The Sierra Nevada–Great Valley Block (SNGV) is a section of the earth's crust in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

encompassing most of the region east of the Great Valley fault system which runs along the eastern foot of the Coast Ranges, and west of the Sierra Nevada Fault which runs along the foot of the

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

's eastern scarp. To the south, the block is bounded by the Garlock Fault. The northern bound is not well defined at present, but generally runs along a line extending across the northern

Sacramento Valley , photo =Sacramento Riverfront.jpg , photo_caption= Sacramento , map_image=Map california central valley.jpg , map_caption= The Central Valley of California , location = California, United States , coordinates = , boundaries = Sierra Nevada (ea ...

. The SNGV has been found to behave like a rigid body relative to the

North American Plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacifi ...

to which it is somewhat loosely attached, for this reason it is sometimes referred to as Sierra Nevada microplate. The block moves in a northwest direction at approximately 12 mm per year while the rest of the North American Plate is moving in a southwest direction. In far northern California, this produces a zone of convergence which has resulted in the compressive uplift of the Coast Ranges. At its core, the SNGV block consists primarily of the

Sierra Nevada batholith The Sierra Nevada Batholith is a large batholith which forms the core of the Sierra Nevada mountain range in California, exposed at the surface as granite. The batholith is composed of many individual masses of rock called '' plutons'', which f ...

which has been tilted westward like a large trapdoor with its "hinge" lying deep beneath the sediments which fill California's Central Valley. This tilt is attributed to the buoyancy of the eastern part of the block due to the greater subterranean heat associated with the tectonics of the adjacent Great Basin, compounded by the weight of sediments accumulating over the western portion of the block. A major feature of the block clearly visible from space and on topographical maps is the

Kern Canyon Fault The Kern Canyon Fault (Late-Quaternary Active Kern Canyon Fault) is a dextral strike-slip fault (horizontal) that runs roughly around 150 km (93 mi) beside the Kern River Canyon through the mountainous area of the Southern Sierra Nevada ...

which is regarded as a fracture resulting from differences in the stresses affecting the southern section of the block.

References

{{DEFAULTSORT:Sierra Nevada-Great Valley Block Geology of California Natural history of the Central Valley (California) Sierra Nevada (United States) Seismic faults of California

See also

References