A Diachronic Analysis of Obsidian Use at Chaco Canyon and the Influence of Social Factors on Obsidian Procurement.

Chaco Canyon in New Mexico was the center of an extensive regional cultural system. The strength of Chaco's regional interactions has been partly defined by the presence of non–local goods including obsidian. We take a diachronic look at Chaco obsidian use from AD 500–1250 using the largest sample of XRF sourced obsidian available to date and combine this with technological analyses to identify significant changes in where and how Chacoans obtained and used obsidian. In the AD 700s obsidian from the more distant Jemez Mountains began to supplant the closer Mt. Taylor obsidian. The obsidian is of roughly equal quality, suggesting this shift relates to social factors and not raw material constraints. We find more variation over time in obsidian source use and acquisition strategies than previously noted. The patterning appears to relate to regional and local cultural diversity, social and organizational heterogeneity, and the development of new exchange networks. [ABSTRACT FROM AUTHOR]