Misplaced Pages

Great Basin: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 21:06, 13 January 2009 edit24.14.182.29 (talk) →Geology← Previous edit Revision as of 21:07, 13 January 2009 edit undoKristen Eriksen (talk | contribs)3,612 editsm Reverted edits by 24.14.182.29 (talk) to last version by StapleguntherNext edit →
Line 101: Line 101:
The Great Basin's internal drainage results from blockage of water movement by high fault-created mountains and by lack of sufficient water flow to merge with larger drainages outside of the Great Basin. Much of the present-day Great Basin would drain to the sea - just as it did in the recent Ice Ages - if there were more rain and snowfall. The Great Basin's internal drainage results from blockage of water movement by high fault-created mountains and by lack of sufficient water flow to merge with larger drainages outside of the Great Basin. Much of the present-day Great Basin would drain to the sea - just as it did in the recent Ice Ages - if there were more rain and snowfall.


==Geology==
ur mom






boob


] ]
] ]
The Great Basin is part of the greater geologic unit aka my giant cock , the ].<ref>U.S. Geological survey, 2004</ref> The Great Basin is part of the greater geologic unit, the ].<ref>U.S. Geological survey, 2004</ref>
The Great Basin is considered by geologists to be in the process of stretching and cracking. Although elevated, the crust here is actually relatively thin, and getting thinner. Some geologists speculate that the ] rift zone may be destined in the distant future to split the Great Basin, possibly by way of the ], letting the sea in from the ]. The Great Basin is considered by geologists to be in the process of stretching and cracking. Although elevated, the crust here is actually relatively thin, and getting thinner. Some geologists speculate that the ] rift zone may be destined in the distant future to split the Great Basin, possibly by way of the ], letting the sea in from the ].

Revision as of 21:07, 13 January 2009

Drainage map showing the Great Basin in orange
Various definitions of the Great Basin (NPS)

The Great Basin is a large, arid region of the western United States. Its boundaries depend on how it is defined. Its most common definition is the contiguous watershed, roughly between the Wasatch Mountains, in Utah and the Sierra Nevada, that has no natural outlet to the sea. Therefore it is endorheic. The Great Basin Desert is defined by the extent of characteristic plant species, and covers a somewhat different (and smaller) area.The Great Basin Culture Area, home to several Shoshonean Great Basin tribes, extends further to the north and east than the hydrographic basin. The Basin and Range Province is a geologic region that is most recognizable in the Great Basin but extends well into the Sonoran and Mojave Deserts.

Description

The 200,000 square mile (520,000 square km) intermontane plateau covers most of Nevada and over half of Utah, as well as parts of California, Idaho, Oregon and Wyoming. The Great Basin is not a single basin, but rather a series of contiguous watersheds, bounded on the west by watersheds of the Sacramento-San Joaquin and Klamath rivers, on the north by the watershed of the Columbia-Snake, and on the south and east by the watershed of the Colorado-Green.

Wheeler Peak, Great Basin National Park, Nevada
File:100 1469.jpg
Mountain ranges separated by valleys are typical in the geography of the Great Basin.
Black Rock Desert, Nevada.
Lake Tahoe on the border of California and Nevada.
File:Boise2008 025.JPG
Dust Devil in southeastern Idaho in the northern Great Basin.

Watersheds within the Great Basin include:

Much of the Great Basin, especially across northern Nevada, consists of a series of isolated mountain ranges and intervening valleys, a geographical configuration known as the Basin and Range Province. Additionally the Great Basin contains two large expansive playas that are the lakebed remnants of prehistoric lakes that existed in the basin during the last ice age but have since largely dried up. Lake Bonneville extended over most of Western Utah and into Idaho and Nevada, leaving behind the Great Salt Lake, the Bonneville Salt Flats, Utah Lake, and Sevier Lake. Likewise Lake Lahontan extended across much of northwestern Nevada and neighboring states, leaving behind such remnants as the Black Rock Desert, Carson Sink, Humboldt Sink, Walker Lake, Pyramid Lake, Winnemucca Lake, and Honey Lake, each of which now forms a separate watershed within the basin.

The Basin and Range province's dynamic fault history has profoundly affected the region's water drainage system. Most precipitation in the Great Basin falls in the form of snow that melts in the spring. Rain that reaches the ground, or snow that melts, quickly evaporates in the dry desert environment. Some of the water that does not evaporate sinks into the ground to become ground water. The remaining water flows into streams and collects in short-lived lakes called playas on the valley floor and eventually evaporates. Any water that falls as rain or snow into this region does not escape out of it; not one of the streams that originate within this basin ever finds an outlet to the ocean. The extent of internal drainage, the area in which surface water cannot reach the ocean, defines the geographic region called the Great Basin.

The Great Basin's internal drainage results from blockage of water movement by high fault-created mountains and by lack of sufficient water flow to merge with larger drainages outside of the Great Basin. Much of the present-day Great Basin would drain to the sea - just as it did in the recent Ice Ages - if there were more rain and snowfall.

Geology

File:PSP 018.jpg
Winter in Great Basin, Utah County, Utah
Bonneville Salt Flats in western Utah

The Great Basin is part of the greater geologic unit, the Basin and Range Province. The Great Basin is considered by geologists to be in the process of stretching and cracking. Although elevated, the crust here is actually relatively thin, and getting thinner. Some geologists speculate that the East Pacific Rise rift zone may be destined in the distant future to split the Great Basin, possibly by way of the Imperial Valley, letting the sea in from the Gulf of California.

The Walker Lane is a trough running from Oregon to Death Valley which may represent the alignment of this future inlet.

On February 21, 2008, a 6.0 magnitude earthquake occurred near the town of Wells, Nevada, centered on the Independence Valley fault system.

Flora and fauna

Further information: Northern Basin and Range (ecoregion)

The Great Basin is predominantly high altitude desert, with the lowest basins just below 4,000 feet (1,200 m) and several peaks over 12,000 feet (3,700 m). Most areas are dominated by shrubs, mostly of the Atriplex genus at the lowest elevations and sagebrush at higher elevations. Open woodlands consisting of Utah Juniper, Single-leaf Pinyon (mostly southern areas) or Curl-leaf Mountain Mahogany (mostly northern areas) form on the slopes of most ranges. Stands of Limber Pine and Great Basin Bristlecone Pine can be found in some of the higher ranges. Cottonwoods and Quaking Aspen groves exist in areas with dependable water.

Juniper tree forests are found throughout the Great Basin.

Lagomorphs such as Black-tailed Jackrabbit and Desert Cottontail and the coyotes that prey on them are the mammals most often encountered by humans. Ground squirrels are common, but they generally venture above ground in only the spring and early summer. Packrats, Kangaroo rats and other small rodents are also common, but these are predominantly nocturnal. Pronghorn, Mule Deer, and Mountain Lion are also present throughout the area. Elk and Bighorn Sheep are present but uncommon.

Small lizards such as the Western fence lizard, Longnose Leopard Lizard and Horned toad are common, especially in lower elevations. Rattlesnakes and Gopher snakes are also present.

Shorebirds such as Phalaropes and Curlews can be found in wet areas. American White Pelicans are common at Pyramid Lake. Golden Eagles are perhaps more common in the Great Basin than anywhere else in the US. Mourning Dove, Western Meadowlark, Black-billed Magpie and Common Raven are other common bird species.

Two endangered species of fish are found in Pyramid Lake that lies in the Great Basin: the Cui-ui sucker fish and the Lahontan cutthroat trout.

Large invertebrates include tarantulas (Aphonopelma genus) and Mormon crickets.

Chukar, Grey Partridge and Himalayan Snowcock have been successfully introduced to the Great Basin, although the latter has only thrived in the Ruby Mountains. Cheatgrass, which was unintentionally introduced, forms a critical portion of their diets. Feral horses (Mustangs) and wild burros are other highly successful, though controversial, alien species. Most of the Great Basin is open range and domestic cattle and sheep are widespread.

History

The history of human habitation in the Great Basin goes back at least 12,000 years. Archaeological evidence of primitive habitation sites along the shore of prehistoric Lake Lahontan date from the end of the ice age when its shoreline was approximately 500 ft (150 m) higher along the sides of the surrounding mountains.

At the time of the arrival of Europeans, the region was inhabited by a broad group of Uto-Aztecan-speaking Native American tribes known collectively as the Great Basin tribes, including the Shoshone, Ute, and Paiute. The first Europeans to encounter the area were the early Spanish explorers in the southwest in the late 18th century. By the early 19th century, fur trappers from the Hudson's Bay Company had explored the upper Basin in the Oregon Country. The first comprehensive and accurate map of the region was made by John C. Frémont during several expeditions across the region in the 1840s.

Pony Express Trail historical marker, Utah

The United States acquired complete control of the area through the 1846 Oregon Treaty (giving it the small portion north of the 42nd parallel) and the 1848 Treaty of Guadalupe Hidalgo. The first large-scale white settlement in the region was by early Mormon pioneers in the late 1840s in the arable areas around Salt Lake City and the Cache Valley. The Mormons quickly established a provisional government and drafted a proposal for a new state, called the State of Deseret, that encompassed the entire Great Basin, as well as the coast of southern California. The region became successively organized by the creation of the Oregon Territory in 1848, the admission of California to the Union in 1850, and the creation of the Utah Territory in 1850. The discovery of gold in California, in 1848, brought waves of migrants across the Great Basin along the California Trail, which followed the Humboldt River across Nevada. In 1860-61, the Pony Express, came through the area transporting mail from the eastern United States to California.

The part of the first North American transcontinental railroad that was built by the Central Pacific railroad crossed the Great Basin between Reno, Nevada, and Ogden, Utah. Another major railroad southwest from Salt Lake City into Nevada led to the founding of Las Vegas, Nevada.

In 1986, the Great Basin National Park was established by the Federal Government, encompassing 122 square miles (320 km) of land in Nevada, near the Utah border. The new National Park subsumed the much smaller Lehman Caves National Monument, which had been established in 1922. All of this land is within the Great Basin, and it includes basin and mountainous land, and it is the home of much wildlife.

In the 1950s, the area northwest of Las Vegas was the site of numerous above-ground atomic bomb tests, followed in the 1960s by underground testing.

Present habitation

The Basin has remained among the most sparsely-inhabited areas of the United States. The two largest cities in the basin are Salt Lake City, Utah on its eastern edge and Reno, Nevada on its western edge. Suburbs of Los Angeles, including Lancaster and Palmdale, and Victorville and Hesperia, California combine for about 600,000 residents on the area's southwestern edge. Smaller cities in the basin include Carson City, Nevada; Winnemucca, Nevada; Elko, Nevada; Ogden, Utah; Provo, Utah; and Logan, Utah.

The Great Basin is traversed by major long-distance railroads and expressways, such as the parts of Interstate 80 between Reno and Salt Lake City, Interstate 15 between southwest Utah and Idaho, and Interstate 70 from its junction with Interstate 15 in central Utah from the Great Basin, across the Colorado Plateau to westernmost Colorado. Railroads, such as the Union Pacific, which through merger now owns the routes of the former Southern Pacific and Western Pacific lines, extend from the major metropolitan areas of Denver, Colorado, through Salt Lake City, Utah, and Reno, Nevada, to the San Francisco, California, Bay Area; and from Salt Lake City to Los Angeles, California.

Black Rock volcano near Fillmore, Utah by Interstate 15

See also

Line notes

  1. U.S. Geological survey, 2004
  2. C.M Hogan, 1987

References

External links

Geography topics
Branches
Human
Physical
Technical
Integrated
Techniques and tools
Quantitative
Qualitative
Institutions
Education
Physical geography
World deserts
Africa
Asia
Arabian Peninsula
Central Asia
East Asia
South Asia
Iranian plateau
Southeast Asia
Europe
North America
Oceania
Australia
New Zealand
South America
Polar regions
Antarctic
Arctic
Regions of the United States
Administrative
Units
Time zones
Census
Courts of
appeals
Physical
Physiographic
Coastal
Historical
Acquisitions
Civil War
Divided
Other
State of California
Sacramento (capital)
Topics
Regions
Metro regions
Counties
Most populous
cities
flag California portal
State of Idaho
Boise (capital)
Topics
Society
Regions
Larger
cities
Smaller
cities
Counties
flag Idaho portal
State of Nevada
Carson City (capital)
Topics
Society
Regions
Metro areas
Counties
Cities and
communities
Former counties
flag Nevada portal
State of Oregon
Salem (capital)
Topics
Society
Regions
Western
Eastern
Southern
Shared
Metro areas
Largest cities
Counties
State of Utah
Salt Lake City (capital)
Topics
Society
Regions
Largest cities
Counties
Important sites
National monuments
National parks
National recreation areas
Ski resorts
Other
History
Flora and fauna
Culture
flag Utah portal
State of Wyoming
Cheyenne (capital)
Topics
Society
Regions
Cities
Counties
flag Wyoming portal
Categories: