Northeast Anatolian obsidians: preliminary results

Obsidian, whose physical properties are suitable for making cutting tools, was one of the most basic commodities traded in prehistoric times. Obsidian, not found everywhere and with its unique chemical composition, is often used to create maps of prehistoric migration and trade routes. There are many important obsidian sources in Anatolia. These sources were utilised in the prehistoric period. One of the most important challenges facing archaeologists is identifying the source area of the raw materials used to create obsidian stone tools in prehistoric settlements. The geochemical properties of the obsidian from Northeastern Anatolia are less well known than those from Central Anatolia. The obsidians of Northeastern Anatolia were formed in three different geotectonic settings from the Upper Miocene to the Plio-Quaternary; i. The obsidians in Erzurum-Kars Plateau were formed due to the crustal thickening caused by the collision of Eastern Anatolia on the Pontides, ii. The obsidians in Gümüşhane-Şiran and Rize-İkizdere were formed within the volcanic arc, iii. The obsidians in Erzincan are on the North Anatolian Fault Zone. Preliminary results of the major oxides and trace elements of Erzincan-Üzümlü, Erzurum-Başköy and Pasinler, Kars-Sarıkamış, and Rize-İkizdere obsidians by using LA-ICP- MS are presented. Although the major oxide compositions of the samples are close to each other, their trace element contents enabled them to be geochemically characterized. Ca, Sr, Ba, and Rb contents of the obsidians of Northeastern Anatolia are characteristic. The ratios of these elements (Sr/Rb, Ba/Rb, Ba/Sr and Ca/Ba) were used to construct the discrimination diagrams. The results are promising and show that chemical databases of these resources still need to be improved.