In India, of the total land mass, Plains : 43.3%, Plateaus : 27.7%, Hills : 18.6%, Mountains: 10.4%.
Physiographic Regions in India can be broadly classified into
1. Northern mountains.
2. Great plains.
3. Deccan plateau
4. Coastal plains and Islands.
On the basis of physical features, India can also be divided into following six divisions:
- The Northern mountains
- The Northern Plains
- The Peninsular Plateau
- The Indian Desert
- The Coastal Plains
- The Islands.
The Northern Mountain
The Himalayan Mountain ranges were formed by the sediment collected on the bed of the Tethys Sea for millions of years. The sediments might have been derived from the two stable land masses—Angara land to the north and peninsular landmass to the south.
Geologists believe that the lateral force came from the northern Angaraland, and the sedimentary strata resting on the Tethys floor were tightly squeezed against the southern rigid mass of peninsular India, commonly known as Gondwanaland.
As a result, the Himalayas originated as folded mountains. The Himalayas follow a general west to east direction exactly in conformity with the alignment of the Tethys Sea. The other mountains like Aravalli, Rajmahal and Meghalaya originated from the Gondwanaland, and are situated approximately in the north-south direction.
The Himalayas are one of the most young folded mountain ranges in the world. One of several major evidences is the occurrence of the sediments of Lake Kashmir at heights of 1500 to 1800 metres near the Pir Panjal range.
The Pamir, popularly known as the Roof of the World, is the connecting link between the Himalayas and the high range of Central Asia.
It is divided into three groups. They are :
(i) The Himalayas
(ii) The Trans Himalayas
(iii) The Eastern or Puranchal hills.
Himalayas are the young fold mountains. This is the highest mountain range of the world. Himalayas act as natural barrier. The extreme cold, snow and rugged topography discourage the neighbors to enter India through Himalayas. They run from west-east direction from Indus to Brahmaputra along the northern boundary of India.
The Himalayas may be divided into three parallel ranges:
(a) Greater Himalayas or Himadari
(b) Lesser Himalayas or Himachal
(c) Outer Himalayas or Siwaliks.
(a) The Greater Himalayas or Himadari:
- The Greater Himalayas comprises of the northern most ranges and peaks.
- It has an average height of 6000 metres and width lies between 120 to 190 Kms .
- It is the most continuous range. It is snow bound and many glaciers descend from this range.
- It has high peaks like Everest (8848 metres), Kanchanjunga (8598 metres), Dhawalgiri (8126 metres), Nanga Parbat (8125 metres), Nanda Devi (7817 metres) and Namcha Barwa (7756 metres) etc.
- Mt. Everest (8848 m) is the highest peak of the world and K2 or Godwin Austin is the highest peak in India. Kanchenjunga is the highest peak of Himalayas in India.
- High Mountain passes also exist in this range, namely, Bara Lacha-La, Shipki-La, Nathu-La, Zoji-La, Bomidi-La etc.
- Indus, Brahmaputra and Alaknanda rivers (Antecedent Rivers) have made antecedent valleys y passing through this range.
- The Ganga and Yamuna rivers originate from the middle of this Himalayas.
(b) The Lesser Himalayas or Himachal:
- The altitude of this range lies between 1000 and 4500 metres and the average width is 80 to 100 km.
- The Prominent ranges in this are Pir Panjal, Dhaula Dhar, Nag Tibba and Mahabharata ranges.
- Kashmir Valley, Lahul & Spiti, Kullu and Kathmandu Valley etc. have developed between the Great Himalayas and the Lesser Himalayas.
- It compresses of many famous hill stations like Shimla, Dalhousie Darjeeling, Chakrata, Mussoorie, Nanital, Ranikhet etc.
- It also comprises of famous valleys like Kashmir, Kullu, Kangra etc.
(c) The Outer Himalayas or the Siwaliks:
- It is the outer most range of the Himalayas.
- The altitude varies between 600-1500 meters and the width lies between 10-50 KM.
- They have low hills like Jammu Hills, etc.
- The valleys lying between Siwalik and Lesser Himalayas (Himachal) are called ‘Duns’ like Dehra Dun, Kotli Dun and Patli Dun in West and Duar like Haridwar in East.
The Trans-Himalayan ranges
- It extends north of greater Himalaya and parallel to it.
- It has Karakoram, Ladakh, Zaskar and Kailash mountain ranges. North of Zaskar range lies Ladakh range.
- The Indus river flows between Zaskar and Ladakh range. It creates the deepest gorge in India (5200m) by cutting Ladakh range at the place called Bunzi.
- The Karakoram range lie extreme north of the country. K2 is the second highest peak of the world and situated in Karakoram range.
The Eastern or Purvanchal hills
- It comprises Mishami, Patkoi, Naga, Mizo hills which are located in eastern side.
- The Meghalaya plateau is also part of these hills which includes the hills of Garo, Khasi and Jaintia.