Physical Features of India (Class 9 Geography Chapter 2 Notes)

Physical Features of India (Class 9 Geography Chapter 2 Notes)
Physical Features of India/Image Source: NROER
India shows a great variety in its physical features. These features has been developed over several geological ages via endogenic forces of earth such tectonic plates. In addition, exogenic forces such as rivers has also played a vital role in shaping its reliefs.

Tectonic Plates
The surface of earth is broken into several, rigid and irregular shaped plates known as tectonic plates. There are seven major and ten minor plates along with several micro plates. The tectonic plates moves a few millimeters a year and change earth surface. Their movement is the main reason behind earthquakes and volcanic activites.

These plates are either moving toward each other or drifting apart from each other or slide passing each other. On the basis of their movement, they form three types of boundaries.

  1. Convergent boundary - when two plates are moving toward each other - In this event, they may collide and crumble or one plate may slide under the other. This cause rise of new mountain ranges. The Himalayas is the result of such convergent movemnt.
  2. Divergent boundary - when two plates are drifting from each other - In this event, magma might fill the space and form the rift valley.
  3. Transform boundary - when two plates slide pass each other - In this event, their friction can cause earthquakes and tremors.

India and Gondwanaland
  1. India along with Australia, South Africa, South America and Antartica were once part of a massive landmass known as Gondwanaland.
  2. The Gondwanaland with another massive landmass Angaraland (or Laurasia) were part supercontinent Pangea.
  3. The tectonic movements resulted into seperation of India from the supercontinent toward north.
  4. The northward shift led to its collision with a much larger Eurasian plate.
  5. This collision resulted into formation of the Great Himalayas and subsidence of northern flank of the peninsular plateau. There was sea named Tethys at the same place where Himalayas stand now.
  6. In mean time, this depression was filled by the works of the Himalayan rivers and northern plains, a flat land of extensive alluvial deposit, emerged out.

Geological Perspective
From geological perspective, the Himalayas and northern plains are very young landforms. The Himalaya region is unstable and still in the process of making. The peninsular plateau represents the oldest section of India. It is composed of igneous and metamorphic rocks with gentle mountains and wide valleys.

Major Physiographic Divisions of India

The physical features of India can be grouped into six physiographic divisions. These are
1. The Himalayan Mountains
2. The Northern Plains
3. The Peninsular Plateau
4. The Indian Desert
5. The Coastal Plains
6. The Islands

The Himalayan Mountain
  1. Himalaya is a geologically young and structurally fold mountain and reprsents a lofty and rugged terrain.
  2. It streches over the northern border of India and runs in west to east direction from the Indus to the Brahmaputra.
  3. It forms an arc of 2400 km in total length and its width ranges from 400 km (Kashmir) to 150 km (Arunachal Pradesh).
  4. Similarly, the western half has lower altitudinal variation than eastern half. The altitude lowers down as we move toward east.
  5. It can be divided into three sub-regions: 1. Himadri (Great Himalayas), 2. Himachal (Lesser Himalayas) and 3. Shiwaliks.
  6. It can be also divided culturally on the basis of river boundaries: 1. Punjab Himalaya, Kumaon Himalaya, Nepal Himalaya, Assam Himalaya and Purvanchal.

Physical Division of the Himalaya
Himadri (Greater Himalayas)
  1. The average height of this range is about 6000 m.
  2. It contains all prominent Himalayan Peaks, namely, Mount Everest, Kanchenjunga, Makalu, Dhaulagiri, Nanga Parbat and Annapurna.
  3. The fold of Himadri is assymetrical in nature.
  4. The core of Himadri section is made up of granite.
  5. It is perenially snow bound and a number of glacier comes down from here.

Himachal
  1. It lies south of Himadri and also known as the Lesser Himalayas.
  2. It composed of highly altered and compressed rocks.
  3. The altitude ranges between 3700-4500 m and its average width is 50 km.
  4. The Pir Panjal, the Dhauladhar and the Mahabharat are important ranges of Himachal.
  5. The Kashmir Valley, the Kangra Valley and Kullu Valley are also part of the lower Himalayas.
  6. This region is well known for its hill stations, namely, Mussorie, Nainital and Ranikhet.

Shiwaliks
  1. It is the outermost range of the Himalayas.
  2. Its width varies between 10-50 km and altitude varies between 900-1100 m.
  3. This range contains sendiments brought down by rivers from the Greater Himalayan and Lesser Himalayan ranges.
  4. The valleys are covered with thick gravels and alluvial soil.
  5. The longitudinal valley between Himachal and Shiwaliks is known as Doon (Dun). Dehradun, Kotlidun and Patlidun are some of prominent duns.

Cultural Division of the Himalaya
  1. The part lying between Indus and Satluj river is known as Punjab Himalaya or Kashmir and Himachal Himalaya.
  2. The part lying between Satluj and Kali river is known as Kumaon Himalaya.
  3. The part lying between Kali and Teesta river is known as Nepal Himalaya.
  4. The part lying between Teesta and Dihang river is known as Assam Himalaya.
  5. The part lying between Dihang and Brahmaputra river is known as Purvanchal or the Eastern Hills. It comprises of Patkai hills, the Naga hills, Manipur hills and the Mizo hills. They form the eastern boundary of India.

The Northern Plain
  1. It is formed by the works of Indus, Ganga and Brahmaputra river system and known its vast stretch of alluvial soil.
  2. It is spread over the area of 7 lakh sq km. It is 2400 km long and 240-320 km broad.
  3. It is one of the densely populated regions in the world and known for its agricultural productivity.
  4. In the lower course of these rivers, one can find riverine islands. Majuli in Brahmaputra river is the largest inhabited island in the world.
  5. The Northern Plain can be divided into three sections. These are 1. Punjab Plains, 2. Ganga Plains and 3. Brahmaputra Plains.
  6. Again, based on relief features, the Northern Plain can be divided into four regions. These are 1. Bhabar, 2. Terai, 3. Bhangar and 4. Khadar.

Punjab Plain
  1. It is the western region of the Northern Plain.
  2. It is also known as Indus plain as it is formed by Indus and its tributaries - Jhelum, Chenab, Ravi,
  3. Beas and Sutlej.
  4. The larger part of this section lies in modern day Pakistan.
  5. It is dominated by doabs, a region by two river meets. Similarly, Punjab means the region of five rivers.

Ganga Plain
It extends between Ghaggar and Teesta rivers and spread over the states of North India. These states are Haryana, Delhi, Uttar Pradesh, Bihar, part of Jharkhand and West Bengal.

Brahmaputra Plain
The area between Teesta and Brahmaputra river, most of the Northeast India, especially Assam falls under the Brahmaputra plains.

On the basis of relief features,
Bhabar
  1. After descending from the Himalayas, rivers deposit pebbles in a narrow belt of 8 to 10 km. This region is known bhabar region.
  2. The bhabar region lies in parallel to the Shiwaliks.
  3. The rivers and stream seem to be disapper from normal sight, especially in winter season.

Terai
  1. Terai falls south of bhawar region. The appoximate width of this region is 10-20 km.
  2. It comprises clay and silt and rivers seem to be appear again this region.
  3. This region has thick vegetation and full of wildlife. In some regions, vegetation is cleared to make land for agriculture.
  4. Some of the important national parks such as Dudhwa National Park lies in this region.

Bhangar
  1. Bhangar is the largest section of the Northern Plains. It is formed of old alluvial soil.
  2. The soil in this region contains calcareous sediments, locally known as kankar.

Khadar
  1. Khadar is the newer deposits of alluvial soil.
  2. They are renewed every year and most fertile and ideal for intensive agriculture.

The Peninsular Plateau
  1. It is a tableland composed of old crystalline, igneous and metamorphic rocks.
  2. It formed due to breaking and drifting of Indo-Austrlia Plate from Gondwanaland, making it one of the oldest landmass on earth.
  3. It has several broad and shallow valleys and rounded hills.
  4. It can be divided into Central Highlands and Deccan Plateau.
  5. The region is known for its black soil also known as Deccan Trap, which have volcanic origin.

Central Highlands
  1. It is the section of peninsular plateau which lies on the northern side of Narmada river.
  2. It is bounded by Vidhyan Ranges from south and Aravali Hills from northwest. The Chhotanagpur Plateau marks the eastward boundary.
  3. Chambal, Sind, Betwa, Ken are some of the most important rivers of this region. These flow from south-west to north-east indicating the slope of the region.
  4. It is wider in the west and narrower in the east. The eastward section is known Bundelkhand and Bhaghelkhand locally.

Deccan Plateau
  1. It is a triangular landmass that lies south to the Narmada river.
  2. Satpura Hills marks it northern boundary whereas Mahadev Hill, Kaimur and Maikal ranges form its eastern boundary.
  3. It is higher in west and slope tilts toward east.
  4. An extention of Plateau is also visible in the Notheast India. It comprises of Meghalaya, Karbi-Anglong plateau and North Cachar Hills. They are separeted from Deccan Plateau by a fault near Chhotanagpur Plateau.

Western Ghats
  1. Western Ghats marks the western boundary of the Deccan Plateau.
  2. It moves parallel to the western coast of India.
  3. They are continuous and can only be crossed through a pass.
  4. Its average elevation is around 900-1600 m. Its height increases from north to south.
  5. Anai Mudi (2695 m) is the tallest peak in the Western Ghats followed by Dodda Betta (2637 m).
  6. It is known by several different names locally such as Sahyadri (Maharashtra and Karnataka), Nilagiri (Tamilnadu) and Sahya Parvatam (Kerala).

Eastern Ghats
  1. Eastern Ghats marks the eastern boundary of the Deccan Plateau.
  2. It moves parallel to the eastern coast of India.
  3. It is not continuous and have several broad plain sections, formed by works of Godawari, Mahanadi, Krishna and Kaveri.
  4. Its average elevation is around 600 m.
  5. Mahendragiri (1501  m) is the tallest peak in the eastern ghat region.

The Indian Desert

  1. It lies on the western margin of the Aravali hills.
  2. It is a sandy plain with an average rainfall of 150 mm and known for low vegetation cover.
  3. It is known for it seasonal river. Luni is only large river here.
  4. It is famous for its crescent shaped dunes known as Barchans, but one can see longitudinal dunes on Indo-Pakistan border.

The Coastal Plains
The Peninsular Plateau is bounded by two long coastal strips, running along the Arabian Sea and the Bay of Bengal.

The Western Coast
The Western Coast is a long coastal plain sandwiched between the Sahayadri (Western Ghats) and the Arbian Sea. It can be divided into three parts. These are the Konkan region (Mumbai–Goa), Kannad Plain (Karnataka) and the Malabar coast (Karnataka and Kerala).

The Eastern Coast

  1. The Eastern Coast is a long coastal strip sandwiched between the Eastern Ghats and the Bay of Bengal. Its northern part is known as the Northern Circars and its western part is known as the Coramandel Coast.
  2. The Krishna, Godawari, Mahanadi and Kaveri are known for their massive deltas in the eastern coast area.
  3. The Eastern Coast is also known for India's largest saltwater lake, Chhilka lake.

The Islands
India has two island groups, namely Andaman and Nicobar Islands and Lakshadweep.

Lakshadweep Islands
  1. It consists of small coral islands. It lies near Malabar coast.
  2. It was earlier known as the Laccadive, Minicoy and Amindive Islands group.
  3. However, the Government of India renamed the region as Lakshadweep in 1973.
  4. Karavatti is the capital city of the Lakshadweep.
  5. It is one of the great biodiversity hotspots and known for its flora and fauna.

Andaman and Nicobar Islands

  1. Andaman and Nicobar Islands are located in the Bay of Bengal and thought to be part of submerged Arakan Mountain range.
  2. It is divided into two groups - Andaman Islands (North) and Nicobar Islands (South).
  3. These Islands are of great strategic importance for India.
  4. The only active volcano in India, the Barren Island, lies here.