Death Valley
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- For other names using Death Valley, see the Death Valley disambiguation page.
Image:Death Valley from space.JPG
Death Valley is a valley located in east-central California southeast of the Sierra Nevada range in the Great Basin. It is bounded on the east by the Grapevine Mountains, Funeral Mountains, and Amargosa Range. It is bounded on the west by the Cottonwood Mountains and the Panamint Range. The geological configuration is considered one of the best examples of the Basin and Range configuration.
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Geography
Death Valley is the lowest point in the western hemisphere, at 282 feet (86 m) below sea level. Generally, the lower the altitude of a place, the higher the temperatures tend to be. The valley radiates extreme amounts of heat, allowing for temperatures that are among the hottest on earth. The hottest temperature recorded in the U.S., and the second hottest in the world, was 134 °F (56.7 °C) at Greenland Ranch near the valley on July 10, 1913. The highest average high temperature in July is 116 °F (47 °C) with temperatures of 120 °F (49 °C) or higher being very common. The valley receives less than 2 in (50 mm) of rain annually. The Amargosa River and Furnace Creek flow through the valley, disappearing into the sands of the valley floor.
While there is very little rain in Death Valley, the valley is prone to flooding during heavy rains because the soil is unable to absorb the bulk of the water. The runoff can produce dangerous flash floods. In August 2004, such flooding occurred, causing two deaths and shutting down the national park.
During the late Pleistocene, the valley was inundated by prehistoric Lake Manly. The valley received its name in 1849 during the California gold rush by emigrants who sought to cross the valley on their way to the gold fields. During the 1850s, gold and silver were extracted in the valley. In the 1880s, borax was discovered and extracted by mule-drawn wagons.
Geology
Composition and occurrence of salts in Death Valley
|
Mineral |
Composition |
Known or probable occurrence |
|
NaCl |
Principal constituent of chloride zone and of salt-impregnated sulfate and carbonate deposits. | |
|
KCl |
With halite. | |
|
NaHCO3 |
Not yet identified; might be found in wintertime as efflorescence or trona or thermonatrite in carbonate zone in Cottonball Basin. | |
|
Na3H(CO3)22H2O |
Carbonate zone of Cottonball Basin, especially in marshes. | |
|
Na2CO3·H2O |
Questionably present on floodplain in Badwater Basin, would be expected in marshes of carbonate zone in Cottonball Basin. | |
|
Na2CO3·10H2O |
Not yet identified but may be expected, especially In winter, immediately following rains or periods of high discharge at marshes in carbonate zone in Cottonball Basin. | |
|
Na2Ca(CO3)2·2H2O |
Not yet identified, may be expected in environments where gaylussite would be dehydrated. | |
|
Na2Ca(CO3)2·5H2O |
Carbonate zone and floodplain in Badwater Basin. | |
|
CaCO3 |
Occurs as clastic grains in sediments underlying salt pan and as sharply terminated crystals in clay fraction of carbonate zone and in sediments underlying sulfate zone. | |
|
MgCO3 |
Obtained in artificially evaporated brines from Death Valley; not yet identified in salt pan; may be expected in carbonate zone of Cottonball Basin. | |
|
CaMg(CO3)2 |
identified only as a detrital mineral; may be expected in carbonate zone. | |
|
</P> and/or
Tychite |
Na3MgCl(CO3)
Na6Mg2(SO4)·(CO3)4 |
An isotropic mineral, having index of refraction in the range of Northupite and Tychite, has been observed in saline facies of sulfate zone in Cottonball Basin. |
|
Na6(CO3)(SO4)2 |
Sulfate zone in Cottonball Basin. | |
|
Na2SO4 |
Common in all zones in Cottonball Basin and in sulfate marshes in Middle and Badwater basins. | |
|
Na2SO4·10H2O |
Occurs on floodplains in Cottonball Basin immediately following winter storms. | |
|
Na2Ca(SO4)2 |
Common on floodplains except in central part of Badwater Basin; sulfate zone in Cottonball Basin. | |
|
CaSO4 |
As layer capping massive gypsum 1 mile (2 km) north of Badwater. Possibly also as dry-period efflorescence on floodplains. | |
|
2CaSO4·H2O |
As layer capping massive gypsum along west side of Badwater Basin and as dry-period efflorescence in floodplains. | |
|
CaSO4·2H2O |
In sulfate caliche, layer in carbonate zone, particularly in Middle and Badwater basins, in sulfate marshes and as massive deposits in sulfate zone. | |
|
MgSO4·6H2O |
Not yet identified but might he expected as dehydration product of epsomite in chloride zone on floodplains. | |
|
MgSO4·7H2O |
Not yet identified; probably will he found as efflorescence on floodplains following storms or floods would dehydrate to hexahydrite during dry periods. | |
|
Na2Mg(SO4)2·4H2O |
Questionably present in efflorescence on floodplain in chloride zone. | |
|
K2Ca2Mg(SO4)4·2H2O |
Questionably present on floodplain in chloride zone. | |
|
BaSO4 |
Not yet identified but probably will be found in carbonate zone and as clastic grains in sediments underlying salt pan. | |
|
SrSO4 |
Found with massive gypsum. | |
|
Na3(SO4)(F,Cl) |
Not yet identified, might he expected in Cottonball Basin or east side of Middle Basin. | |
|
Na6ClF(SO4)2 |
Not yet identified, might he expected in Cottonball Basin or east side of Middle Basin. | |
|
Na2B4O7·5H2O |
Possibly present in Middle Basin in surface layer of layered sulfate and chloride salts. | |
|
Na2B4O7·10H2O |
Probably occurs as dehydration product of borax. | |
|
Na2Mg(SO4)2·4H2O |
Floodplains and marshes in Cottonball Basin. | |
|
Ca2B6O11·13H2O |
Questionably present (X-ray determination but unsatisfactory) in floodplain in Badwater Basin. | |
|
Ca2B6O11·7H2O |
Found in all zones in Badwater Basin and in rough silty rock salt in Cottonball Basin | |
|
Ca2B6O11·5H2O |
Questionably present (X-ray determination but unsatisfactory) in floodplain in Badwater Basin. | |
|
NaCaB5O9·8H2O |
Common in floodplain in Cottonball Basin; known as "cottonball" | |
|
NaCaB5O9·5H2O |
A fibrous borate with index of refraction higher than ulexite occurs on dry areas in Cottonball Basin following hot dry spells and in surface layer of smooth silty rock salt. | |
|
NaNO3 |
Weak, but positive chemical tests obtained locally. |
Native population
Death Valley is home to the Timbisha tribe, who have inhabited the valley for at least the past 1000 years. Some families still live in the valley at Indian Village. The name of the valley, tümpisa, means 'rock paint' and refers to the valley as a source of red ochre paint. Another village in the valley was located in Grapevine Canyon near the present site of Scotty's Castle. It was called maahunu, the meaning of which is uncertain although hunu means 'canyon'. See Timbisha Language.
See also
For a detailed examination of the geology and other features of the valley, see Death Valley National Park.
References
- U.S. Geological Survey Professional Paper 494, Hunt, C.B., and Mabey, D.R., 1966, General geology of Death Valley, California (adapted public domain table)[1]
Categories: Rift valleys | Deserts of North America | Great Basin | California valleys | Death Valley
