Identification and characterization of a new obsidian source in the Nemrut volcano (Eastern Anatolia, Turkey) : the Sıcaksu obsidian
Résumé
In the frame of GeObs project (http://geobs.univ-rouen.fr/), we started an exhaustive field study of obsidian lavas outcrops in the Nemrut Volcano (Eastern Anatolia, Turkey). We propose here to present results from analyses of the macroscopic facies and chemical characteristics of all sub-sources, and its comparison to each other. A first conclusive remark is that most Nemrut sub-sources are distinguishable using geochemical data (LA–ICP–MS). In addition, on the western flank of the volcano we identify and characterize (in the field as well as in the laboratory) two yet unknown obsidian outcrops (Kayacık and Sıcaksu) which are close to each other, with regard both to its geography and geochemistry. No previous research on obsidian sourcing around this volcano was able to identify these sub-sources.Statistical treatments (classification and discriminant analyses) applied to a set of data composed of our results from both (i) all our sub-sources sampled in the Nemrut, together with (ii) the artifacts attributed by L. Khalidy et al. to the Nemrut Volcano, clearly connect the artifacts to the group formed by these newly found sub-sources. Results of the combination of field work data, geochemical analyses, and statistical treatments comparing geological and archaeological obsidians, evidence the importance of two obsidian outcrops sampled by us on the western flank on Nemrut Volcano, which is the most up-to-date collection of samples from the Nemrut.In further detail, only one of the two new sub-sources, the ―Sıcaksu‖ obsidian, is particularly homogenous and suitable for chopping. Accordingly, Sıcaksu obsidian is now the best candidate for being the source addressed by Neolithic populations who collected raw material in the Nemrut Volcano for tool-making.