Give a detailed description of the Himalayan Mountains.
- Over the northern borders of India a chain of young fold mountains extends which is known as the Himalayas. These mountain ranges run in a west-east direction from the Indus to the Brahmaputra. The Himalayas represent the loftiest and one of the most rugged mountain barriers of the world. They form an arc, which covers the distance of about 2,400 km. Their width varies from 400 km in Kashmir to 150 km in Arunachal Pradesh. The altitudinal variations are greatest in the eastern half than those in the western half. The Himalaya consists of three parallel ranges in its longitudinal extent. A number of valleys lie between these ranges :-
- 1. The northernmost range is known as the Great or Inner Himalayas or the 'Himadri'. It is the most continuous range consisting of the loftiest peaks with an average height of 6,000 meters. It contains all the major Himalayan peaks.
- (ii) The range lying to the south of the Himadri forms the most rugged mountain system and is known as Himachal or lesser Himalaya. The ranges are mainly composed of highly compressed and altered rocks. The altitude varies between 3,700 and 4,500 meters and the average width is of 50 km. While the Pir Panjal range forms the longest and the most important range, the Dhaula Dhar and the Mahabharat ranges are also important. This range consists of the famous valley of Kashmir, the Kangra and Kullu Valley in Himachal Pradesh.
- (iii) The outermost range of the Himalayas is called the Shiwaliks. They extend over a width of 10-50 km and have an altitude varying between 900 and 1100 meters. These ranges are composed of unconsolidated sediments brought down by rivers from the main Himalayan range located farther north. These valleys are covered with thick gravel and alluvium.