Geochemical fingerprinting of obsidian sources was first applied in the Mediterranean region nearly four decades ago. Since then, a number of analytical methods (e.g. INAA, XRF, SEM/Microprobe, ICP-MS) have proven successful in distinguishing the Mediterranean island sources of Giali, Lipari, Melos, Palmarola, Pantelleria, and Sardinia. Moreover, recent geoarchaeological surveys of the central Mediterranean sources have resulted in the more precise location and documentation of each obsidian flow or outcrop, and multiple chemical groups have been identified on at least three of the islands. The ability to specifically attribute artifacts to one of at least five obsidian flows in the Monte Arci region of Sardinia, for example, has enabled the study of specific patterns of source exploitation and the trade mechanisms which resulted in the distribution of obsidian hundreds of kilometers away during the Neolithic period (ca. 6000-3000 BC).
Results are presented here from the chemical analysis of 186 artifacts from several sites in Sardinia and Corsica as part of the largest and most comprehensive study of obsidian sources and trade in the Mediterranean. Analyses of large numbers of artifacts demonstrate the differential use of island subsources, which may be attributed to factors such as access (e.g. topography, distance from coast), size and frequency of nodules, and mechanical and visual properties. The patterns of source exploitation revealed by this study specifically support a down-the-line model of obsidian trade during the neolithic period. In addition, the spatial and chronological patterns of obsidian distribution may be used to address such issues as the colonization of the islands; the introduction of neolithic economies; and the increasing social complexity of neolithic and bronze age societies in the central Mediterranean.