All the obsidians from the undisturbed Early Neolithic (Cardial ware phase I) layer of the Su Carroppu rock-shelter (Sardinia island) were studied. Their elemental composition and that of obsidians from the Monte Arci (Sardinia) volcanic complex was determined by ion beam analysis (PIXE). A comparison between the composition of Su Carroppu artefacts, analysed non-destructively, and that of Western Mediterranean analysed in the same conditions shows that the archaeological material belongs to the SA, SB2 and SC Monte Arci-types, to the exclusion of the SB1 type. The typological/technological study of this industry allowed us to reconstruct two chaînes opératoires, for the production of blades (using predominantly SC obsidians) and of flakes (based exclusively on SA and SB2 obsidians), respectively, but on the whole, assemblage blade/bladelet production was performed somewhat preferably with SA and SB2 types. Thus, in the earliest EN culture known on the island, ancient man had, for the making of its obsidian toolkit, a highly adaptive behaviour applied to the reduction of different useful obsidian sources.