Class 9 Geography

The Himalayan Mountains

The Himalayas are the youngest mountains in the world and are, structurally, the folded mountains. The Himalayas run along the northern border of India. The Himalayas form an arc which is about 2,400 km long. The width varies from 400 km in Kashmir to 150 km in Arunachal Pradesh. The altitudinal variations are greater in the eastern part than in the western part. There are three parallel ranges in its longitudinal extent.

The Great or Inner Himalayas:

This is the northernmost range and is also known as Himadri. This is the most continuous range. It contains the loftiest peaks. The average height of peaks in this range is 6,000 metres. All the prominent Himalayan peaks are in this range. The folds of the Great Himalayas are asymmetrical in nature and the core of this part is composed of granite. Because of the lofty heights, the peaks of this range are perennially snow-bound, i.e. they remain snow-capped throughout the year.

Himalya Himachal Shivalik

The Lesser Himalaya or Himachal:

This lies towards the south of the Great Himalayas. The altitude of peaks in this range varies from 3,700 m to 4,500 m. Average width of this range is 50 km. This range is mainly composed of highly compressed and altered rocks.

The Shiwaliks:

This is the outermost range of the Himalayas. The altitude varies between 900 and 1100 km in this range and the width varies between 10 to 50 km. These ranges are composed of unconsolidated sediments. The longitudinal valleys lying between the Himachal and Shiwaliks are called ‘Dun’.

PeakCountryHeigh (in m)
Mt. EverestNepal8848
Nanga ParbatIndia8126
Nanda DeviIndia7817
Namcha BarwaIndia7756
Gurla MandhataNepal7728

Himalayan Regions from East to West

  1. Punjab Himalayas: This part lies between the Indus and Sutlej. From west to east, this is also known as Kashmir Himalaya and Himachal Himalaya; respectively.
  2. Kumaon Himalayas: This part lies between Sutlej and Kali rivers.
  3. Nepal Himalayas: This part lies between the Kali and Tista rivers.
  4. Assam Himalayas: This part lies between the Tista and Dihang rivers.

Eastern Hills and Mountains: The Brahmaputra marks the eastern border of the Himalayas. Beyond the Dihang gorge, the Himalayas bend sharply towards south and form the Eastern hills or Purvachal. These hills run through the north eastern states of India. They are mostly composed of sandstones. These hills are composed of the Patkai Hills, Naga Hills, Manipuri Hills and Mizo Hills.