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Stop 32, Baker Beach Serpentinite: The Setting

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Stop 32 is the classic Franciscan mélange at San Francisco's Baker Beach, just south of the Golden Gate Bridge. (more below)
A postcard locality
Photo (c) 2006 Andrew Alden, licensed to About.com (fair use policy)
San Francisco's bedrock is several nappes of Franciscan rocks with thick, chaotic shear zones between them, all running from northwest to southeast. Baker Beach exposes the Hunters Point Shear Zone, between the Alcatraz nappe to the east and the Marin Headlands nappe behind us and at our feet. The same red chert we saw at stop 1 appears here, along with coarse-grained graywacke and serpentinite.

The guide book recommends walking down the cliff to the far end of this vista, but I approached from the public beach. If you visit, try to pick a time around low tide to avoid scrambling over some steep, sandy rocks. Since I made this visit, a new public trail has been opened at the far end of this view. Give it a try.

Day 1, Coast Range: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

Day 2, Sierra Nevada: 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18

Day 3, Sierra Nevada: 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28

Day 4, Coast Range: 29 | 30 | 31 | 32 | 33

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