The Himalayan Mountains - Concepts - Chapter 2 Class 9 Geography - Physical Features of India - Geography

• They are geologically young and structurally fold mountains stretching over the northern borders of India.
• These mountain ranges run from west- east direction, from the Indus to Brahmaputra rivers.
• Himalayas represent the loftiest (of great heights) , most rugged mountain barriers of the world.
• They form an arc which covers a distance of about 2400 km. Their width varies from 400 km in Kashmir to 150 km in Arunachal Pradesh.

HIMALAYAN RANGES :

The 3 Himalayan Ranges

• The Himalayas consist of 3 parallel ranges in its longitudinal extent. A number of valleys lie between these ranges.
• Northern most range is called Great or Inner Himalayas or HIMADRI.
• Most continuous range consisting of the loftiest peaks with an average height of 6,000 metres.
• It contains all prominent Himalayan peaks.
• Folds of Great Himalayas are asymmetrical in nature. Core of this part of Himalayas is composed of granite.
• It is constantly covered with snow, and a lot of glaciers descend from this range.

• Range lying to the south of Himadri forms the most rugged mountain system called HIMACHAL or lesser Himalayas.
• The ranges are composed of highly compressed and altered rocks.
• Altitude varies between 3700 and 4500 metres and average width is of 50km.
• Longest and the most important range : Pir Panjal range.
• Most prominent ranges : Dhaula Dhar and Mahabharata range.
• This range consists of the famous Kashmir valley, Kangra and Kullu valleys in Himachal Pradesh.
• This region is well known for its hill stations.

• Outer most range of Himalayas is called the SHIWALIKS.
• They extend over a width of 10-50km and have an altitude varying between 900-1100 metres.
• These valleys are covered with thick gravel and alluvium.
• Longitudinal valley lying between lesser Himalaya and the Shiwaliks are known as DUNS.
• Dehra Dun, Kotli Dun, Patli Dun are some of the well known Duns.

Regional Himalayas :

• Besides longitudinal divisions, Himalayas have also been divided on the basis of regions from west to east. These divisions are marked by river valleys.
• Part of Himalayas lying between Indus and Satluj are called Punjab Himalaya, but regionally it is known as Kashmir and Himachal Himalaya from west to east respectively.
• Part of the Himalayas lying between Satluj and Kali rivers is known as Kumaon Himalayas.
• Kali and Teesta rivers mark the Nepal Himalayas and the part between Teesta and Dihang rivers is called Assam Himalayas.                   

Brahamaputra marks the eastern most boundary of Himalayas.

• Beyond the Dihang river, Himalayas bend sharply to the south and spread along the eastern boundary of India. They are known as the Purvanchal or Eastern Hills and mountains.
• These hills running through north eastern states are composed of strong sandstones, which are sedimentary rocks . Covered with dense forests, they mostly run as parallel ranges and valleys.
• Purvachal comprises the Patkai Hills, the Naga hills, the Manipur hills and the Mizo hills.