Plateau

Plateau

Overview

In geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 and earth science
Earth science
Earth science is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences...

, a plateau (icon or ˈ; plural plateaus or rarely plateaux), also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain
Terrain
Terrain, or land relief, is the vertical and horizontal dimension of land surface. When relief is described underwater, the term bathymetry is used...

. A highly eroded plateau is called a dissected plateau
Dissected plateau
A dissected plateau is a plateau area that has been severely eroded so that the relief is sharp. Such an area may be referred to as mountainous, but dissected plateaus are distinguishable from orogenic mountain belts by the lack of folding, metamorphism, extensive faulting, or magmatic activity...

. A volcanic plateau
Volcanic plateau
A volcanic plateau is a plateau produced by volcanic activity. There are two main types: lava plateaus and pyroclastic plateaus.-Lava plateau:...

 is a plateau produced by volcanic activity.

Plateaus can be formed by a number of processes, including, upwelling of volcanic magma
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

, extrusion of lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

, and erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 by water and glaciers.
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In geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 and earth science
Earth science
Earth science is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences...

, a plateau (icon or ˈ; plural plateaus or rarely plateaux), also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain
Terrain
Terrain, or land relief, is the vertical and horizontal dimension of land surface. When relief is described underwater, the term bathymetry is used...

. A highly eroded plateau is called a dissected plateau
Dissected plateau
A dissected plateau is a plateau area that has been severely eroded so that the relief is sharp. Such an area may be referred to as mountainous, but dissected plateaus are distinguishable from orogenic mountain belts by the lack of folding, metamorphism, extensive faulting, or magmatic activity...

. A volcanic plateau
Volcanic plateau
A volcanic plateau is a plateau produced by volcanic activity. There are two main types: lava plateaus and pyroclastic plateaus.-Lava plateau:...

 is a plateau produced by volcanic activity.

Plateaus can be formed by a number of processes, including, upwelling of volcanic magma
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

, extrusion of lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

, and erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 by water and glaciers. Magma rises from the mantle
Mantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....

 causing the ground to swell upward, in this way large, flat areas of rock are uplifted. Plateaus can also be built up by lava spreading outwards from cracks and weak areas in the crust, an example of such a plateau is the Columbia Plateau
Columbia Plateau
The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River...

 in the northwestern United States of America. Plateaus can also be formed due to the erosional processes of glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

s on mountain ranges, in this case the plateaus are left sitting between the mountain ranges. Water can also erode mountains and other landforms down into plateaus.

Plateaus are classified according to their surrounding environment, common categories are: intermontane
Intermontane
Intermontane is a physiographic adjective formed from the prefix "inter-" and the adjective "montane" Usage includes intermontane basin such as New Zealand's Mackenzie Basin and intermontane...

, piedmont
Piedmont
Piedmont is one of the 20 regions of Italy. It has an area of 25,402 square kilometres and a population of about 4.4 million. The capital of Piedmont is Turin. The main local language is Piedmontese. Occitan is also spoken by a minority in the Occitan Valleys situated in the Provinces of...

, and continental plateaus.
  • Intermontane plateaus are the highest in the world, these plateaus are bordered by mountains. The Tibetan plateau
    Tibetan Plateau
    The Tibetan Plateau , also known as the Qinghai–Tibetan Plateau is a vast, elevated plateau in Central Asia covering most of the Tibet Autonomous Region and Qinghai, in addition to smaller portions of western Sichuan, southwestern Gansu, and northern Yunnan in Western China and Ladakh in...

     is one such plateau.
  • Piedmont plateaus are bordered on one side by mountains and on the other by a plain or sea.
  • Continental plateaus are bordered on all sides by the plains or seas, form away from mountains.

Major plateaus of the world


The largest and highest plateau in the world is the Tibetan Plateau
Tibetan Plateau
The Tibetan Plateau , also known as the Qinghai–Tibetan Plateau is a vast, elevated plateau in Central Asia covering most of the Tibet Autonomous Region and Qinghai, in addition to smaller portions of western Sichuan, southwestern Gansu, and northern Yunnan in Western China and Ladakh in...

, called the "roof of the world
Roof of the World
Roof of the World is a metaphoric description of the highest region in the world, also known as "High Asia", or the Trans-Himalaya, the mountainous interior of Asia.The term is also used for parts of this region, for* the Pamirs,* Tibet* the Himalayas...

", which is still being formed by the collisions of the Indo-Australian
Indo-Australian Plate
The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and surrounding ocean, and extends northwest to include the Indian subcontinent and adjacent waters...

 and Eurasian
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...

 tectonic plates. In all the Tibetan plateau covers an area of some 2.5 million square kilometres which is approximately 5000 m above sea level. The height of this plateau is such that it is enough to reverse the Hadley cell convection cycles
Hadley cell
The Hadley cell, named after George Hadley, is a circulation pattern that dominates the tropical atmosphere, with rising motion near the equator, poleward flow 10–15 kilometers above the surface, descending motion in the subtropics, and equatorward flow near the surface...

 and to drive the monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...

s of India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 towards the south.
The second-largest current plateau in the world is the Antarctic Plateau
Antarctic Plateau
The Antarctic Plateau is a large area of Central Antarctica, which extends over a diameter of about , and which includes the region of the South Pole and the Amundsen-Scott Station...

, which covers most of the central part of Antarctica. In that region of Antarctica, there are no mountains that we know of, but rather, there are 3000 meters or more of ice - which very slowly spreads towards its coastline via enormous glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

s. This ice cap
Ice cap
An ice cap is an ice mass that covers less than 50 000 km² of land area . Masses of ice covering more than 50 000 km² are termed an ice sheet....

 is so massive that echo location sound measurements of the thickness of the ice have shown that large parts of the "dry land" surface of Antarctica have been pressed below sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

. Thus, if the icecap were somehow removed, large areas of Antarctica would be flooded by the oceans. On the other hand - more realistically - if that icecap were to gradually melt away, the surface of the land beneath it would gradually rebound
Post-glacial rebound
Post-glacial rebound is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostasy...

 away from the center of the Earth, and that land would become land above sea level.

The third-largest plateau in the world is probably the one in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 that lies in the middle of the Andes Mountains. This Andean Plateau
Altiplano
The Altiplano , in west-central South America, where the Andes are at their widest, is the most extensive area of high plateau on Earth outside of Tibet...

 covers most of Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

, central Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

, central Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, northern Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

 and northern Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

.

Major plateaus of North America


In North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, the largest plateau is the Colorado Plateau
Colorado Plateau
The Colorado Plateau, also called the Colorado Plateau Province, is a physiographic region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. The province covers an area of 337,000 km2 within western Colorado, northwestern New Mexico,...

 covering an area of about 337000 square kilometres (130,116.4 sq mi) in Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

, Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

 and New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

.

The Colorado Plateau in northern Arizona and southern Utah is bisect
Bisect
Bisection is the general activity of dividing something into two equal parts.Bisect may mean:*bisection, in geometry, dividing something into two equal parts* bisection of earthworms to study regeneration...

ed by the valley of the Colorado River
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

 and the Grand Canyon
Grand Canyon
The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...

. How this came to be is that over 10 million years ago, a river was already there, though not necessarily on exactly the same course. Then, subterranean geological forces caused the land in that part of North America to gradually rise by about a centimeter per year for millions of years. An unusual balance occurred: the river that would become the Colorado River was able to erode its way down into the crust of the Earth just as fast as the land rose. Now, millions of years later, the North Rim of the Grand Canyon is at an elevation of about 3000 meters (9800 ft) above sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

, and the South Rim of the Grand Canyon is about 2500 meters (8200 ft) above sea level. At its deepest, the Colorado River is about 1600 meters (5200 ft) below the level of the North Rim.

The southern edge of the plateau in northern Arizona is called the Mogollon Rim
Mogollon Rim
The Mogollon Rim is a topographical and geological feature running across the U.S. state of Arizona. It extends approximately from northern Yavapai County eastward to near the border with New Mexico.-Description:...

, where the elevation of the land starts declining rather steeply into central Arizona. This Mogollon Rim is located about 50 kilometers south of these cities and towns: Flagstaff, Holbrook, Sedona, Winslow, and Williams, Arizona
Williams, Arizona
Williams is a city in Coconino County, Arizona, United States west of Flagstaff. Its population was 2,842 at the 2000 census; according to 2006 Census Bureau estimates, the population of the city is 3,094. It lies on the route of Historic Route 66, Interstate 40, and the Southwest Chief Amtrak...

. Because of the snowy plateau and the San Francisco Mountains to its north, the Mogollian Rim area is prominient for its many natural springs and artesian wells.

See also


  • Oceanic plateau
    Oceanic plateau
    An oceanic plateau is a large, relatively flat submarine region that rises well above the level of the ambient seabed. While many oceanic plateaus are composed of continental crust, and often form a step interrupting the continental slope, some plateaus are undersea remnants of large igneous...

     for submarine or undersea plateaux
  • Altiplano
    Altiplano
    The Altiplano , in west-central South America, where the Andes are at their widest, is the most extensive area of high plateau on Earth outside of Tibet...

  • Mesa
    Mesa
    A mesa or table mountain is an elevated area of land with a flat top and sides that are usually steep cliffs. It takes its name from its characteristic table-top shape....

  • Potrero
    Potrero
    -See also:*Potrero Hill, San Francisco, a neighborhood in San Francisco, California, USA*Potrero Chico, a rock climbing area in Mexico*Potrero Point, a land mass extending into San Francisco Bay, San Francisco, California*Point Potrero, Richmond, California...

  • Tuya
    Tuya
    A tuya is a type of distinctive, flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet. They are somewhat rare worldwide, being confined to regions which were covered by glaciers and also had active volcanism during the same time period.-Formation:Tuyas are...

  • Butte
    Butte
    A butte is a conspicuous isolated hill with steep, often vertical sides and a small, relatively flat top; it is smaller than mesas, plateaus, and table landform tables. In some regions, such as the north central and northwestern United States, the word is used for any hill...

  • Atherton Tableland
    Atherton Tableland
    The Atherton Tableland is a fertile plateau which is part of the Great Dividing Range in Queensland, Australia. It is located west to south-south-west inland from Cairns, well into the tropics, but its elevated position provides a climate suitable for dairy farming. It has an area of around...

  • Chapada
    Chapada
    A chapada is a plateau found in the Brazilian Highlands. The chapadas, which are usually described as mountain ranges, are capped by horizontal strata of sandstone and show the original surface, which has been worn away by the rivers, leaving here and there broad flat-topped ridges between river...

  • Tepuis