Sourcing obsidian from Tell Aswad and Qdeir 1 (Syria) by SEM-EDS and EDXRF: Methodological implications

Multiple sources: The pXRF analysis of obsidian from Kenan Tepe, S.E. Turkey

“…Although thickness probably starts to have a small impact for some elements at less than c.8mm thickness, this seems to be well controlled by the internal calibration of the instrument until the thickness becomes less than c.1.7mm. This compares to previous studies with similar instruments which have suggested that measurements below 2mm become dubious (Davies et al 2011;Orange et al 2013;Le Bourdonnec et al 2013). While usable readings can be feasible below this threshold (e.g.…”

“…In the Kenan Tepe artefacts, the two groups correspond well with source material representing the two peralkaline sources Nemrut Dağ (339 artefacts) and Bingöl A (122 artefacts) apart from the small number (4) that fall between them where the exact peralkaline sub-source has to remain undetermined. While multiple sub-groups at Nemrut Dağ have been attested by a range of studies Frahm 2012;Orange et al 2013), most have not been identified in archaeological contexts, perhaps due to being of insufficient quality for knapping and it now seems likely that most come from the Sicaksu source (Robin et al 2015). In most archaeological studies (e.g.…”

“…In the past the two peralkaline sources, Nemrut Dağ and Bingöl A, have proved difficult to distinguish but recent analyses have regularly been able to reliably distinguish them using a range of element combinations and ratios (e.g. Frahm 2012;Orange et al 2013;Carter et al 2013). In the Kenan Tepe artefacts, the two groups correspond well with source material representing the two peralkaline sources Nemrut Dağ (339 artefacts) and Bingöl A (122 artefacts) apart from the small number (4) that fall between them where the exact peralkaline sub-source has to remain undetermined.…”

“…The lack of attention to these choices at a site-level has been amplified by the fact that only a small proportion of the artefacts from each site have been provenanced. It is only recently that exceptions have started to emerge, such as Çatalhöyük in Central Anatolia and Tell Aswad and Qdeir 1 in Syria where comprehensive analyses using laboratory based instruments has afforded a highly nuanced picture of obsidian use in central Anatolia (Carter et al 2005;2006;Carter and Shackley 2007;Poupeau et al 2010) and extended our understanding of the use of eastern sources (Orange et al 2013). Now that non-destructive analysis and portable instruments are readily available, opportunities for analysing large numbers of obsidian artefacts from a single site have become much more practical.…”

On sourcing obsidian assemblages from the Mediterranean area: analytical strategies for their exhaustive geochemical characterisation

“…Its capacity to measure elements within the mid-Z X-ray region (mainly between Ti and Nb; see Shackley, 2011;Glascock, 2011) allows to discriminate between the obsidian sources of many geographical areas, i.e. Near East (Carter and Shackley, 2007;Nadooshan et al, 2013;Orange et al, 2013), Northeast Asia (Hall and Kimura, 2002;Ikeya, 2014), North and South America (Smith et al, 2007;Glascock, 2011), Western Mediterranean (Francaviglia, 1988;Lugliè et al, 2014) inter alia. As a surface analysis, when used in non-destructive mode this method is sensitive to eventual surface irregularities and weathering, and to the geometry and size/thickness of the samples (see Davis et al, 2011), all of which can often be a limiting factor when analysing excavated artefacts (Shackley, 2011).…”