Plateau

For other uses, seePlateau (disambiguation).

Satellite image of theTibetan Plateaubetween the Himalayan mountains to the south and theTaklamakan Desertto the north

Ingeologyandphysical geography,aplateau(/pləˈtoʊ,plæˈtoʊ,ˈplætoʊ/;French:[plato];pl.:plateausorplateaux),also called ahigh plainor atableland,is an area of ahighlandconsisting of flatterrainthat is raised sharply above the surrounding area on at least one side.Often one or more sides have deep hills orescarpments.Plateaus can be formed by a number of processes, includingupwellingofvolcanicmagma,extrusionoflava,anderosionby water andglaciers.Plateaus are classified according to their surrounding environment as intermontane, piedmont, or continental. A few plateaus may have a small flat top while others have wider ones.

Formation

Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava,plate tectonicsmovements, and erosion by water and glaciers.

Volcanic

Main article:Volcanic plateau

ThePajarito Plateauin New Mexico is an example of a volcanic plateau.

Volcanic plateausare produced byvolcanic activity.TheColumbia Plateauin the north-western United States is an example. They may be formed by upwelling of volcanic magma or extrusion of lava. The underlining mechanism in forming plateaus from upwelling starts when magma rises from themantle,causing the ground to swell upward. In this way, large, flat areas of rock are uplifted to form a plateau. For plateaus formed by extrusion, the rock is built up from lava spreading outward from cracks and weak areas in the crust.

Tectonic

Tectonic plateaus are formed by tectonic plate movements which cause uplift, and are normally of a considerable size, and a fairly uniform altitude. Examples are theDeccan PlateauinIndiaand theMeseta Centralon theIberian Peninsula.

Erosion

Plateaus can also be formed by the erosional processes ofglacierson mountain ranges, leaving them sitting between the mountain ranges. Water can also erode mountains and other landforms down into plateaus.Dissected plateausare highly eroded plateaus cut by rivers and broken by deep narrow valleys. An example is theScottish Highlands.

Classification

Plateaus are classified according to their surrounding environment.

• Intermontane plateaus are some of the highest and most extensive plateaus in the world, enclosed by fold mountains. Examples are theTibetan Plateaubetween theHimalayasandKunlun Mountains,Altiplanoplateau between two ranges ofAndes.
• Lava or volcanic plateaus are the plateau that occur in areas of widespread volcanic eruptions. The magma that comes out through narrow cracks or fissures in the crust spread over large area and solidifies. These layers of lava sheets form lava or volcanic plateaus. TheAntrim PlateauinNorthern Ireland,theDeccan PlateauinIndia,and theColumbia Plateauin theUnited Statesare examples of lava plateaus.
• Piedmont plateaus are bordered on one side by mountains and on the other by a plain or a sea. ThePiedmont Plateauof theEastern United Statesbetween theAppalachian Mountainsand theAtlantic Plainis an example.
• Continental plateaus are bordered on all sides by plains or oceans, forming away from the mountains. An example of a continental plateau is theAntarctic PlateauinEast Antarctica.

Large plateaus by continent

Africa

The highest African plateau is theEthiopian Highlandswhich cover the central part of Ethiopia. It forms the largest continuous area of its altitude in the continent, with little of its surface falling below 1,500 metres (4,921 ft), while the summits reach heights of up to 4,550 metres (14,928 ft). It is sometimes called the Roof of Africa due to its height and large area.

Another example is theHighveldwhich is the portion of the South African inland plateau which has an altitude above approximately 1,500 metres, but below 2,100 metres, thus excluding the Lesotho mountain regions. It is home to some of the largest South Africanurban agglomerations.

In Egypt are theGiza PlateauandGalala Mountain,which was once called Gallayat Plateaus, rising 3,300 ft above sea level.

Antarctica

Another very large plateau is the icyAntarctic Plateau,which is sometimes referred to as the Polar Plateau orKing Haakon VIIPlateau, home to the geographicSouth Poleand theAmundsen–Scott South Pole Station,which covers most ofEast Antarcticawhere there are no known mountains but rather 3,000 m (9,800 ft) high of superficial ice and which spreads very slowly toward the surrounding coastline through enormousglaciers.Thepolar ice capis so massive that theecholocationmeasurements of ice thickness have shown that large areas are belowsea level.But, as the ice melts, the land beneath willreboundthroughisostasyand ultimately rise above sea level.

Asia

The largest and highest plateau in the world is theTibetan Plateau,sometimes metaphorically described as the "Roof of the World",which is still being formed by the collisions of theIndo-AustralianandEurasiantectonic plates.The Tibetan Plateau covers approximately 2,500,000 km²(970,000 sq mi), at about 5,000 m (16,000 ft) above sea level. The plateau is sufficiently high to reverse theHadley cellconvection cycles and to drive themonsoonsof India towards the south. TheDeosai Plainsin Pakistan are situated at an average elevation of 4,114 meters (13,497 ft) above sea level. They are considered to be the second highest plateaus in the world.

Other major plateaus in Asia are:Najdon theArabian Peninsula,elevation 762 to 1,525 m (2,500 to 5,003 ft),Armenian Highlands(≈400,000 km²(150,000 sq mi), elevation 900–2,100 metres (3,000–6,900 ft)),Iranian Plateau(≈3,700,000 km²(1,400,000 sq mi), elevation 300–1,500 metres (980–4,920 ft)),Anatolian Plateau,Mongolian Plateau(≈2,600,000 km²(1,000,000 sq mi), elevation 1,000–1,500 metres (3,300–4,900 ft)), and theDeccan Plateau(≈1,900,000 km²(730,000 sq mi), elevation 300–600 metres (980–1,970 ft)).

North America

A large plateau in North America is theColorado Plateau,which covers about 337,000 km²(130,000 sq mi) inColorado,Arizona,New Mexico,andUtah.

In northern Arizona and southern Utah the Colorado Plateau isbisectedby theColorado Riverand theGrand Canyon.This came to be 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 into the crust of the Earth at a nearly equal rate to the uplift of the plateau. Now, millions of years later, the North Rim of the Grand Canyon is at an elevation of about 2,450 m (8,040 ft) abovesea level,and the South Rim of the Grand Canyon is about 2,150 m (7,050 ft) above sea level. At its deepest, the Colorado River is about 1,830 m (6,000 ft) below the level of the North Rim.

Another high-altitude plateau in North America is theMexican Plateau.With an area of 601,882 km²(232,388 sq mi) and average height of 1,825 metres, it is the home of more than 70 million people.

Oceania

TheWestern Plateau,part of theAustralian Shield,is an ancientcratoncovering much of the continent's southwest, an area of some 700,000 square kilometres. It has an average elevation between 305 and 460 metres.

TheNorth Island Volcanic Plateauis an area of high land occupying much of the centre of theNorth Islandof New Zealand, with volcanoes, lava plateaus, and crater lakes, the most notable of which is the country's largest lake,Lake Taupō.The plateau stretches approximately 100 km east to west and 130 km north to south. The majority of the plateau is more than 600 metres above sea level.

South America

Further information:Tepui

Atepui(/ˈtɛpwi/), ortepuy(Spanish:[teˈpuj]), is atable-top mountainormesafound in theGuiana Highlandsof South America, especially inVenezuelaand westernGuyana.The word tepui means "house of the gods" in the native tongue of thePemon,theIndigenous peoplewho inhabit theGran Sabana.

Tepuis can be considered minute plateaus and tend to be found as isolated entities rather than in connected ranges, which makes them the host of a unique array ofendemicplant and animal species. Some of the most outstanding tepuis areNeblina,Autana,AuyanandMount Roraima.They are typically composed of sheer blocks ofPrecambrianquartz arenitesandstonethat rise abruptly from the jungle, giving rise to spectacular natural scenery.Auyán-tepuiis the source ofAngel Falls,the world's tallestwaterfall.

The Colombian capital city of Bogota sits on an Andean plateau known as theAltiplano Cundiboyacenseroughly the size of Switzerland. Averaging a height of 2,600 m (8,500 ft) above sea level, this northern Andean plateau is situated in the country's eastern range and is divided into three main flat regions: theBogotá savanna,the valleys ofUbatéandChiquinquirá,and the valleys ofDuitamaandSogamoso.

Road to theALMA's Operations Support Facility and then on further to theChajnantor Plateauat 5,000 metres above sea level.

The parallel Sierra of Andes delimit one of the world highest plateaux: theAltiplano,(Spanish for "high plain" ), Andean Plateau or Bolivian Plateau. It lies 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. The bulk of the Altiplano lies within Bolivian and Peruvian territory while its southern parts lie in Chile. The Altiplano plateau hosts several cities like Puno, Oruro, El Alto and La Paz the administrative seat of Bolivia. Northeastern Altiplano is more humid than the Southwestern, the latter of which hosts severalsalares,or salt flats, due to its aridity. At the Bolivia-Peru border liesLake Titicaca,the largest lake in South America.

See also

• Atherton Tableland– Fertile plateau in northern Queensland, Australia
• Butte– Isolated hill with steep, often vertical sides and a small, relatively flat top
• Chapada– plateau found in the Brazilian HighlandsPages displaying wikidata descriptions as a fallback
• Deosai National Park– National park in Gilgit Baltistan, Pakistan
• Mesa– Elevated area of land with a flat top and sides, usually much wider than buttes
• Oceanic plateau– Relatively flat submarine region that rises well above the level of the ambient seabed
• Potrero– Long mesa that at one end slopes upward to higher terrain
• Tuya– Flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet

References

Bibliography

• Huggett, Richard John (2011).Fundamentals Of Geomorphology.Routledge Fundamentals of Physical Geography Series (3rd ed.).Routledge.ISBN978-0-203-86008-3.

External links

Media related toPlateausat Wikimedia Commons

• "Plateau" at scienceclarified.com
• nationalgeographic.com
• travel-university.org
• britannica.com