Plateau (geography)
A plateau is a flat, elevated landform that stands out from its surroundings, unlike mountains or hills, which have a more rugged profile. Plateaus can arise from significant geological processes, including tectonic uplift and volcanic activity. They are categorized into two main types: dissected and volcanic. Dissected plateaus, such as the Tibetan Plateau, are formed by the collision of tectonic plates, while volcanic plateaus, like the Colorado Plateau, result from lava flows and volcanic eruptions.
Plateaus are found on every continent, including Antarctica, and can vary significantly in their environmental conditions. For instance, the harsh Tibetan Plateau is known as "the roof of the world" due to its extreme altitude and climate, whereas the Loess Plateau in China features fertile wind-blown soil that supports a large population but has faced challenges like erosion and poverty. Other notable plateaus include the Deosai Plains of Pakistan, rich in biodiversity, and the Columbia Plateau in North America, a key geological feature. Overall, plateaus are significant landforms that contribute to Earth's diverse landscapes and ecosystems.
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Plateau (geography)
The primary types of land, or landforms, on earth are mountains, hills, plateaus, and plains. Like a mountain or hill, a plateau consists of raised land that is steeply elevated from its surroundings; however, unlike a mountain or hill, a plateau is flat. Immense geologic forces lift the land, and the erosion of wind and rain sculpts them into various forms. Plateaus are also formed by volcanic action. Every continent, including Antarctica, has plateaus.
Background
Plateaus can be classified as dissected or volcanic. When two tectonic plates collide, the upward movement of the displaced crust forms a dissected plateau. Among dissected plateaus are intermontane plateaus, bordered by mountains and the highest in the world; piedmont plateaus, defined by mountains on one side and a coastal plain or sea on the other; and continental plateaus, which are surrounded on all sides by lowlands. Among the continental plateaus, two examples are the mesa (Spanish for “table”) and the butte. Both of these plateaus are defined by steep sides rising from low, level areas; if the top measures more than the sides, it is a mesa. A study published in 2024 revealed through computer simulation that powerful waves deep within the Earth occur when tectonic plates break apart, eventually forming plateaus, even in regions previously considered stable. These waves cause erosion that moves across a continental region over tens of millions of years and result in rising landmasses.
In the case of volcanic plateaus, lava consisting of fluid basalt flows from multiple effusive, mild nonexplosive volcanic eruptions over time. Such geologic features are referred to as “shield volcanoes.” They are formed when extremely hot basalt lava flows out of fissures in the crust and creates layers away from the source as it cools and solidifies; these layers eventually make up a “shield.”
Overview
Of the dissected plateaus, the Tibetan Plateau is the world’s largest and highest, occupying some 970,000 square miles (2.5 million square kilometers). Nestled in the Himalaya Mountains, it is also the highest plateau, earning it the nickname “the roof (or rooftop) of the world.” Its harsh high-altitude environment is primarily one of permafrost steppes, a bitter cold, oxygen-poor, arid environment that supports little vegetation and few people, who lead nomadic lives.
Further north and east, in central China, is the Loess Plateau (known in China as Huangtu), which derives its name from the powdery wind-blown soil that covers much of the area. The vast area of about 247,100 square miles (640,000 square kilometers) supports a population of about fifty million. In the past, the soft, fertile soil provided excellent protection against the elements as farmers created subterranean homes called yao dong; however, over time, overgrazing caused extreme erosion and, along with the area’s isolation, contributed to intense poverty in those provinces. At more than 13,100 feet (4,000 meters) in elevation, the Deosai Plains in northern Pakistan form the second-highest plateau in the world. This extraordinarily rich ecosystem covers an area of about 1,200 square miles (or 3,000 square kilometers) and is considered a protected region as the Deosai National Park.
Over 9,800 feet (3,000 meters) of ice is another of the world’s highest plateaus, the Antarctic Plateau, which encompasses most of the central part of that continent, including the South Pole. The ice is so heavy that it has actually pressed the landmass below sea level. Frigid winds that roar across the flat expanse make the fierce, inhospitable region the coldest place on the earth (−93.2 degrees Celsius, or −135.8 degrees Fahrenheit), rendering it uninhabitable even to penguins.
Though the most famous plateaus in the United States are volcanic plateaus, the Piedmont region in the eastern part of the country is actually a plateau; the Piedmont Plateau stretches from New Jersey in the north all the way to Alabama in the south. The name Piedmont is derived from the French for “foothill”; indeed, it is bordered along the west by the Appalachian Mountains and along the east by coastal plain.
Of the volcanic plateaus, the largest is the Colorado Plateau, whose 130,000 square miles (approximately 337,000 square kilometers) covers parts of Colorado, Arizona, New Mexico, and Utah. The rock that makes up the plateau was lifted by magma that was unable to break through the earth’s crust. The Colorado River, which bisects this plateau, formed the Grand Canyon, the water of the river eroding the land, creating one of the natural wonders of the world. This region, also called the Four Corners, is home to a large number of national parks, wilderness areas, and national monuments.
Most volcanic plateaus, however, form when lava breaks through cracks in the ground and spreads out overland, often for distances of hundreds of miles over many years. The Columbia Plateau, stretching across the United States and Canadian Pacific Northwest, and the Deccan Plateau of the central Indian subcontinent were formed this way. In central Siberia, the basalt Putorana Plateau, formed similarly through plume volcanism, is so high and inaccessible that its subarctic climate has made it one of the most pristine places on the earth. Though few people have even heard of this region, it has been declared a UNESCO World Heritage site and is protected.
The most remarkable volcanic plateau is deep under the Indian Ocean, the Mascarene Plateau, the deepest part being an abyssal plain. It is one of the few submarine geologic features visible from outer space.
Bibliography
Annerino, John. Colorado Plateau—Wild and Beautiful. Farcountry, 2014.
Blakey, Ron. Ancient Landscapes of the Colorado Plateau. Grand Canyon Assn., 2008.
Cascades Volcano Observatory. “Columbia River Basalt Group Stretches from Oregon to Idaho.” U.S. Geographical Survey, 7 Dec. 2023, www.usgs.gov/observatories/cvo/science/columbia-river-basalt-group-stretches-oregon-idaho. Accessed 15 Nov. 2024.
Filmore, Robert. Geological Evolution of the Colorado Plateau of Eastern Utah and Western Colorado. U of Utah P, 2011.
Frisch, Wolfgang, et al. Plate Tectonics: Continental Drift and Mountain Building. Springer, 2011.
Gernon, Thomas M., et al. "Coevolution of Craton Margins and Interiors during Continental Break-Up." Nature, vol. 632, no. 8024, 2024, pp. 327-335. doi.org/10.1038/s41586-024-07717-1. Accessed 16 Nov. 2024.
Montaigne, Fen. “Remote Russia: Expedition to the Putorana Plateau.” Illust. Randy Olson. National Geographic, Nov. 2000, pp. 32–49. www.nationalgeographic.com/science/article/putorana-plateau-article. Accessed 15 Nov. 2024.
Schaller, George B. Tibet Wild: A Naturalist’s Journeys on the Roof of the World. Island, 2012.
Sorkhabi, Rasoul, et al. "' Roof of the Earth' Offers Clues about How Our Planet Was Shaped." Eos, Transactions American Geophysical Union, vol. 77, no. 40, 1996, pp. 385-387. doi.org/10.1029/96EO00264. Accessed 16 Nov. 2024.
Stump, Edmund. The Roof at the Bottom of the World: Discovering the Transarctic Mountains. Yale UP, 2011.