Preliminary Sediment Core Analysis and Paleoenvironmental Reconstruction: Northern Channel Islands Platform, California

Luke Johnson, San Diego State University, San Diego, CA, United States, Jillian M Maloney, University of California, San Diego, San Diego, United States, Shannon Klotsko, University of North Carolina at Wilmington, Earth and Ocean Science, Wilmington, NC, United States, Amy E. Gusick, Natural History Museum of Los Angeles County, Los Angeles, United States, Todd Braje, San Diego State University, Department of Anthropology, San Diego, CA, United States and David Ball, Bureau of Ocean Energy Management (formally Minerals Management Service), Camarillo, CA, United States
Abstract:
Rising sea levels following the last glacial maximum (LGM) submerged vast subaerial landscapes on continental shelves around the world. Offshore 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. Here, 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 more robust understanding of the paleoenvironment and geologic history of the northern Channel Islands. 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 and to correlate stratigraphy to the Chirp data, resulting in a preliminary model of depositional environments. Future radiometric dating, as well as specialized pollen 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 develop a methodology to better identify potential 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.
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