NCERT Folder 9th Geography Chapter 2 : Physical Features of India

Geography

Class 9

Chapter 2

Physical Features of India

Revision Notes

Important Terms

  • Gondwanaland : It is the name of an ancient super continent that incorporated present day South America, Africa, Arabia, Madagascar, India, Australia and Antarctica.
  • Eurasian Plate : The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia, with the notable exceptions of the Indian sub-continent, the Arabian sub-continent and the area east of the Chersky Range in East Siberia.
  • Convergent boundary : It is a boundary, where two plates are moving towards each other and colliding. It is also termed as folding movement or destructive boundary.
  • Divergent boundary : It is a boundary, where plates move away from each other, it is also called faulting movement.
  • Transform boundary : It is a boundary, where in the event of coming together, plates may collide or may slide under each other.
  • Himadri : The northern-most range is known as the Greater or Inner Himalayas or the `Himadri´.
  • Himachal : The range lying to the south of the Himadri forms the most rugged mountain system and is known as Himachal or Lesser Himalaya.
  • Purvanchal : Mountains along the eastern boundary of India are called the Purvanchal.
  • Shiwaliks : The outer-most range of Himalayas is called the Shiwaliks.
  • Bhabar : Bhabar is a belt of pebbles extending from 8-16 km in width in which stream disappears.
  • Terai : Terai is a wet, swampy, marshy region with thick forests and wildlife.
  • Bhangar : Bhangar is a terrace-like feature made of old alluvium. It contains calcareous deposits called Kankar.
  • Khadar : Khadar is the flood plain which is renewed every year and is very fertile.
  • Central Highlands : The part of the Peninsular Plateau which lies to the north of the Narmada River.
  • Deccan Plateau : The part of the Peninsular Plateau which lies to the south of the Narmada River.
  • Stream : A natural flow of water that is smaller than a river.
  • Barchan : A crescent-shaped sand dune with the convex side in the direction of the wind.
  • Western Coastal Plain : A thin strip of coastal plain between the Western Ghats and the Arabian Sea.
  • Eastern Coastal Plain : A wide stretch of landmass of India, lying between the Eastern Ghats and the Bay of Bengal.
  • Island : A piece of land that is completely surrounded by sea, a river or lake.
  • Coral polyps : Short-lived microscopic organisms, which live in colonies.
  • Flora : The plants of a particular region or period.
  • Fauna : The collective term for the species of animals in a particular region or period.

Summary

Major Physiographic Divisions

  • India is a large landmass formed during different geological periods which has influenced its relief.
  • Besides geological formations, a number of processes such as weathering, erosion and deposition are also responsible for creating and modifying the relief to its present form.
  • Theory of Plate Tectonics :
    • According to this theory, the crust (upper part) of the earth has been formed out of seven major and some minor plates.
    • The movement of the plates leads to folding, faulting and volcanic activities.
    • These plate movements are classified into three types :
      • Convergent boundary : When some plates come towards each other.
      • Divergent boundary : When some plates move away from each other.
      • Transform boundary : In the event of two plates coming together, they may either collide and crumble or one may slide under the other. At times, they may also move horizontally past each other.
    • The position and size of the continents have changed by the movement of these plates over millions of years.
    • Such movements have also influenced the evolution of the present landform features of India.
  • The Gondwanaland included India, Australia, South Africa, South America and Antarctica as one single land mass.
  • Geologically, the Peninsular Plateau constitutes one of the ancient landmasses on the earth’s surface. The Himalayas and the Northern Plains are the most recent landforms.
  • Most volcanoes and earthquakes in the world are located at plate margins, but some do occur within the plates.
  • Major Physiographic Divisions
    • The physical features of India can be grouped under the following physiographic divisions :
      • The Himalayan Mountains
      • The Northern Plains
      • The Peninsular Plateau
      • The Indian Desert
      • The Coastal Plains
      • The Islands

The Himalayan Mountains

  • The Himalayan Mountains
    • The Himalayas, geologically young and structurally fold mountains, stretch over the northern borders of India.
    • These mountain ranges run in a west-east direction from the Indus to the Brahmaputra.
    • An arc is formed by the mountains that cover a distance of about 2,400 Km.
    • The altitudinal variations are greater in the eastern half than those in the western half.
    • The Himalayas consists of three parallel ranges in its longitudinal extent.
      • Great or Inner Himalayas or the Himadri : The northern-most range, consisting of the loftiest peaks with an
        average height of 6,000 metres.
      • Himachal or Lesser Himalaya : The range lying to the south of the Himadri forms the most rugged mountain system. The altitude varies between 3,700 and 4,500 metres and the average width is 50 km.
      • Shiwaliks : The outermost range of the Himalayas. Their width varies from 10 – 50 km and has an altitude varying between 900 and 1100 metres.
    • The longitudinal valley lying between lesser Himalaya and the Shiwaliks are known as ‘Duns’.
    • Apart from longitudinal divisions, the Himalayas have also been divided by river valleys on the basis of regions from west to east.

The Northern Plains

  • The Northern Plains
    • The Northern Plains have been formed by the interplay of the three major river systems, i.e. the Indus, Ganga and Brahmaputra along with their tributaries.
    • This densely populated physiographic division spreads over an area of 7 lakh sq. km.
    • With rich soil cover, combined with adequate water supply and favourable climate, it is agriculturally a very productive part of India.
    • The Northern Plains is broadly divided into three sections – Punjab Plain, Ganga Plain and Brahmaputra Plain.
    • Bhangar is the largest part of the Northern Plains, formed of older alluvium.
    • Majuli in the Brahmaputra River is the largest inhabited riverine island in the world.

The Peninsular Plateau

  • The Peninsular Plateau
    • The Peninsular Plateau is a tableland composed of the old crystalline, igneous and metamorphic rocks.
    • This plateau consists of two broad divisions – the Central Highlands and the Deccan Plateau.
    • The part of the Peninsular Plateau lying to the north of the Narmada River covering a major area of the Malwa plateau is known as the Central Highlands.
    • The Deccan Plateau is a triangular landmass that lies to the south of the river Narmada.
    • The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan Plateau respectively.
    • The continuous Western Ghats lie parallel to the western coast.
    • The discontinuous and irregular Eastern Ghats stretch from the Mahanadi Valley to the Nilgiris in the south.
    • The highest peaks of the Western Ghats are the Anai Mudi (2,695 metres) and the Doda Betta (2,637 metres).
    • Mahendragiri (1,501 metres) is the highest peak in the Eastern Ghats.
    • The Deccan Trap, the region of black soil, is one of the distinct features of the Peninsular Plateau.

The Indian Desert

  • The Indian Desert
    • The Indian Desert lies towards the western margins of the Aravalli Hills.
    • The region is characterized by arid climate, very low rainfall below 150 mm per year with scanty vegetation cover.
    • Luni is the only large river in this region.
    • Barchans or the crescent shaped dunes and longitudinal dunes are very prominent here.

The Coastal Plains

  • The Coastal Plains
    • The Peninsular Plateau is flanked by stretch of narrow coastal strips, running along the Arabian Sea on the west and the Bay of Bengal on the east.
    • The western coast consists of three sections – Konkan Coast, Kannad Plain and Malabar Coast.
    • The eastern coast is divided into the Northern Circar and Coromandal Coasts.
    • The Chilika Lake is the largest salt water lake in India.

The Islands

  • The Islands
    • The small coral islands, the Lakshadweep Islands group, lies close to the Malabar Coast of Kerala.
    • Kavaratti Island is the administrative headquarters of Lakshadweep.
    • There is a bird sanctuary in the Pitti island.
    • The elongated chain of islands extending from north to south is located in the Bay of Bengal. These are Andaman and Nicobar Islands.
    • These islands lie close to the Equator and experience equatorial climate and have thick forest cover.
    • India’s only active volcano is found on the Barren Island in Andaman and Nicobar group of Islands.
    • The diverse physical features of the land have immense future possibilities of development.

Intext Questions

Find Out

(Page No. 8)

Question.1. Find out the names of the glaciers and passes that lie in Great Himalayas. 
Answer. Glaciers in the Great Himalayas — Gangotri, Chaturangi, Bhagirathi, Kharak, Satopanth, Kamet, Milam and Pindari.
Passes in the Great Himalayas — Karakoram pass, Shipkila pass, Nathula, Bomdila pass.

Question.2. Find out the name of the states where highest peaks are located. 
Answer. 

Mountain peaksStates
KanchenjungaSikkim
Nanga ParbatJammu and Kashmir
Nanda Devi Uttarakhand
KametUttarakhand
Namcha BarwaAssam

Find Out

(Page No. 8)

Question.1. Find out location of Mussoorie, Nainital, Ranikhet from your atlas and also name the states where they are located.
Answer.

MussoorieUttarakhand
NainitalUttarakhand
Ranikhet Uttarakhand

NCERT Solution

(Page No. 15)

Question.1. Choose the right answer from the four alternatives given below :
(i) A landmass bounded by sea on three sides is referred to as

(a) Coast
(b) Island
(c) Peninsula
(d) None of the above.

Answer. (c) Peninsula

(ii) Mountain ranges in the eastern part of India forming its boundaries with Myanmar are collectively called :

(a) Himachal
(b) Uttaranchal
(c) Purvanchal
(d) None of the above.

Answer. Purvanchal

(iii) The western coastal strip south of Goa is referred to as

(a) Coromandel
(b) Konkan
(c) Kannad
(d) Northern Circar

Answer. Konkan

(iv) The highest peak in the Eastern Ghats is

(a) Anai Mudi
(b) Kanchenjunga
(c) Mahendragiri
(d) Khasi

Answer. Mahendragiri

Question.2. Answer the following questions briefly
(i) What are tectonic plates?
Answer. Large fragments of the Earth’s crust torn due to the rising currents are called tectonic plates.

(ii) Which continents of today were part of the Gondwanaland?
Answer. South America, Africa and Australia.

(iii) What is the ‘Bhabar’?
Answer. Bhabar is a pebble studded formation situated at the junction of mountain and plain.

(iv) Name the three major divisions of the Himalayas from north to south.
Answer. The Great or the Inner Himalayas or the Himadri, the Middle Himalayas or the Himachal, and the Outer Himalayas or the Shivaliks.

(v) Which plateau lies between the Aravali and the Vindhya ranges?
Answer. The Malwa plateau lies between the Aravali and the Vindhya Ranges.

(vi) Name the island group of India having coral origin.
Answer. Lakshadweep Islands is the island group of India having coral origin.

Question.3. Distinguish between
(i) Converging and Diverging Tectonic Plates.
Answer.

Converging Plates Diverging Plates
(a) When tectonic plates move towards each other, they are called converging plates. (a) When tectonic plates move away from each other, they are termed as diverging plates.
(b) When they move towards each other, they collide or crumble or one of them slides under the other. (b) When they move away from each other, they do not collide or crumble.
(c) Converging plates cause folds. (c) Diverging plates cause fractures in the crust.

(ii) Distinguish between Bangar and Khadar.
Answer.

Bangar Khadar
(a) Formed of older alluvium (a) Renewed every year.
(b) Lies above flood plains of rivers. (b) Is newer, younger deposit of flood
(c) Presents a terrace like feature.(c) Contains calcerous deposits locally known as Kankar.
(d) Less fertile (d) More fertile

(iii) Distinguish between the Western Ghats and the Eastern Ghats.
Answer.

Western Ghats Eastern Ghats
(a) They stand like a continuous wall and can be crossed through passes only. Thal Ghat provides passage to rails and roads. (a) They are discontinuous and irregular. They have been dissected by rivers which have made their passages to reach the Bay of Bengal.
(b) This range is a source of many large rivers. (b) No big river originates from this range.
(c) It obstructs the monsoon winds coming from the Arabian Sea which causes heavy rainfall in the Western Coastal Plain.(c) They are almost parallel to the monsoons originating in the Bay of Bengal and do not cause much rainfall.

Question.4. Describe how the Himalayas were formed.
Answer. Geologists claim that a sea was located where the Himalayas now stand. Internal and external changes of Earth’s crust occurred. It is said that one of the crustal plates, called the Indo-Australian plate, separated from the super-continent named Gondwanaland. It drifted slowly towards the north to collide with the Eurasian plate five million years ago. The northern edge of the Indo-Australian plate was pushed beneath the Eurasian plate. After the collision of these two plates, the sedimentary rocks of enclosed ocean folded to form the Himalayas.

Question.5. Which are the major physiographic divisions of India? Contrast the relief of the Himalayan region with that of the Peninsular Plateau.
Answer. The major physiographic divisions of India are :

(i) The Great Mountains of the North.
(ii) The North Indian Plain.
(iii) The Peninsular Plateau
(iv) The Coastal Plains and
(v) The Islands.

Himalayan Region Peninsular Plateau
(a) This region comprises greatest and highest mountain ranges of the world.(a) Rugged and dissected terrain plateau is a remnant portion of the supercontinent the Gondwanaland.
(b) The ranges have I-shaped and U-shaped valleys. (b) It has horsts, rift valleys and troughs.
(c) It is the origin of perennial rivers. (c) It has rainfed, seasonal rivers.
(d) Young fold mountains made from the uplift of the strata formed by the sedimentary rocks.(d) Created from igneous and metamorphic rocks after splitting of Gondwanaland.
(e) Parallelly arranged mountain ranges are separated by valleys and plains.(e) Rivers dissect. Faults and vertical movement of the Earth mark the plateau.

Question.6. Give an account of the Northern Plains of India.
Answer. The Northern Plains have been formed from the alluvium that the mountain rivers deposited here. This turned the soil on the surfaced land fertile for growing a rich harvest of variety of crops. This led to the development of the Indus River Valley Civilisation. The rich soil was further aided by favourable climate and constant water supply from the rivers. Between the mouths of the Indus and the Ganga-Brahmaputra, the North Indian Plain covers a distance of 3200 km. It is 300 to 150 km wide at some places. The North Indian Plains have the Indus river system in the west and the Ganga-Brahmaputra river system in the east. The first includes Jhelum, Chenab, Ravi, Beas, Satluj. The Indus flows into the Arabian Sea.

The second includes Ganga, its tributaries and the Brahmaputra which combine as Meghna as they drain into the Bay of Bengal. They form the world’s largest and fastest growing delta. The difference in relief has led the North Indian Plains to be divided into four zones :
(i) Bhabhar,
(ii) Tarai,
(iii) Bangar and
(iv) Khadar.

Question.7. Write short notes on the following.
(i) The Indian Desert
Answer. Lying towards the western margins of the Aravali Hills, the Indian desert is formed of sandy plain covered with sand dunes. Receiving less than 10 mm rainfall in a year, the region has arid climate, low vegetation and streams that appear only in the rainy season. But they soon disappear into the sands, lacking enough water to reach the sea. Large areas of the deserts have crescent shaped sand dunes, i.e. barchans, while longitudinal dunes are abundant near Indo-Pakistan boundary.

(ii) Central Highlands.
Answer. The northern part of the Peninsular Plateau consists of plateaus, denuded mountain ranges and low hills made of igneous rocks. In the north-west are the Aravali range, running in south-west, north-east direction forming a discontinuous ridge. Thar Desert lies to the west of Aravali ranges. The southern boundary is demarcated by the Vindhya Range with Kaimur Hills in the eastern extent. The Malwa plateau lies between Aravalis and Vindhyas. Between the valleys of Narmada and the Son, escarpments are formed by the Vindhyan Kaimur range.

(iii) Island groups of India.
Answer. The Lakshadweep consists of many small islands located opposite the Kerala coast in the Arabian Sea. The islands of this group are formed of coral deposits called ‘atolls’ in Malayalam which refer to their ring or ‘horse-shoe’ shape. The Andaman and Nicobar Islands, on the other hand, are larger in size. They are more in number and more widely scattered. There are about 200 islands in the Andaman group and 19 islands in the Nicobar group.

Map Skills

Question.1. On an outline map of India show the following.
(i) Mountain and hill ranges — the Karakoram, the Zaskar, the Patkai Bum, the Jaintia, the Vindhya range, the Aravali, and the Cardamom hills.
(ii) Peaks — K2, Kanchenjunga, Nanga parbat and the Anai Mudi.
(iii) Plateaus — Chhota Nagpur and Malwa
(iv) The Indian Desert, Western Ghats, Lakshadweep Islands.
Answer.Map-question-01-geo-chap-02

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