www.elleryfrahm.com • Research Scientist (Faculty), Yale University • Director, Yale Initiative for the Study of Ancient Pyrotechnology • Co-Editor-in-Chief, "Journal of Archaeological Science: Reports"
The newly excavated rockshelter of Yeghegis-1 in Armenia reflects an occupation of five centuries... more The newly excavated rockshelter of Yeghegis-1 in Armenia reflects an occupation of five centuries, as attested by radiocarbon dates from ∼ 4100 to 4000 cal BCE in the lowest layer to ∼ 3600-3500 cal BCE at the top. It is a partially collapsed cave in which pastoralists, we hypothesize, wintered with their herds. The stone tool assemblage is predominantly obsidian (92.1%), despite the shelter being > 60 km on foot from the nearest sources. We use obsidian sourcing to investigate two purported trends in the Southern Caucasus during the Chalcolithic Period: (1) occupation of more varied high-altitude environments and (2) more expansive social networks. Our data show both trends were dynamic phenomena. There was a greater balance in use of the nearest pasturelands over time, perhaps linked to risk management and/or resource sustainability. During later occupations, artifacts from distant sources reveal more extensive connections. This increase in connectivity likely played a central role in the shifts in societal complexity that gave rise to widely shared material culture throughout the Armenian Highlands around the start of the Early Bronze Age. In such a model, greater social connectivity becomes a key mechanism for, rather than a product of, the spread of cultural and/or technological innovations. The Chalcolithic Period of the Southern Caucasus (5000-3500 BCE) corresponds to a phase of increased copper production alongside the continued use of lithic technology, chronologically situated between the agricultural settlements of the Neolithic Period and the far-reaching Kura-Araxes material culture "package" of the Early Bronze Age. Despite the relevance of this time period for understanding the development of social complexity across the Southern Caucasus, relatively little is known about these transformations during the Chalcolithic in this region. Sagona 1 notes that, in the 20th century, the Chalcolithic "was an elusive period, characterized by fuzzy concepts, multiple traditions, and an array of patchy evidence weakly glued together by a small number of radiocarbon readings" from Soviet-era excavations. Work of that time, as described by Lyonnet 2 , was "extremely abundant and fundamental but often imprecise" and lacked dates, hindering the potential to make chronological correlations among sites. In contrast, the 21st century has seen a shift toward scientific collaboration between national and international research centers (e.g., the collaborative work that we report here). Collaboration at the Chalcolithic site of Areni-1 Cave, for example, has led to detailed chronological 3 , geoarchaeological 4 , botanical 5 , and faunal 6 results. Recent excavations have yielded a wealth of new data, much of it at odds with the older studies. For decades, Chalcolithic sites found in the Southern Caucasus were assigned to one of two archaeological
The monograph L'obsidienne au Proche et Moyen Orient: Du volcan à l'outil (Cauvin et al., 1998) w... more The monograph L'obsidienne au Proche et Moyen Orient: Du volcan à l'outil (Cauvin et al., 1998) was first published 25 years ago, and between its covers, Poidevn’s (1998) chapter summarized the geochemical and geochronological data for obsidian sources that lie within what is now western, central, and eastern Turkey and the Caucasus. That chapter was a highly valuable resource at the time. A revision, though, is long overdue, and this is the second of two articles (see Frahm, 2023) in which I endeavor to provide an update. Here I focus on the obsidian sources from the Greek islands in the South Aegean Volcanic Arc to the Central Anatolian Volcanic Province in central Turkey. Many more elemental data are available for these sources today than during the 1990s. For example, Poidevin (1998) listed 17 analyses of Nenezi Dağ obsidian from seven different facilities. In contrast, here I summarize 359 measurements of Nenezi Dağ obsidian from 26 different laboratories using a variety of analytical techniques. Consequently, there is an opportunity to derive robust elemental consensus values for such well-characterized obsidian sources. Of the 24 obsidian sources that I summarize in this article, however, not all have been so well studied, and there remains important work to be done, especially in western Turkey.
Obsidian sourcing studies have a long history in the Near East, but relatively few have focused o... more Obsidian sourcing studies have a long history in the Near East, but relatively few have focused on obsidian exchange after the Early Bronze Age. Here, we present a multi-technique analysis of an assemblage of 111 obsidian artifacts from excavated Late Bronze and Early Iron Age (LBA-EIA; c. 15th-6th c BCE) contexts at Mtsvane Gora, southern Georgia. Because the site is situated in the lowland Kura Valley and the nearest obsidian sources are in the highlands to the south and west, obsidian provenance can serve as a proxy for mapping highland-lowland interactions. Chemical compositions analyzed via portable X-ray fluorescence spectrometry (pXRF), electron microprobe analysis (EMPA), and laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS), were compared with existing geological datasets of chemical analyses to identify the source of all but one of the artifacts analyzed. The results show that Chikiani, a source in the highlands of southern Georgia, was the geological origin of >90% of the objects analyzed. While acknowledging that obsidian exchange is just one aspect of highland-lowland interaction, this finding implies that Mtsvane Gora's connections with the adjacent highlands were skewed towards greater engagement with some highland areas relative to others. More generally, the research suggests that geographic adjacency of highlands and lowlands does not necessarily mean that they were highly interconnected.
It has been 25 years since the publication of the monograph L'obsidienne au Proche et Moyen Orien... more It has been 25 years since the publication of the monograph L'obsidienne au Proche et Moyen Orient: Du volcan à l'outil (Cauvin et al., 1998) and, within it, Poidevin's (1998) chapter that summarized all available geochemical and geochronological data for obsidian sources in Turkey and the Caucasus. It was a highly valuable resource to those of us working on Near Eastern obsidian sourcing in the early 2000s; however, an update is long overdue. Poidevin (1998) compiled 229 analyses for obsidian sources in eastern Turkey and the Caucasus, and while he recognized the importance of independent analytical data, he was also frustrated that the few available data obscured real differences in obsidian composition versus variation among the different analytical facilities. Today we are closer to Poidevin's (1998) goal. Here I summarize more than 7300 elemental analyses for 58 geochemically distinct obsidian sources. For example, Poidevin (1998) had just two analyses for Meydan Dag, a highly important obsidian source, whereas here I report consensus values for 22 elements in Meydan Dag obsidian based on 423 analyses from 25 independent techniques and laboratories. Not all 58 of the known obsidian sources within this region, however, have been so well characterized, and it is clear that there remains work to be done. are, though, a few differences. For instance, "Transcaucasia" and "the Transcaucasus" are Russia-centric termsonly from a Russian
Sourcing archaeological amber has hitherto been limited by a reliance on chemical techniques that... more Sourcing archaeological amber has hitherto been limited by a reliance on chemical techniques that require some degree of destructive sampling. The majority of amber artifacts are friable, weakened after millennia spent unprotected from environmental stressors, and as such are especially vulnerable during analysis or even sampling. Here, we assess the capability of an entirely nondestructive analytical technique-Diffuse Reflectance Infrared Spectroscopy (DRIFTS)-to scientifically identify archaeological Baltic amber. Using a reference collection of geological amber specimens, our direct comparison of DRIFTS spectra to those collected via conventional transmission FTIR, which necessitates destructive sampling, demonstrates the validity of the new technique. Thirteen beads from the archaeological site of Dura-Europos in Syria were subsequently analyzed using DRIFTS alone. Five of the beads showed spectral features indicative of Baltic amber, whereas the others were too degraded to yield diagnostically measurable spectra. Our study thus confirms the capability of the DRIFTS technique to analyze whole, untreated amber artifacts when their integrity is of high concern. Furthermore, our results indicate a previously unestablished connection between Dura-Europos and northern Europe during the first two centuries CE through long-distance exchange networks stemming from the Mediterranean basin.
Archaeologists' access to analytical infrastructure has grown exponentially over the last two dec... more Archaeologists' access to analytical infrastructure has grown exponentially over the last two decades. This is especially the case for benchtop X-ray fluorescence (XRF) and portable XRF (pXRF) instruments, which are now practically commonplace in archaeological laboratories and provide users with a non-destructive and rapid means to analyze the elemental compositions of archaeological specimens. As XRF has become more accessible, the volume of analytical measurements available in archaeological datasets as well as the number and diversity of researchers participating in data collection have inherently increased. Those researchers, who have various levels of experience with the nuances of lithic sourcing procedures, are also often the ones attempting to interpret the elemental data they produce. While standardized analytical procedures have enabled inexperienced analysts to take accurate and reproducible XRF measurements, interpreting the resulting data is more difficult to convert and standardize with the same degree of user-friendliness. To address this challenge, we have bundled a series of statistical approaches and data exploration tools into an intuitive open-source graphical user interface designed to facilitate reproducible and robust outcomes during lithic sourcing studies. Our application, SourceXplorer, permits easy access to and exploration of numeric baseline data using a map interface while facilitating a guided interpretation of source affiliations for archaeological specimens (e.g., lithics) within any natural context using multivariate statistical analyses. We demonstrate SourceXplorer's functionality in relation to a complex archaeological challenge by examining evidence for the procurement and use of lithic material from previously undocumented toolstone source locations in southwestern British Columbia, Canada. We also provide open access to SourceXplorer, including both a deployed version of the application that can be used with any Internet browser and the packaged script, which can be run locally in the open-source R statistical programming environment.
Here we introduce a set of well-characterized historical brick and geological specimens intended ... more Here we introduce a set of well-characterized historical brick and geological specimens intended to aid the calibration of portable XRF (pXRF) instruments for archaeological ceramics. Known as the BRICC Bricks and Rocks for Instruments Ceramic Calibration sets, each of the ten matched sets consists of 20 specimens mounted in epoxy discs: 12 bricks and 8 geological specimens to use for calibration. Additionally, a certified reference material a shale standard measured by 85 labs is included with each set to assess the resulting accuracy, and a high-purity silica blank is included to check for spectral interferences or other calibration issues. The BRICC sets provide an open-source alternative to pXRF calibration approaches that are proprietary, were devised for oil shales instead of ceramics, and/or rely on expensive and often unavailable certified standards. A set can be tested at Yale or borrowed following loan policies of the Yale Peabody Museum. Publishing all information for the historical bricks and geological specimens from their origins to the data used to derive the recommended values fulfills the requirements of scientific transparency. Ultimately, these sets are intended and designed as a means to meet and exceed experts practices regarding accuracy, reproducibility, and scientific transparency when analyzing ceramics using pXRF and (2) to reduce siloed production of knowledge within established laboratories and, hence, facilitate integration of more diverse perspectives into elemental studies of archaeological ceramics.
Investigations of organic lithic micro-residues have, over the last decade, shifted from entirely... more Investigations of organic lithic micro-residues have, over the last decade, shifted from entirely morphological observations using visible-light microscopy to compositional ones using scanning electron microscopy and Fourier-transform infrared microspectroscopy, providing a seemingly objective chemical basis for residue identifications. Contamination, though, remains a problem that can affect these results. Modern contaminants, accumulated during the post-excavation lives of artifacts, are pervasive, subtle, and even "invisible" (unlisted ingredients in common lab products). Ancient contamination is a second issue. The aim of residue analysis is to recognize residues related to use, but other types of residues can also accumulate on artifacts. Caves are subject to various taphonomic forces and organic inputs, and use-related residues can degrade into secondary compounds. This organic "background noise" must be taken into consideration. Here we show that residue contamination is more pervasive than is often appreciated, as revealed by our studies of Middle Palaeolithic artifacts from two sites: Lusakert Cave 1 in Armenia and Crvena Stijena in Montenegro. First, we explain how artifacts from Lusakert Cave 1, despite being handled following specialized protocols, were tainted by a modern-day contaminant from an unanticipated source: a release agent used inside the zip-top bags that are ubiquitous in the field and lab. Second, we document that, when non-artifact "controls" are studied alongside artifacts from Crvena Stijena, comparisons reveal that organic residues are adhered to both, indicating that they are prevalent throughout the sediments and not necessarily related to use. We provide suggestions for reducing contamination and increasing the reliability of residue studies. Ultimately, we propose that archaeologists working in the field of residue studies must start with the null hypothesis that miniscule organic residues reflect contamination, either ancient or modern, and systematically
Institute of Archaeology and Ethnography, National Academy of Sciences of the Republic of Armenia... more Institute of Archaeology and Ethnography, National Academy of Sciences of the Republic of Armenia – Arménie University of Arizona – États-Unis Yale University – États-Unis University of Winchester – Royaume-Uni University of Wollongong – Australie University of Leiden – Pays-Bas Institute of Geosciences, National Academy of Sciences of the Republic of Armenia – Arménie University of Connecticut – États-Unis
Barozh 12 is a late Middle Paleolithic open-air locality in western Armenia dating from ~ 60,000 ... more Barozh 12 is a late Middle Paleolithic open-air locality in western Armenia dating from ~ 60,000 to 31,000 years ago. Stratified deposits with high densities of obsidian artifacts permit the analysis of diachronic trends in manufacture, reduction, discard, and toolstone provisioning as related to technological organization in the context of hunter-gatherer mobility and land use. Throughout much of Marine Isotope Stage (MIS) 3, the occupants of Barozh 12 employed consistent unidirectional-convergent and unidirectional Levallois and “para-Levallois” core reduction techniques. Site occupation intensity varied over time, with changing emphasis on local core reduction and tool discard. Obsidian artifact sourcing indicates predominantly local toolstone exploitation, while blanks bearing retouch were intermittently transported to Barozh 12 over distances up to ~ 190 linear km. As a repeatedly visited, persistent place in regional settlement systems, this site records a range of mobility st...
Most descriptions of obsidian-bearing rhyolitic lava flows and domes are largely based on relativ... more Most descriptions of obsidian-bearing rhyolitic lava flows and domes are largely based on relatively simple cases of tectonic plate subduction in North America, but Armenian geologists proposed since the 1960s that these models are less suitable for describing rhyolitic volcanism in their research area. Obsidian-producing volcanoes that lie in the Armenian Highlands, they argued, are more complex in form and stratification. Hatis volcano in central Armenia is one such example. As we document, Hatis is highly unusual, perhaps unique, in that its obsidian changes in composition with elevation. Prior studies of Hatis obsidian recognized the existence of two different chemical types. Here, though, we report a series of four obsidian chemical types and their spatial distributions across the slopes. Our findings were enabled by the use of portable XRF during our field surveys of Hatis. Additionally, we recognized each of these four chemical types of Hatis obsidian at the Lower Palaeolithic site of Nor Geghi 1, where thousands of obsidian artifacts reflect Pleistocene hominin behaviors from Marine Isotope Stage (MIS) 11 (~424–34 ka) to 9 (~33–300 ka). Thus, all four types of Hatis obsidian are archae- ologically significant despite the fact that their outcrops span more than 00 m (from <1600 to greater than 2100 m asl) in elevation on the volcanic slopes, thereby enabling future studies on links between altitude and hominin toolstone acquisition behaviors over hundreds of millennia.
Obsidian sourcing in the Near East was principally developed to investigate the Neolithic Revolut... more Obsidian sourcing in the Near East was principally developed to investigate the Neolithic Revolution, but limitations of these early studies were soon recognized. Critics noted that sites included in the models span millennia and vary in size and function. Greater insight is offered by a more contextualized examination of the nature and timing of sites. Within the Neolithic sequence, one phase of considerable interest is the Halaf period (c. 6000–4500 BCE) in Northern Mesopotamia. The spread of Halaf “tradition,” arguably the earliest example of a widely shared material culture in the region, has been tied to varied hypotheses of movement (of people, objects, and/or ideas) that remain largely untested. The use of obsidian sourcing to investigate Halafian phenomena (e.g., the spread of Halaf ceramics, the practice of dryland farming) would ideally involve high temporal resolution and consider settlement function and scale (e.g., an early urban center, a small farming village). Umm Qseir, the smallest known Halaf site, fulfills both. Occupied for less than two centuries, Umm Qseir was an environmentally marginal farmstead managed year-round by just two or three families at a time. The closest contemporary settlement was more than 30 km to the north, within the conventional limits of dryland farming (annual rainfall > 250 mm). Here we reconstruct and refine obsidian sourcing data for Umm Qseir artifacts from 1990s and 2000s studies, and we present new data for a small assemblage. We also highlight techno-typological clues that elucidate production, use, and maintenance of such artifacts. Ultimately, such findings offer insights into the exchange strategy of Syrian steppe farmsteaders and reflect an important means of risk management.
With its well-preserved archaeological and environmental records, Aghitu-3 Cave permits us to exa... more With its well-preserved archaeological and environmental records, Aghitu-3 Cave permits us to examine the settlement patterns of the Upper Paleolithic (UP) people who inhabited the Armenian Highlands. We also test whether settlement of the region between ∼39-24,000 cal BP relates to environmental variability. The earliest evidence occurs in archaeological horizon (AH) VII from ∼39-36,000 cal BP during a mild, moist climatic phase. AH VI shows periodic occupation as warm, humid conditions prevailed from ∼36-32,000 cal BP. As the climate becomes cooler and drier at ∼32-29,000 cal BP (AH V-IV), evidence for occupation is minimal. However, as cooling continues, the deposits of AH III demonstrate that people used the site more intensively from ∼29-24,000 cal BP, leaving behind numerous stone artifacts, faunal remains, and complex combustion features. Despite the climatic fluctuations seen across this 15,000-year sequence, lithic technology remains attuned to one pattern: unidirectional r...
Here we report the findings from excavations at the open-air Middle Palaeolithic site of Alapars-... more Here we report the findings from excavations at the open-air Middle Palaeolithic site of Alapars-1 in central Armenia. Three stratified Palaeolithic artefact assemblages were found within a 6-m-thick alluvial-aeolian sequence, located on the flanks of an obsidian-bearing lava dome. Combined sedimentological and chronological analyses reveal three phases of sedimentation and soil development. During Marine Oxygen Isotope Stages 5-3, the manner of deposition changes from alluvial to aeolian, with a development of soil horizons. Techno-typological analysis and geochemical sourcing of the obsidian artefacts reveal differential discard patterns, source exploitation, and artefact densities within strata, suggesting variability in technological organization during the Middle Palaeolithic. Taken together, these results indicate changes in hominin occupation patterns from ephemeral to more persistent in relation to landscape dynamics during the last interglacial and glacial periods in central Armenia.
Nemrut Dağ volcano was a highly important obsidian source in the ancient Near East for millennia,... more Nemrut Dağ volcano was a highly important obsidian source in the ancient Near East for millennia, and its circular caldera is a conspicuous landmark on the landscape. In contrast to its archaeological relevance as an obsidian source, Nemrut Dağ was poorly understood for decades, starting with the work of Renfrew and col- leagues. Fortunately, in the last decade or two, archaeologists not only have geological studies from which to draw information about the volcano but also have conducted their own research, including the work of Robin (2017) and colleagues (Robin et al., 2015, 2016; Khalidi et al., 2016). One key finding is that all of the tested Nemrut Dağ obsidian artifacts from a variety of sites match the chemical fingerprint of an outcrop near the village of Sıcaksu. Since then, it has been presumed that the Sıcaksu outcrop is the source for Nemrut Dağ obsidian artifacts at sites in various regions and times. In contrast, four types of Nemrut Dağ obsidian, including the Sıcaksu type, occur among the artifacts at Körtik Tepe, Domuztepe, and Tell Mozan, at which there are indications of a diachronic change. Developing our knowledge of field relationships among the types of Nemrut Dağ obsidian advances our ability to make behaviorally relevant interpretations.
The Hrazdan River valley in Armenia contains Lower, Middle, and Upper Paleolithic archaeological ... more The Hrazdan River valley in Armenia contains Lower, Middle, and Upper Paleolithic archaeological sites and offers access to the Gutansar Volcanic Complex, a large and important source of obsidian. The sites' occupants primarily acquired lithic material from this obsidian source, which is manifested throughout the local landscape, but its obsidian exposures, produced during a single eruptive phase, exhibit the same geochemical signature. This situation inspired the development of rock magnetic characterization as a means to recognize obsidian from different spots across the volcanic complex (i.e., intra-source, not inter-source, characterization). This intra-source approach was first applied to the Middle Palaeolithic site of Lusakert Cave 1, where the data revealed that the occupants collected obsidian throughout the river valley, rather than a preferred outcrop, quarrying area, or secondary deposit. Such a finding implied that the toolstone procurement spatially coincided with the valley and was embedded in subsistence activities. In this new study, the same approach to intra-source magnetic characterization is applied to the Lower Palaeolithic site of Nor Geghi 1-specifically, to obsidian debris dated between 440 and 335 millennia ago. The magnetic measurements show that, like at Lusakert Cave 1, toolstone acquisition occurred within the valley. If, as we propose, obsidian procurement reflects the spatial distribution of subsistence activities, it attests that archaic hominins at both sites and in both periods were able to effectively exploit a resource-rich riparian ecosystem. Consequently, this study provides an example of behaviors shared by Middle and Lower Palaeolithic hominins whereby, placed within the same landscape, their resource exploitation behaviors appear indistinguishable.
Given the importance of the Levant in understanding the origins and dispersals of modern humans, ... more Given the importance of the Levant in understanding the origins and dispersals of modern humans, there has been great interest in archaeological evidence to support population movements between the Levant and ad- jacent regions. The link, if any, between the Aurignacian tradition across Europe and the “Levantine Aurignacian” is a particular focus. Ksar Akil in Lebanon not only is one of the most deeply stratified Levantine sites but also has the longest record of Upper Paleolithic behaviors, so it is a benchmark to which developments in the Levant are often compared. Schmidt and Zimmermann (2019) recently proposed that the European Aurignacian tradition might best be understood in terms of connectivity, as evidenced by long-distance lithic transfers that can act as a proxy for mobility and social networks. Here we document a previously unreported obsidian burin from Ksar Akil. Portable X-ray fluorescence reveals that it matches a source ≥700 km away on foot in central Turkey. Two recent dating programs have calculated ages of ~41–38 and ~39–37 ka cal BP for its layer, which also included an obsidian flake and immediately precedes the Levantine Aurignacian at the site. The obsidian artifacts from Ksar Akil are roughly contemporaneous obsidian from Yabroud Rockshelter II in Syria and Shanidar Cave in Iraq. Such instances of long-distance obsidian transport imply that connectivity might have risen ahead of the Levantine and Zagros Aurignacian. Unfortunately, due to the limited chronological resolution of older excavations at these sites, only at Ksar Akil can we have confidence that the layer containing obsidian artifacts immediately precedes the earliest Levantine Aurignacian sensu stricto layer. Given the apparent rarity of obsidian in the Levant, this region will benefit from endeavors to nondestructively source other toolstone ma- terials as a means to create datasets similar to those recently used to model cultural areas of the European Aurignacian.
A series of well-characterized specimens, known as the Peabody-Yale Reference Obsidians (PYRO) se... more A series of well-characterized specimens, known as the Peabody-Yale Reference Obsidians (PYRO) sets, has been designed to aid with calibrating and assessing X-ray fluorescence analysis (XRF) data, including portable XRF (pXRF) measurements, for obsidian sourcing. Each of these ten matched sets consists of 35 specimens: 20 specimens for calibration and 15 specimens for evaluation. These sets include not only obsidians with common geochemical compositions (i.e., alkaline rhyolites) but also rarer ones (i.e., peralkaline rhyolitic, trachytic, and andesitic specimens, including East African Rift obsidians). When used as described, the PYRO sets are suitable to calibrate and evaluate XRF data for obsidians worldwide. A set can be borrowed following loan policies of the Peabody Museum of Natural History, which will also accession a set. Publishing all source information – from their names and GPS coordinates to the datasets used for the recommended values – not only allows the sets to be replicated by others but also fulfills the demands of scientific transparency. Their main purpose is facilitating collaborations and “big data” projects, and the PYRO sets were designed to complement existing protocols for calibration and evaluation. In short, the sets are intended as a tool for almost anyone (e.g., a student who borrows an instrument to source artifacts) to meet – and even exceed – experts' practices involving transparency, accuracy, and reproducibility.
Excavations at Aghitu-3 Cave in Armenia revealed stratified Upper Palaeolithic archaeological hor... more Excavations at Aghitu-3 Cave in Armenia revealed stratified Upper Palaeolithic archaeological horizons (AHs), spanning from 39 to 36,000 cal BP (AH VII) to 29-24,000 cal BP (AH III) and from which we identified the sources of 1120 obsidian artifacts. Not only does AH III-deposited at the onset of the Last Glacial Maximum-have the most artifacts from non-regional sources but also the artifacts originate from the greatest variety of sources, including two ≥ 270 km on foot in different directions. The amount of retouch and density of lithics-as expressed by whole assemblage behavioral indicators (WABI)-suggest a trend from more expediency to more curation between the deposition of AHs VII and IV. This was followed by a substantial shift back to expediency during the deposition of AH III, corresponding to greater logistical mobility. Here, we use agent-based modeling (ABM) to interpret these data. Greater interactions between foraging groups are not an unavoidable outcome of a shift from residential to logistical mobility. Some variables (i.e., lithic stock, use intensity, provi-sioning strategy) can be ruled out, while other variables (i.e., decreased source abundance , a shift to direct procurement) appear inconsistent with the archaeological data. Territory spacing, in contrast, has a clear and predictable effect. A small decrease in territory spacing can yield notable increases in inter-group contact opportunities and can be explained by an increase in population densities as the climate cooled. Following this scenario, we assume that, as AH III accumulated, the cave's occupants not only moved farther distances but also more frequently encountered neighboring groups.
The newly excavated rockshelter of Yeghegis-1 in Armenia reflects an occupation of five centuries... more The newly excavated rockshelter of Yeghegis-1 in Armenia reflects an occupation of five centuries, as attested by radiocarbon dates from ∼ 4100 to 4000 cal BCE in the lowest layer to ∼ 3600-3500 cal BCE at the top. It is a partially collapsed cave in which pastoralists, we hypothesize, wintered with their herds. The stone tool assemblage is predominantly obsidian (92.1%), despite the shelter being > 60 km on foot from the nearest sources. We use obsidian sourcing to investigate two purported trends in the Southern Caucasus during the Chalcolithic Period: (1) occupation of more varied high-altitude environments and (2) more expansive social networks. Our data show both trends were dynamic phenomena. There was a greater balance in use of the nearest pasturelands over time, perhaps linked to risk management and/or resource sustainability. During later occupations, artifacts from distant sources reveal more extensive connections. This increase in connectivity likely played a central role in the shifts in societal complexity that gave rise to widely shared material culture throughout the Armenian Highlands around the start of the Early Bronze Age. In such a model, greater social connectivity becomes a key mechanism for, rather than a product of, the spread of cultural and/or technological innovations. The Chalcolithic Period of the Southern Caucasus (5000-3500 BCE) corresponds to a phase of increased copper production alongside the continued use of lithic technology, chronologically situated between the agricultural settlements of the Neolithic Period and the far-reaching Kura-Araxes material culture "package" of the Early Bronze Age. Despite the relevance of this time period for understanding the development of social complexity across the Southern Caucasus, relatively little is known about these transformations during the Chalcolithic in this region. Sagona 1 notes that, in the 20th century, the Chalcolithic "was an elusive period, characterized by fuzzy concepts, multiple traditions, and an array of patchy evidence weakly glued together by a small number of radiocarbon readings" from Soviet-era excavations. Work of that time, as described by Lyonnet 2 , was "extremely abundant and fundamental but often imprecise" and lacked dates, hindering the potential to make chronological correlations among sites. In contrast, the 21st century has seen a shift toward scientific collaboration between national and international research centers (e.g., the collaborative work that we report here). Collaboration at the Chalcolithic site of Areni-1 Cave, for example, has led to detailed chronological 3 , geoarchaeological 4 , botanical 5 , and faunal 6 results. Recent excavations have yielded a wealth of new data, much of it at odds with the older studies. For decades, Chalcolithic sites found in the Southern Caucasus were assigned to one of two archaeological
The monograph L'obsidienne au Proche et Moyen Orient: Du volcan à l'outil (Cauvin et al., 1998) w... more The monograph L'obsidienne au Proche et Moyen Orient: Du volcan à l'outil (Cauvin et al., 1998) was first published 25 years ago, and between its covers, Poidevn’s (1998) chapter summarized the geochemical and geochronological data for obsidian sources that lie within what is now western, central, and eastern Turkey and the Caucasus. That chapter was a highly valuable resource at the time. A revision, though, is long overdue, and this is the second of two articles (see Frahm, 2023) in which I endeavor to provide an update. Here I focus on the obsidian sources from the Greek islands in the South Aegean Volcanic Arc to the Central Anatolian Volcanic Province in central Turkey. Many more elemental data are available for these sources today than during the 1990s. For example, Poidevin (1998) listed 17 analyses of Nenezi Dağ obsidian from seven different facilities. In contrast, here I summarize 359 measurements of Nenezi Dağ obsidian from 26 different laboratories using a variety of analytical techniques. Consequently, there is an opportunity to derive robust elemental consensus values for such well-characterized obsidian sources. Of the 24 obsidian sources that I summarize in this article, however, not all have been so well studied, and there remains important work to be done, especially in western Turkey.
Obsidian sourcing studies have a long history in the Near East, but relatively few have focused o... more Obsidian sourcing studies have a long history in the Near East, but relatively few have focused on obsidian exchange after the Early Bronze Age. Here, we present a multi-technique analysis of an assemblage of 111 obsidian artifacts from excavated Late Bronze and Early Iron Age (LBA-EIA; c. 15th-6th c BCE) contexts at Mtsvane Gora, southern Georgia. Because the site is situated in the lowland Kura Valley and the nearest obsidian sources are in the highlands to the south and west, obsidian provenance can serve as a proxy for mapping highland-lowland interactions. Chemical compositions analyzed via portable X-ray fluorescence spectrometry (pXRF), electron microprobe analysis (EMPA), and laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS), were compared with existing geological datasets of chemical analyses to identify the source of all but one of the artifacts analyzed. The results show that Chikiani, a source in the highlands of southern Georgia, was the geological origin of >90% of the objects analyzed. While acknowledging that obsidian exchange is just one aspect of highland-lowland interaction, this finding implies that Mtsvane Gora's connections with the adjacent highlands were skewed towards greater engagement with some highland areas relative to others. More generally, the research suggests that geographic adjacency of highlands and lowlands does not necessarily mean that they were highly interconnected.
It has been 25 years since the publication of the monograph L'obsidienne au Proche et Moyen Orien... more It has been 25 years since the publication of the monograph L'obsidienne au Proche et Moyen Orient: Du volcan à l'outil (Cauvin et al., 1998) and, within it, Poidevin's (1998) chapter that summarized all available geochemical and geochronological data for obsidian sources in Turkey and the Caucasus. It was a highly valuable resource to those of us working on Near Eastern obsidian sourcing in the early 2000s; however, an update is long overdue. Poidevin (1998) compiled 229 analyses for obsidian sources in eastern Turkey and the Caucasus, and while he recognized the importance of independent analytical data, he was also frustrated that the few available data obscured real differences in obsidian composition versus variation among the different analytical facilities. Today we are closer to Poidevin's (1998) goal. Here I summarize more than 7300 elemental analyses for 58 geochemically distinct obsidian sources. For example, Poidevin (1998) had just two analyses for Meydan Dag, a highly important obsidian source, whereas here I report consensus values for 22 elements in Meydan Dag obsidian based on 423 analyses from 25 independent techniques and laboratories. Not all 58 of the known obsidian sources within this region, however, have been so well characterized, and it is clear that there remains work to be done. are, though, a few differences. For instance, "Transcaucasia" and "the Transcaucasus" are Russia-centric termsonly from a Russian
Sourcing archaeological amber has hitherto been limited by a reliance on chemical techniques that... more Sourcing archaeological amber has hitherto been limited by a reliance on chemical techniques that require some degree of destructive sampling. The majority of amber artifacts are friable, weakened after millennia spent unprotected from environmental stressors, and as such are especially vulnerable during analysis or even sampling. Here, we assess the capability of an entirely nondestructive analytical technique-Diffuse Reflectance Infrared Spectroscopy (DRIFTS)-to scientifically identify archaeological Baltic amber. Using a reference collection of geological amber specimens, our direct comparison of DRIFTS spectra to those collected via conventional transmission FTIR, which necessitates destructive sampling, demonstrates the validity of the new technique. Thirteen beads from the archaeological site of Dura-Europos in Syria were subsequently analyzed using DRIFTS alone. Five of the beads showed spectral features indicative of Baltic amber, whereas the others were too degraded to yield diagnostically measurable spectra. Our study thus confirms the capability of the DRIFTS technique to analyze whole, untreated amber artifacts when their integrity is of high concern. Furthermore, our results indicate a previously unestablished connection between Dura-Europos and northern Europe during the first two centuries CE through long-distance exchange networks stemming from the Mediterranean basin.
Archaeologists' access to analytical infrastructure has grown exponentially over the last two dec... more Archaeologists' access to analytical infrastructure has grown exponentially over the last two decades. This is especially the case for benchtop X-ray fluorescence (XRF) and portable XRF (pXRF) instruments, which are now practically commonplace in archaeological laboratories and provide users with a non-destructive and rapid means to analyze the elemental compositions of archaeological specimens. As XRF has become more accessible, the volume of analytical measurements available in archaeological datasets as well as the number and diversity of researchers participating in data collection have inherently increased. Those researchers, who have various levels of experience with the nuances of lithic sourcing procedures, are also often the ones attempting to interpret the elemental data they produce. While standardized analytical procedures have enabled inexperienced analysts to take accurate and reproducible XRF measurements, interpreting the resulting data is more difficult to convert and standardize with the same degree of user-friendliness. To address this challenge, we have bundled a series of statistical approaches and data exploration tools into an intuitive open-source graphical user interface designed to facilitate reproducible and robust outcomes during lithic sourcing studies. Our application, SourceXplorer, permits easy access to and exploration of numeric baseline data using a map interface while facilitating a guided interpretation of source affiliations for archaeological specimens (e.g., lithics) within any natural context using multivariate statistical analyses. We demonstrate SourceXplorer's functionality in relation to a complex archaeological challenge by examining evidence for the procurement and use of lithic material from previously undocumented toolstone source locations in southwestern British Columbia, Canada. We also provide open access to SourceXplorer, including both a deployed version of the application that can be used with any Internet browser and the packaged script, which can be run locally in the open-source R statistical programming environment.
Here we introduce a set of well-characterized historical brick and geological specimens intended ... more Here we introduce a set of well-characterized historical brick and geological specimens intended to aid the calibration of portable XRF (pXRF) instruments for archaeological ceramics. Known as the BRICC Bricks and Rocks for Instruments Ceramic Calibration sets, each of the ten matched sets consists of 20 specimens mounted in epoxy discs: 12 bricks and 8 geological specimens to use for calibration. Additionally, a certified reference material a shale standard measured by 85 labs is included with each set to assess the resulting accuracy, and a high-purity silica blank is included to check for spectral interferences or other calibration issues. The BRICC sets provide an open-source alternative to pXRF calibration approaches that are proprietary, were devised for oil shales instead of ceramics, and/or rely on expensive and often unavailable certified standards. A set can be tested at Yale or borrowed following loan policies of the Yale Peabody Museum. Publishing all information for the historical bricks and geological specimens from their origins to the data used to derive the recommended values fulfills the requirements of scientific transparency. Ultimately, these sets are intended and designed as a means to meet and exceed experts practices regarding accuracy, reproducibility, and scientific transparency when analyzing ceramics using pXRF and (2) to reduce siloed production of knowledge within established laboratories and, hence, facilitate integration of more diverse perspectives into elemental studies of archaeological ceramics.
Investigations of organic lithic micro-residues have, over the last decade, shifted from entirely... more Investigations of organic lithic micro-residues have, over the last decade, shifted from entirely morphological observations using visible-light microscopy to compositional ones using scanning electron microscopy and Fourier-transform infrared microspectroscopy, providing a seemingly objective chemical basis for residue identifications. Contamination, though, remains a problem that can affect these results. Modern contaminants, accumulated during the post-excavation lives of artifacts, are pervasive, subtle, and even "invisible" (unlisted ingredients in common lab products). Ancient contamination is a second issue. The aim of residue analysis is to recognize residues related to use, but other types of residues can also accumulate on artifacts. Caves are subject to various taphonomic forces and organic inputs, and use-related residues can degrade into secondary compounds. This organic "background noise" must be taken into consideration. Here we show that residue contamination is more pervasive than is often appreciated, as revealed by our studies of Middle Palaeolithic artifacts from two sites: Lusakert Cave 1 in Armenia and Crvena Stijena in Montenegro. First, we explain how artifacts from Lusakert Cave 1, despite being handled following specialized protocols, were tainted by a modern-day contaminant from an unanticipated source: a release agent used inside the zip-top bags that are ubiquitous in the field and lab. Second, we document that, when non-artifact "controls" are studied alongside artifacts from Crvena Stijena, comparisons reveal that organic residues are adhered to both, indicating that they are prevalent throughout the sediments and not necessarily related to use. We provide suggestions for reducing contamination and increasing the reliability of residue studies. Ultimately, we propose that archaeologists working in the field of residue studies must start with the null hypothesis that miniscule organic residues reflect contamination, either ancient or modern, and systematically
Institute of Archaeology and Ethnography, National Academy of Sciences of the Republic of Armenia... more Institute of Archaeology and Ethnography, National Academy of Sciences of the Republic of Armenia – Arménie University of Arizona – États-Unis Yale University – États-Unis University of Winchester – Royaume-Uni University of Wollongong – Australie University of Leiden – Pays-Bas Institute of Geosciences, National Academy of Sciences of the Republic of Armenia – Arménie University of Connecticut – États-Unis
Barozh 12 is a late Middle Paleolithic open-air locality in western Armenia dating from ~ 60,000 ... more Barozh 12 is a late Middle Paleolithic open-air locality in western Armenia dating from ~ 60,000 to 31,000 years ago. Stratified deposits with high densities of obsidian artifacts permit the analysis of diachronic trends in manufacture, reduction, discard, and toolstone provisioning as related to technological organization in the context of hunter-gatherer mobility and land use. Throughout much of Marine Isotope Stage (MIS) 3, the occupants of Barozh 12 employed consistent unidirectional-convergent and unidirectional Levallois and “para-Levallois” core reduction techniques. Site occupation intensity varied over time, with changing emphasis on local core reduction and tool discard. Obsidian artifact sourcing indicates predominantly local toolstone exploitation, while blanks bearing retouch were intermittently transported to Barozh 12 over distances up to ~ 190 linear km. As a repeatedly visited, persistent place in regional settlement systems, this site records a range of mobility st...
Most descriptions of obsidian-bearing rhyolitic lava flows and domes are largely based on relativ... more Most descriptions of obsidian-bearing rhyolitic lava flows and domes are largely based on relatively simple cases of tectonic plate subduction in North America, but Armenian geologists proposed since the 1960s that these models are less suitable for describing rhyolitic volcanism in their research area. Obsidian-producing volcanoes that lie in the Armenian Highlands, they argued, are more complex in form and stratification. Hatis volcano in central Armenia is one such example. As we document, Hatis is highly unusual, perhaps unique, in that its obsidian changes in composition with elevation. Prior studies of Hatis obsidian recognized the existence of two different chemical types. Here, though, we report a series of four obsidian chemical types and their spatial distributions across the slopes. Our findings were enabled by the use of portable XRF during our field surveys of Hatis. Additionally, we recognized each of these four chemical types of Hatis obsidian at the Lower Palaeolithic site of Nor Geghi 1, where thousands of obsidian artifacts reflect Pleistocene hominin behaviors from Marine Isotope Stage (MIS) 11 (~424–34 ka) to 9 (~33–300 ka). Thus, all four types of Hatis obsidian are archae- ologically significant despite the fact that their outcrops span more than 00 m (from <1600 to greater than 2100 m asl) in elevation on the volcanic slopes, thereby enabling future studies on links between altitude and hominin toolstone acquisition behaviors over hundreds of millennia.
Obsidian sourcing in the Near East was principally developed to investigate the Neolithic Revolut... more Obsidian sourcing in the Near East was principally developed to investigate the Neolithic Revolution, but limitations of these early studies were soon recognized. Critics noted that sites included in the models span millennia and vary in size and function. Greater insight is offered by a more contextualized examination of the nature and timing of sites. Within the Neolithic sequence, one phase of considerable interest is the Halaf period (c. 6000–4500 BCE) in Northern Mesopotamia. The spread of Halaf “tradition,” arguably the earliest example of a widely shared material culture in the region, has been tied to varied hypotheses of movement (of people, objects, and/or ideas) that remain largely untested. The use of obsidian sourcing to investigate Halafian phenomena (e.g., the spread of Halaf ceramics, the practice of dryland farming) would ideally involve high temporal resolution and consider settlement function and scale (e.g., an early urban center, a small farming village). Umm Qseir, the smallest known Halaf site, fulfills both. Occupied for less than two centuries, Umm Qseir was an environmentally marginal farmstead managed year-round by just two or three families at a time. The closest contemporary settlement was more than 30 km to the north, within the conventional limits of dryland farming (annual rainfall > 250 mm). Here we reconstruct and refine obsidian sourcing data for Umm Qseir artifacts from 1990s and 2000s studies, and we present new data for a small assemblage. We also highlight techno-typological clues that elucidate production, use, and maintenance of such artifacts. Ultimately, such findings offer insights into the exchange strategy of Syrian steppe farmsteaders and reflect an important means of risk management.
With its well-preserved archaeological and environmental records, Aghitu-3 Cave permits us to exa... more With its well-preserved archaeological and environmental records, Aghitu-3 Cave permits us to examine the settlement patterns of the Upper Paleolithic (UP) people who inhabited the Armenian Highlands. We also test whether settlement of the region between ∼39-24,000 cal BP relates to environmental variability. The earliest evidence occurs in archaeological horizon (AH) VII from ∼39-36,000 cal BP during a mild, moist climatic phase. AH VI shows periodic occupation as warm, humid conditions prevailed from ∼36-32,000 cal BP. As the climate becomes cooler and drier at ∼32-29,000 cal BP (AH V-IV), evidence for occupation is minimal. However, as cooling continues, the deposits of AH III demonstrate that people used the site more intensively from ∼29-24,000 cal BP, leaving behind numerous stone artifacts, faunal remains, and complex combustion features. Despite the climatic fluctuations seen across this 15,000-year sequence, lithic technology remains attuned to one pattern: unidirectional r...
Here we report the findings from excavations at the open-air Middle Palaeolithic site of Alapars-... more Here we report the findings from excavations at the open-air Middle Palaeolithic site of Alapars-1 in central Armenia. Three stratified Palaeolithic artefact assemblages were found within a 6-m-thick alluvial-aeolian sequence, located on the flanks of an obsidian-bearing lava dome. Combined sedimentological and chronological analyses reveal three phases of sedimentation and soil development. During Marine Oxygen Isotope Stages 5-3, the manner of deposition changes from alluvial to aeolian, with a development of soil horizons. Techno-typological analysis and geochemical sourcing of the obsidian artefacts reveal differential discard patterns, source exploitation, and artefact densities within strata, suggesting variability in technological organization during the Middle Palaeolithic. Taken together, these results indicate changes in hominin occupation patterns from ephemeral to more persistent in relation to landscape dynamics during the last interglacial and glacial periods in central Armenia.
Nemrut Dağ volcano was a highly important obsidian source in the ancient Near East for millennia,... more Nemrut Dağ volcano was a highly important obsidian source in the ancient Near East for millennia, and its circular caldera is a conspicuous landmark on the landscape. In contrast to its archaeological relevance as an obsidian source, Nemrut Dağ was poorly understood for decades, starting with the work of Renfrew and col- leagues. Fortunately, in the last decade or two, archaeologists not only have geological studies from which to draw information about the volcano but also have conducted their own research, including the work of Robin (2017) and colleagues (Robin et al., 2015, 2016; Khalidi et al., 2016). One key finding is that all of the tested Nemrut Dağ obsidian artifacts from a variety of sites match the chemical fingerprint of an outcrop near the village of Sıcaksu. Since then, it has been presumed that the Sıcaksu outcrop is the source for Nemrut Dağ obsidian artifacts at sites in various regions and times. In contrast, four types of Nemrut Dağ obsidian, including the Sıcaksu type, occur among the artifacts at Körtik Tepe, Domuztepe, and Tell Mozan, at which there are indications of a diachronic change. Developing our knowledge of field relationships among the types of Nemrut Dağ obsidian advances our ability to make behaviorally relevant interpretations.
The Hrazdan River valley in Armenia contains Lower, Middle, and Upper Paleolithic archaeological ... more The Hrazdan River valley in Armenia contains Lower, Middle, and Upper Paleolithic archaeological sites and offers access to the Gutansar Volcanic Complex, a large and important source of obsidian. The sites' occupants primarily acquired lithic material from this obsidian source, which is manifested throughout the local landscape, but its obsidian exposures, produced during a single eruptive phase, exhibit the same geochemical signature. This situation inspired the development of rock magnetic characterization as a means to recognize obsidian from different spots across the volcanic complex (i.e., intra-source, not inter-source, characterization). This intra-source approach was first applied to the Middle Palaeolithic site of Lusakert Cave 1, where the data revealed that the occupants collected obsidian throughout the river valley, rather than a preferred outcrop, quarrying area, or secondary deposit. Such a finding implied that the toolstone procurement spatially coincided with the valley and was embedded in subsistence activities. In this new study, the same approach to intra-source magnetic characterization is applied to the Lower Palaeolithic site of Nor Geghi 1-specifically, to obsidian debris dated between 440 and 335 millennia ago. The magnetic measurements show that, like at Lusakert Cave 1, toolstone acquisition occurred within the valley. If, as we propose, obsidian procurement reflects the spatial distribution of subsistence activities, it attests that archaic hominins at both sites and in both periods were able to effectively exploit a resource-rich riparian ecosystem. Consequently, this study provides an example of behaviors shared by Middle and Lower Palaeolithic hominins whereby, placed within the same landscape, their resource exploitation behaviors appear indistinguishable.
Given the importance of the Levant in understanding the origins and dispersals of modern humans, ... more Given the importance of the Levant in understanding the origins and dispersals of modern humans, there has been great interest in archaeological evidence to support population movements between the Levant and ad- jacent regions. The link, if any, between the Aurignacian tradition across Europe and the “Levantine Aurignacian” is a particular focus. Ksar Akil in Lebanon not only is one of the most deeply stratified Levantine sites but also has the longest record of Upper Paleolithic behaviors, so it is a benchmark to which developments in the Levant are often compared. Schmidt and Zimmermann (2019) recently proposed that the European Aurignacian tradition might best be understood in terms of connectivity, as evidenced by long-distance lithic transfers that can act as a proxy for mobility and social networks. Here we document a previously unreported obsidian burin from Ksar Akil. Portable X-ray fluorescence reveals that it matches a source ≥700 km away on foot in central Turkey. Two recent dating programs have calculated ages of ~41–38 and ~39–37 ka cal BP for its layer, which also included an obsidian flake and immediately precedes the Levantine Aurignacian at the site. The obsidian artifacts from Ksar Akil are roughly contemporaneous obsidian from Yabroud Rockshelter II in Syria and Shanidar Cave in Iraq. Such instances of long-distance obsidian transport imply that connectivity might have risen ahead of the Levantine and Zagros Aurignacian. Unfortunately, due to the limited chronological resolution of older excavations at these sites, only at Ksar Akil can we have confidence that the layer containing obsidian artifacts immediately precedes the earliest Levantine Aurignacian sensu stricto layer. Given the apparent rarity of obsidian in the Levant, this region will benefit from endeavors to nondestructively source other toolstone ma- terials as a means to create datasets similar to those recently used to model cultural areas of the European Aurignacian.
A series of well-characterized specimens, known as the Peabody-Yale Reference Obsidians (PYRO) se... more A series of well-characterized specimens, known as the Peabody-Yale Reference Obsidians (PYRO) sets, has been designed to aid with calibrating and assessing X-ray fluorescence analysis (XRF) data, including portable XRF (pXRF) measurements, for obsidian sourcing. Each of these ten matched sets consists of 35 specimens: 20 specimens for calibration and 15 specimens for evaluation. These sets include not only obsidians with common geochemical compositions (i.e., alkaline rhyolites) but also rarer ones (i.e., peralkaline rhyolitic, trachytic, and andesitic specimens, including East African Rift obsidians). When used as described, the PYRO sets are suitable to calibrate and evaluate XRF data for obsidians worldwide. A set can be borrowed following loan policies of the Peabody Museum of Natural History, which will also accession a set. Publishing all source information – from their names and GPS coordinates to the datasets used for the recommended values – not only allows the sets to be replicated by others but also fulfills the demands of scientific transparency. Their main purpose is facilitating collaborations and “big data” projects, and the PYRO sets were designed to complement existing protocols for calibration and evaluation. In short, the sets are intended as a tool for almost anyone (e.g., a student who borrows an instrument to source artifacts) to meet – and even exceed – experts' practices involving transparency, accuracy, and reproducibility.
Excavations at Aghitu-3 Cave in Armenia revealed stratified Upper Palaeolithic archaeological hor... more Excavations at Aghitu-3 Cave in Armenia revealed stratified Upper Palaeolithic archaeological horizons (AHs), spanning from 39 to 36,000 cal BP (AH VII) to 29-24,000 cal BP (AH III) and from which we identified the sources of 1120 obsidian artifacts. Not only does AH III-deposited at the onset of the Last Glacial Maximum-have the most artifacts from non-regional sources but also the artifacts originate from the greatest variety of sources, including two ≥ 270 km on foot in different directions. The amount of retouch and density of lithics-as expressed by whole assemblage behavioral indicators (WABI)-suggest a trend from more expediency to more curation between the deposition of AHs VII and IV. This was followed by a substantial shift back to expediency during the deposition of AH III, corresponding to greater logistical mobility. Here, we use agent-based modeling (ABM) to interpret these data. Greater interactions between foraging groups are not an unavoidable outcome of a shift from residential to logistical mobility. Some variables (i.e., lithic stock, use intensity, provi-sioning strategy) can be ruled out, while other variables (i.e., decreased source abundance , a shift to direct procurement) appear inconsistent with the archaeological data. Territory spacing, in contrast, has a clear and predictable effect. A small decrease in territory spacing can yield notable increases in inter-group contact opportunities and can be explained by an increase in population densities as the climate cooled. Following this scenario, we assume that, as AH III accumulated, the cave's occupants not only moved farther distances but also more frequently encountered neighboring groups.
Between Syria and the Highlands: Studies in Honor of Giorgio Buccellati and Marilyn Kelly-Buccellati, 2019
It has long been debated whether the Hurrians, who inhabited the zone between the Anatolian highl... more It has long been debated whether the Hurrians, who inhabited the zone between the Anatolian highlands and Mesopotamian lowlands, were immigrants from the northeast or indigenous to the region. I consider the implications of new obsidian studies on the issue of social networks that linked Mesopotamian settlements to the Caucasus.
Scanning electron microscopy (SEM; this acronym is used for both the instrument itself and the te... more Scanning electron microscopy (SEM; this acronym is used for both the instrument itself and the technique) has been broadly used in archaeology for over four decades. The SEM is capable of two basic functions: imaging and providing compositional information. Consequently, it has been utilized for nearly every archaeological application in which one wishes to examine magnified images of a specimen and/or determine its composition on a microscopic scale, everything from determining the raw-material sources of stone tools to examining the five-millennia-old skin of Ötzi the Iceman.
The NARNIA Project: Integrating Approaches to Ancient Material Studies, 2014
Work Package 7 of NARNIA, Portable XRF Applications in Archaeology, had an objective of contrast... more Work Package 7 of NARNIA, Portable XRF Applications in Archaeology, had an objective of contrasting applications in the field with those in laboratory/museum settings and establishing effective means of field-based analyses. Portable XRF (pXRF) is a means to bring traditionally lab-based studies into the field, and it allows archaeologists to collaborate on-site with colleagues who might otherwise conduct their research off-site. This technology permits us to analyze many more artifacts or samples faster and non-destructively, and those chosen for study can be affected less by export limitations and more by the intellectual framework within which the research was conceived. Ultimately, pXRF enables new (or previously cost- and/or time-prohibitive) research designs. Tasked with teaching and research involving a broad range of archaeological materials, the broad remit of Work Package 7 can be summarized as “work where we couldn’t work before, answer what we couldn’t answer before.” In other words, a core objective was to shift chemical analyses from the realm of “white lab coats” in controlled environments to “muddy boots” in the field. A particular goal was to source obsidian artifacts as they are unearthed at archaeological sites, enabling new research frameworks and informing excavation strategies and interpretations in the field. The setting for this research was Armenia, one of the most obsidian-rich natural and cultural landscapes in the world. I developed two methods to source artifacts on-site in only 10 seconds, including automatic source identification calculated in realtime.
In his chapter titled “Tracing to Source” in Science and the Past, Hughes (1991) draws an analogy... more In his chapter titled “Tracing to Source” in Science and the Past, Hughes (1991) draws an analogy between the chemical analyses of artifacts for sourcing and the classification of objects based on visual characteristics. He argues that a particular “object’s appearance is the first way we recognise where it comes from: a Volkswagen ‘Beetle’ is an instantly recognisable shape even if the VW badge has fallen off the car; likewise we recognise a Rolls Royce” (99). The analogy is not carried through, though, to an underlying issue in sourcing research: what is the definition of a “source”? The “sources” of Volkswagen and Rolls Royce automobiles are complex. Should the Beetle’s source be considered the Volkswagen Corporation, or would a specific factory be the source? Volkswagen is a German company; however, Beetles were also manufactured in Ireland, South Africa, Brazil, Australia, and Mexico. To clutter the issue further, Rolls Royce Motors was sold to Volkswagen in 1998. Depending on the definition, a 1963 Volkswagen Beetle and a 2010 Rolls Royce sedan may have identical “sources.” Hughes’ analogy inadvertently accentuates the importance of a clear conceptualization of “source.”
Two illustrations from the 1968 Scientific American article by John Dixon, Joseph Cann, and Coli... more Two illustrations from the 1968 Scientific American article by John Dixon, Joseph Cann, and Colin Renfrew are, without doubt, the most frequently reproduced figures in all of obsidian sourcing. Their map generalising the spatial distribution of obsidians across the Neolithic Near East and their graph of the “fall-off curves” for obsidian abundance in the corresponding flaked-stone assemblages are, amongst many other venues, included in Colin Renfrew and Paul Bahn’s textbook Archaeology: Theories, Methods, and Practice. The book, now in its sixth edition, has been used by more than 200,000 archaeology students since 1991. Like most of those students, my first exposure to obsidian sourcing was that part of the “Trade and Exchange” chapter (soon followed by Kent Flannery’s The Early Mesoamerican Village). The figures, which represented the research of Renfrew, Cann, and Dixon (hereafter RDC for simplicity) so succinctly, had core roles in popularising obsidian sourcing. Approaching 50 years old, their work still represents the largest single regional-scale obsidian-sourcing study in the Near East. Today, however, obsidian sourcing in Near East archaeology lags behind that in the New World (where the largest regional-scale study included over 9000 obsidian artefacts from over 130 Pacific Northwest sites; Skinner 1995). What was the archaeological backdrop that led RDC to start their obsidian work in 1962? What led a lull in Near Eastern obsidian sourcing during the 1980s and 1990s until a recent “new wave”? What can the past and present of obsidian sourcing tell us about its future?
International Association for Obsidian Studies Bulletin, 2017
A few of the major portable X-ray fluorescence (pXRF) manufacturers have released new models in t... more A few of the major portable X-ray fluorescence (pXRF) manufacturers have released new models in the past year or two. The technologies in these latest instruments have advanced so much that any performance appraisals more than a few years old are essentially obsolete. The X-ray detectors and associated electronics inside a new pXRF analyzer are more sensitive than those in many benchtop models just five or ten years ago. This report summarizes initial tests of the newest pXRF series – Vanta – from Olympus Scientific Solutions. The tests included sourcing 40 artifacts from two Early Bronze Age settlements in Armenia and analyzing a collection of geological specimens that had been measured using other techniques, including neutron activation analysis and energy- dispersive XRF at the University of Missouri Research Reactor as well as electron probe X-ray microanalysis at the University of Minnesota. This report is intended as documentation of the Vanta’s high potential for non-destructive obsidian artifact sourcing that is fast, precise, and accurate.
Syrian Studies Association Newsletter, Jan 1, 2011
Societal responses to climate change in marginally productive areas. Social networks and new mode... more Societal responses to climate change in marginally productive areas. Social networks and new modes of communication. Maintenance of identity and cultural practices among immigrants and ethnic minorities. Sustainability under population and resource pressures. Colonial empires with geopolitical interests in controlling natural resources. State formation in ethnically diverse regions. Domestic production versus foreign trade in an increasingly connected world. Farmers and herders becoming city dwellers under economic pressures. Flow of people, goods, and ideas and the effects on local cultures during globalizing movements. This could be a list of topics in an upcoming Syrian studies conference or a seminar course on modern Middle East issues. They are also subjects of great interest to archaeologists who study Chalcolithic (4500-3500 BCE) and Bronze-Age (3500-1200 BCE) Syria. These issues are not as inextricably linked to modernity as they first seem, and archaeology offers a way to explore them with time depth.
Our research involves a novel combination of techniques to investigate the ceramic tradition at a... more Our research involves a novel combination of techniques to investigate the ceramic tradition at ancient Urkesh. Preparing and observing large numbers of samples for traditional ceramic petrography is expensive, time-consuming, and impractical in the field. Our alternative approach uses a flatbed scanner on- site to collect high-resolution images of sectioned sherds. We selected a portion of the scanned sherds for subsequent microanalysis. Element maps of these sherds were made using an electron microprobe (also called an electron probe microanalyzer). Image analysis software correlated the two image sets. The result is a promising way to analyze large numbers of sherds, crucial for understanding chronological and stylistic variations at this particular site and throughout the region.
Geological Society of America Abstracts with Programs, 2007
Ideally chemical analyses used for sourcing studies could be conducted in the field, quickly, and... more Ideally chemical analyses used for sourcing studies could be conducted in the field, quickly, and nondestructively. Unfortunately, most techniques require immobile instruments. One technique with great potential for on-site analysis is portable energy-dispersive X-ray fluorescence (ED-XRF). Thermo Fisher Scientific's NITON analyzer is a handheld ED-XRF device about the size and shape of a cordless drill. It is typically used for environmental monitoring and scrap-metal testing. I evaluated an "off-the-shelf" model of NITON analyzer to see if it could differentiate Anatolian obsidian sources. The analyzer was used in a factory-set "bulk/soil" mode without further calibration, and the 21 elements measured were also preset. NIST standards were also analyzed to determine if its accuracy and precision for trace elements are sufficient for sourcing. Like all ED-XRF systems, this analyzer is susceptible to X-ray peak overlaps, causing misidentified elements and spurious element detection. A sample-size effect was also observed for some elements, as has been previously documented for XRF. Element concentrations were often under- or over-reported, typically by a factor of 2 to 3, although more at times. This strongly underscores the need for users to create custom calibrations for each material (e.g., obsidian based on rhyolitic glass standards) to improve accuracy. Testing established, though, that errors were mostly systematic. About two-thirds of the obsidian sources were clearly distinguished. Other source fingerprints overlapped, and some overlaps had important implications for archaeological interpretation. Also, if the data are only internally consistent, one cannot use them directly with existing source databases. Any archaeological applications of the analyzer must play to its strengths, notably portability. This instrument might be most useful in archaeology as a "first sort" tool: one can analyze hundreds of artifacts on-site, explore the data for chemical clusters, select representative samples from each cluster for export and later lab-based analyses, and supply the initial data in artifact export requests. Portable ED-XRF is one of only a handful of techniques that shows potential for initial on-site chemical sorting of artifacts, and I am planning further tests using my own custom calibrations.
Field guides are essential components of both the archaeologist’s and geologist’s toolkits but mu... more Field guides are essential components of both the archaeologist’s and geologist’s toolkits but must also be worth their weight in a pack. This trio of books, all revised from prior editions, has been updated for Wiley-Blackwell’s Geological Field Guide Series, and their subjects are relevant to a sizable proportion of geoarchaeological research: sedimentary and igneous rocks as well as geophysical surveying. The books are touted as pocket-sized guides for use in the field, and indeed they are perfectly sized to fit in the cargo pocket of field pants (one at a time, not all three at once). The potential for useful field guides on the three topics is exciting, and these books are certainly poised to fill notable voids.
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