Notes of Physical Features of India Chapter 2 Class 9th Social Science Geography

1. Major features of the earth are mountain, plateaus, plains islands and dessert.

Origin of the Earth

• Theory of plate tectonics- According to this theory, the upper part of the earth (crust) is made up of 7 major and some minor plates.
• The movement of the plates results in folding, faulting, and volcanic activity.
• There are 3 plates movements

(a) Convergent Boundary- When some plates come towards each other convergent boundary is formed

(b) Divergent Boundary- When some plates someone away from each other divergent boundary is formed.

(c)Transform Boundary- When two plates come together, they may either collide or crumble or one may slide under the other.

How were the Himalayas formed?

• The Himalayas were once the part of Gondwana land.
• The Gondwana land included India, Australia, South America, South Africa and Antarctica as one single land mass.
• The conventional currents split the crust into pieces.
• The Indo-Australia plate, which was separated from Gondwana land began to move towards the north.
• Then, it collided with the much larger Eurasian plate.
• As the result of the collision, Tethys was folded and the Himalayas were uplifted.

Formation of Northen Plains

• The Himalayan uplift out of Tethys Sea, resulted is the formation of a large basin.
• In the due cause of time, these plains get filled with sediments brought down by Himalayan river.
• A flat land of alluvial deposits led to the formation of Northen Plain.

Major Physiographic Division

• The Himalayan Mountains
• The Northen plains
• The Peninsular Plateau
• The Indian Desert
• The Coastal Plains
• The Islands

The Himalayan Mountain

They are young fold mountains and runs in the west-east direction.

They are highest and the most rugged mountains barriers in the world.

They form an arc and covers the distance of 2400 km.

The Himalayas consists of 3 parallel ranges i.e., Himadri, Himachal, Shivalik.

                                                            Himadri

Himadri is the northern most range of Himalayas also known as great or inner Himalayas.

Important Himalayas peaks are located here with the average height of 6000 m.

It is composed of granite and snow bound.

Himachal

The range lying to the south of Himadri is called Himachal, also known as lesser Himalayan.

Their height varies from 3700 m and 4500 m.

The famous valleys like Kashmir, Kangra, and Kullu are located here.

Shivalik

It is the outer most range of Himalayas.

These valleys are covered with gravel and aluminum. some important dunes are located like Deharadun, pattidum, and Kotlidum and located here. [Dunes – The valley lying lesser Himalayas and shivaliks]

How are the Himalayas divided on the basis of the region?

(i) Punjab Himalayas.

The region lying between Indus and Satluj river.

(II) Kumaon Himalayas

The region lying between satluj and Kali river.

(III) Nepal Himalayas

The region lying between kali and Tista river.

(IV) Assam Himalayas

The region lying between Tista and Dihag river.

Purvanchal/Eastern Hills

• Beyond Dihang gorgl, the Himalayas bend sharply towards the south and spread along the eastern boundary.
• They are composed of sand stone and covered with dense forests.
• Purvanchal comprised of Parkai Hills, Naga Hills, Manipur hills and Mizo hills.

Northern Plains

• Northern Plains has been formed by the three rivers, i.e. Indus, Ganga, and the Brahmaputra.
• They are formed of alluvial soil and are very fertile.
• They are densely populated and agriculturally a very productive part of India. Due to sufficient water supply, favorable climate and fertile soil.

River in Island

In the lower course, the velocity of the river decrease which results in the formation of the river in the island.

Distributes

The river in their lower course split into numerous channels.

Tributaries

Many streams/rivers join the main rivers.

Sections of Northern Plain

Northern plain is divided into 3 sections.

Punjab Plain-

It lies to the western part of Northern Plain. It is formed by Indus and its tributaries.

Ganga Plain

It lies between ghagger and Tista rivers.

Brahmaputra Plain

It lies to the east of Ganga Plains.

A region of Northern Plain

The northern plain is divided into 4 regions.

• Bhabur 

The river after descending from mountains, deposit pebbles in a narrow belt of 8 to 16 km.

• Terai

All the streams disappear in the Bhabur belt and reemerge in a wet and marsley region.

• Bhangar

The region with older alluvium.

• Khadar

The region with newer alluvium. They are renewed every year and are very fertile.

The Peninsular Plateau

• The peninsular plateau is a tableland and composed of igneous, metamorphic and crystalline rocks.
• It has broad and shallow valleys and rounded hills. It is divided into two:-

(i) Central Highlands

(ii) Deccan Plateau

Compare and contrast western ghats and eastern ghats.

They are continuous and higherthan eastern ghats,

Deccan Trap

The black soil are in the peninsular plateau.

The Indian Desert

• The Indian desert lies to the western margins of the Aravali hills.
• It is ab undulating sandy plain covered with sand dunes.
• This area receive very low rainfall and has an arid climate with low vegetation.
• Luni is the only large river.

Barch and – The crescent-shaped dunes.

Coastal Plains

India has two coastal plain:-

• Western Coast.
• Eastern Coast
• Western Costs lies between the Western Ghats and Arabian sea.
• Eastern Coast lies between Eastern Ghats and Bay of Bengal.

Western Coast

It is divided into 3 sections

• Konchan- Northern part of the western coast.
• Kannad- untral part of the western coast.
• Malabar- Southern part of the western coast.

Also, Check: Chapter-1 India- Size and Location Notes Class 9th SST

Eastern Coast

It is divided into 2 sections.

• Northern Circar – The northern part of Eastern Coast
• Corom andel Coast- The southern part of Eastern Coast.

The Islands

India has two island groups

• Andaman and Nicobar
• Lakshadweep

Lakshadweep Islands

They lie close to Malabar coast of Kerala.

Earlier they were known as Laccadive, Minicoy and Amindiee.

In 1973 these islands  are name as Lakshadweep.

It covers a small area of 32 sq. km.

Kavaratti flead quarters.

Andaman and Nicobar Islands

They are located in Bay of bengal

They are bigger in size, mumerous and scattered.

Andaman islands are located in the north and nicobar islands in the south.

They lie close to the equator and so they have an equatarial climate.

Portblair is the headquarter of Andaman and Nicobar Islands.

Each Physiographic divisions complements the others explain.

The mountains are the major sources of water and forest. The northern plains are the granaries of the country..

The plateau is the storehouse of minerals.

The coastal regions and island groups provide sites for fishing and part activities.