The Himalayas Important Topic For UPSC Mains
Indian states involved:
Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim, Arunachal Pradesh, Nagaland, Manipur, Mizoram, West Bengal
- The Geosynclinal Origin:
- The disintegration of Pangaea led to the formation of a long Tethys Sea between the Lauratian Sheild of the north and the Gondwana land of the south.
- This swa was occupying the region of the Himalayas during the Mesozoic Era.
- At the end of the palaeozoic and beginning of the Mesozoic era, the Tethys almost girdled the whole Earth running from Europe in the west to China in the east.
- Erodedmaterial from thr two land masses was deposited in the Tethys Sea and assumed considerable thickness due to the sinking nature of the sea bed.
- During the cretaceous period, the bed of sea started rising which led to the folding of three successive ranges of Himalayas.
- The Plate Tectonic Origin:
- This is based in the concept of Sea Floor Spreading.
- According to this theory, about 70m years ago, there was an extensive geosynclines called Tethys, in place of Himalayas.
- The Indian plate came very close to the subducting under the Asian plate.
- This caused lateral compression due to which the sediments of the Tethys were squeezed and folded into three parallet rangesof Himalayas.
- Since the northward movement of the Indian plate is still continuing, the height if the Himalayan peak is increasing.
- The Indian plate is moving northward and the centre of rotation is constantly changing.
Classification of Himalayas:
It can be classified as:
Longitudinal classification of Himalayas:
- The Trans-Himalayas
- The Greater Himalayas
- The Lesser Himalayas
- The Outer Himalayas
The Trans Himalayas:
- Average width of the region is 40kms at the eastern and western extreams and 222kms in the central part.
- Region of lofty peaks and vast glaciers.
- Rocks of this region contain the fossils bearing marine sediments which are underlain by Tertiary Granite.
The Greater Himalayas:
- Also known as Himadri/Inner or Central Himalayas.
- 25kms wide with an average height of above 6100m
- Contains almost all the lofty peaks like Mt.Everest, Kanchanjunga, Nanga Parbat etc.
- Few Gaps mainly provided by antecedent rivers.
- Less rainfall
- Being lofty, they have very little forest area.
The Lesser Himalayas:
- Also known as Middle Himalayas
- Width is aboiut 80km with an average height of 1300-4600m.
- Consists of unfossiliferous sediments or metamorphosed crystalline.
- Main rocks are slate, limestone and quartzite.
- This region is subjected to extensive erosion due to heavy rainfall, deforestation and urbanization.
The Outer Himalayas:
- Also known as The Shiwaliks/Sub-Himalayas
- Extends from Jammu and Kashmir to Assam.
- 8kms in east to 45kms in the west.
- Average elevation of about 900-1500m above Sea level.
- Not a continuous range.
- Broader in the west and narrows down in the east.
- Several Doon areas.
Regional/Transverse Classification of Himalayas
- Kashmir Himalayas
- Himachal Himalayas
- U.P Himalayas
- Nepal Himalayas
- Darjeeling-Bhutan-Assam Himalayas
Passes through the mountain wall:
- The Khyabar
- Leadsfrom Peshawar to Kabul.
- Most famous of all the passes
- The Gomal
- South of Khyber Pass
- Served as a trade route passing through Waziristan(Pakistan)
- The Bolan
- Between Sulaiman and the Kirthar ranges
- Leads from Kandhar to Quetta
- In the very north, there are two difficult routes via the Karakoram Pass and the Z ozila Pass where there are roads communicating with Srinagar.
- Leads from Punjab to Tibet
- Bomdila Pass
- In Arunachal Pradesh
- Climatic Influence
- Source of Perennial Rivers
- Source of fertile soils
- Generation of Hydroelectricity
- Forest Wealth/Richness of Flora and Fauna