Great Basin - Geology, Flora and Fauna, History, Present Habitation

Vast interior region in W USA, between (W) the Sierra Nevada and the Cascade Range and (E) the Wasatch Range and Colorado Plateau; area c.500 000 km²/200 000 sq mi; covers parts of Oregon and Idaho, most of Nevada, W Utah, and part of SE California; rugged N–S mountain ranges; semi-arid climate; the few streams (largest are the Humboldt and Carson Rivers) drain into saline lakes or sinks; biggest lakes are the Great Salt, Utah, Sevier, Pyramid, and Walker, remnants of the enormous prehistoric lakes, Bonneville and Lahontan; also several deserts (Great Salt Lake, Mojave, Colorado, Black Rock, Smoke Creek, Death Valley, Carson Sink); Black Rock site of land speed record, 1997; agriculture possible only with irrigation; some minerals and grazing land.

The Great Basin is a large, arid region of the western United States. 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. 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.

Watersheds within the Great Basin include:

Great Salt Lake - Utah, Idaho, Wyoming Death Valley - California, Nevada Honey Lake - California Mono Lake - California Humboldt Sink - Nevada (drainage of the Humboldt River, the longest river in the Great Basin) Pyramid Lake - Nevada Black Rock Desert - Nevada, Oregon Carson Sink - Nevada Walker Lake - Nevada Harney Basin - Oregon Sevier Lake - Utah Abert Lake - Oregon Surprise Valley - California, Nevada Escalante Desert - Utah

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. 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

The Great Basin is considered by geologists to be in the process of stretching and cracking. Some geologists speculate that the 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.

Flora and Fauna

The Great Basin is predominantly high altitude desert, with the lowest basins just below 4,000 feet and several peaks over 12,000 feet. Stands of Limber Pine and Great Basin Bristlecone Pine can be found in some of the higher ranges. Golden Eagles are perhaps more common in the Great Basin than anywhere else in the US.

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.

Chukar, Grey Partridge and Himalayan Snowcock have been successfully introduced to the Great Basin, although the latter has only thrived in the Ruby Mountains. 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.

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. By the early 19th century, fur trappers from the Hudson's Bay Company had explored the upper Basin in the Oregon Country. The Mormons quickly established a provisional government and drafted a proposal for a new state, called the State of Deseret, that encompass the entire Great Basin, as well as the coast of southern California. 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.

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.

In 1986, the Great Basin National Park was established by the Federal Government, encompassing 122 square miles of land in Nevada, near the Utah border. All of this land is within the Great Basin, and it includes basin and mountainous land, and it is the home of much wildlife.

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. Smaller cities in the basin include Carson City, Nevada;

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 California and Idaho, and Interstate 70 between its junction with Interstate 15 in Utah and westmost Colorado.