Plateau has a large elevated area on its top unlike a mountain and has nearly even surface out there. Very often rivers or streams cut out deep valleys and gorges in a plateau region. In place of its original smooth topography, it then changes into a disected plateau.
A plateau remains much higher above the sea level of the nearby areas. Though normally 600 metres above sea level, there are plateau of Tibet and Bolivia, more than 3600 metres above sea level.
Classification of Plateaus
On the basis of their geographical location and structure of rocks, the plateaus are classified as:
The plateau which are bordering the fold mountain range or are partly or fully enclosed within them are the intermontane plateaus.
The extensive and over 4500 metres high plateau of Tibet is one such example. It is surrounded by folded mountains like Himalaya, Karakoram, Kunlun, Tien Shah on its two sides. The plateau of Colorado is another well known example, over one km high into which rivers have cut the Grand Canyon and a series of gorges. The plateau of Mexico, Bolivia and Iran are all other examples of this type.
The plateaus that are situated at the foot of the mountains and are bounded on other sides by a plain or an ocean are called piedmount plateau.
The plateau of Malwa in India, those of Patagonia facing the Atlantic ocean and the Appallachian situated between the Appalachian Mountain and the Atlantic Coastal Plain in U.S.A are examples.
These are formed either by an extensive continental uplift or by the spread of horizontal basic lava sheets completely covering the original topography to a great depth. The volcanic lava covered plateau of Maharashtra in India, Snake River Plateau in North West USA are the examples of this type. These are also, called the ptateau of accumulation.