Obsidian provenance determination by means of a portable XRF spectrometer

A portable XRF spectrometer particularly suitable for the quantitative analysis of trace elements in obsidian samples is presented. The system, designed and realised at the LNS/INFN laboratories (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare) of Catania, works by using radioactive sources as incident X-rays beam and ensure an efficient excitation of Rb, Sr Y, Zr, Nb and Mo typically present as trace elements in obsidian and fine ceramic samples. Calibrating the system by means of geological standards and using a multi linear-regression method, the Rb, Sr, Y, Zr and Nb content has been determined and results have been used for provenancing studies of unknown obsidian samples.