Major Land Surface Types

The surface of the earth is not the same everywhere. Some parts of the lithosphere may be rugged and some flat. These land forms are a result of two processes. Within the earth, a continuous movement is taking place. The first, or the internal process leads to the upliftment and sinking of the earth’s surface at several places.

The second, or the external process is the continuous wearing down and rebuilding of the land surface. The wearing away of the earth’s surface is called erosion. The surface is being lowered by the process of erosion and rebuilt by the process of deposition. These two processes are carried out by running water, ice and wind.

Broadly, you can group different land forms depending on elevation and slope as mountains, plateaus and plains.

Mountains

A mountain is any natural elevation of the earth surface. It is considerably higher than the surrounding area. As you go higher, the climate becomes colder. In some mountains, there are permanently frozen rivers of ice. They are called glaciers.

Mountains may be arranged in a line known as range. Many mountain systems consist of a series of parallel ranges extending over hundreds of kilometres. The Himalayas, the Alps and the Andes are mountain ranges of Asia, Europe and South America, respectively. There are three types of mountains:

1. Fold Mountains
2. Block Mountains
3. Volcanic Mountains

Fold Mountains

The Himalayan Mountains and the Alps are young fold mountains with rugged relief and high conical peaks. The Aravali range in India is one of the oldest fold mountain systems in the world. The range has considerably worn down due to the processes of erosion. The Appalachians in North America and the Ural mountains in Russia have rounded features and low elevation. They are very old fold mountains.

Block Mountains

Block Mountains are created when large areas are broken and displaced vertically. The uplifted blocks are termed as horsts and the lowered blocks are called graben. The Rhine valley and the Vosges mountain in Europe are examples of such mountain systems.

Volcanic Mountains

Volcanic mountains are formed due to volcanic activity. Mt.Kilimanjaro in Africa and Mt.Fujiyama in Japan are examples of such mountains.

Plateau

A plateau is an elevated flat land. It is a flat-topped table land standing above the surrounding area. A plateau may have one or more sides with steep slopes. The height of plateaus often varies from few hundred metres to several thousand metres. Plateaus, like mountains may be young or old.

The Deccan plateau in India is one of the oldest plateaus. The East African Plateau in Kenya, Tanzania and Uganda and the Western plateau of Australia are other examples. The Tibet plateau is the highest plateau in the world with a height of 4,000 to 6,000 metres above the mean sea level.

Plains

Plains are large stretches of flat land. They are not more than 200 metres above mean sea level. Some plains are extremely level. Others may be slightly rolling and undulating. Most of the plains are formed by rivers and their tributaries. 

The rivers flow down the slopes of mountains and erode them. They carry forward the eroded material. Then they deposit their load consisting of stones, sand and silt along their courses and in their valleys. It is from these deposits that plains are formed.