Plateau or tableland is one of the important landforms of the earth created by geological forces and movement of the earth's plates. It is a raised ground or a highland with relatively flat terrain. Plateaus (including enclosed basins) cover about 45% of the earth surface and are found both on land and in the oceans. Higher plateau regions are often suitable for grazing of livestock and lower plateau regions are useful for farming.
Formation of Plateaus
Plateaus, as landforms, are formed in different ways - by glacial or river erosions, by the outpouring of volcanic magma, by the extrusion of lava, or by plate tectonic movements.
Erosion by Glacier and Water:
Like any elevated land, plateau is exposed to erosion of water, which removes the surface of the upland and shape the plateau. Erosion of mountains also lower them down to flat plateaus.
Rising of Volcanic Magma: Magma flows out from the earth's mantle causing the surface to puff up, resulting elevation of larger flat area and causes plateau formation.
Extrusion of Lava:
Spreading out of lava from cracks on the surface of the earth also causes plateau formation.
Plate Tectonic Movements:
Folding and faulting causes formation of plateaus. When two tectonic plates collide, the crust lifts upwards causing formation of either folded mountains or plateaus. Normal vertical faulting also causes plateau formation. The Colorado Plateau of USA was formed by such a movement of the earth's plates.
Types of Plateaus:
Plateau can be categorized into different types as per their surroundings.
Intermontane Plateau: Plateaus surrounded by mountains are called intermontane plateaus. The Tibetan Plateau is an Intermontane Plateau; similarly the Columbian Plateau is surrounded by Cascade Mountains to the west and by the Rocky Mountains to the east.
It is surrounded on one side by mountains and on other side by plains or sea. The region between the Atlantic Coastal Plain and the main Appalachian Mountains in United States is a piedmont region.
Continental Plateaus: These plateaus are surrounded by plains or sea and are generally formed away from the mountains.
These plateaus are formed by volcanic activities like by dispersion of lava on the surface of the earth or by outpouring of magma from interior of the earth. The Deccan Plateau of India is a volcanic plateau.
Dissected Plateaus: Plateaus formed by erosion of mountains by rivers and glaciers are called dissected plateaus.
Famous Plateaus of the World:
Plateaus are formed both on land and in the ocean beds. Some of the famous land plateaus include Tibetan Plateau in Asia, which is also the highest and largest in the world; the Antarctic Plateau; the Andean Plateau in South America; the Colorado Plateau in North America; the Columbia Plateau of the United States, and the Deccan Plateau of India. The Laurentian Plateau in Canada, also called Canadian Shield, covers about 40% of Canada's total area and was formed millions of years ago by volcanic activities. Some of the oceanic plateaus or submarine plateaus of the world are Mascarene Plateau and Kerguelen Plateau in the Indian Ocean, the Challenger, and Campbell Plateau in the South Pacific etc.
Beside the known plateau there are many plateaus which are yet to be named in the world. The plateau map depicts some of the famous and well-known plateaus of the world.