VII T1 SS Landforms - Textbook Solutions

 

LANDFORMS

I. Choose the correct answer:

1. Alluvial fan is a deposition of river sediments along the foot-hills.

2. Courtallam falls is located across the Chittar river.

3. The landform created by glacial deposition is Moraine

4. Large deposits of loess are found in China

5. Landforms which are not associated with wave erosion Beaches.

II. Fill in the blanks:

1. The process of breaking and crumbling up rocks is weathering.

2. The place where the river joins a lake or a sea is known as river mouth

3. Inselbergs are found in the Kalahari desert in South Africa.

4. A cirque is known as Kar in Germany.

5. The first longest beach in the world is Miami.

III. Match the following:

1. 1. Breaking and crumbling of rocks - Weathering 

2. Abandoned meander loops - Ox-bow lake

3. Large body of moving ice - Glacier 

4. Crescent shaped sand dunes  - Barchans

IV. Consider the following statement:

Tick the appropriate answer:

1. Assertion (A): The deltas are formed near the mouth of the river.

Reason (R) : The velocity of the river becomes slow when it approaches the sea.

Ans: Both A and R are correct

2. Assertion (A): Sea arches in turn become Sea Stacks.

Reason (R) : Sea Stacks are the results of wave deposition.

Ans: A is correct and R is wrong

V. Answer the following:

1. Define erosion.

Erosion is the wearing down of the landscape by different agents like water, wind, ice and sea waves.

2. What is a plunge pool?

Plunge pool is a hollow feature at the base of a waterfall which is formed by cavitation.

3. How are Ox – bow lakes formed?

Due to continuous erosion and deposition along the sides of the meander, the end of the meander loop comes closer and closer.In due course of time the meander loop cuts off from the river and forms a  cut-off lake, called an Ox-bow lake.

4. Name the major landforms formed by glacier erosion.

Cirque, Arete, U’ shaped valley

5. Give a note on Mushroom rocks.

Winds erode the lower section of the rock more than the upper part. Therefore, such rocks have narrower bases and wider tops. Wider top rocks in the shape of a mushroom, commonly called mushroom rocks.

6. What is a lagoon? Give an example.

Lagoon is a shallow stretch of water partially or completely separate from the sea. Eg.Chilka Lake in Odisha, Pulicat Lake in Tamil Nadu and Andhra Pradesh and Vembanad Lake in Kerala are the famous lagoons in India.

VI. Distinguish the following:

1. Tributary and Distributary

Tributary	Distributary
A stream or river that flows into and joins a main river.	A stream that branches off and flows away from the mainstream.

2. ‘V’ shaped valley and ‘U’ shaped valley

V’ shaped valley	‘U’ shaped valley
The running water in the river erodes the mountainous track, which creates a steep-sided valley like the letter ‘V’  known as ‘V’ shaped valley.	U’ Shaped Valley is found beneath the  glaciers which is deepened and widened by the lateral and vertical erosion.

3. Continental glacier and Mountain glacier

Continental glacier	Mountain glacier
The glacier covers vast areas of a continent with thick ice sheets.	Mountain or Valley Glacier is a stream of ice, flowing along a valley.  It usually follows former river courses and are bounded by steep sides.
E.g. Antarctica, Greenland	E.g. The Himalayas and the Alps.

VII. Give Reason:

1. The ends of the meander loops come closer and closer.

 Due to continuous erosion and deposition of rivers along the slides of a meander, ends of the meander loop comes closer and closer

2. Flood plains are very fertile.

 At times the river overflows its banks. This leads to the flooding of the neighboring areas. As the river floods, deposit layers of time soil and other material called sediment along its banks. This leads to the formation of flat fertile flood plain

3. Sea caves are turned into stacks.

As the cavities of sea caves become bigger, only the root of the caves remains to form sea arches. When erosion further breaks the roots, only walls are left, thus forming stacks.

VIII. Answer in a paragraph:

1. Explain different landforms produced by river erosion.

• The running water in the river erodes the landscape, which creates a steep-sided valley like the letter ‘V’ known as ‘V’ shaped valley.

• Falling of river water over a vertical step in the river bed is called a waterfall. E.g.Coutrallam falls across the river Chittar in Tamil Nadu.

• Plunge pool is a hollow feature at the base of a waterfall which is formed by cavitations.

• As the river enters the plain it twists and turns forming large bends known as Meanders. Eg. Meanders along the River Vellar near Sethiyathope in Cuddalore

2. Describe the landforms associated with wind.

 Winds erode the lower section of the rock more than the upper part.

• An isolated residual hill, standing like a pillar with rounded tops are called Inselbergs. E.g. Inselberg in the Kalahari Desert of South Africa.

• When the wind blows, it lifts and transports sand from one place to another. When it stops blowing the sand falls and gets deposited in low hills – like structures. These are called sand  dunes. 

• The crescent shaped sand dunes are  called Barchans.

• When the grains of sand are very fine and light, the wind can carry it over very long distances. When such sand is deposited in large areas, it is called Loess.

3. How are aretes formed?

When two adjacent cirques erode towards each other, the previously rounded landscape is transformed into a narrow rocky, steep – sided ridges called Arete.

Cirque is a glacially eroded rock basin, with a steep side wall and steep head wall, surrounding an armchair-shaped depression.

Share This:

Whatsapp Whatsapp