Natural and Cultural History of the Obsidian Butte Source, Imperial County, California

Located in the Salton Basin of Imperial County in southeastern Alta California, Obsidian Butte was the major prehistoric obsidian toolstone source in southern Alta California and northern Baja California and is frequently referenced in the archaeological literature. Reported in detail geoarchaeologically by Richard Hughes in the 1980s, the study herein considerably amplifies his research in that it focuses on the natural (geological) and cultural (archaeological) history of this source and its impact on the prehistory and archaeological interpretations of the region. A thorough in-field examination of the source and analysis of over 500 obsidian artifacts from San Diego County and western Imperial County archaeological contexts enlarges the database of artifacts assigned to that source, as well as providing recent geochronological data in support of the cultural history. This study can be seen as a companion to the recent work on sources of archaeological obsidian in northern Baja California by Panich et al. (2012, 2015, 2017).