NCERT Chapter Summary and Solutions For Class 6 Social Science Geography Chapter 6 - Major Landforms of the Earth

CHAPTER - 6 

MAJOR LANDFORMS OF THE EARTH

MajorLandforms of the Earth - The landform is a natural or artificial feature of the solid surface of the Earth or the planetary body.

• The Major type of landform is - 1. Mountains, 2. Hills, 3. Plateau, 4. Plains
•  The Minor type of landform is - 1. Buttes, 2. Canyons, 3. Valleys, 4. Basins

The Landforms are results of 2 processes:- 1. Internal process, 2. External process

• Internal Process - It is a type of continuous movement within the earth that lead to the upliftment and sinking of the earth's surface at several places. The earth beneath the feet is continuously moving and it is driven by the heat (in the form of energy) in the earth's interior. E.g. Convection, Tectonic plate movement, Rock formation, Earthquake, Volcanic eruptions, etc.

• External Process - It is the continuous wearing off and rebuilding of the land surface. They are powered by solar energy. E.g. Soil erosion, deposition, etc.

Fig. Landforms

Erosion: The wearing off the earth's surface. It is being lowered by the external process.            

  Fig. Soil Erosion

Deposition: When the river loses its energy, it drops any of the material it has been carrying. The surface is being rebuilt by the external process.            

Fig. The force of moving river water - Erosion & Deposition 

The major type of landform (Depending on Elevation & Slope):-

A. Mountains: 

• Mountains are natural elevations of the earth's surface. They vary in shape and size.
• They are higher than in the surrounding area. Some of them are even higher than the clouds.
• Glaciers, a permanently frozen river of ice. 
• Rivers have their sources in the mountains and it is used for irrigation and the generation of hydro-electricity.
• The climate of the mountain is harsh, which makes them less suitable for human habitation.
• The river valley and terraces are ideal for crop cultivation, though some mountains have steep slopes. Hence, farming is quite difficult there.
• Mountains have a rich variety of flora and fauna. Fuel, food, fodder, shelter, timber, and other products like gum, raisins, etc. can easily get from mountain and forest.
• Mountain provides an idyllic scene and their scenic beauty for tourists. They can enjoy recreational activities like paragliding, hang gliding, river rafting, and skiing.
• The mountain may be arranged in a series of parallel extending over hundreds of kilometers known as, Range. E.g. the Himalayas (in Asia), the Alps (in Europe), the Andes (in South America).

There are 3 types of Mountains: 1. Fold mountain, 2. Block mountain, 3. Volcanic mountain

1. Fold Mountain: It is created by where two or more of Earth's tectonic plates are pushed together. As this colliding, compressing boundaries of rocks, and debris are wrapped and folded into rocky outcrops, hills, mountains, and the entire mountain ranges.
2. It is divided into 3 types of fold mountains.
3. Young fold mountain: Age- 10 to 25 million years old. They have rugged relief and high conical peaks. E.g. The Himalaya mountain (in Asia) and the Alps mountain (in Europe), the Rocky (in North America)
4. Old mountain: Age- 200 million years old. They do not have pointed high peaks due to erosional activities of exogenic forces. E.g. The Aravali range (in India), The Appalachians (in North America), Ural mountain (in Russia).

    

Fig. Young Fold Mountain                                                                     Fig. Old Fold Mountain 

2. Block Mountain: These are created when a block of bedrock is broken and split into vertically by tectonic activity. It is also called Fault block mountains.

1. The upliftment blocks are - horsts.
2. The lower blocks are - graben.
3. Example: Satpura= seven mountain, and Vindhya range= group of the discontinuous chain of mountain ridges, plateau escarpment, highland, hill ranges (in India), The Great American rift valley (graben, valley floor), Vosges mountain in Europe (horst).

        

Fig. Satpura Range (India)                                                           Fig. Vosges Mountain (Europe)

                                                             Fig. Block Mountain

3. Volcanic Mountain: They are formed by volcanic activity. It is formed when magma or lava (molten rock) of deep earth erupts and heap upon the surface. When the ash, steam, gases, and magma cool down, then build a cone of rock. E.g. Mt. Kilimanjaro (in Africa) and Mt.  Fujiyama (in Japan).

        

Fig. Volcanic Mountain                                                                         Fig. Mt. Fujiyama (in Japan)

B. Plateau: High Plane or Tableland.

• Plateau is the flat-topped tableland standing above the surrounding area and, have one or more sides with steep slopes.
• They may be young or old and their heights vary from a few hundred-meter to thousand meters.
• It is the "storehouse" of minerals like Iron (Fe), coal (C), gold (Au), and diamond. E.g. Gold and Diamond (in African Plateau), Iron, Coal, Manganese in Chotanagpur plateau (in India).
• There are several waterfalls flow in the plateau area, as the river falls a great height. E.g. Hundru fall (in Chotanagpur plateau) on the river Subarnarekha, Jog waterfall (in Karnataka).
• Many plateaux have scenic beauty spots and are great attractions for tourists. Eg. Deccan Plateau.
• Soil - Black soil, which is fertile and good for cultivation.
• The oldest plateau in the world - The Deccan plateau (in India), The East African plateau (in Kenya, Tanzania, Uganda), Western plateau (in Australia) 
• Highest plateau in the world - The Tibet plateau, in Tibet, China (elevation = 4,000 m to 6,000 m above the sea level).

              

 Fig. Mumbai-Pune Expressway on Deccan Plateau       Fig. Tibet Plateau (Highest plateau in the world)

                                                                             

             

Fig.East African Plateau (Oldest plateau)                              Fig. Hundru Fall (Ranchi) on Subarnarekha River

C. Plains: Flat and Sweeping landmass.

• Height - about 200 m above sea level.
• Mostly plains are formed by the rivers and their tributaries. The river flows down the slopes of the mountains and gradually destroyed. The river water carries the eroded materials and deposits their load consisting of stones, sand, and slit along with their journey. 
• Due to the deposition of alluvial soil usually, plains are fertile region, which is suitable for cultivation. Hence, a higher concentration of population lives there. E.g. Indus-Ganga-Brahmaputra plains (in India), and the Yangtze plains (in China).
• It is easy to build a house, flat, buildings, roads, etc. in plains.

Fig. Cultivation in Plains

                                           NECRT EXERCISES

Q. The difference between a mountain and a plateau is given below:

Mountain	Plateau
A mountain is a natural elevation of the earth's surface.	A plateau is an elevated flat land.
It is considerably higher than the surrounding area.	It is a flat-topped tableland, standing above the surrounding area.
Peaks of mountains is the pinnacle. E.g. Himalaya (in India)	Plateau is flat from the top and steep to gentle from the sides. E.g. Deccan Plateau (in India)

2. Tick the correct answer.

(a)The mountains differ from the hills in terms of
(i) elevation    (ii) slope     (iii)aspect.

(b)Glaciers are found in
(i) the mountains (ii) the plains(iii)the plateaus.

(c)The Deccan plateau is located in
(i) Kenya (ii) Australia (iii)India.

(d)The river Yangtze flows in
(i) South America(ii) Australia (iii)China.

(e)An important mountain range of Europe is  ‘
(i) the Andes (ii) the Alps (iii)the Rockies.

3. Fill in the blanks.
(a)A………plain… is an unbroken flat or a low-level land.
(b)The Himalayas and the Alps are examples of……………young, fold……… types of mountains.
(c) ……Plateau… areas are rich in mineral deposits.
(d)The……range…… is a line of mountains.
(e) The ………plain.  Areas are most producing for farming.