Archaeometric characterization of obsidian artifacts at Casa dei Francesi (Ustica island, Italy)and clues of a hidden Prehistoric settlement

At Ustica island (Palermo, Italy), in the area of Casa dei Francesi, 119 fragments of obsidian artifacts were collected on the surface of an agricultural field at an altitude of 50 m asl. In the same area, until now, scientific literature reports only the presence of late Roman pottery (4th–6th centuries AD), and no evidence has appeared that it could be the site of a prehistoric settlement. The most important prehistoric settlement, the Faraglioni Village (Middle Bronze Age) is located 700 m further north, overlooking the sea. Obsidian provenance analyses, performed on the 119 samples with absolutely non-destructive techniques WD-XRF and SEM-EDS, indicate two sources areas: Lipari (93 samples, 78%) and Pantelleria (26 samples, 22%). Concerning the obsidians from the island of Pantelleria, it was possible to also establish the sub-source of Salto la Vecchia. The typological and functional analyses of the 119 obsidian fragments point out that 115 are debitages, some of which show evidence of percussion bulbs, and only 4 are tools with micro-retouching. This work focuses on the geochemical and typological characterization of the obsidian assemblage collected, the characteristics of which suggest the existence of a prehistoric settlement in the area of the Casa dei Francesi or nearby.