Plateau - Landform

On Earth, there are several types of geographical features of landmasses. Examples include various kinds of landforms mountains, plains, plateaus that are created over eras of geological history. A plateau landform is a landform made up of an extensive area of flat land which is usually bounded by a steep slope on all sides. Sometimes it can be enclosed by elevated portions of land such as hills and mountains. 

The criteria which determine the physical features of a plateau are relatively low relief structures and some altitude. Even though both the mountains and plateaus are higher than their surrounding areas, the significant difference between them is that the mountains keep on elevating continuously forming an inverted cone-like structure whereas the plateaus are flat-lands with some altitude.

Definition of Plateau Landform

Mentioned above was a brief description of the plateau landform. Based on the given information the plateau landform definition can be stated as follows:

Plateau: In geology and physical geography, a plateau, also known as a high plain or a flatland, is an area of elevated or raised terrains as compared to all the surrounding sides or at least one side, which are completely almost flat surfaces at the top. 

A plateau can be surrounded by deep hills on all or at least one side. This is because they are formed because of a number of processes such as volcanic magma, lava extrusions, or erosions due to the water and the glaciers. Usually, the top of the plateaus is a wide flat area of landmass but some of them can be short flatlands as well. Also, depending on their surrounding or neighbouring environment plateau landforms can be classified into intermontane, piedmont or continental. Given below is the picture of plateau landform:

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Geological and Geographical Features of Plateau Landform

As the plateau landforms are formed like the mountain landforms owing to the volcanic activity, lava extrusions, or erosions due to water and glaciers, these landforms are differentiated and classified into various types depending on the geological and geographical features, surrounding or creating them.

Classification of Plateau Landform Based on the Formation

Depending on the basis of the geologic activity, the plateau landform is distributed into the following types:

• Volcanic: 

Volcanic plateau is also a lava plateau landform. Hence, the lava plateau definition is any flat-land landform produced due to any volcanic activity. The lava plateau formation is also caused by the volcanic upwelling of magma or lava extrusion. The magma rising from the mantle causes the ground to swell upward. Because of this large, flat areas of rock get uplifted to form a plateau. In the extrusion phenomenon, the lava spreads outward from cracks and weak areas in the crust, resulting in the formation of a lava plateau.

• Erosion: 

When the glaciers from the mountain tops erode away, they leave huge flat areas between the mountain ranges which forms the plateau. Rivers are also responsible for creating large flat-lands by eroding huge surfaces and broken by deep narrow valleys giving dissected plateau landform. Computer modelling studies provide some information that plateau landform can also be formed as a result of the feedback between tectonic plates. The Appalachian plateau landforms are an example of the dissected plateau landforms. 

Classification of Plateau Landform Based on Surrounding Environment

Given below are the classifications of the plateaus based upon the surrounding environment:

• Intermontane plateaus are the ones that are classified based on the surrounding mountains. The plateaus are the flat-lands with bordering mountains. The Tibetan plateau is one such example.

• Lava plateau or volcanic plateau is the one surrounded by volcanic activity centres as clear from the definition of lava plateau. The magma comes out of the fixtures and cracks in the crust and leads to lava plateau formation. The Deccan Plateau in India is one such lava plateau. Other such examples, including Antrim plateau in Netherland, Columbia plateau landforms in the United States are examples of the lava plateau.

• Piedmont plateau landforms are the ones that are surrounded by the mountains on one side and by a plain or a sea on the other. The Piedmont plateau in the Eastern United States falling between the Appalachian Mountains and the Atlantic coastal plain is one such example. 

• The last one is the continental plateau landforms. These are the ones surrounded by oceans or plains, forming away from the mountains. One such example is the Antarctic Plateau in East Antarctica.

Geographic Distribution of the Plateau Landforms

There are many different types of plateaus found all over the world across all the continents. The plateaus formed owing to the thermal expansion of the lithosphere are associated with the hotspots. Examples include Yellowstone plateau in the USA, the Massif Central in France, Ethiopian Plateau in Africa. 

The plateaus formed due to the crustal shortening and internal natural drainage lie within major mountain ranges and generally in dry climates. They are usually found in North Africa, Turkey, Iran and Tibet at the points of collision of the African, Arabian, and Indian continental landmasses with the Eurasian continent. The Altiplano is lying between the Cordillera Occidental which is composed of volcanoes and the Cordillera Oriental beneath which the Brazilian shield is being thrust. These areas correspond to the period of Cenozoic time when they underwent crustal shortening. In each of the cases, the surface of the plateau flat-lands includes strongly deformed pre-Cenozoic rocks and the flat-land sediment. 

The Serra Geral is mostly formed of basalt rocks, cap a plateau on the Atlantic coast of Brazil. This plateau landform erupted about 135 million years ago before the separation of the African and South American tectonic plates. In North America, the Columbia plateau landforms, along the Columbia river which is composed of basalts, ejected over the same hotspot which underlies the Yellowstone landform today. These are some of the most unique forms of lava plateau landmasses.

Fun Fact

One of the interesting facts about plateau landform is that the origin of some of them is unknown. Examples include the Iberian Peninsula and north-central Mexico which show a topography that is largely high and flat. The Mexican crustal shortening occurred during the Late Cretaceous and Early Cenozoic period. Another example of crustal shortening is some parts of Spain formed during the Cenozoic period. Even though there are these high elevations at both the plateau landforms they are not supported by a thick crust. Instead, they are probably underlined by a hot mantle, until conclusively proved otherwise.