- published: 10 Jan 2009
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In geology and earth science, a plateau ( /pləˈtoʊ/ or /ˈplætoʊ/; plural plateaus or rarely plateaux), also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain.
Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Magma rises from the mantle 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 outward from cracks and weak areas in the crust. Plateaus can also be formed by the erosional processes of glaciers on mountain ranges, leaving them sitting between the mountain ranges. Water can also erode mountains and other landforms down into plateaus.
Plateaus are classified according to their surrounding environment.
The largest and highest plateau in the world is the Tibetan Plateau, called the "roof of the world", which is still being formed by the collisions of the Indo-Australian and Eurasian tectonic plates. In all, the Tibetan plateau covers an area of some 2.5 million square kilometres, approximately 5000 m above sea level. The height of this plateau is such that it is enough to reverse the Hadley cell convection cycles and to drive the monsoons of India towards the south.