Origin and Divisions of the Himalayas

The Himalaya (from Sanskrit "abode of snow") is the highest and youngest mountain system in the world. It guards India's north and shapes its climate, rivers and culture.

Facts at a glance

• Length: about 2,400 km from the Indus gorge (Nanga Parbat) in the west to the Brahmaputra gorge (Namcha Barwa) in the east.
• Width: 400 km in Kashmir to about 150 km in Arunachal Pradesh.
• Height: greater in the east than in the west when measured by peaks.
• Arc: curved (like a bow) with convex side toward India.
• Type: young fold mountains formed in the collision of the Indian and Eurasian plates.

Longitudinal divisions (north to south)

Trans-Himalaya (Tibetan Himalaya)

• Lies north of the Great Himalaya; about 40 km wide, extending 1,000 km.
• Includes the Karakoram Range (K2), Ladakh Range and Zanskar Range.
• Cold, dry, rain-shadow desert; sparse vegetation; Pangong, Tso Moriri lakes.
• Karakoram: K2 (Godwin Austen), 8,611 m, second highest peak in the world, in the area of Gilgit-Baltistan that India claims; Siachen glacier; Karakoram Pass 5,540 m.

Greater Himalaya (Himadri)

• Continuous, 6,000 m average, with peaks above 8,000 m: Mt Everest (8,848 m, Nepal-China), Kangchenjunga (8,586 m, India-Nepal, highest in India), Makalu, Dhaulagiri, Nanga Parbat (8,126 m), Annapurna.
• Core of granite and gneiss; glaciers such as Gangotri, Yamunotri.
• Rivers cross it in deep gorges (antecedent drainage): Indus, Sutlej, Alaknanda, Kosi, Brahmaputra.

Lesser Himalaya (Himachal)

• Pir Panjal (longest and most important range of the Lesser Himalaya; lies in Jammu and Kashmir and Himachal), Dhauladhar, Nag Tibba, Mussoorie, Mahabharat (in Nepal).
• Hill stations Shimla, Mussoorie, Nainital, Darjeeling; valleys of Kashmir and Kathmandu.
• Broad valleys between ranges; Kashmir valley lies between Pir Panjal and Great Himalaya.

Outer Himalaya (Shiwalik)

• Youngest of all: rocks are unconsolidated sand, gravel, clay washed down from the higher ranges.
• Longitudinal valleys called Duns (Dehradun, Kotli Dun, Patli Dun) in the west and Duars in the east (West Bengal, Assam).
• Gaps in the Shiwalik ridge are called Duns/Doon; Chandigarh and Jammu lie at the foot of the Shiwaliks.

Regional divisions (Sidney Burrard)

The Himalaya is also divided west to east by the river valleys between them.

Eastern hills (Purvanchal)

South of the Brahmaputra bend, the Himalaya turns south and spreads into the Purvanchal hills along the India-Myanmar border: Patkai Bum, Naga Hills, Manipur Hills, Mizo (Lushai) Hills. They are made of sandstone and are lower than the Himalaya.

• Patkai Bum (Arunachal-Myanmar), Dapha Bum (4,578 m highest of the Patkai range), Saramati (3,841 m, Nagaland, highest in Nagaland), Japfu, Phawngpui / Blue Mountain (2,157 m, Mizoram).
• Garo, Khasi, Jaintia hills belong to the Peninsular block (Meghalaya Plateau), not to the Himalaya.

Western vs eastern Himalaya