New Directions in Central Mediterranean Obsidian Studies
Tykot, Robert H., Ammerman, Albert J., Antiquity
Mediterranean obsidian-provenance studies are changing in direction and focus of modern research, with characterization of the Sardinian sources, application of minimally destructive and inexpensive analytical techniques, analysis of complete or large parts of assemblages, and the integration of provenance data with reduction technology and use-wear traces.
Recent years have seen much new research on the sources, distribution and use of obsidian in the Mediterranean during the Neolithic. The aim of this note is to present recent work on the central Mediterranean, and to discuss new directions in obsidian studies there. There has been important field research and chemical characterization of the geological sources in Sardinia; new non- or minimally-destructive, inexpensive analytical techniques are being applied to archaeological artefacts; the analysis of large numbers of artefacts - even the comprehensive sourcing of entire assemblages - is now stressed; and much greater emphasis is placed on the integration of provenance work with studies of reduction technology (production) and use-wear (consumption). In contrast with Williams-Thorpe's (1995) review of provenance studies in the Mediterranean and Near East, we see no sign that the pace of research on obsidian has declined in the last decade, nor that it will in the next. As is common for a success story in the sciences, it is the focus of research that has naturally shifted over time.
The Monte Arci (Sardinia) obsidian sources
Unlike the other three sources of obsidian in the western Mediterranean (Palmarola, Lipari and Pantelleria - all comparatively small islands), Sardinia comprises a larger land-mass and poses a greater challenge for investigation [ILLUSTRATION FOR FIGURE 1 OMITTED]. Obsidian beds in the Monte Arci volcanic complex were first described by della Marmora (1839-40) and later by Washington (1913); in a comprehensive survey of the Monte Arci zone, Puxeddu (1958) found 246 locations with obsidian, including four which he classified as sources, in a zone of c. 200 sq. km. The later realization that at least three chemical groups (SA, SB, SC) were represented among analysed archaeological material raised questions about which sources were being utilised, since only one geological source (Conca Cannas) had been analysed (Cann & Renfrew 1964; Hallam et al. 1976), and both translucent and opaque obsidian had long been recognized in archaeological assemblages.
Following detailed geological surveys of the entire Monte Arci complex (Beccaluva, Deriu et al. 1974; Beccaluva, Maccioni et al. 1974; Assorgia et al. 1976), several attempts were made to characterize chemically the multiple obsidian outcrops. Results of the first study are available only in a brief conference paper (Mackey & Warren 1983); Francaviglia (1986) provides no details about the obsidian deposits themselves; and Herold (1986) made no attempt to match chemically-defined geological source groups with archaeological materials in his unpublished dissertation.
A more recent survey of the Monte Arci zone located the SC source in situ for the first time (Tykot 1992), and geological material from the five sources represented among archaeological artefacts has been fully described and chemically characterized in Tykot (1995a; 1997a; 1997b; cf. also Herold 1986) so only a summary is necessary here [ILLUSTRATION FOR FIGURE 2 OMITTED]:
Type SA obsidian - very glassy, black but highly translucent, with nodules up to 40 cm - is found in situ near Conca Cannas and Su Paris de Monte Bingias. Individual microlite crystals are visible in transmitted light, often with some flow orientation.
Type SB1 - less glassy and black, but usually opaque - is found in situ at high elevations on Punta Su Zippiri and Monte Sparau North, and in the form of bombs up to 30 cm in length on the slopes of Cuccuru Porcufurau.
Type SB2 - often very glassy, ranging from transparent to nearly opaque - sometimes has phenocrysts up to 2 mm in diameter. …