PROVENANCE STUDIES OF CHALCOLITHIC OBSIDIAN ARTEFACTS FROM NEAR LAKE URMIA, NORTHWESTERN IRAN USING WDXRF ANALYSIS

In 2005–2006 we initiated a major archaeological survey and chemical characterization study to investigate the long-term use of obsidian along the eastern shores of Lake Urmia, northwestern Iran. Previous research in the area suggested that almost all archaeological obsidian found in this area originated from the Nemrut Daĝ source located in the Lake Van region of Anatolia (Turkey). More recent research on obsidian artefacts from the Lake Urmia region has identified a significant number of obsidian artefacts with compositions different from the sources near Lake Van. This suggests that the obsidian artefacts are from a yet to be identified geological source, but possibly one that was not too distant. In order to advance our knowledge of Iranian obsidians and eventually refine provenance criteria we analysed obsidian from 22 Chalcolithic sites and some source areas. The compositions of both obsidian source samples and artefacts were determined using wave length dispersive X-ray fluorescence spectrometry (WDXRF). This paper presents results from the trace elemental analysis of both geological and archaeological obsidians, providing important new data concerning the diachronic relationship between lithic technology and raw material in the north-west of Iran.     

Geochemical composition of source obsidians from Kenya

Here we provide a reference resource to archaeologists interested in the sources of obsidian in Kenya, through electron microprobe analyses of 194 obsidian samples from 90 localities. Averaged analyses of each sample and eleven published analyses are categorized into 84 compositional groups of which only about 21 are known to have been used to produce artifacts, possibly because studies of artifactual material in the region are lacking. We also provide trace element analyses determined by XRF and LA-ICP-MS for these same obsidians. In northern Kenya 27 distinct compositions of obsidian have been found, including some of Miocene age, but the source of the most abundant obsidian found in archaeological sites in this part of Kenya remains obscure. The Baringo region contains at least 13 varieties of low-silica obsidian. The Naivasha–Nakuru region contains an abundance of obsidian with 38 compositional types recognized, and is the only region in Kenya apart from the Suregei (northern Kenya) that contains rhyolitic obsidian. Nine compositionally distinct types of obsidian are known from southern Kenya. Although Kenyan obsidians span the compositional range from phonolite to rhyolite, low-silica, nepheline-normative obsidians occur only south of 1°N latitude. One obsidian type, the Lukenya Hill Group, appears to have been derived from a regionally extensive ash flow tuff with a distribution of over 8000 km². From previous studies it is known that obsidians of lowest (Mundui) and highest iron content were used for tool manufacture, as were some obsidians (e.g., Kisanana) with the highest alkali content, and obsidians with both high (Njorowa) and low (Kisanana) silica content.     

Through the Glass Darkly: Prehispanic Obsidian Procurement and Exchange in Southern Peru and Northern Bolivia

Recent discovery of the major geological sources of Central Andean obsidian permits a new understanding of the patterns of obsidian procurement and exchange by the Prehispanic societies of southern Peru and northern Bolivia. Based on the trace element analysis of obsidian artifacts from 160 archaeological sites, it can be established that the two major deposits of obsidian were being exploited by 9400 BP, and that volcanic glass was being transported over long distances throughout Andean prehistory. Inhabitants of the Cuzco region acquired most obsidian from the Alca source in central Arequipa, while those in the high plateau surrounding Lake Titicaca obtained most obsidian from the Chivay source in southern Arequipa. Obsidian evidence suggests close ties between the Cuzco and Circum-Titicaca regions throughout prehistory, except during the Middle Horizon (ca. 1400–1050 BP), when the expansion of the Huari and Tiahuanaco states disrupted this pattern.     

Characterization of New Zealand obsidian using PXRF

New Zealand has some of the most active areas of rhyolitic volcanism in the world and this has produced numerous obsidian sources in the northern half of the North Island. In total archaeologists have recognized 27 named locations from which obsidian can be obtained scattered across 4 geological source regions. Shortly after colonization in the late 13th century AD Polynesian settlers began transporting this material some thousands of kilometers throughout the country and across the sea in small quantities to distant neighbors in the Kermadecs and Chatham islands. Although considerable research has been conducted on obsidian sourcing in New Zealand the complexity of geochemical source discrimination and the lack of a practical method of non-destructive geochemical analysis has hindered progress. We present the results of our use of PXRF to provide geochemical data on New Zealand obsidian sources and to compare the use of discriminant analysis and classification tree analysis to discriminate among sources and attribute archaeological samples to sources. Our research suggests that classification tree analysis is superior to discriminant analysis in sourcing studies. A large case study using an important settlement phase site (S11/20) from the Auckland region demonstrates the utility of the methods and the results support a model of high degrees of mobility and interaction during the early settlement of New Zealand.     

PROVENANCE OF OBSIDIAN EXCAVATED FROM LATE CHALCOLITHIC LEVELS AT THE SITES OF TELL HAMOUKAR AND TELL BRAK,SYRIA*

X‐ray fluorescence and laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) analyses conducted on 40 obsidian samples from the Late Chalcolithic 2 levels at Tell Hamoukar and Tell Brak in north‐east Syria have shown trends towards the exploitation of obsidian sources in the eastern Taurus. While the Bingöl region appears to provide the majority of obsidian to both sites, there is also evidence of more minor exploitation of a source in the Lake Van area and an altogether unknown source (X). This paper presents the data acquired from the analyses of the archaeological obsidian and situates these results within their chronological and regional contexts.     

Measuring prehistoric mobility strategies based on obsidian geochemical and technological signatures in the Owens Valley,California

We compare the organization of obsidian flaked stone technologies in two different time periods at CA-INY-30, a village site in southern Owens Valley, eastern California. Previous archaeological studies suggest a reorganization in settlement patterns between the Newberry (ca. 3500–1500 BP) and Marana (ca. 650-contact) periods, from a highly mobile to a more residentially sedentary one. New geochemical data, based on laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of obsidian artifacts associated with discrete house floors, support this basic settlement model, but reveal new detail in how people moved across the landscape and accessed, extracted, reduced and used obsidian resources. In the earlier Newberry period, there is no relationship between flake size and distance-to-source, and the falloff curve relating frequency of obsidian against distance is more gradual, as expected, but contrary to our expectations, source diversity is not higher. These factors suggest extremely high mobility, but also selective extraction of particular sources. Newberry obsidian may have been acquired by groups of hunters who embedded quarrying within long-distance trips to distant hunting grounds, and subsequently transported bifacial cores to base camps. By contrast, Marana patterns show strong relationships between flake size and distance from source and steeper fall-off curves, suggesting groups acquired their obsidian primarily from closer sources, likely via exchange networks. At the same time, geochemical diversity, especially among smaller resharpening flakes, is higher in the Marana period, highlighting the wide-ranging conveyance systems through which obsidian moved.     

How reliable are our published archaeometric analyses? Effects of analytical techniques through time on the elemental analysis of obsidians

To assess the analytical accuracies and precisions of archaeometric elemental analyses by different techniques, a relatively homogeneous material such as obsidian must be studied. An assessment of published elemental concentration data from two Anatolian obsidian sources shows that while in most cases analytical accuracy is as high as is commonly expected, in some cases it is not. It also shows that the dispersions of elemental concentration data (indicators of analytical precisions) coming from modern analytical procedures are akin to the estimated homogeneity of the obsidian. Based on this latter observation, if one has element dispersion data from a single analytical technique, with a single source of obsidian as a control, data sets that contain multiple, but similar sources of obsidian may be differentiated.     

Obsidian types from Holocene sites around Lake Turkana,and other localities in northern Kenya

Obsidian has been widely used by early Holocene hunter-gatherers and succeeding Pastoral Neolithic peoples in northern Kenya. Here we report the results of over 2000 electron microprobe analyses of artifactual and non-artifactual obsidian from the greater Lake Turkana region. Of the 15 compositional types of obsidian observed, a preponderant type is widespread across the region from the Barrier in the south to Ileret in the north and east as far as Kargi. This obsidian is the principal type at Lowasera and most Pastoral Neolithic sites, including the Jarigole Pillar site and Dongodien (GaJi4). The source of this obsidian is not known, but based on its distribution the source may be located on the Barrier or in the Suguta Valley immediately to the south of Lake Turkana. Although there are several possible sources of local obsidian identified for minor types, in stark contrast to the central part of the Kenyan Rift, major sources of obsidian available for artifact manufacture are not known in the Lake Turkana region. The lack of obsidian from demonstrable Ethiopian Rift and central Kenyan Rift sources, and the absence of obsidian with compositions found at the Turkana area sites in assemblages in the central part of the Kenyan Rift suggests that the earlier Pastoral Neolithic peoples around Lake Turkana interacted with each other, but perhaps not as strongly with people farther south along the Rift Valley, even as herding practices were expanding to the southward into central Kenya.     

Obsidian use at the Ushki Lake complex,Kamchatka Peninsula (Northeastern Siberia): implications for terminal Pleistocene and early Holocene human migrations in Beringia

A study of the movement of people within Northeast Asia at the end of the Pleistocene is critical for understanding how and when some of the first human populations entered North America. Chemical source studies of obsidian may provide the evidence necessary to document people's migrations between these regions. Sixty two obsidian artifacts from the late Pleistocene and Holocene Ushki Lake sites in Kamchatka Peninsula were analyzed by instrumental neutron activation analysis (INAA). Data generated demonstrate that multiple obsidian sources throughout Kamchatka were exploited by the inhabitants of Ushki Lake, and allow us to document long-distance population movements during the late Pleistocene and Holocene. It is reasonable to expect that obsidian from Kamchatka might have been transported to Alaska. This is true for the Chukotka region of Northeastern Siberia; obsidian from Chukotka has been found in late Holocene archaeological sites in Alaska. Ultimately, an expanded study that includes all areas of Northeast Asia and Alaska may provide the data necessary to document the earliest movements of people in these regions.     

The Hungarian and Slovak sources of archaeological obsidian: an interim report on further fieldwork,with a note on tektites

This report describes the results of fieldwork carried out in the Zemplén Mountain area of north-eastern Hungary in 1975. The aim of this work was to locate and sample geological sources of obsidian which may have been used by prehistoric man. These sources are of increased importance since the work of Nandris (1975) showed that the Romanian “sources” do not produce workable obsidian. During the fieldwork three sources in Hungary were visited and sampled; one of these was the previously unlocated source of Csepegö Forräs. A number of other possible localities for geological obsidian are mentioned in 19th and 20th century geological and archaeological literature, and the present state of knowledge with regard to these is summarized. Further sources exist in central and in south-eastern Slovakia. These sources were not visited but material has been obtained from both areas. The central Slovak sources do not produce workable obsidian and are not therefore relevant to archaeological studies. Obsidian from three localities in south-eastern Slovakia is of good glassy quality and further fieldwork is now needed to check the validity of these localities as geological sources. Reference is made to obsidian sources in the western U.S.S.R., and the problem of the use of tektites in archaeological sites is discussed.The obsidian samples obtained during this work are currently being analyzed using neutron activation, in order to characterize the sources on the basis of their trace element analysis and thus to relate them to archaeological obsidian from central and eastern Europe.     

New Data on the Exploitation of Obsidian in the Southern Caucasus (Armenia,Georgia) and Eastern Turkey,Part 2: Obsidian Procurement from the Upper Palaeolithic to the Late Bronze Age

Within the framework of the French archaeological mission ‘Caucasus’, in a previous paper we have presented new geochemical analyses on geological obsidians from the southern Caucasus (Armenia, Georgia) and eastern Turkey. We present here the second part of this research, which deals with provenance studies of archaeological obsidians from Armenia. These new data enhance our knowledge of obsidian exploitation over a period of more than 14 000 years, from the Upper Palaeolithic to the Late Bronze Age. The proposed methodology shows that source attribution can be easily made by plotting element contents and element ratios on three simple binary diagrams. The same diagrams were used for source discrimination. As the southern Caucasus is a mountainous region for which the factor of distance as the crow flies cannot be applied, we have explored the capacity of the Geographic Information System to evaluate the nature and patterns of travel costs between the sources of obsidian and the archaeological sites. The role of the secondary obsidian deposits, which enabled the populations to acquire raw material at a considerable distance from the outcrops, is also considered.     

Obsidian sources in highland Yemen and their relevance to archaeological research in the Red Sea region

The Red Sea and surrounding area formed through dynamic uplift and rifting of Afro-Arabia, and associated volcanism (both oceanic and continental in character). As a result, volcanic landforms and products are widespread and play a vital role in the natural and cultural landscapes of humans occupying the highlands and lowlands on both sides of the Red Sea. Archaeologists have suggested for some time that Afro-Arabian trade in obsidian had its roots in the prehistoric period and that the region was very likely the source of an abundance of obsidian artefacts found as far afield as Egypt, the Persian Gulf and Mesopotamia, and which do not match the well-known Anatolian, Transcaucasian or Mediterranean sources. Nonetheless, the southern Red Sea is one of the few obsidian-rich regions exploited in antiquity that has been barely investigated. In this paper, we highlight new geochemical analyses (carried out by LA-ICP-MS) of obsidian sources in Southern Arabia and beyond, that enhance our knowledge of obsidian exploitation from as early as the Neolithic period, and which enable us to evaluate the role that highland Yemen obsidian sources played in prehistoric long-distance trade. In addition, we present new evidence for explosive volcanic eruptions that likely affected the highland populations of Yemen in the 4th millennium BC.     

THE OBSIDIAN IN THE AEGEAN BEYOND MELOS: AN OUTLOOK FROM YALI

Summary.   Obsidian is an important material circulated throughout the Aegean. Melian obsidian is found at many sites and researchers have concentrated on Melos without acknowledging obsidian from other sources. This article endeavours to highlight obsidian of non-Melian origin, such as that from the Carpathians, central Anatolia, Antiparos and, particularly, Yali. It is demonstrated that this latter source was a central one for certain islands, with its obsidian found at a number of sites in the Dodecanese and beyond. It is also emphasized that there were circulation modes of obsidian parallel to that of Melos, as well as different procurement conditions. Therefore, by including important regional sources such as Yali in the obsidian discourse, our understanding of obsidian exchange and circulation is enriched.     

Obsidian source characterization in the Cordillera Real and eastern piedmont of the north Ecuadorian Andes

Recent research in the Quijos and Cosanga valleys of the eastern piedmont of Ecuador’s Cordillera Real has revealed and substantiated previous knowledge of obsidian sources that are unrelated to obsidian flow systems in the Sierra de Guamaní, Ecuador. Neutron Activation Analysis (NAA) and X-ray Fluorescence (XRF) were carried out on 47 obsidian source samples collected from several contexts in and adjacent to the study area. From samples within the study area three distinct obsidians were characterized: Cosanga A, Cosanga B, and Bermejo. These obsidians originate from a number of obsidian-bearing rhyolitic domes recently identified in the hills west of the Río Cosanga. Extensive survey of these dome localities has identified obsidian cobbles large enough for formal and informal tool manufacture. Beyond the study area, samples were collected and analyzed from the El Tablón source in the Sierra de Guamaní, providing much needed data on this poorly understood source. In addition, a sample from the newly identified Conda Dome source, near the Cotopaxi volcano, was characterized with XRF. All samples were then compared to 57 pre-existing samples from the Mullumica–Callejones, Yanaurco–Quiscatola and Carboncillo sources in the Ecuadoran Cordillera Real, as well as to artifacts from the Sumaco area in the Ecuadorian Amazon. Results of the elemental characterization indicate that the Cosanga Valley, El Tablón and Conda Dome obsidians are chemically distinct. Further, visual characteristics of Cosanga Valley obsidian types are useful in source attribution for the large artifact samples from the region. Finally, obsidian collected from the El Tablón flow suggests that this source may have produced obsidian suitable for tool manufacture.     

Possible obsidian sources for artifacts from Timor: narrowing the options using chemical data

Measurements made at the Australian National University using laser ablation ICPMS show that none of the 88 analyzed obsidian artifacts from East Timor match either the known Papua New Guinea or the five Island SE Asian source samples in our ANU collections. There is a coastal journey of more than 3000 km between the occurrence of obsidians from the Bismarck Archipelago volcanic province of Papua New Guinea and the Sunda-Banda Arc volcanic chain, yet obsidian artifacts from the two important PNG sources of Talasea and Lou Island are found at coastal Bukit Tengkorak in eastern Sabah at a similar distance along with material that has no known source. Timor lies south of the eastern section of the active volcanic Banda Arc island chain but it is within range of possible rhyolite sources from there. Although there is a continuous chain of around 60 active volcanoes stretching from west Sumatra to the Moluccas most are basaltic to andesitic with few areas likely to produce high silica dacite–rhyolite deposits. This does not exclude the possibility that the volcanic landscapes may contain obsidian, but without detailed survey and chemical analysis of sources from the Sunda-Banda Arc the attribution of the Timor obsidian artifacts remains to be demonstrated. Timor may seem to be an unlikely source for the presence of obsidians as it lacks reports of the silica-rich rhyolite volcanic centers necessary to produce this material. Despite the absence of detailed survey and analysis of Indonesian obsidian sources, especially from the volcanically active Banda Arc, this paper presents evidence that one of two obsidian sources is clearly from Timor while the other, with less certainty, is also from an unknown local source.     

A provenance study of archaeological obsidian from the Andahuaylas region of southern Peru

To date, most obsidian sourcing studies in the Andes have concentrated on the highlands and Titicaca Basin of far southern Peru and northern Bolivia. Toward achieving a more complete understanding of the region, this paper offers new data on the long-term prehistoric obsidian procurement and consumption patterns in the Andahuaylas region of the south-central Peruvian highlands. Obsidian sourcing data from Andahuaylas are particularly interesting since the area is centrally located among several important regional obsidian sources. A total of 94 obsidian samples from a range of sites of different temporal periods were chemically analyzed using portable X-ray fluorescence (PXRF), as well as laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results demonstrate a number of interesting trends, the first of which is the long-term importance of the Potreropampa obsidian source to populations of the Andahuaylas region from at least the early Formative period (∼2500 BCE). Secondly, the results indicate that procurement strategies by local populations in Andahuaylas were primarily reliant on nearby (<150 km) obsidian sources. Finally, the paucity of more distant, yet widely exchanged, high quality obsidian (i.e., Chivay, Alca) confirm that as a region, Andahuaylas was more heavily connected economically (and likely culturally) with local areas to the south (Apurímac) and to the west (Ayacucho).     

Obsidian Sources in the Regions of Erzurum and Kars (North‐East Turkey): New Data

The obsidian sources on the Erzurum–Kars Plateau have not been extensively surveyed, and their geochemical signatures are still poorly understood. Yet a significant number of artefacts from archaeological sites in Georgia and Armenia have produced chemical compositions that are unrelated to any Turkish or Caucasian source analysed so far. Their origins may lie in these poorly known deposits. The objective of the collaborative project undertaken by the University of Erzurum and the French mission ‘Caucasus’ is to study the sources of obsidian in the Erzurum and Kars regions, in order to shed light on the intensity of exploitation of this material, and to highlight the exchange networks that may have existed between north‐eastern Turkey and the southern Caucasus. The analyses that we have carried out on the samples taken during this exploratory survey have enabled a definite extension of the territory of circulation of this obsidian to western Transcaucasia. The lack of knowledge concerning the diffusion of obsidian from the regions of Erzurum and Kars thus appears for the moment mainly related to insufficient geochemical characterization of the sources, confirming the importance of future surveys.     

Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence

X-ray fluorescence analysis of obsidian artifacts from sites located in Chaco Canyon and from three Chaco-era communities in New Mexico permits determination of their geological origin. These source data are used to describe patterning in obsidian procurement in sites located in Chaco Canyon dating from A.D. 500–1150, and in a three non-Canyon communities occupied during the period of Chaco Canyon's regional prominence (ca. A.D. 875–1150). These data demonstrate that the most proximate sources generally dominate the sourced obsidian assemblages from sites of all periods, but also suggest differences in procurement patterning both over time and across space. Within Chaco Canyon, there is a notable shift from Mount Taylor obsidian to use of Jemez Mountains sources over time. These data also suggest that earlier analyses of obsidian from sites in Chaco Canyon misidentified some obsidian artifact sources; these new data indicate the central areas of disagreement and provide a revision of procurement patterning. In the Chaco-era communities located outside Chaco Canyon, procurement patterning diverges. The Blue J community shows an increase in use of the nearby Mount Taylor source over time. Two communities located toward the southern extent of the Chaco great house distribution reveal a markedly distinct procurement pattern, obtaining nearly all of their obsidian from southern sources largely unrepresented at Chaco Canyon. Combined, these data provide new insights into raw material procurement and artifact production at sites in Chaco Canyon, and in communities occupied during the Chaco Phenomenon, the period of the Canyon's greatest regional influence.     

XRF obsidian analysis from Ayacucho Basin in Huamanga province,south-eastern Peru*

Obsidian was broadly used along the Andean Cordillera in South America. Particularly in Peru, its use can be traced to the earliest human occupations, continuously through pre-Columbian times to contemporary Andean agro-pastoralist societies. In order to distinguish the provenance of obsidians from Peru, this paper reports a new X-ray fluorescence (XRF) analysis on several obsidians obtained in surface collections of the Ayacucho region. The analysis and source determination were made by XRF on 52 specimens. The source assignments involved comparisons between the compositional data for the specimens and the University of Missouri Research Reactor (MURR) XRF obsidian database for sources in Peru. After analysing the samples, obsidian sources were recognized and documented. All had small nodules not larger than about 4 cm. They were recovered from Ñahuinpuquio and Marcahuilca hill which belonged to the previously identified Puzolana source. Another identified source was the well-known Quispisisa, located 120 km south of the city of Ayacucho, and distributed through a vast region in central Peru. The results expand previous observations made on the obsidian provenance at Ayacucho Basin, as well as the extension of the Puzolana source between Yanama and Huarpa hills, south of Ayacucho city.