistics for flakes from

Figure 3. Obsidian Butte OHD ages for CA-SDI-2537 vs. depth, showing effects of extreme
turbation. The best fit line has no statistical significance.
IAOS Bulletin No. 62, Winter 2019
Pg. 22

Table 5. Obsidian Butte flakes from outside the shelter, column sample.

inside the shelter are: mean age = 498 cyb2k,
standard deviation = 309 years, probable errorof the mean = 50 years, and CV = 0.62 (N =38).
Obsidian Butte flakes recovered fromoutside the shelter are listed in Table 5. Figure
2 shows a plot of ages, from which it appears
there were two occupation stages: an early one(five data points) around 5000 cyb2k, and alater one around 450 cyb2k (15 data points).
Two data points are transitional and are
excluded from the statistics. For the early use
period the statistics are: mean age 5077 cyb2k,
standard deviation 1217 years, probable errorof the mean 54 years, and CV =0.24 (N = 5).
For the later use period the mean is 456 cyb2k,
standard deviation 311 years, probable error of
the mean is 80 years, and CV = 0.68 (N = 15).
Table 6 shows the flakes collected on thesurface outside the shelter. One data point, Cat.
No. S84-16, is anomalous and is excluded fromthe statistics. Mean age is 439 cyb2k, standard
deviation is 204 years, probable error of themean is 46 years, and CV is 0.47 (N = 20).

Chronological Narrative
Figure 3 shows there is no consistentvariation of OHD age with depth, confirming
the impression of extreme turbation at the site.
Figure 4 shows the plot for the radiocarbon
dates at SDI-2537 (MacDonald 1992: 102,
Table 5, calibrated and converted to cyb2k).
Dates are plotted in ascending order from left
to right, and if site use had been uniform, theplot would be a straight line. Periods of intenseuse, evidenced by many dates, tend to appear
as plateaus, while intervals of sparse use arerepresented by fewer dates and a steeper slope.
Examination of Figure 4 shows relatively
intense use between 5000 - 4000 cyb2k,
between 3000 - 2500 cyb2k, and less than 1000
cyb2k.
For comparison, Figure 5 plots thecorresponding OHD ages from Tables 3, 4, and5 above. The earliest use period is slightly
older, between 6000 - 5000 cyb2k and the
middle use period is 4800 - 3800 cyb2k. The
youngest use period is again less than 1000
cyb2k.

IAOS Bulletin No. 62, Winter 2019
Pg. 23

Figure 4. Use-density plot for dates derived from radiocarbon at CA=SDI-2537, showing plateaus
indicating periods of sustained use.

Table 7 presents a statistical summary of
the radiocarbon and OHD ages for these threeuse periods. It can be seen that, although there
is an offset in ages, it is not statisticallysignificant by t-test.
The slight discrepancy between OHD andradiocarbon dates can be explained byconsidering what is being measured.
Radiocarbon
dates
represent
physicaloccupation evidence, such as hearths, while
OHD dates represent use of toolstone. If thetoolstone is being recycled, as would be thecase for an exotic obsidian, some of the

Figure 5. Use-density plot for dates derived from OHD of Obsidian Butte obsidian at CA-SDI2537, showing plateaus indicating periods of sustained use.
IAOS Bulletin No. 62, Winter 2019
Pg. 24

Table 6. Obsidian Butte flakes from outside the shelter, surface collected.

hydration ages may represent earlier collection
events.
In addition, the hydration rate is based ona single data point and clearly needs refinementwith further data. It is probably close to theright value, because the ages for the
Cottonwood Triangular and Desert SideNotched points are in the expected range, but if
it is slightly too large it would cause the offset
in ages.
The ages of the Dos Cabezas Serrated(DCS) points are an issue as well. This pointtype is not mentioned in Justice (2002), but islisted on www.projectilepoints.net, whichstates the type was defined by Wilkie and
MacDonald, who assigned the age to 1600 800 cal BP. No references are given, so we
assume the ages are based on MacDonald's
dissertation on CA-SDI-2537 (MacDonald

1992). MacDonald (1992:181ff) describes thepoints and their provenience, but does notdiscuss the age attribution. The points wererecovered from moderate depths, up to
approximately 50 cm below the surface, andFigure 6 shows that the radiocarbon age for that
depth is indeed in the 1600 – 800 BP range.
However, Figure 3 shows the severe degree of
turbation that has affected the obsidian
specimens, so that depth is not a good indicatorof age for them. (Of course, it was not possible
to compute the data plotted in Figure 3 in the
1980s.) Further, the ages determined by OHD
ages are younger, 446 ± 174 cyb2k. Given thesevere turbation that obviously occurred, it islikely the appropriate age for the DCS type isthat computed by OHD.

Table 7. Radiocarbon and OHD age statistics; all ages are in cyb2k

IAOS Bulletin No. 62, Winter 2019
Pg. 25

Figure 6. Ages derived fromradiocarbon at CA-SDI-2537 vs.
depth. Data points are from hearthfeatures only. Despite turbation theages show reasonable consistency.

Conclusions
In summary, this analysis shows the IndianHills Rockshelter site experienced a sequenceof three occupation or use episodes, for which
there is good agreement between radiocarbonbased ages and OHD ages. The ages
determined for temporally-sensitive projectile
points are as expected, which suggests thetemperature parameters for the site are valid, as
is the hydration rate computed for the Obsidian
Butte source.
The case of the Dos Cabezas Serrated
points is of great interest methodologically.
The DCS type was originally dated based onradiocarbon association, which was areasonable assumption at the time. However,
now that the obsidian ages can be computed, it
is clear that severe turbation of the obsidian
specimens had occurred and the DCS points
were out of place stratigraphically. Obsidian
hydration dating permits directly dating themto the Late Prehistoric period, less than 1000
BP. This was not possible in the 1980s.
As a case study, this analysis also shows
the potential of applying the OHD technique,even with an old and previously-intractabledata set. The principal difference between the
OHD state of the art in the 1980s and at present
is that now the physics and chemistry ofobsidian hydration are much better understood.
In addition, the necessary mathematical models

for conducting the OHD analysis are now inplace and published, so that OHD analyses
become another element of the archaeologicalchronometric tool box.
Acknowedgements
We thank Meg MacDonald and her teamfor the hard work of excavating the rockshelter,and for incorporating the obsidian data in adocument where it could be accessed for reanalysis some 30 years later. The fact that we
can now make sense of the obsidian data is due
to progress in the corporate knowledge ofobsidian and the hydration process, and is not a
criticism of the work done back then.
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Rogers, A.K. (2015b) An Equation for
Estimating Effective Hydration Rate of
Obsidian from Intrinsic Water Content.
Bulletin of the International Association
for Obsidian Studies 53: 5-13.
Rogers, A.K. (2018) A Computer Program in
MatLab for Obsidian Hydration Age
Computations. Bulletin of theInternational Association for ObsidianStudies 59: 10-18.
Rogers, A.K. and D. Duke (2011) An
Archaeologically Validated Protocol for
Computing Obsidian Hydration Rates
from Laboratory Data. Journal ofArchaeological Science 38: 1340-1345.
Schiffer, M.E. (1987) Site Formation
Processes of the Archaeological Record.
University of Utah Press, Salt Lake City.
Schmitt, A.K., A. Martin, D.F. Stockli, K.A.
Farley, and O.M. Lovera. (2013) (UTh)/He Zircon and Archaeological Ages
for a Late Prehistoric Eruption in the
Salton Trough, California, Earth andPlanetary Science Letters 252: 260-274.
Schmitt, A.K., A.R. Perrine, E.J. Rhodes, and
C. Fischer (2019) Age of Obsidian Buttein Imperial Valley, California, ThroughInfrared Stimulated Luminescence Datingof Potassium Feldspar from Tuffaceous
Sediment. California Archaeology 11: 5-20.

Stevenson, C.M., M. Gottesman, and M.
Macko (2000) Redefining the Working
Assumptions for Obsidian Hydration
Dating. Journal of California and GreatBasin Anthropology 22(2): 223-236.
West, G.J., W. Woolfenden, J.A. Wanket, and
R.S. Anderson (2007) Late Pleistoceneand Holocene Environments. In
California Prehistory: Colonization,
Culture, and Complexity, edited by T.L.
Jones and K.A. Klar, pp. 11-34. Altamira
Press, Walnut Creek, California.
Wright, H.M., J.A. Vasquez, D.E. Champion,
A.T. Calvert, M.T. Hangan, M.E. Stelton,
K.M. Cooper, C.Herzig, and A. Schriener(2015) Episodic Holocene Eruption of the
Salton Sea Rhyolites, California, from
Paleomagnetic, U-Th, and Ar/Ar Dating.
Geochemistry, Geophysics, Geosystems
16: 1198-1210.
Zhang, Y. (2008) Geochemical Kinetics.
Princeton University Press, New Jersey.
Zhang, Y., E.M. Stolper, and G.J. Wasserburg(1991) Diffusion of Water in Rhyolytic
Glasses. Geochimica et Cosmochimica
Acta 55: 441-456.
Zhang, Y, and H. Behrens (2000) H2O
Diffusion in Rhyolitic Melts and Glasses.
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IAOS Bulletin No. 62, Winter 2019
Pg. 28

ABOUT OUR WEB SITE

CALL FOR ARTICLESThe IAOS maintains a website at
http://www.deschutesmeridian.com/IAOS/
The site has some great resources available tothe public, and our webmaster, Craig Skinner,continues to update the list of publications andmust-have volumes.

Submissions of articles, short reports, abstracts,
or announcements for inclusion in the Bulletin
are always welcome. We accept submissions in
MS Word. Tables should be submitted as Excel
files and images as .jpg files. Please use theAmerican Antiquity style guide for formattingreferences and bibliographies.
http://www.saa.org/Portals/0/SAA%20Style%2
0Guide_Updated%20July%202018.pdf

You can now become a member online or
renew your current IAOS membership using
PayPal. Please take advantage of thisopportunity to continue your support of the
IAOS.
Other items on our website include:







World obsidian source catalog
Back issues of the Bulletin.
An obsidian bibliography
An obsidian laboratory directory
Photos and maps of some source
locationsLinks

Thanks to Craig Skinner for maintaining thewebsite. Please check it out!

Submissions can also be emailed to the Bulletin
at IAOS.Editor@gmail.com Please include thephrase “IAOS Bulletin” in the subject line. An
acknowledgement email will be sent in reply, so
if you do not hear from us, please email again
and inquire.
Deadline for Issue #63 is May 1, 2020.
Email or mail submissions to:
Dr. Carolyn Dillian
IAOS Bulletin, Editor
Department of Anthropology & Geography
Coastal Carolina University
P.O. Box 261954
Conway, SC 29528
U.S.A.
Inquiries, suggestions, and comments about the
Bulletin can be sent to IAOS.Editor@gmail.com
Please send updated address information to Matt
Boulanger at Boulanger.Matthew@gmail.com

IAOS Bulletin No. 62, Winter 2019
Pg. 29

MEMBERSHIPThe IAOS needs membership to ensure successof the organization. To be included as a member
and receive all of the benefits thereof, you may
apply for membership in one of the following
categories:
Regular Member: $20/year*
Student Member: $10/year or FREE withsubmission of a paper to the Bulletin for
publication. Please provide copy of current
student identification.
Lifetime Member: $200
Regular Members are individuals or institutions
who are interested in obsidian studies, and whowish to support the goals of the IAOS. Regularmembers will receive any general mailings;
announcements of meetings, conferences, andsymposia; the Bulletin; and papers distributedby the IAOS during the year. Regular members
are entitled to vote for officers.
*Membership fees may be reduced and/or
waived in cases of financial hardship or
difficulty in paying in foreign currency. Please
complete the form and return it to the SecretaryTreasurer with a short explanation regardinglack of payment.

NOTE: Because membership fees are very low,
the IAOS asks that all payments be made in U.S.
Dollars, in international money orders, orchecks payable on a bank with a U.S. branch.
Otherwise, please use PayPal on our website to
pay with a credit card.
http://www.deschutesmeridian.com/IAOS/membership.html
For more information about membership in the
IAOS, contact our Secretary-Treasurer:
Matthew Boulanger
Department of Anthropology
Southern Methodist University
P.O. Box 750336
Dallas, TX 75275-0336
U.S.A.
Boulanger.Matthew@gmail.com
Membership inquiries, address changes, orpayment questions can also be emailed to
Boulanger.Matthew@gmail.com

ABOUT THE IAOS
The International Association for Obsidian Studies (IAOS) was formed in 1989 to provide a forum for
obsidian researchers throughout the world. Major interest areas include: obsidian hydration dating, obsidian
and materials characterization (“sourcing”), geoarchaeological obsidian studies, obsidian and lithic
technology, and the prehistoric procurement and utilization of obsidian. In addition to disseminating
information about advances in obsidian research to archaeologists and other interested parties, the IAOS
was also established to:
1. Develop standards for analytic procedures and ensure inter-laboratory comparability.
2. Develop standards for recording and reporting obsidian hydration and characterization results
3. Provide technical support in the form of training and workshops for those wanting to develop theirexpertise in the field.
4. Provide a central source of information regarding the advances in obsidian studies and the analytic
capabilities of various laboratories and institutions

IAOS Bulletin No. 62, Winter 2019
Pg. 30MEMBERSHIP RENEWAL FORM
We hope you will continue your membership. Please complete the renewal form below.
NOTE: You can now renew your IAOS membership online! Please go to the IAOS website at
http://www.deschutesmeridian.com/IAOS/ and check it out! Please note that due to changes in themembership calendar, your renewal will be for the next calendar year. Unless you specify, the Bulletin will
be sent to you as a link to a .pdf available on the IAOS website.
___ Yes, I’d like to renew my membership. A check or money order for the annual membership fee is enclosed(see below).
___ Yes, I’d like to become a new member of the IAOS. A check or money order for the annual membershipfee is enclosed (see below). Please send my first issue of the IAOS Bulletin.
___ Yes, I’d like to become a student member of the IAOS. I have enclosed either an obsidian-related article
for publication in the IAOS Bulletin or an abstract of such an article published elsewhere. I have also
enclosed a copy of my current student ID. Please send my first issue of the IAOS Bulletin.
NAME: _______________________________________________________________________________TITLE: _________________________ AFFILIATION:_________________________________________STREET ADDRESS: ____________________________________________________________________
CITY, STATE, ZIP: _____________________________________________________________________
COUNTRY: ___________________________________________________________________________WORK PHONE: _______________________________ FAX: ___________________________________HOME PHONE (OPTIONAL): ____________________________________________________________EMAIL ADDRESS: _____________________________________________________________________My check or money order is enclosed for the following amount (please check one):___ $20 Regular___ $10 Student (include copy of student ID)___ FREE Student (include copy of article for the IAOS Bulletin and student ID)___ $200 Lifetime
Please return this form with payment:(or pay online with PayPal http://www.deschutesmeridian.com/IAOS/paypal.html)

Matthew Boulanger
Department of Anthropology
Southern Methodist University
P.O. Box 750336
Dallas, TX 75275-0336
U.S.A.

IAOS Bulletin No. 62, Winter 2019
Pg. 31