thumb|A map of the Colorado Plateau.

thumb|The [[Four Corners region and the Colorado Plateau.]]

The Colorado Plateau is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the Southwestern United States. This plateau covers an area of within western Colorado, northwestern New Mexico, southern and eastern Utah, northern Arizona, and a tiny fraction in the extreme southeast of Nevada. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. Most of the remainder of the plateau is drained by the Rio Grande and its tributaries. lies the Grand Canyon of the Colorado River. Much of the Plateau's landscape is related to the Grand Canyon in both appearance and geologic history. The nickname "Red Rock Country" suggests the brightly colored rock left bare to the view by dryness and erosion. Domes, hoodoos, fins, reefs, river narrows, natural bridges, and slot canyons are only some of the additional features typical of the Plateau.

The Colorado Plateau has the greatest concentration of U.S. National Park Service (NPS) units in the country outside the Washington, DC metropolitan area. Among its nine national parks are Grand Canyon, Zion, Bryce Canyon, Capitol Reef, Canyonlands, Arches, Black Canyon, Mesa Verde, and Petrified Forest. Among its 18 national monuments and other protected areas managed by the NPS, the United States Forest Service, and the Bureau of Land Management are Bears Ears, Rainbow Bridge, Dinosaur, Hovenweep, Wupatki, Sunset Crater Volcano, Grand Staircase–Escalante, Vermillion Cliffs, El Malpais, Natural Bridges, Canyons of the Ancients, Chaco Culture National Historical Park and the Colorado National Monument.

Geography

thumb|The [[Book Cliffs of Utah|400px]]

thumb|The [[Green River (Colorado River)|Green River runs north to south from Wyoming, briefly through Colorado, and converges with the Colorado River in southeastern Utah.]]

This province is bounded by the Rocky Mountains in Colorado and by the Uinta Mountains and Wasatch Mountains branches of the Rockies in northern and central Utah. It is also bounded by the Rio Grande rift, Mogollon Rim, and the Basin and Range Province (at the Hurricane Fault). Isolated ranges of the Southern Rocky Mountains, such as the San Juan Mountains in Colorado and the La Sal Mountains in Utah, intermix into the central and southern parts of the Colorado Plateau.

It is composed of six sections:

  • Uinta Basin Section
  • High Plateaus Section
  • Grand Canyon Section
  • Canyon Lands Section
  • Navajo Section
  • Datil Section

As the name implies, the High Plateaus Section is, on average, the highest section. North-south trending normal faults that include the Hurricane, Sevier, Grand Wash, and Paunsaugunt separate the section's component plateaus.

  • Plateau Sedimentary Province in northern Arizona and southern Utah
  • Black Mesa Basin in northeastern Arizona
  • San Juan Basin in northwestern New Mexico
  • Paradox Basin in southwestern Colorado and southeastern Utah

Human history

The Ancestral Puebloan People lived in the region from roughly 2000 to 700 years ago. Despite having lost one arm in the American Civil War, U.S. Army Major and geologist John Wesley Powell explored the area in 1869 and 1872. Using wooden oak boats and small groups of men, the Powell Geographic Expedition charted this largely unknown region of the United States for the federal government.

Construction of the Hoover Dam in the 1930s and the Glen Canyon Dam in the 1960s changed the character of the Colorado River. Dramatically reduced sediment load changed its color from reddish brown (Colorado is Spanish for "red-colored") to mostly clear. The apparent green color is from algae on the riverbed's rocks, not from any significant amount of suspended material. The lack of sediment has also starved sand bars and beaches, but an experimental 12-day-long controlled flood from Glen Canyon Dam in 1996 showed substantial restoration. Similar floods are planned for every 5 to 10 years.

The Precambrian and Paleozoic history of the Colorado Plateau is best revealed near its southern end, where the Grand Canyon has exposed rocks with ages that span almost 2 billion years. The oldest rocks at river level are igneous and metamorphic and have been lumped together as Vishnu Basement Rocks; the oldest ages recorded by these rocks fall from 1950 to 1680 million years. An erosion surface on the Vishnu Basement Rocks is covered by sedimentary rocks and basalt flows, and these rocks formed in the interval from about 1250 to 750 million years ago: in turn, they were uplifted and split into a range of fault-block mountains. Eventually, the great block of Colorado Plateau crust rose a kilometer higher than the Basin and Range. As the land rose, the streams responded by cutting ever deeper stream channels. The most well-known of these streams, the Colorado River, began to carve the Grand Canyon less than 6 million years ago.

Energy resources

thumb|[[Castle Gate Power Plant near Helper, Utah.]]

Electrical power generation is one of the major industries that takes place in the Colorado Plateau region. Most electrical generation comes from coal fired power plants. The rocks of the Colorado Plateau are a source of oil and a major source of natural gas. Major petroleum deposits are present in the San Juan Basin of New Mexico and Colorado, the Uinta Basin of Utah, the Piceance Basin of Colorado, and the Paradox Basin of Utah, Colorado, and Arizona. The Colorado Plateau holds major uranium deposits, and there was a uranium boom in the 1950s. The Atlas Uranium Mill near Moab has left a problematic tailings pile for cleanup. , 10 million tons of tailings had been relocated out of an estimated 16 million tons. Major coal deposits are being mined in the Colorado Plateau in Utah, Arizona, Colorado, and New Mexico, though large coal mining projects, such as on the Kaiparowits Plateau, have been proposed and defeated politically. The ITT Power Project, eventually located in Lynndyl, Utah, near Delta, was originally suggested for Salt Wash near Capitol Reef National Park. After a firestorm of opposition, it was moved to a less controversial site. In Utah the largest deposits are in aptly named Carbon County. In Arizona the biggest operation is on Black Mesa, supplying coal to Navajo Power Plant. Perhaps the only one of its kind, a gilsonite plant near Bonanza, southeast of Vernal, Utah, mines this unique, lustrous, brittle form of asphalt, for use in "varnishes, paints,...ink, waterproofing compounds, electrical insulation,...roofing materials."

Protected lands

This relatively high, semi-arid to arid province produces many distinctive erosional features such as arches, arroyos, canyons, cliffs, fins, natural bridges, pinnacles, hoodoos, and monoliths that, in various places and extents, have been protected. Also protected are areas of historic or cultural significance, such as the pueblos of the Ancestral Puebloan culture. There are nine U.S. National Parks, a National Historical Park, nineteen U.S. national monuments and dozens of wilderness areas in the province along with millions of acres in U.S. National Forests, many state parks, and other protected lands. In fact, this region has the highest concentration of parklands in North America.