Obsidian provenance determination by using the beam stability controlled BSC-XRF spectrometer: the case of Milena (sicily)

The trace elements determination in archaeological obsidians gives information about the provenance. In many cases the obsidians sourcing can be performed with satisfactory results by a non-destructive analysis limited to few trace elements. In the present work a portable XRF spectrometer equipped with a system to control the stability of the excitation beam emitted by a tube and a quantitative method based on a multilinear regression approach are used to determine the content of Rb, Sr, Y, Zr and Nb in 57 obsidian artefacts from the site of Milena (Sicily). The artefacts were collected from archaeological layers dated back from the Neolithic to the final Copper age; they were preliminary identified by the archaeologists on the basis of a macroscopic investigation to come from the islands of Lipari and Pantelleria. The non destructive analytical results allowed to verify these hypotheses and to identify some samples of doubtful origin. Finally the distribution of obsidians coming from the different sources was investigated during the time.