New data on source characterization and exploitation of obsidian from the Chikiani area (Georgia)

The characterization of the obsidian specimens collected during the 2012 and 2014 surveys evidence the existence of at least 3 main obsidian chemical groups at Chikiani. The possible presence of different eruptive phases was already pointed out (Nomade et al. 2015). An age ranging from 2.4 Ma to 2.8 Ma being associated with the studied samples presenting respectively the lowest and highest barium content (638 ppm and 682 / 727 ppm). These datings are however still discussed (Lebedev and Vashakidze 2015). The perfect match observed between the chemical composition patterns of the high barium artefact groups and those of groups 2, 3a and 3b, confirms the attribution of these artefacts to the Chikiani obsidian outcrops. According to the available data, Mt. Chikiani obsidian sources were exploited throughout a long period, ranging from the Early Neolithic to the Middle Bronze Age. The supply zone covers a wide territory. Nevertheless, at present little is still known of the modes of exploitation of the different Chikiani flows, and even less of the precise location of the exploitation zones during the different periods. The new characterizations presented here, according to which three Chikiani obsidian groups have been identified and precisely geo referenced for the first time (fig. 9), help interpret the complexity of the role played by Caucasian obsidian exploitation and its modes of circulation inside and outside this Caucasus.