Obsidian in the Western Mediterranean: Characterisation by Neutron Activation Analysis and Optical Emission Spectroscopy

In the history of west Mediterranean contacts and communications, obsidian has a special place, being the first traded commodity documented in the archaeological record. The commercial contacts which it reveals precede those of the Mycenaeans by more than three millennia. The general outlines of this trade and the principal sources exploited have previously been documented by trace element analysis undertaken by optical emission spectrography. The present article presents the data obtained by a different trace element approach—neutron activation analysis—and sets out to compare and evaluate the results obtained by the two methods. One important new archaeological outcome is the significance of the Sardinian sources, and the extent to which southern France participated in the contacts of the time. Regional and temporal trends now becoming apparent have a wide significance for Mediterranean prehistory and clarify the role of interregional contacts within it. No direct contacts with the east Mediterranean or Aegean are documented over the time range studied, nor do obsidian finds suggests that southern Iberia was in close touch with the west-central Mediterranean during the neolithic period. Four zones of interaction, each with a natural source of obsidian as focus, may be identified.