Geography Revision Notes for Class 9th |Physical Features of India

Major Physiographic Divisions : The physical features of India are grouped under the following physiographic divisions:

Let’s discuss each of them in detail:

The Himalayan Mountains

Himalayan mountains are stretched over the northern borders of India. These mountain ranges run in a west-east direction from the Indus to the Brahmaputra. The Himalaya consists of 3 parallel ranges in its longitudinal extent.

1. The northern-most range is known as the Great or Inner Himalayas or the Himadri. It is the mos t continuous range consisting of the loftiest peaks with an average height of 6,000 metres.

2. The folds of the Great Himalayas are asymmetrical in nature. The core of this part of Himalayas is composed of granite.

3. The range lying to the south of the Himadri forms the most rugged mountain system and is known asHimachal or lesser Himalaya.

4. Pir Panjal range forms the longest and the most important range.

5. The outermost range of the Himalayas is called the Shiwaliks. These ranges are composed of unconsolidated sediments.

6. The longitudinal valley lying between lesser Himalaya and the Shiwaliks are known asDuns. DehraDun, Kotli Dun and Patli Dun are some of the well-known Duns

.The Himalayas have also been divided on the basis of regions from west to east.

1. The part of Himalayas lying between Indus and Satluj has been traditionally known as Punjab Himalaya but it is also known regionally as Kashmir and Himachal Himalaya from west to east respectively.

2. The part of the Himalayas lying between Satluj and Kali rivers is known as Kumaon Himalayas.

3. The Kali and Teesta rivers divide the Nepal Himalayas and the part lying between Teesta and Dihang rivers is known asAssam Himalayas.

4. The Brahmaputra marks the eas tern-most boundary of the Himalayas.

5. Beyond the Dihang gorge, the Himalayas bend sharply to the south and spread along the eastern boundary of India, which is known as the Purvachal or the Eastern hills and mountains. The Purvachal comprises the Patkai hills, the Naga hills, the Manipur hills and the Mizo hills.

The Northern Plain

The northern plain has been formed by the interplay of the 3 major river systems – the Indus, the Ganga and the Brahmaputra along with their tributaries. It spreads over an area of 7 lakh sq. km.The Northern Plain is broadly divided into 3 sections as mentioned below:

1. The Western part of the Northern Plain is referred to as the Punjab Plains. This plain is formed by the Indus and its tributaries – the Jhelum, the Chenab, the Ravi, the Beas and the Satluj.

2. TheGanga plain extends between Ghaggar and Teesta rivers. It is spread over the states of North India, Haryana, Delhi, U.P., Bihar, partly Jharkhand and West Bengal.

3. Brahmaputra plain lies in the state of Assam. According to the variations in elevation points, the Northern plains can be divided into 4 regions.

1. The rivers, after descending from the mountains, deposit pebbles in a narrow belt of about 8 to 16 km in width lying parallel to the slopes of the Shiwaliks, which is known as bhabar. All the streams disappear in this bhabar belt.2. The streams and rivers re-emerge and create a wet, swampy and marshy region known asterai. 3. The largest part of the northern plain is formed of older alluvium. It lies above the floodplains of the rivers and presents a terracelike feature which is known asbhangar. 4. The soil in the bhangar region contains calcareous deposits and is known askankar. The newer, younger deposits of the floodplains are called khadar

The Peninsular Plateau

WESTERN AND EASTERN GHATS

The Peninsular plateau is a tableland composed of the old crystalline, igneous and metamorphic rocks. It was formed due to the breaking and drifting of the Gondwana land. One of the distinct features of the Peninsular plateau is the black soil area known as Deccan Trap.

This plateau consists of 2 divisions:

1. The Central Highlands: 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 eastward extensions of this plateau are locally known as the Bundelkhand and Baghelkhand

2. The Deccan Plateau: It is a triangular landmass that lies to the south of the river Narmada. An extension of the Plateau is also visible in the northeast which is known as the Meghalaya, Karbi-Anglong Plateau and North Cachar Hills.The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan Plateau respectively.

The Indian Desert

The Indian desert lies towards the western margins of the Aravali Hills. It is a sandy plain covered with sand dunes. This region receives very low rainfall below 150 mm per year.•It has a dry climate with low vegetation cover.

The Coastal Plains

A coastal plain is a flat, low-lying piece of land next to the ocean. To the east and west of the peninsular plateau, 2 narrow strips of plain lands are found, which are respectively called Eastern Coastal Plain and Western Coastal Plain.Eastern Coastal PlainThe Eastern Coastal Plains is a wide stretch of the landmass lying between the Eastern Ghats and the Bay of Bengal. In the northern part, it is referred to as the Northern Circar, while the southern part is known as theCoromandel Coast. Large rivers, such as the Mahanadi the Godavari, the Krishna and the Kaveri have formed extensive delta on this coast. Lake Chilika is an important feature along the eastern coastWestern Coastal PlainThe western coast is sandwiched between the Western Ghats and the Arabian Sea. It is a narrow plain and consists of 3 sections as mentioned below:•The northern part of the coast is called the Konkan (Mumbai – Goa)•The central stretch is called theKannad Plain•The southern stretch is referred to as the Malabar coastThe Is la ndsAn island is a piece of sub-continental land that is surrounded by water. Lakshadweep Islands group is composed of small coral isalnds which were earlier known as Laccadive, Minicoy and Amindive.The entire group of islands is divided into 2 broad categories:1. The Andaman in the north2. The Nicobar in the southThese islands lie close to the equator and experience equatorial climate and have thick forest cover.The diverse physical features of India have immense future possibilities of development because of the following reas ons .•The mountains are the major sources of water and forest wealth.•The northern plains are the granaries of the country. They pro vide the base for early civilisations.•The plateau is a storehouse of minerals, which has played a crucial role in the industrialisation of India.•The coastal region and island groups provide sites for fishing and port activities.