SEM-EDS microanalysis of microphenocrysts of Mediterranean obsidians : a preliminary approach to source discrimination

Abstract

SEM-EDS non-destructive analysis allows the source discrimination of the various microphenocrysts in obsidian rocks of the Mediterranean. Samples of six Mediterranean sources, Monte Arci (Sardinia), Palmarola, Lipari, Pantelleria, Gyali and Melos were studied using SEM-EDS non-destructive techniques in order to obtain a data base of their microphenocryst content. The results demonstrate that provenance of an obsidian can be distinguished on the basis of its petrography, in particular by quantitative analyses of Fe-Mg microphenocrysts; this information is particularly useful when coupled with data obtained by other non-destructive techniques such as glass microanalysis of artefacts (Acquafredda et al. , 1999). Such investigations, carried out by SEM, an analytical technique relatively accessible to geoarchaeologists, are relatively rapid, effective and above all non-destructive.