GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 115-7
Presentation Time: 9:00 AM-6:30 PM


JOHNSON, Luke1, MALONEY, Jillian M.2, KLOTSKO, Shannon A.3, GUSICK, Amy E.4, BRAJE, Todd J.3 and BALL, David5, (1)Department of Geological Sciences, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182, (2)Department of Geological Sciences, San Diego State University, San Diego, CA 92115, (3)Department of Geological Sciences, San Diego State University, San Diego, CA 92182, (4)Natural History Museum of Los Angeles County, Los Angeles, CA 90007, (5)U.S. Department of Interior, Bureau of Ocean Energy Management, Camarillo, CA 93010

Rising sea levels following the last glacial maximum (LGM) submerged vast subaerial landscapes on continental shelves around the world. Offshore of southern California, the four northern Channel Islands were connected by land bridges into a super island known as Santarosae during the LGM. Evidence from terrestrial archaeological sites indicates that people lived on Santarosae beginning at least 13,000 years ago. Reconstructing the paleolandscape of drowned portions of Santarosae could be instrumental in the search for terminal Pleistocene and Early Holocene archaeological sites. We present preliminary analysis of sediment cores from the northern Channel Islands platform, which helps refine our interpretations of Chirp data from the region, providing a better understanding of the paleoenvironment and geologic history. During two research cruises, twenty-six sediment cores were collected using a Rossfelder P-5 vibracore. Computed tomography (CT) scans, magnetic susceptibility, density, p-wave velocity, and resistivity data were used for sediment core analysis in order to correlate stratigraphy to the Chirp data. This analysis has resulted in a preliminary model of depositional environments. Future radiometric dating, specialized pollen analysis, and EDNA analysis will provide further context to paleoenvironmental reconstructions. This study contributes to a larger project by San Diego State University, the Bureau of Ocean Energy Management, and partner institutions which aims to identify submerged archaeological resources in the Pacific Outer Continental Shelf using geophysical surveys, radiometrically dated cores, analysis of terrestrial archaeological sites, biological surveys, and ArcGIS modeling.