Salton Sink
Encyclopedia
The Salton Sink is a geographic sink
in the Coachella
and Imperial
valleys of southeastern California
. It is in the Colorado Desert
subregion of the Sonoran Desert
ecoregion
. Drainage to the endorheic sink collects in the Salton Sea
which occupies the topographically
lowest area of the sink.
. The Salton Trough is a result of crustal
stretching and sinking by the combined actions of the San Andreas Fault
and the East Pacific Rise
. The Brawley seismic zone
forms the southeast end of the basin and connects the San Andreas Fault system with the Imperial Fault Zone
to the south. The Salton Buttes
are rhyolite
lava dome
s within the basin which were active 10,300 (+/- 1000) years BP.
, existed in the area from about 20,500 to 3,000 years ago and left evidence as wave cut benches on the higher portions of the Salton Buttes. A beach mark outlines the shoreline of ancient Lake Cahuilla where archeologists found rock fish traps and charred remains of razorback sucker and bonytail bones. High water lines suggest the basin has filled many times, creating a lake some 105 miles in length and nearly 300 feet deep. Its most recent incarnation is evidenced by fish traps found some 30 feet below the high watermark that were estimated to be between 300 and 1,000 years old.
In recent times, the 1862 Colorado River flood waters reached the Salton Sink filling it creating a lake some 60 miles long and 30 miles wide. In 1884 and 1891 the Colorado River
had escapement flow into the Salton Sink. The 1891 flood created a lake that covered an area 30 miles long and 10 miles wide.
A larger 1905 Colorado flood escaped into a diversion canal, forming the Alamo
and New Rivers and creating the current Salton Sea in the sink's Coachella Valley
. A 1907 dam prevents flood escapements, but leakage still occurs to the Salton Sea.
Sink (geography)
A geographic sink is a depression within an endorheic basin where water collects with no visible outlet. Instead of discharging, the collected water is lost due to evaporation and/or penetration...
in the Coachella
Coachella Valley
Coachella Valley is a large valley landform in Southern California. The valley extends for approximately 45 miles in Riverside County southeast from the San Bernardino Mountains to the saltwater Salton Sea, the largest lake in California...
and Imperial
Imperial Valley
The Imperial Valley is an agricultural area of Southern California's Imperial County. It is located in southeastern Southern California, centered around the city of El Centro. Locally, the terms "Imperial Valley" and "Imperial County" are used synonymously. The Valley is bordered between the...
valleys of southeastern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. It is in the Colorado Desert
Colorado Desert
California's Colorado Desert is a part of the larger Sonoran Desert, which extends across southwest North America. The Colorado Desert region encompasses approximately , reaching from the Mexican border in the south to the higher-elevation Mojave Desert in the north and from the Colorado River in...
subregion of the Sonoran Desert
Sonoran Desert
The Sonoran Desert is a North American desert which straddles part of the United States-Mexico border and covers large parts of the U.S. states of Arizona and California and the northwest Mexican states of Sonora, Baja California, and Baja California Sur. It is one of the largest and hottest...
ecoregion
Ecoregion
An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...
. Drainage to the endorheic sink collects in the Salton Sea
Salton Sea
The Salton Sea is a shallow, saline, endorheic rift lake located directly on the San Andreas Fault, predominantly in California's Imperial Valley. The lake occupies the lowest elevations of the Salton Sink in the Colorado Desert of Imperial and Riverside counties in Southern California. Like Death...
which occupies the topographically
Topography
Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...
lowest area of the sink.
Geology
The Salton Sink is the topographic low area within the Salton Trough, an active tectonic pull apart basinPull Apart Basin
250px|thumb|[[Cami Lake]] in [[Tierra del Fuego]] develops on a [[Patagonian Ice Sheet|glacially]] excavated pull apart basin along the [[Magallanes-Fagnano Fault]], hence its elongated form...
. The Salton Trough is a result of crustal
Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...
stretching and sinking by the combined actions of the San Andreas Fault
San Andreas Fault
The San Andreas Fault is a continental strike-slip fault that runs a length of roughly through California in the United States. The fault's motion is right-lateral strike-slip...
and the East Pacific Rise
East Pacific Rise
The East Pacific Rise is a mid-oceanic ridge, a divergent tectonic plate boundary located along the floor of the Pacific Ocean. It separates the Pacific Plate to the west from the North American Plate, the Rivera Plate, the Cocos Plate, the Nazca Plate, and the Antarctic Plate...
. The Brawley seismic zone
Brawley seismic zone
The Brawley Seismic Zone , also known as the Brawley fault zone, is a predominantly extensional tectonic zone that connects the southern terminus of the San Andreas Fault with the Imperial Fault in Southern California...
forms the southeast end of the basin and connects the San Andreas Fault system with the Imperial Fault Zone
Imperial Fault Zone
The Imperial Fault Zone is a system of geological faults located in Imperial County in the Southern California region, along the border of the United States and Mexico.-Geology:...
to the south. The Salton Buttes
Salton Buttes
The Salton Buttes are a group of five small lava domes in the lower Coachella Valley, in Imperial County, California. The Salton Buttes domes are on the southeast shoreline of the Salton Sea and are associated with the Salton Sea geothermal field within the Salton Trough...
are rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
lava dome
Lava dome
|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...
s within the basin which were active 10,300 (+/- 1000) years BP.
History
A large lake, Lake CahuillaLake Cahuilla
Prehistoric Lake Cahuilla was an extensive freshwater lake that filled the Coachella, Imperial, and Mexicali valleys of southeastern California and northeastern Baja California during the centuries prior to Spanish entry into the region...
, existed in the area from about 20,500 to 3,000 years ago and left evidence as wave cut benches on the higher portions of the Salton Buttes. A beach mark outlines the shoreline of ancient Lake Cahuilla where archeologists found rock fish traps and charred remains of razorback sucker and bonytail bones. High water lines suggest the basin has filled many times, creating a lake some 105 miles in length and nearly 300 feet deep. Its most recent incarnation is evidenced by fish traps found some 30 feet below the high watermark that were estimated to be between 300 and 1,000 years old.
In recent times, the 1862 Colorado River flood waters reached the Salton Sink filling it creating a lake some 60 miles long and 30 miles wide. In 1884 and 1891 the Colorado River
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...
had escapement flow into the Salton Sink. The 1891 flood created a lake that covered an area 30 miles long and 10 miles wide.
A larger 1905 Colorado flood escaped into a diversion canal, forming the Alamo
Alamo River
The Alamo River is a river flowing west and north from the Mexicali Valley across the Imperial Valley . The river drains into the Salton Sea....
and New Rivers and creating the current Salton Sea in the sink's Coachella Valley
Coachella Valley
Coachella Valley is a large valley landform in Southern California. The valley extends for approximately 45 miles in Riverside County southeast from the San Bernardino Mountains to the saltwater Salton Sea, the largest lake in California...
. A 1907 dam prevents flood escapements, but leakage still occurs to the Salton Sea.