Ch – 2 Physical Features Of India (Part 1)

Important Notes:

  • India’s relief has been influenced by different geological periods and processes such as weathering, erosion and deposition.
  • According to the “Theory of Plate Tectonics“, the crust of the earth has been formed out of several major and some minor plates.
  • The movement of plates leads to folding, faulting and volcanic activities.
  • The plate movements are classified into three types: Convergent boundary (plates come towards each other), Divergent boundary (plates move away from each other) and Transform boundary (plates move horizontally past each other).
  • Most volcanoes and earthquakes in the world are located at the plate margins.
  • Gondwanaland is the southern part of the ancient super continent Pangea with Angara land in the northern part.
  • The Peninsula part of India was a part of Gondwanaland.
  • Gondwanaland included India, Australia, South Africa and South America as one single land mass.
  • Indo-Australian plate got separated from Gondwanaland because the convectional currents split the crust into a number of pieces.
  • After getting separated from Gondwanaland, the Indo-Australian plate drifted northwards.
  • During this drift, it collided with the Eurasian plate.
  • This collision resulted in the formation of Tethys which forms the mountain system of western Asia and Himalaya.
  • The Himalayan uplift from the Tethys Sea and subsidence of the northern flank of the peninsular plateau resulted in the formation of a large basin.
  • In due course of time this depression, gradually got filled with deposition of sediments by the rivers flowing from the mountains in the north and the peninsular plateau in the south.
  • A flat land of extensive alluvial deposits led to the formation of the northern plains of India.
  • The Peninsular Plateau of India is one of the oldest land masses on the earth’s surface.
  • The Himalayas and Northern Plains are the most recent landforms.
  • The Peninsular Plateau is composed of igneous and metamorphic rocks, while Northern Plains is made up of alluvial deposits.
  • The geographical features of India can be grouped as:
  • The Himalayan Mountains:
    • These mountain ranges run in a west-east direction from Indus to Brahmaputra.
    • They form an arc of distance of about 2,400 km.
    • Their width varies from 400 km in Kashmir to 150 km in Arunachal Pradesh.
    • It consists of three parallel ranges.
    • The northernmost range is known as the Great or Inner Himalayas or the Himadri. It contains all the prominent peaks. The core of these mountains is composed of granite.
    • The range lying south of Himadri forms the most rugged mountain system and is known as Himachal or lesser Himalaya. Its altitude varies between 3,700 and 4,500 metres. It consists the famous valleys of Kashmir, Kangra and Kullu in Himachal Pradesh.
    • The outer most range of Himalayas is known as Shiwaliks. Their altitude varies between 900 and 1,100 metres. The longitudinal valleys lying between lesser Himalayas and Shiwaliks are known as Duns. Eg: Dehra Dun, Patli Dun, etc.
    • The divisions of Himalayas are demarcated by river valleys.
    • The part of Himalayas lying between Satluj and Kali rivers is known as Kumaon Himalayas.
    • The part of Himalayas lying between Satluj and Indus are traditionally known as Punjab Himalaya and are regionally known as Kashmir and Himachal Himalaya.
    • The part of Himalayas lying between Tista and Dihang rivers is known as Assam Himalayas.
    • Beyond the Dihang gorge, the Himalayas bend sharply to the south and spread along the eastern boundary of India. They are known as Purvanchal or Eastern hills and mountains.
    • The Purvanchal comprises of Patkai hills, Naga hills, Manipur hills and Mizo hills.

Published by Priya Prakash

In the midst of winter, i found there was within me an invincible summer ~ Albert Camus

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