Chapter 6. Major Landforms of Earth

Overview
• The earth has an infinite variety of landforms. These landforms are result of two processes.
• The first: internal process that leads to upliftment and sinking of earth’s surface.
• The second is external process that leads to continuous wearing down and rebuilding of land surface.
Erosion: It is process of wearing away of earth’s surface.
Deposition: It is process of rebuilding of earth’s surface.

Mountains
• It is any natural elevation of Earth’s surface.
• Many mountain systems consist of a series of parallel ranges extending over hundreds of kilometers like Himalayas, Alps, & Andes are mountain ranges of Asia, Europe & South America, respectively.
• There are three types of mountains– Fold Mountains, Block Mountains and Volcanic Mountains.
• The Himalayan Mountains and Alps are young fold mountains with rugged relief and high conical peaks.

(Himalayas)
• The Aravali range in India is one of oldest fold mountain systems in world.
• Block Mountains are created when large areas are broken and displaced vertically. The uplifted blocks are termed as horsts and lowered blocks are known as graben.
• Volcanic mountains are formed due to volcanic activity. Mt.Kilimanjaro in Africa and Mt.Fujiyama in Japan are examples of such mountains.

Plateaus
• A plateau is an elevated flat land. It is a flat-topped table land standing above surrounding area like East African Plateau in Kenya, Tanzania & Uganda, Western plateau of Australia and Tibet.
• Tibet plateau is highest plateau in world with a height of 4,000 to 6,000 metres above mean sea level.
• The Deccan plateau in India is one of oldest plateaus.

Plains
• Plains are large stretches of flat land. They are, generally, not more than 200 metres above mean sea level.
• The river deposit consists of stones, sand & silt along their courses and in their valleys. Plains are made from these deposits.
• Generally, plains are very fertile. Construction of transport network is easy. Thus, these plains are very thickly-populated regions of world.
• Plains are most useful areas for human habitation. Due of fertile soils, land is highly productive for cultivation e.g., Indo-Gangetic plains.

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