Landslide complex at Palomarin Beach, Point Reyes National Seashore, Marin County, California

A large slump is an impressive landscape feature at Palomarin Beach in southern Point Reyes National Seashore (Marin County). A great landslide complex extends along the coast in this area for several miles. Near the center of the image is a great slump block that is gradually slipping seaward. The landslide is forming in soft marine mudrocks of the Santa Cruz Mudstone of late Miocene-age (about 8 million years old). The large slump of Santa Cruz Mudstone is capped by younger marine terrace deposits. These marine terrace deposit were originally horizon but are now tilted and offset by rotation of the large slump block. At low tide, a small plunging syncline is exposed and may represent a structure associated with the development of the of the slump in the past, but coastal erosion has carved the sea cliff landward to its present position. Note the Marin Headlands in the distance (to the northwest).

The URL of this page is http://3dparks.wr.usgs.gov/landslide/big/21.htm