Salinian Block

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. It was named for the Salinas Valley in Monterey County, California.

Geology

The Salinian Block is largely granitic, in accordance with its continental crustal origin. This composition 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 far to the east.

During the past 30 million years the North American Plate has been overriding the East Pacific Rise and transform faulting along the developing San Andreas fault zone. Successive "stretched out" slivers of the Sierra Nevada - the Peninsular Batholith - have been and currently still are moving 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.

In the years since the 1974 study by Johnson and Normark the connection with the southern Sierra Nevada has been questioned, stating that "it more nearly resembles granite in the Mojave Desert".^[2]

Notable Features

Some of the more notable portions of the block are visible as:

Bodega Head – Promontory in California, United States
Point Reyes – Cape in Northern California
The Farallon Islands – Group of islands off the coast of California, United States
Devil's Slide – Promontory in San Mateo County, California
Monterey Peninsula – Peninsula in California, USA
Pebble Beach – Unincorporated community in California, United States
Point Lobos – Cape in California, USA
McWay Falls – Tidefall in Julia Pfeiffer Burns State Park, California, United States
Anderson Canyon – river in California, United States
Pinnacles National Park – National park in California, United States
Mount Pinos – Mountain of the Transverse Ranges in California, United States

Much of the mountainous terrain along the Salinian Block is protected under the US Forest Service and U.S. Fish and Wildlife Service, most notably within Los Padres National Forest, Julia Pfeiffer Burns State Park, and Point Reyes National Seashore.

References

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

External links

Marin College: "Feldspar Staining of the Plutonic Rocks of the Salinian Terrane"

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

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[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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v t e Seismically active fault zones and tectonic blocks of California
Statewide Faults	San Andreas Fault Salinian Block
Southern California	Brawley Seismic Zone Chino Fault Elsinore Fault Zone Elysian Park Fault Garlock Fault Hollywood fault Hosgri Fault Imperial Fault Zone Laguna Salada Fault Newport–Inglewood Fault Northridge Blind Thrust Fault Peninsular Ranges Puente Hills Fault Raymond Fault Rose Canyon Fault Salton Trough San Cayetano Fault San Diego Trough Fault Zone San Felipe Fault Zone San Gabriel Fault San Jacinto Fault Zone Santa Maria River Fault Santa Ynez Fault Shoreline Fault Sierra Madre Fault Zone Ventura Fault White Wolf Fault Whittier Fault Yorba Linda Fault
Northern California	Bartlett Springs Fault Calaveras Fault Clayton-Marsh Creek-Greenville Fault Concord Fault Hayward Fault Zone Healdsburg Fault Maacama Fault Mendocino Fracture Zone Mendocino Triple Junction Mount Diablo Thrust Fault Monta Vista Fault Nacimiento Fault Pleasanton Fault Rinconada Fault San Gregorio Fault San Pablo Fault Seal Cove Fault Serra Fault Silver Creek Fault Tesla Fault West Napa Fault
Sierra Nevada	Death Valley Fault Zone Furnace Creek Fault Zone Honey Lake Fault Zone Kern Canyon Fault Maria fold and thrust belt Owens Valley Fault Rescue Lineament-Bear Mountains fault zone Sierra Nevada Batholith Sierra Nevada Fault Sierra Nevada-Great Valley Block Smartville Block Walker Lane
Category California Geological Survey Seismic Hazards Mapping Act Mexico (list)