Chemical Characterization of Obsidians from Different Mediterranean Sources by Non-destructive SEM-EDS Analytical Method

Abstract The aim of our research is to check the SEM-EDS non-destructive analytical method for discriminating and locating the possible sources of obsidian artefacts. Moreover, in order to obtain a significant discrimination of Mediterranean obsidians, we analysed samples collected from outcrops of the major sources: Monte Arci (Sardinia) and Palmarola, Lipari, Pantelleria, Gyali and Melos islands. All samples were analysed by both XRF (whole rock) and SEM-EDS (glass and microliths-microphenocrysts). The XRF analysis reveals that major elements discriminate obsidian. The discrimination using major elements is very useful because the amount of trace elements is lower than the detection limit of a Si(Li) ED Detector. The major elements, particularly SiO 2 , Al 2 O 3 , CaO, Na 2 O and K 2 O, of obsidian glass discriminate the six main Mediterranean sources. Our work demonstrates, therefore, the possibility of discriminating different provenance of obsidian artefacts using SEM-EDS, by means of a relatively rapid, effective and above all non-destructive method.