Obsidian procurement and exploitation strategies during the Middle Neolithic B: two case studies from central-western Sardinia, Italy

The aim of this study is to reconstruct the technological behaviours and obsidian acquisition strategies of the Middle Neolithic B communities settled in the proximity of obsidian sources in central-western Sardinia. This objective has been achieved by employing nondestructive techniques, including visual and instrumental analysis (PIXE and EDXRF), on selected assemblages from two contemporary contexts, Gribaia- Nurachi and Cuccuru Is Arrius 411-Cabras; these sites comprise multiple pits exhibiting distinctive features, filling, and unearthed materials. While such pits are commonly discovered in European archaeological sites, their precise function remains uncertain. In all the examined assemblages, obsidian from Monte Arci is by far the most common raw material exploited for chipped stone production, with the SC geochemical group being the most common. In both contexts, reduction activities occurred in situ, as evidenced by the recurrence of cortical elements, debris and refitting pieces. The first stages of the chaîne(s) opératoire(s) are, therefore, always well represented, even if we have observed a lack of cores, which are commonly recovered exhausted. A general impression of low technological investment gives off from these industries, mostly composed of flakes, that are systematically marked by a low standardization and a medium-small size. The achieved results provide insights on raw material selection and technological habits of the inhabitants of the analysed sites and, more generally, of coeval middle Neolithic Sardinian communities in the period of highest distribution of obsidian from the Monte Arci source. Furthermore, this research offers new interpretive hypotheses about the function of the deep negative structures in which our lithic remains were discovered. Indeed, the analysis of these assemblages, in conjunction with the available data on the techno-functional features of the associated pottery, has enabled us to postulate that the function of the pits may extend beyond the realm of ordinary daily activities.