Chapter Notes and Summary
• internal process leads to upliftment and sinking of earth’s surface at several places.
• external process is continuous wearing down and rebuilding of land surface.
• wearing away of earth’s surface is called erosion.
• There are different landforms depending on elevation and slope as mountains, plateaus and plains.
Mountains
• A mountain is any natural elevation of earth surface.
• There are permanently frozen rivers of ice. They are called glaciers.
• Mountains may be arranged in a line known as range.
• Himalaya, Alps and Andes are mountain ranges.
• There are three types of mountains—Fold Mountains, Block Mountains and Volcanic Mountains.
• Himalayan Mountains and Alps are young fold mountains.
• Aravali range in India is one of oldest fold mountain systems.
• Block Mountains are created when large areas are broken and displaced vertically.
• Volcanic mountains are formed due to volcanic activity, e.g. Mt. Kilimanjaro in Africa.
• Water from mountains is also used for irrigation and generation of electricity.
Plateaus
• A plateau is an elevated flat land.
• Deccan plateau in India is one of oldest plateaus.
• Tibet plateau is highest plateau in world.
• African plateau is famous for gold and diamond mining.
• lava plateaus are rich in black soil that are fertile and good for cultivation.
Plains
• Plains are large stretches of flat land.
• Most of plains are formed by rivers and their tributaries.
• In India, Indo-Gangetic plains are most densely populated region of country.
Landforms and People
• Humans have been living on different kinds of landforms in different ways.
• Sometimes, natural calamities such as earthquakes, volcanic eruptions, storms and floods cause widespread destruction.