Formation of Himalayas
The Himalayas are believed to have formed over 50 million years ago with the collision of the Indian plate with the Eurasian plate. The Indian plate slid below the Eurasian plate, due to its density being higher, and in the process crumbling and buckling up the Eurasian plate into the various mountain ranges that are now a part of the Himalayas.
Ranges of Himalayas
The Himalayas are a series of parallel mountain ranges extending along the North-West to the South-East direction (known as the Strike of the Himalayas). These ranges are separated by longitudinal valleys. They include,
- The Greater Himalayas or Himadri
- The Lesser Himalayas or Himachal
- Shiwalik or the Outer Himalayas
- The Eastern Hills or Purvanchal
- They are made of the ocean sediments of the Tethys Sea which was consumed during the collision of Indian and Eurasian plate boundaries.
- They include the ranges of Karakoram, Ladakh, and Zanskar.
- Karakoram ranges have their one end originating from the Pamir Knot. Karakoram ranges hold the largest amounts of snow and ice among all of the Himalayan ranges. This is because they are situated in higher latitudes where the snow line (altitude above which there is permanent ice and snow cover).
- The Karakoram is home to some of the largest glaciers such as Siachen (the second longest glacier outside of Polar Regions), Biafo (longest glacier outside of Polar Regions), Baltoro, Hispar, Trango etc.
- They are home to some of the tallest peaks in the world such as Mt. K2/Godwin-Austin (8611m), Gasherbrum 1 (8080m), Broad Peak (8051m) etc.
- Karakoram ranges have gaps in them, which are known as passes. Important among them are – Khunjerab Pass, Karakoram Pass, Sia La Pass, and Bilafond La Pass (immediately west of the Siachen glacier) etc.
- Ladakh ranges are to the south-east of the Karakoram ranges. They separate the rivers Indus and Shyok (a tributary of Indus). Khardung La Pass (India’s highest motorable pass falls in these ranges). These ranges extend into China where they are known as the Kailash ranges. They include Mt. Kailash and Mansarovar Lake.
- Pangong Tso (largest saline lake between India and China) and Spanggur Tso are the two saltwater lakes situated in these ranges.
- To the south of the Ladakh, ranges are the Zanskar ranges, which are cut across by the Zanskar River. These ranges extend into Uttarakhand. They contain some prominent peaks like Mt. Kamet, Nanda Devi (a biosphere reserve) Kedarnath etc. Liphu Lekh Pass that leads to Mansarovar and Mt. Kailash forms a part of these ranges. Spiti Valley, Lahaul Valley, and Kinnaur Valley are also a part of these ranges.
- They extend for about 2400 km, making them one of the longest-running fold mountain ranges in the world.
- Of the 28 tallest peaks in the world (higher than 8000 m), 14 are situated in the Himadri.
- Everest, Mt. Kanchenjunga, Mt. Makalu etc. are a part of these ranges.
- Some of the important passes of these ranges include Zojila Pass (connects Srinagar with Leh), Shipki La Pass, Burzil Pass, Nathu La Pass etc.
- Important glaciers of these ranges include – Rongbuk glacier (largest in the Himadri), Gangotri, Zemu etc.
- They are separated from the lesser Himalayas by longitudinal valleys which are filled with sediments. These are called the Doons. Prominent Doons include Paatli Dun, Chaukamba Dun, Dehra Dun etc.
Lesser Himalayas or the Himachal
- They are divided into the Pir Panjal range and the Dhauladhar range
- Pir Panjal range is the longest range of the lesser Himalayas. It is cut across by the Jhelum river, Chenab river. Famous passes of this range include – Pir Panjal Pass, Banihal Pass (connects Jammu and Srinagar)
- Dhauladhar ranges are the extension of Pir Panjal into Himachal Pradesh. They are cut across by the river Ravi.
- Mussoorie ranges are also a part of the lesser Himalayas. They divide the waters of Sutlej and Ganga
- Also known as the outer Himalayas, they are known by different names in different places. For example, they are called Jammu hills in Jammu, Dudhwa ranges in Uttarakhand, Darjeeling hills in West Bengal etc.
- River Teesta cuts across these ranges in Sikkim.
- Beyond Sikkim, these ranges merge with the lesser Himalayas.
Apart from these ranges, Himalayas are also divided on the basis of the regions in which they are found.
- Kashmir Himalayas – they comprise they trans Himalayan ranges of Karakoram, Ladakh, Zanskar and the Pir Panjal range of the lesser Himalayas. The cold desert of Ladakh lies in between the Greater Himalayas and the Karakoram range. Kashmir Valley is located between the Greater Himalayas and the Pir Panjal range.
- Himachal and Uttarakhand Himalayas – they comprise the ranges between river Ravi in the west and river Kali in the east. It is drained by the Indus and the Ganga river systems.
- Darjeeling and Sikkim Himalayas – they are situated between rivers Kali and Teesta.
- Arunachal Himalayas – they extend from the east of Bhutan Himalayas up to the Diphu pass in the east. Their orientation is from the southwest to the northeast direction, unlike the earlier ranges of the Himalayas. Some important rivers crossing these ranges include – Kameng, Subansiri, Dihang, Dibang, Lohit etc. Prominent hills of these ranges include the Dafla hills, Abor Hills, Mishmi hills etc. which are named after the ethnic communities residing in these hills.
- Eastern Hills – They are aligned from the north to the south. They include the ranges of Patkai Bum, Naga hills, Manipur hills, Mizo/Lushai hills.
- The collision between the Indian and Eurasian plate first happened on the Northwest corner. This resulted in a general Northwest to Southeast orientation to the Himalayas.
- There are U-shaped bends in the Himalayan ranges at the northwest and southeast corners which are known as the Syntaxial bends.
- The southern slopes of Himalayas (on the Indian side) are much steeper than the northern slopes (on the Chinese/Tibetan side).
- Karewa – these are the glacial deposits comprising clay and rocks. They are found in the Kashmir Himalayas and are useful for the cultivation of Zafron (a local variety of saffron)
- Meandering Jhelum – meanders of a river are usually found in the plains with soft strata. But Jhelum is found meandering in the Kashmir Valley because of the base provided by an erstwhile larger lake. The Dal Lake in Kashmir is a remnant of the erstwhile lake.
- Duns – longitudinal valleys which the Himadri and the Himachal ranges. They are filled with the deposits of rivers flowing down from the Himalayan ranges.
- Bugyals – summer grasslands found in the upper reached of the Himalayas. They are used by the nomadic groups to herd their cattle in summers. The Valley of Flowers is a part of such grasslands, found in the Uttarakhand Himalayas
- Darjeeling Himalayas are known for their Tea plantations, which came up because of their moderate slope, thick soil cover with good organic content and rainfall which is distributed throughout the year.
- The Eastern hills are inhabited by tribal groups who practice Jhum cultivation.
- Loktak lake – situated in Manipur, is surrounded by hills on all sides. It contains the only floating national park in the world viz., Keibul Lamjao National Park.