Indian Physical Geography Notes

Origin and Evolution of Himalayas

Origin of Himalayas

1. Tectonic Setting (Pre Collision)
   • Around 200 million years ago the Indian plate was part of super continent, located near the southern edge of ancient Tethys sea.
   • During Jurassic period, about 150 million years ago Gondwana began to break apart and the Indian plate started drifting northward about 100 million years ago.
   • The Tethys ocean was subducting beneath the southern margin of Eurasian plate.
2. Initial Collision (50 to 55 million years ago)
   • Around 50 to 55 million years ago early Eocene, Indian plate collided with Eurasian plate, marking the onset of Himalayan orogeny.
   • Tethys ocean close as the continental crust of Indian plate began to push against Eurasian plate, initiating the uplift of proto Himalayas.
   • The collision was not abrupt, it involved the scraping of oceanic sediments and volcanic rocks, forming the initial Himalayan foot hills.
3. Evolution of Himalayas
   • Early Phase (50 to 30 million years ago) The collision caused intense folding due to abduction process, formation of Indo-Tsangpo-Suture Zone, formation of greater Himalaya.
   • Middle Phase (30 to 10 million years ago) Formation of main central thrust to the south of greater Himalayas, upliftment of middle Himalayas. South to middle Himalayas main boundary thrust was formed.
   • Late Phase (10 million years ago to present) Formation of Shivalik and formation of Himalayan frontal fault between Shivalik and plains.

Latitudinal Division of Northern Himalayas

1. Trans Himalayas
2. The Himalayas

Trans Himalayas

1. Karakoram Range It is about 500 km long. Its highest peak is K2/ Godwin Austin (second highest peak of the world.) K2 is highest peak of India.
2. Ladakh Range It extends south of Karakulam. It is smallest among all.
3. Zanskar Range It extends south of Ladakh; between Ladakh and Zanskar, Indus river flows. It is about 300km long.

The Himalayas

1. Greater Himalayas
   • Its average altitude is greater than 6000m.
   • Its highest peak is Mt. Everest in Nepal followed by Kanchenjunga in Sikkim i.e. highest peak of Himalaya in India, 8586m. Makalu and Annapurna are other important peaks.
   • It extends about 2400km between Pakistan, India, China, Nepal and Bhutan.
   • Greater Himalaya have old lake deposit which are found at high altitude. These are locally called Karewa. This Karewa soil is used for saffron cultivation.
   • Greater Himalayas is abode of glaciers from where numerous river originates e.g. Gangotri, Yamunotri, and Pindari, etc.
2. Middle Himalayas
   • Middle Himalayas are also known as Lesser Himalayas.
   • It extends south to Greater Himalayas.
   • It is divided into number of ranges, valleys, located between middle of Greater Himalayas include Kashmir valley and Kathmandu valley.
   • The ranges of Middle Himalaya include
     1. Pir Punjab Range
        • It separate Jammu from Kashmir.
        • It paved way to National Highway 44, newly constructed railways, Mata Vaishno Devi and Patnitop hill station.
     2. Dhauladhar Range
        • It is in Himachal Pradesh.
        • It is famous for hill station and apple cultivation.
     3. Nag Tibba Hills
        • Nag Tibba range is famous for its scenic beauty and tracking enthusiast.
     4. Missouri Hills
        • It is Uttarakhand.
        • It is called Queen of hills because of presence of beautiful hill stations.
     5. Mahabharat Range
        • It extends mainly in Nepal. Kathmandu valley lie between Mahabharat range and Greater Himalaya.
     6. Dafla Hills, Miri Hills, Abor Hills and Mishmi Hills
        • These are known of Middle Himalaya in Arunachal Pradesh.
3. Shivalik Hills
   • It is youngest among all three ranges.
   • The valleys between Himalaya and Shivalik are called Duns in the west e.g. Dehradun, Paatlidun and Dwar in the east e.g. Haridwar, Kotdwar, etc.
   • Shivalik also divided into multiple ranges like
     • Jammu Hills- Jammu
     • Dudhwa Hills- Uttar Pradesh
     • Churia Hills - Nepal India (Uttar Pradesh) border
     • Someshwar Hills - Nepal, India (Bihar) border

Longitudinal Division of Northern Himalayas

1. Kashmir Himalayas
   • It is also called Punjab Himalaya.
   • It extends between Indus river in the west to Satluj river in the east.
   • It include Greater Himalaya of Jammu and Kashmir, Himachal, Vir Punjab Range and Dhauladhar range and the Jammu hills of Shivalik.
   • It is origin point of numerous rivers including Chenab, Ravi, Vyas and Jhelum.
2. Kumaon Himalayas
   • It extends between Satluj river in the west to Kali river in the east.
   • It includes Greater Himalaya, Nag Tibba hills and Missouri Hills.
   • It is world famous for its hill stations and glaciers like Gangotri, Yamunotri and Milan, Gaumukh glacier.
   • Ganga, Yamuna and Alaknanda originates from here.
3. Nepal Himalayas
   • It is longest Himalayas.
   • It extends between Kali river in west to Teesta river in east.
   • It contains money highest peak including Mt. Everest and Kanchenjunga.
   • It has Kathmandu valley and Pokhara valley.
   • Various river pass through this like Ghagra, Gandak, and Kosi.
4. Assam Himalayas
   • It is second longest.
   • It is famous for its biological hotspot status.
   • It extends from Teesta to Brahmaputra river.

Important Passes in Himalayas