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U.S. Geological Survey
Scientific Investigations Report 2004-5183

Late Quaternary Deposition in the Inner Basins of the California Continental Borderland—Part A. Santa Monica Basin

By William R. Normark and Mary McGann


map of the coast showing geology and slide areas
Bathymetric map of Santa Monica Basin showing position of cores used in this study

Radiocarbon dating of sediment core samples from Santa Monica Basin document Holocene (younger than approximately 11 ka) landslides and fault offsets along the basin margin. The new dates include 17 from six piston cores on the continental slope and 11 from Ocean Drilling Program Site 1015 on the basin floor. The dates, which are based on data from pelagic and benthic foraminifera in addition to several dates from mollusk shells, are used to provide chronostratigraphic control for a previously determined basin-wide seismic stratigraphy. The geologic setting at the core sites and a sediment log for each core are shown. In addition, each sediment log is accompanied by a color core photograph as well as P-wave velocity and gamma-ray density profiles. The primary purpose of the report is to make the radiocarbon dates available for other studies in the Santa Monica Basin. A comparison of sediment accumulation rates between the late Pleistocene and Holocene provides insight to the effects of sea-level change on sediment input to the basin. In addition, the results can be used to evaluate the effectiveness of wire-line piston coring in providing age control for earthquake hazard and sedimentologic studies.

Download Scientific Investigations Report 5183 as a 24-page PDF file (sir2004-5183.pdf; 11.1 MB)

For questions about the content of this report, contact Bill Normark

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Maintained by: Michael Diggles
Created" December 30, 2004
Last modified: February 15, 2005 (mfd)