Cerithideopsis californica as a sea-level index tool for the Southern California coast

Abstract

Relative sea-level (RSL) curves are required for better understanding and predicting future effects of sea-level rise on coastlines. In California, records of past sea level also provide excellent datums for determining rates of vertical tectonic motion. However, only one regional tectonically corrected RSL curve is available for the entire US Pacific Coast, and this curve has errors of up to +/- 3 m. One challenge for reconstructing past RSL is identifying suitable methods for doing so. In this study we examine the utility of the gastropod, Cerithideopsis californica, for its use as an RSL indicator. We measured its distribution in four southern California estuaries in the fall, winter, and spring seasons. We find that Cerithideopsis californica inhabits elevations of 0.28 +/- 0.47 m (relative to mean sea level) in Carpinteria Salt Marsh and 0.37 +/- 0.52 in Tijuana Estuary, and thus provides a valuable sea level-index point for the reconstruction of past relative sea levels. Furthermore, we report on the radiocarbon age and elevations of C. californica obtained from four estuaries within Southern California, which are used to constrain past RSL at each site.

AAPG Datapages/Search and Discovery Article #90372 © 2020 AAPG Pacific Section Convention, 2020 Vision: Producing the Future, Mandalay Beach, Oxnard, CA, April 4-8, 2020 (Cancelled)