Sea Beam Evidence of Recent Tectonic Activity in the California Continental Borderland
Mark R. Legg, 1991. "Sea Beam Evidence of Recent Tectonic Activity in the California Continental Borderland", The Gulf and Peninsular Province of the Californias, J. Paul Dauphin, Bernd R. T. Simoneit
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Sea Beam provides a new tool for accurately mapping sea-floor morphology. Recent maps compiled from Sea Beam data collected in the California Continental Borderland show many sea-floor geomorphic features that are similar to tectonic landforms observed along subaerial fault zones. In particular, numerous features associated with recently active strike-slip faults have been mapped along the offshore San Clemente-San Isidro, San Diego Trough-Bahia Soledad, and Coronado Bank-Agua Blanca fault zones. Linear scarps, trenches and ridges, hillside benches and valleys, and small closed depressions are aligned along what are inferred to be active traces of these major offshore fault zones. Other nontectonic sea-floor geomorphic features observed include submarine canyons and channels; these may be truncated, offset, or deviated by tectonic movements in the area. Detailed study of such features may provide data necessary to determine the displacement and slip-rates on submarine faults.
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The Gulf of California is an excellent laboratory for studying sedimentary processes on time scales that are not resolvable in the open ocean. The high biological productivity and the unique physical character of the gulf combine to produce sedimentological processes that preserve annual phenomena. This volume is organized into six sections. Part 1 covers historical exploration of the area. Part 2 includes 5 chapters detailing information contained on the 5 fold-out maps that accompany the volume. Part 3 consists of chapters on regional geophysics and geology. Part 4 covers satellite geodesy. Part 5's seven chapters discuss physical oceanograpy, primary productivity, and sedimentology. Part 6 covers hydrothermal processes.