Test: Mountains & Plateaus - UPSC MCQ

Fold Mountains are caused by large scale earth movements, when stresses are set up in earth crust. Stresses may be due to increased load of overlying rocks, flow movements in mantle, magmatic intrusions into the crust, expansion or contraction of some part of earth.

• Formation of Fold Mountains: Rivers deposit huge quantities of sediments in depressions called geosynclines. Over millions of years, the sediments arc compressed into sedimentary rocks such as sandstone and limestone. The plates move together forcing the sedimentary rocks upwards into a series of folds by the movement of tectonic plates. This causes the thickness of the rocks in fold mountains.

• There are three types of mountains: Fold Mountains, Block Mountains and the Volcanic Mountains.

• The Himalayan Mountains and the Alps are young fold mountains with rugged relief and high conical peaks. The Aravalli 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

- Option 1: True. The high altitudes of fold mountains often lead to snow and ice accumulation on their peaks, such as the Himalayas and the Alps.
- Option 2: False. Fold mountains are formed by the collision of tectonic plates, not the contraction of the Earth's crust.
- Option 3: True. Fold mountains have rugged peaks due to tectonic activity and erosion.
- Option 4: True. Fold mountains are often located along continental margins where tectonic plates converge, like the Andes and Rockies.

The correct answer is D: 1, 3, and 4.

All are due to tectonic reasons. Some plateaus like these are found between fold mountains such as the Bolivian plateau. These are distinct from the volcanic plateaus that are formed due to the flow and consolidation of lava.

• A dissected plateau is an area that has been severely eroded and divided into several smaller pieces.

• The natural agents, such as the Sun, the rain, the wind, the running water and the Glacier, wear away the soft rocks of the upland areas.

• The resistant rock masses are left there standing on the ground above the surroundings.

• The sometimes from the almost level surface, cut by rivers and streams. These upland areas together form a dissected plateau.

Doda Betta, mountain peak, the highest point in Tamil Nadu state, southeastern India, near Udhagamandalam. Rising to an elevation of 8,652 feet (2,637 metres), Doda Betta is a grass-covered hill that is frequently climbed by summer visitors, and the summit is accessible by automobile.