Home | Session 5 | Features of SF Bay Pg 1, 2, 3

Features of San Francisco Bay: From River Valley to Estuary

Presented by Lise White
San Francisco State University

  1. Features Along the Continental Shelf: Marine Terraces

    How have marine terraces been shaped by sea level change and tectonism?


Figure 11		 Pleistocene marine terraces are uplifted wave-cut platforms that are some of the most distinctive features along continental margin of California. Their origin is related to coastal and oceanographic processes as inner parts of continental shelves are cut as planar surfaces by wave processes, particularly during high stands of sea level. Along the coast of Santa Cruz (figure 11, left) marine terraces are especially well developed along the southwest flank of Ben Lomond Mountain. Transpressional stresses that result from a bends in the main trace of the San Andreas fault here result in high rates of uplift that vary from 0.2 to 0.4 m/k.y. Figures 12 and 13 show that realationship of modern wave-cut platforms, sea cliffs and uplifted terrace surfaces in Santa Cruz County.

Figure 12

Figure 13

Diagrams that support the preceding text and illustrate the evolution of San Francisco Bay are taken from the following articles in the USGS/NAGT guidebook:

The Geology from Santa Cruz to Point Aņo Nuevo-The San Gregorio Fault Zone and Pleistocene Marine Terraces by Weber, G., and Allwardt. A., In: Stoffer, Philip W. and Gordon, Leslie C. 2001 (eds.). Geology and Natural History of the San Francisco Bay Area, A Field-Trip Guidebook. U.S. Geological Survey, Bulletin 2188. Field Trip 1, pp. 1-32.

Geology of the Golden Gate Headlands by Elder, W., (2001). In: Stoffer, Philip W. and Gordon, Leslie C. 2001 (eds.). Geology and Natural History of the San Francisco Bay Area, A Field-Trip Guidebook. U.S. Geological Survey, Bulletin 2188. Field Trip 3, pp. 61-86.

San Andreas Fault and Coastal Geology, from Half Moon Bay to Fort Funston-Crustal Motion, Climate Change, and Human Activity by Andersen D., Sarna-Wojcicki, A., Sedlock, R. (2001). In: Stoffer, Philip W. and Gordon, Leslie C. 2001 (eds.). Geology and Natural History of the San Francisco Bay Area, A Field-Trip Guidebook. U.S. Geological Survey, Bulletin 2188. Field Trip 4, pp. 87-104.

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updated April 1, 2002

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