New Mexico Geological Society Annual Spring Meeting — Abstracts

Comprehensive semi-quantitative X-ray fluorescence (XRF) analyses of geologic obsidian from different regions from throughout New Mexico and Arizona have established distinctive geochemical trends (especially in Zr, Nb, Rb, and Sr concentrations, possibly related to geologic source and geologic age (Shackley, 1988, 2005) that can be used to identify specific sources of archeological obsidian. In Cañada Alamosa in southwestern Socorro County, more than 500 obsidian artifacts collected from the past 10 years of excavation have been analyzed in order to study human stability, movement, and interaction in the area. Few studies in the American southwest have analyzed such a large number of samples of archaeological obsidian from one place. Analyses of these obsidian artifacts has revealed complex patterns of obsidian procurement that is quite different from earlier theories of predominant use from secondary obsidian deposits in Rio Grande gravels.

Approximately 31% of the archaeological obsidian from Cañada Alamosa originates from the Mule Creek area in Catron County and approximately 25% of the obsidian originates from the Mt. Taylor volcanic field in Cibola County. Other sources are from Gwynn Canyon (10%) and Red Hill, north of Mule Creek and the Jemez Mountains in northern New Mexico. Approximately 13% of the obsidians examined have not been correlated to a known source and could be from an unidentified local source in the San Mateo Mountains. The sample percentages by source vary between the four archaeological sites and through time. These results suggest that Pueblo Indians that lived in Cañada Alamosa from 700-1400 A.D. obtained obsidian through trade and interaction with Mogollon groups to the southwest, Tularosa Phase groups to the northwest, and Ancestral Puebloan groups to the north.