GEO (VI)-LESSON-6 MAJOR LANDFORMS OF THE EARTH (LESSON NOTES)

    

GEO (VI)-LESSON-6

MAJOR LANDFORMS OF THE EARTH

(LESSON NOTES)

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v INTRODUCTION

  Ø As you know that the surface of the earth is not the same everywhere. The earth has an infinite variety of landforms such as rivers, hills, mountains, deserts, plateaus, delta, lakes etc.

  Ø In this lesson we will try to know the different landforms. How they formed and importance of some land forms. We will try to know about the people in different landforms.

v FORMATIONS OF LANDFORMS

  Ø The landforms on the Earths are a result of two processes: -

§  INTERNAL PROCESS

·      The activity which happens inside the Earth and cause the upliftment and sinking of some part of the earth. Foe example Earthquake, Volcanic eruption etc.

§  EXTERNAL PROCESS

·      The process which happens on the land surface and create change. For example, Erosion and Deposition activity.

·      Erosion: - The wearing away of the earth’s surface by water, ice or wind is called erosion.

·      Deposition: - The process in which wind and rivers deposited the sediments in lower areas is called as deposition.

v TYPES OF LAND FORMS 

  Ø MOUNTAINS

  Ø PLATEAUS

  Ø PLAINS

v MOUNTAINS: -

  Ø Natural elevation (more than 600 metres) of the earth surface is called as mountain. Less than 600 metres elevation is termed as Hills. Some mountains are higher than 8000 metres. Mountains may be arranged in a line known as mountain range.

  Ø In some mountains, there are permanently frozen rivers of ice, which are called glaciers.

  Ø There are some mountains which we cannot see as they are under the sea. For example, Mauna Kea (Hawaii) in the Pacific Ocean.

  Ø Less people live in the mountain areas due to harsh climate and less land for farming.

Ø TYPES OF MOUNTAINS

§  FOLD MOUNTAINS

·      The mountain which formed by folding process is termed as fold mountain. They may ne classified as old and young fold mountain.

·      Old fold mountain: - Appalachians in North America and the Ural Mountains in Russia, Aravalli Mountain in India.

·      Young Fold Mountain: - Himalaya Mountain in Asia, Alps in Europe, Andes in North America, Rockies in South America.

§  BLOCK MOUNTAINS

·      Block Mountains are created when large areas are broken and displaced vertically.

·      The uplifted blocks are termed as horsts and the lowered blocks are called graben.

·      The Rhine valley and the Vosges Mountain in Europe are examples of such mountain systems

§  VOLCANIC MOUNTAINS

·      The mountains which are formed due to volcanic activity are called as volcanic mountains.

·      Example Mt. Kilimanjaro in Africa and Mt. Fujiyama in Japan.

Ø IMPORTANCE OF MOUNTAINS

§  The mountains are a storehouse of water as many rivers origin from glaciers in the mountains.

§  Water from the mountains is also used for irrigation and generation of hydro-electricity.

§  The river valleys and terraces are ideal for cultivation of crops.

§  Mountains have a rich variety of flora and fauna.

§  Mountains provide an idyllic site for tourists as Kashmir, Ladakh etc.

§  Several sports like paragliding, hang gliding, river rafting and skiing are popular in the mountains.

v PLATEAUS

  Ø An elevated land which is flat from the top is refereed as plateaus. It is like a table land standing above the surrounding area. They are formed by lava deposits.

  Ø The height of plateaus often varies from few hundred metres to several thousand metres. The Tibet plateau is the highest plateau in the world with a height of 4,000 to 6,000 metres above the mean sea level.

  Ø The Deccan plateau in India is one of the oldest plateaus. The East African Plateau in Kenya, Tanzania and Uganda and the Western plateau of Australia are other examples.

 

v IMPORTANCE OF PLATEAUS

  Ø Plateaus are very useful because they are rich in mineral deposits. For example, African plateau is famous for gold and diamond mining. Chhotanagpur plateau in India famous for iron, coal and manganese.

  Ø Many waterfalls are there in plateaus as Hundru falls in the Chhotanagpur plateau on the river Subarnarekha and the Jog falls in Karnataka.

  Ø The lava plateaus are rich in black soil that are fertile and good for cultivation.

 

v PLAINS

  Ø The large stretches of flat land which is not more than 300 metres above mean sea level is known as plains.

  Ø The plains are formed by the deposition of eroded materials of rivers. So, these are very fertile.

  Ø Some plains as Ganga- Brahmaputra plain in India, Yangtze in China, Nile plain of Egypt etc.

  Ø Plains are very thickly populated because of these reasons as :-

§  Plains are the most useful areas for human habitation.

§  Plains are very fertile so these are good for cultivation.

§  In plains there are good network of roads and railways network.

§  fertile and construction of transport network is also easy. Thus, these plains are very thickly-populated regions of the world.

v LANDFORMS AND THE PEOPLE 

  Ø Humans have been living on different kinds of landforms in different ways. Life is difficult in mountainous areas. Plains provide much better conditions. It is easy to grow crops, build a house or a road in a plain than a mountain. Let’s see different situation in different landforms: -

§  In desert areas camel is used as means of transportation. It is called as Ship of desert.

§  In hilly areas people do the cultivation by making stairs that is known as terrace farming.

§  In high rain fall areas the houses have slanting roofs.