Through the glass darkly: Prehispanic obsidian procurement and exchange insouthern Peru and northern Bolivia

Recent discovery of the major geological sources of Central Andean obsidian permits a new understanding of the patterns of obsidian procurement and ex change by the Prehispanic societies of southern Peru and northern Bolivia. Based on the trace element analysis of obsidian artifacts from 160 archaeol ogical sites, it can be established that the two major deposits of obsidian were being exploited by 9400 BP, and that volcanic glass was being transpo rted over long distances throughout Andean prehistory. Inhabitants of the C uzco region acquired most obsidian from the Alca source in central Arequipa , while those in the high plateau surrounding Lake Titicaca obtained most o bsidian from the Chivay source in southern Arequipa. Obsidian evidence sugg ests close ties between the Cuzco and Circum-Titicaca regions throughout pr ehistory, except during the Middle Horizon (ca. 14001050 BP), when the expa nsion of the Huari and Tiahuanaco states disrupted this pattern.