ICSE Solutions for Class 9 Geography – Landforms of the Earth
chapter _ LANDFORMS OF THE EARTH
Question
1. What causes orogenic movement?
Answer:
due to mountain buidings
Question
2. What is meant by a landform ?
Answer:A
landform is a natural feature on the surface of the earth with a particular
shape.
Question
3. Give two examples of old fold mountains?
Answer:
Urals mountain and Aravalli mountain
Question
4. Why are the fold mountains called so?
Answer:
Fold mountains are called so because of the result of large- scale earth
movements caused by stresses in the earth’s crust. Such stresses may be caused
by weight of the overlying rocks, movements in the mantle, the expansion or
contraction of some part of the earth, etc. These stresses subject the rocks to
compressive forces, producing wrinkling or folding along the lines of weakness.
This is shown in fig. the raising of folds makes the fold mountains.
Question
5. Give two chief characteristics of the fold mountains.
1.
Answer:
The fold mountain system has parallel ranges.
2.
A
fold mountain region is also a region of sudden forces such as of volcanoes and
earthquakes.
Question
6. Give one example of each :
(a)
Young fold mountains=(a) These mountains are made of light sedimentary rocks of
recent tertiary age and are the highest mountain system which are still
increasing their heights due to gradual up thrust force. The Himalayas are
called young fold mountains.
(b)
Old fold mountain. Why they are called so?
Answer:
(b) The Alpine-Himalayan system and Circum Parific mountain belt are the ‘Old
Fold Mountains’ which existed as geosynclines 50-60 million years ago.
Question
7. What is the most recent type of mountains that has been formed?
Answer:
Himalayas is the most recent type of mountains that has been formed.
Question
8. Give example of residual mountains.
Answer:
Examples of Residual mountains are Nilgiri, Parasnath and Rajmahal Hills in
India and the Catskill range in the USA.
Question
9. Name two belts of the young fold mountains in the world?
Answer:
Circum pacific belts and mid world mountain belts.
Question
10. How is a rift valley formed? Give one example of a rift valley.
Answer:
A rift valley is formed by the submergence of a big landmass between two high
block mountains, e.g. the Rhine river flows through a rift valley in its middle
course.
Question
11. Give a brief definition of a plateau.
Answer:
The Himalayas are an important form of folding being the highest mountain range
in the world.
Question
12. Give one example of each:
(a)
Intermontane plateau
(b)
Volcanic plateau and
(c)
Piedmont plateau
Answer:(a)
The Tibetan plateau
(b)
The Plateau of Peninsular India.
(c)
The Patagonian plateau of South America.
Question
13.what is an intermontane plateau? Give an example?
Answer:
in some places, high plateaus lie between the mountain ranges, for example, the
plateau of Anatolia in turkey and the plateau of Tibet. these are called an
intermontane plateaus.
Question
14. Give two points of importance of landforms.
Answer:
Various landforms display the internal and external forces of the earth,
different climatic effects and features, forests, snow lands giving birth to
rivers, coasts and islands as fishing regions. All these together make the
earth beautiful and ideal for living and various activities.
Question
15. What are known as epeirogenic movements?
Answer:
The movements such as uplift and submergence working in vertical direction are
known as epeirogenic movements. ‘Epeiros’ in Greek means continent ‘genic’
means building. As this movement created continents coming out higher from the
oceans.
Question
16. Name two landforms created by epeirogenic movements.
Answer:
Block mountains, Rift valleys and basins are produced by epeirogenic movements.
Question
17. Why are the sudden forces described as ‘Constructive forces?
Answer:
Earthquakes and volcanic activities are described as sudden forces. These
forces are described as ‘Constructive Forces’ because they create relief
features on the surface of the earth. As volcanic eruptions result in the
formation of volcanic mountains, extensive plateaus and also plains.
Question
18. What are called endogenic forces?
Answer:
Endogenic forces are the internal diastrophic forces working inside the
interior of the earth related to the tectonic forces.
Question
19. Name four relief features on the surface of the earth.
Answer:The
four major landforms are mountains, plateaus, plains, valleys and basins.
Question
20. What are known as exogenic forces?
Answer:Exogenic
forces work on the surface of the earth through water, wind and ice, resulting
in changing the shape of landforms slowly.
Question
21. Name the two land forms produced by exogenic forces.
Answer:
Alluvial and erosional plains of Glacial landforms.
Question
22. Give one chief characteristic of the fold mountains.
Answer:
The fold mountains are formed by the lateral compression of sedimentary rocks
as seen by the different layers of various types of rocks one upon another.
Question
23. Give one example of volcanic mountains.
Answer:
Volcanic mountains are formed by erupting magma from the inner core on the
surface e.g. Mt. Krakatoa is an active volcano on the western side of Java.
Question
24. How is a rift valley formed? Give one example.
Answer:
A rift valley is formed by the submergence of a big landmass between two high
block mountains, e.g. the Rhine river flows through a rift valley in its middle
course.
Question
25. Give a brief definition of a plateau.
Answer:
A plateau is a higher tableland between mountain and valley, lower than
mountain and higher than valley.
Question
26. How are erosional plains formed?
Answer:
Erosional plains are formed by the agents of erosion in millions of years, when
the higher landforms are eroded into level plain areas, e.g. Lorraine plain in
France.
Question 27. Give two points of importance of
landforms.
Answer:
Various landforms display the internal and external forces of the earth,
different climatic effects and features, forests, snow lands giving birth to
rivers, coasts and islands as fishing regions. All these together make the
earth beautiful and ideal for living and various activities.
Question
28. Distinguish between Anticlines and synclines
Question
29. Young fold mountains and old fold mountains.
Question
30.
Distinguish
between Fold Mountains and Block Mountains.
Answer
|
Fold Mountains |
Block Mountains |
|
They are formed due to folding of the
rocks. |
Block mountains are formed due to
faulting. |
|
Fold Mountains are formed when two
tectonic plates move towards each other leading to the folding of the layers
of the Earth. |
Block Mountains are formed when the two
tectonic plates move away from each other causing cracks on the surface of
the Earth. |
|
They are characterized by large scale
complex folds that have greater height but are comparatively narrow in width. |
They are characterized by steep slopes
and flat slopes. |
|
For example- the Himalayas in India |
For example- Black forest mountains in
Europe. |
Question
31. Distinguish between Intermontane plateaus and Volcanic plateaus.
|
Intermontane plateaus |
Volcanic plateaus |
|
These are surrounded by hills and
mountains on all the sides. They are formed along with fold mountains. |
They are formed by numerous volcanic
eruptions that slowly build up over time. |
|
For example- the Tibetan plateau. |
For example- the Peninsular plateau of
India. |
Question
33. Structural plains and Depositional plains.
Answer
|
Structural plains |
Depositional
plains |
|
These plains are formed due to uplift or
subsidence of land |
These plains are formed by the
deposition of materials which have been brought by various agents of
transportation. |
|
For example- the Great Plains of USA |
For example- Northern Plains of India. |
Question
34.
Describe
the characteristics of structural plains.
Answer:
Structural
plains are created by uplifting of a large landmass due to Diastrophic
movements, e.g. plainofU.S.A. Erosionalplains are formed by eroding highlands
into plain areas, e.g. Lorraine plain in France. Srinagar Valley of Kashmir is the
result of glacial erosion, Sahara desert plain is the result of wind erosion.
Karst plains are created by erosion of limestone rocks by ground water, e.g.
Karst plain of Yugoslavia. Depositional plains are caused by large scale
deposition of debris and silt deposited by the running water or rivers, e.g.
Northern plain of India.
Question
35.
Explain
the chief characteristics of depositional plains and their types.
Answer:Depositional
plains These plains are formed by the deposition of materials which have been
brought by various agents of transportation, eg.
River
Deposition : The most widespread of these are alluvial plains like the Northern
Plains of India; the flood plains like the Mississippi Plains in the USA,
deltaic plains in Egypt and India
Wind
Deposition : Most such plains are sandy deserts like the Sahara in Africa and
the Thar desert in India. They have irregular and undulating surface made by
existence of sand dimes and hallows.
Marine
Deposition : These plains are found in coastal regions. Examples are the east
coast of India, the estuarine banks in the Netherlands, coast of Germany and
Denmark.
Question
36.
Describe
the direction in which the following mountain systems lie and also point out
the continents where they are found.
(a)
Alpine Himalayan System
(b)
Rocky-Andean System
Answer:
(a)
Alpine and Himalayan System both run from West to East direction in Europe and
Asia continents respectively.
(b)
Rocky-Andean System both run from North to South in the western margins of
North America and South America continents.
Question
37.Describe the different stages in the growth of mountains.
Answer:
There
are three different stages in the growth of mountains.
The
geosyncline stage : The deposition of sediments in the sea-bed to form large
geosynclines.
The
Orogenic stage : The tectonic forces working horizontally push and press there
geosynclines to form various folds.
Epeirogenic
stage : When the whole mass of geosynclines is raised and buckled up and form a
distinct series of troughs (synclines) and arcs (anticlines) i.e. Mountains and
Valleys.
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