NCERT Summary: Major Landforms of the Earth | NCERT Video Summary: Class 6 to Class 12 (English) - UPSC PDF Download

Major Landforms of the Earth

• Landform is a natural feature of the earth’s surface.
• The surface of the earth varies from one place to another. The main landforms are; mountains, plateau and plains.
• There are two processes which lead to formation of different landforms:
  (i) Internal process
  (ii) External process

Internal Process

• The movement of earth’s surface results in internal process. 
• The internal process results in a portion of the earth’s surface getting elevated or getting sunk.

External Process

• Continuous wearing down and rebuilding of the earth’s surface is the result of external process.

Erosion

• Removal of materials is called erosion.
• Erosion results in lowering of the earth’s surface.
• It is carried out by various agents; like wind and water.

Deposition

• Deposition of materials results in rebuild of the earth’s surface. It also results in the surface getting elevated. Wind and water are the main agents of deposition.

Glacier

• Permanently frozen rivers of ice are called glaciers. Glaciers are found in some of the very high mountains.

Mountains

• A mountain is the natural elevation of the earth’s surface.
• It may be narrow at top and broad at the base.
• The elevation of mountain is considerably more than that of surrounding area.
• Temperature reduces with increase in altitude. Due to this, very high mountains are usually covered with snow.

Population at Mountains

• Because of steep slopes, less amount of land is available for farming on mountains. This is also difficult to build houses on steep slopes. Hence, less number of people lives on the mountains.

Mountain Range

• When mountains are arranged in a line, then it is called a mountain range.
• Some of the mountain systems contain ranges spread over hundreds of kilometres.

Types of Mountains

• There are three types of mountains, viz. fold mountains, Block Mountains and volcanic mountains.
  (i) Fold Mountains: When a tectonic plate gets pressure from two sides, it gets folded. Some of its portion becomes elevated and forms the mountains. The depressions form the valleys. The Himalayas, The Andes and the Alps are examples of Fold Mountain.
  (ii) Block Mountains: When large areas are broken and displaced vertically, Block Mountains are formed. In this case, the uplifted blocks are called horsts.
  (iii) Volcanic Mountains: A mountain formed due to volcanic activity is called Volcanic Mountain. Examples of Volcanic Mountains are; Mt. Kilimanjaro and Mt. Fujiyama.

Importance of Mountains

• Mountains are rich sources of water. Many important rivers originate from glaciers on mountains.
• River valleys and terraces are ideal for cultivation.
• Mountains are rich in flora and fauna.
• Mountains provide many forest produce; like wood, herbs, medicinal plants, honey, catechu, etc.
• Mountains are ideal tourist spots.

Plateau

• A plateau is a flat and elevated land.
• A plateau is at higher elevation than the surrounding areas.
• It may have one or more sides with steep slopes.
• It can be young or old.
• The height of plateau can be from a few hundred meters to several thousand meters.

Importance of Plateau

• Plateaus are rich in mineral deposits. Many mining belts in the world are located in the plateau areas.
• Most of the mining areas in India are in the Chhotanagpur Plateau in Jharkhand, Orissa and Chhattisgarh.
• The African plateau is famous for mines of gold and diamond.

Plains

• Plains are flat lands and are generally not more than 200 m above mean sea level. Some plains are extremely level, while others may be slightly rolling and undulating.

Importance of Plains

• Plains are usually highly fertile and hence most ideal for cultivation.
• It is very easy to make transport network in the plains.
• Due to above mentioned factors, plains are the best areas for human habitation.
• Most of the densely populated areas of the world are in the plains.
• The Indo-Gangetic Plains in India is among the most densely populated regions of the world.

Landforms and the People

• Humans have been living in most of the terrains.
• Life is difficult in mountain areas because of rugged terrain. Hence, mountain areas are sparsely populated.
• Life is somewhat easier in the plateaus; compared to in mountains.
• Life is the easiest in the plains.
• In all types of terrains, natural calamities always pose threat. Earthquakes, storms and floods can hit any area. Volcanic eruption can be potential risk in areas near volcanic activity.
• But people need to learn to live with natural disasters. Proper precautions can help save life and property; in case of natural disasters.