Landforms of the Earth

Answer the following questions

Question 1

What are plains?

Answer

Extensive flat areas of low altitude, a gently and undulating terrain without prominent hills or depressions are known as plains. For example, the Indo-Gangetic plains of North India.

Question 2

What is orogenesis?

Answer

The process of mountain building on large scale leading to the formation of the intensely deformed belts which constitute mountain ranges is called orogenesis.

Question 3

Name the different types of mountains. Describe each of them with examples.

Answer

The different types of mountains are as follows:

1. Fold mountains — The fold mountains are formed by horizontal movements of the crust resulting in wrinkle like folds that vary greatly in size. The folds have arched or upraised parts known as anticlines and troughs known as synclines. Based on the period of their formation they are of two types — young fold mountains like the Himalayas and old fold mountains like the Aravalis.
2. Block mountains — Sometimes movement of earth's crust causes cracks or faults, where such movement leaves a block of higher land standing between two areas of lower land, the highland is known as a 'Block Mountain' or Horst. For example — the Vosges and Black forest mountains, Satpura and Vindhya mountains in India.
3. Residual mountains — When an area of highland remains standing above the general level after rivers and other natural agents have lowered the surface of the surrounding area, the term residual mountain is used. Sometimes such highlands are called mountains of denudation. For example — Helvellyn Residual Mountain

Question 4

What are plateaus?

Answer

Plateau is an elevated tract of relatively flat land, usually limited on at least one side by a steep slope falling abruptly to lower land. They are results of diastrophism (large scale deformation of the Earth's crust). They have been modified by various agents of erosion and in many cases by volcanism and minor Earth movements.

For example, Plateau of Tibet, the Mexican Plateau.

Question 5

Name the various types of plateaus with examples.

Answer

Various types of plateaus with examples are:

1. Intermontane Plateaus — Plateau of Tibet, The Mexican Plateau.
2. Volcanic Plateaus — Deccan Plateau, South African Plateau.

Question 6

State a few advantages of plains.

Answer

A few advantages of plains are:

1. Construction of settlements, rails, roads, etc. is easy on flat and soft surface.
2. Fertile soil of alluvial plains are granaries of the world. In arid areas, irrigation can be provided easily and economically.
3. Most of the big cities are situated in plains as most of the plains provide fine climate and fertile land. Movement is easy which encourages agricultural and industrial development.

Question 7

Explain the types of depositional plains.

Answer

The types of depositional plain are:

1. Alluvial plains — These are formed by gradual accumulation of silt brought down by rivers. These deposits may be fan shaped known as Piedmont alluvial fan. When the river widens its valley or overflows its banks during floods, the clay and sand deposit to make flood plains. Examples are Indo-Gangetic plains, Plains of northern China and Mississippi plain. At the mouth of a river, triangular shaped plain of deposited material is called delta plain.
2. Glacial deposits — When the glaciers melt, the debris are deposited. Such plains are extensive in size and very fertile. They have irregular surface. For example, Plains of Central North America and Western European plain.
3. Aeolion Loess Plains or deposition by winds — These plains are formed by the materials which have been transported or deposited by winds. For example, Loess deposits of North China.
4. Lacustrine plains or river deposits — These plains result from the fillings of lake beds. When rivers enter a lake, they are muddy. The plains of Hungary in Europe and the plains of surrounding great lakes of North America are examples.

Question 8

State the main uses of mountains.

Answer

The main uses of mountains are:

1. Mountains are effective climatic barriers.
2. The swift streams of mountains are frequently sources of hydro-electric power.
3. They have deposits of minerals. They provide gold, silver, copper, lead etc.
4. They provide scope for lumbering industries.
5. Agriculture has been developed on the slopes of mountains.
6. They provide pastures.
7. They act as natural barriers or borders between two countries.

Question 9

Differentiate between intermontane plateau and volcanic plateaus.

Answer

Question 10

Define a plain. How does it differ from a plateau?

Answer

Plain is an extensive fertile tract of flat land, a gently and undulating terrain without prominent hills or depressions, usually formed by deposition of eroded material brought by rivers, glaciers and wind.

Question 11

What are mountains?

Answer

A portion of land surface rising considerably above the surrounding area, either as a single eminence, (generally above 600 mts), or as an extensive chain are called mountains.

For example, Himalayan mountain range.

Question 12

State any two characteristics of young fold mountains.

Answer

Two characteristics of young fold mountains are:

1. Ruggedness of relief and rounded contours of mountain areas.
2. Most of the active volcanoes are found in their neighbourhood.

Question 13

How are the young fold mountains useful? State one example.

Answer

Young fold mountains are useful as they act as climatic barriers. For example, the Himalayas prevent the cold Siberian winds from entering the Indian sub-continent. Also, these mountains provide us swift rivers to harness hydroelectricity, make perfect tourist destination and they are rich in mineral deposits.

Question 14

How are alluvial plains formed?

Answer

Alluvial plains are formed by gradual accumulation of silt brought down by rivers. As a river leaves the mountains, the water spreads out and fast speed is arrested. The sluggish water deposits the material brought by it forming the plains. They mostly deposit the eroded materials along the foot of hills forming Piedmont Alluvial plain, like Bhabhar in India. Plains are also formed by the flooded rivers and are known as flood plains.

Examples of fertile alluvial plains are Indo-Gangetic plains, Mississippi plain, etc.

Question 15

Give an example each of the following :

1. Fold mountains
2. Block mountain
3. Volcanic plateau
4. Structural plain

Answer

1. Fold Mountain — The Himalayas
2. Block mountain — Fault Block Mountain (Pakistan)
3. Volcanic plateau — The Columbian Plateau
4. Structural plain — Russian platform

Define the following terms

Question 1

Intermontane plateaus

Answer

The plateaus that are surrounded by high hills and mountains on all sides are called intermontane plateaus. For example — Tibetan plateau.

Question 2

Block Mountains

Answer

The mountains that are formed as a result of cracking of earth's crust or faulting, when there is deep submergence of a large landmass leaving behind raised platform, are called Block mountains. For example, the Vosges.

Diagrams

Question 1

Draw a neat diagram to show the formation of Block Mountains.

Answer

Below diagram shows the formation of Block Mountains:

Question 2

With the help of a neat diagram show the formation of a floodplain.

Answer

Below diagram shows the formation of a floodplain:

Give a reason for the following statements

Question 1

Plateaus are called tablelands.

Answer

As they have flat top with steep sided slope.

Question 2

Residual mountains are called the mountains of denudation.

Answer

As these mountains are formed when surrounding area of a highland is lowered down by the long term denudation and erosion by various agents of gradation.

Question 3

The alluvial plains are called the granaries of the world.

Answer

Alluvial plains are formed by the deposition of alluvium by the rivers; therefore they have fertile soil which enhances the cultivation of grains.

Question 4

The plateau of Tibet is called the intermontane plateau.

Answer

As Tibet is enclosed by Kunlun Mountain from the north & Himalayas from the south.

Question 5

The old fold mountains are much lower and less rugged than young fold mountains.

Answer

The old fold mountains have been subjected to the forces of denudation (such as weather, rivers, glaciers, etc.) for long geological periods. Due to this, they are much lower and less rugged than young fold mountains.

Question 6

North western Deccan is an example of Lava plateau.

Answer

The north western Deccan is an example of a lava plateau because it was formed by extensive volcanic activity that deposited large amounts of basaltic lava over the area millions of years ago, resulting in a broad, flat plateau with distinctive basaltic rock formations.

Choose the correct option

Question 1

The systematic study of the earth’s relief features is called

1. Geology
2. Pedology
3. Hydrology
4. Geomorphology

Answer

Geomorphology

Question 2

The Vosges & Black Forest Mountains are the examples of

1. Fold Mountain
2. Volcanic Mountain
3. Residual Mountain
4. Block Mountain

Answer

Block Mountain

Question 3

Which of the following mountains is called the mountain of denudation?

1. Fold Mountain
2. Volcanic Mountain
3. Residual Mountain
4. Block Mountain

Answer

Residual Mountain

Question 4

Identify the type of mountain in this Image marked as a, b, c.

1. Fold Mountain
2. Volcanic Mountain
3. Residual Mountain
4. Block Mountain

Answer

Block Mountain

Question 5

Which of the following is an example of Young Fold Mountain?

1. Appalachians
2. Ural Mountains
3. Aravali mountains
4. Alps

Answer

Alps

Question 6

Which of the following is an example of intermontane plateau?

1. Ethiopian plateau
2. Bolivian Plateau
3. South African Plateau
4. The Deccan Plateau

Answer

Bolivian Plateau

Question 7

Which of the following is an example of structural plain?

1. Plains of Northern China
2. Hungary plain
3. Great Plains of USA
4. The Western European Plain

Answer

Great Plains of USA

Question 8

The plain which is formed at the foothills of mountain in the shape of fan is called

1. Flood plain
2. Bhabhar
3. Glacial Plains
4. Piedmont alluvial plain

Answer

Piedmont alluvial plain

Question 9

Refer to the image & identity the relief feature.

1. Lava plateau
2. intermontane plateau
3. Piedmont alluvial plain
4. None of the above

Answer

intermontane plateau

Question 10

Which of the following relief features is formed by the squeezing & wrapping of the sediments of the crust?

1. Block mountain
2. Fold Mountain
3. Plateaus
4. Plains

Answer

Fold Mountain

Question 11

The plain which is formed as a result of emergence of sea bottom near coast is called

1. Piedmont alluvial plain
2. Flood plain
3. Karst plain
4. Structural plain

Answer

Structural plain

Question 12

Orogenesis is the process of

1. Hill formation
2. Mountain building
3. Rift valley formation
4. Trench building

Answer

Mountain building