Social Science Geo Forms of the Earth (notebook exercise)

Geo – Forms of the Earth.

New words

1.      Compression

2.      Evolve

3.      Mass

4.      Vents

5.      Wrinkling

Q.3. Answer the following questions in 10 to 20 words.

a) How are residual mountains formed?

Ans. a) Continuous erosion of old fold mountains or block mountains over the years form residual mountains. For eg. Mt. Manodnock in U.S.A.

b) State any two importance of plains.

Ans. b) The two importance of plains are as follows.

·        Fertile soil of plains is useful for agriculture.

·        Rivers flowing through plains provide enough water for human settlements.

Q. 4. Answer the following questions in 50 to 70 words.

a) why are mountains important to us?

Ans.a) Mountains are most thinly populated regions of the world; but they are very useful to mankind.

·        Mountains are sources of glaciers and perennial rivers (the Ganga in India). These rivers provide water for irrigation and power generation (hydroelectricity).

·        River valleys and mountain slopes are used for cultivation of crops and fruits.

·        Mountains are rich sources of minerals used in industries.

·        They also provide stones for construction, medicinal herbs and other products.

·        Mountains are home to a variety of plants and animals.

·        Sometimes, mountain ranges influence the climate of a land.

·        Snow capped peaks and picturesque valleys attract thousands of tourists every year.

·        Mountains also provide locations for adventurous sports such as river rafting, skiing, trekking, rock climbing etc.

b) Explain the types of tectonic plateaus with one example for each.

Ans. b) Tectonic plateaus – These are formed due to Earth’s movements. They are considerable size and uniform altitude. Tectonic plateaus are of three types.

·        Conitnental Plateau: Upliftment of a block of land from the adjacent lowland or sea forms are known as Continental Plateau e.g. Chota Nagpur plateau in India.

·        Intermontane Plateau: is the one which is surrounded by fold mountains. E.g The Tibetan plateau between Himalayas and the Kunlun fold mountains.

·        Piedmont Plateau: it the one that lies at the foot of mountains, for eg. Plateau of Patagonia in Argentina.

Q.5. Differentiate between mountains, plateaus and plains with examples.

Mountains	Plateaus	Plains
1.      A mountain is a naturally elevated large mass of land forming peaks above the surrounding area.	1.      Plateaus are vast elevated flat lands bounded by steep slopes.	1.      Plains are low flat lands, with an average height of 200 metres above the sea level.
2.      There are four types of mountains Fold mountain, block mountain, volcanic mountain, residual mountain.	2.      There are three types of plateaus Continental plateaus, Volcanic plateaus, Residual Plateaus.	2.      There are three types of plains Structural plains, Depostional Plains, Erosional Plains.
3.      Examples are Gangotry in the Himalays and Siachen in Karakoram range.	3.      Examples are chota Nagpur plateau in India, The Tibetan plateau, Deccan plateau of  India and Cumberland plateau in the U.S.A	3.      Central lowlands of Australia, Plains of Indiana in North America and Interior plains of Canada.
4.      Some mountains are formed due to Large Earth movements, some are formed due to forces of compression and tension within the Earth’s Crust and some are formed when hot molten lava erupts from vents on the Earth’s Surface.	4.      Plateaus are formed by tectonic or volcanic actions and some are formed due to erosion caused by natural agents such as wind, rain, rivers etc.	4.      Plains are formed either by the erosion of old high landforms or by the deposition activity of the rivers.