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A machine learning approach to Nemrut Dağ and Bingöl geological obsidians was performed to determine the provenance of source material of nine obsidian blades from the archaeological site of Tulūl al Baqarat (Iraq).
Obsidians tools have been chemically analysed with a non-invasive and non-destructive approach by a low vacuum SEM-EDS microprobe for determining major and minor elements and by a bench-to-top micro-XRF for trace elements.
To identify the supply volcanic complex which produced the blocks from which they were knapped, a geochemical identification of Turkish obsidian sources, from the volcano to the artefact samples, was carried out introducing the use of the machine learning approach as exhaustive discriminative approach with complementary well-known geochemical comparisons and Principal Component Analysis.
Obsidian tools show a rather homogeneous comendite and peraluminous rhyolite composition with an high Zr amount which excludes most obsidian outcrops in Turkish and Armenian volcanic sites as original obsidian sources. However, only using a machine learning approach to major, minor and trace elements, the obsidian tools have resulted geochemically comparable to Nemrut Dağ mild alkaline rhyolitic obsidians from pre-caldera eruptions, and now outcropping inside the caldera and in Sicaksu exposure.
This source provenance from Nemrut Dağ stratovolcano in South-eastern Turkey, located near the Turkish route of the Tigris River, supports the evidence of a network of trade and broad exchange since 4th Millennium from Turkey and the South Near East, presumably through the basins of the Tigris and Euphrates to the shores of the Persian Gulf.
Results of geochemical analyses of obsidian artefacts from the Neolithic site of Tell Labwe South, Lebanon
Obsidian artifacts are geochemically traceable to their geological sources of origin. The results of their analysis provide some of the most accurate testimonies of interaction, exchange and population movement. This article presents results of obsidian analyses of artifacts from twelve sites from the Middle Euphrates to the Arabian Gulf. We demonstrate that the Sıcaksu flow of Nemrut Dağ in eastern Turkey consistently supplied obsidian to the majority of sites across this region from the 7th to 4th millennia BCE. This outcrop predominated in analyzed assemblages and as a production material for the region, across all site positions, sizes and periods; this has been argued to be a result of the quality, quantity and accessibility of this flow (Robin et al., 2016). The analyses demonstrate the presence of mainly finished products from a variety of additional sources in eastern Anatolia and Armenia (average > 4 sources) on northern Mesopotamian sites during this time span. We argue that the Nemrut region was a major economic node and chief actor in the establishment and dynamics of networks in the greater region. The diachronic persistence or breaks in obsidian supply from more minor sources are an additional source of information on the inner workings and development of subtle interregional socio-political and economic relations. Obsidian analysis provides a detailed picture of the contributions of increasingly complex networks and channels of communication to intensified adoption of common practices and styles across regions, to intensification of processes leading to urbanization and state formation, and to accentuating periods of stress and conflict. These data nourish and update existing models on social networks during the crucial Ubaid to Late Chalcolithic periods and advance debates on the role and impact of these networks on early state formation.
