A Preliminary Petrologic and Provenance Analysis of Groundstone Artifacts from the Northern Channel Islands and Coastal Southern Alta California

ABSTRACT The Chumash of the southern Central Coast of Alta California have long been recognized for their complex sociopolitical systems and extensive exchange networks. This study employs petrologic geoarchaeological methods to examine groundstone bowl and mortar fragments from Chumash archaeological sites along the Northern Channel Islands and the Oxnard Plain region of the southern Central Coast. Through comparison of macroscopic and microscopic descriptions, our purpose is to establish the rock units from which the artifacts were likely produced to determine whether these tools were locally manufactured, or if non-local, the possible distances over which these artifacts were transported. The results of our preliminary study suggest that during the early late Holocene, the local Chumash obtained their groundstone mortars via both local production and intraregional exchange, with some finished tools found at least 80 km distant from probable raw material sources.