Salinian Block

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Salinian Block granite at Point Lobos

The Salinian Block or Salinian terrane is a geologic terrane which lies west of the main trace of the San Andreas Fault system in California. It is bounded on the south by the Big Pine Fault in Ventura County, and on the west by the Nacimiento Fault. The block was named for the Salinas Valley in Monterey County, California.


The prominent, upward-sloping Salinian Block formation can be seen here from the Point Reyes Lighthouse.

The Salinian Block is largely granitic, in accordance with its continental crustal origin. This contrasts sharply, and paradoxically, with much of the crust to its east, which is sedimentary and oceanic in origin. The block's granitic core, fragments of the batholith of the Peninsular Ranges, shares its origins with the Sierra Nevada Mountains.

During the past 30 Ma the North American Plate overrode the East Pacific Rise and complex transform faulting along the developing San Andreas fault zone sliced successive slivers of the Sierra Nevada - Peninsular batholith, moving the "stretched out" slices to the northwest to their current location.[1] The granitic plutons of the Salinas block stretch from Bodega Head (38°18′39.6″N 123°03′57.6″W / 38.311000°N 123.066000°W / 38.311000; -123.066000) in the north to Mount Pinos (34°48′46.1″N 119°08′43.4″W / 34.812806°N 119.145389°W / 34.812806; -119.145389) at the southern end of the block.

The connection to the southern Sierra Nevada has been questioned in the years since the 1974 study by Johnson and Normark. "...[I]t more nearly resembles granite in the Mojave Desert". [2]


Today, northern portions of the block are visible as Bodega Head, Point Reyes, the Farallon Islands, and the picturesque coastal scenery of the Monterey Peninsula, exemplified prominently at Point Lobos and Pebble Beach.


  1. ^ Jeffrey D. Johnson and William R. Normark, Neogene Tectonic Evolution of the Salinian Block, West-Central California, Geology 1974;2;11-14
  2. ^ Alt, David; Hyndman, Donald W. (2000), Roadside Geology of Northern and Central California, Missoula: Mountain Press, p. 176 

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Coordinates: 36°24′17.9″N 121°29′31.8″W / 36.404972°N 121.492167°W / 36.404972; -121.492167