Formation of Himalayas and Indo-Gangetic Plain

Formation of Himalayas

• The Himalayas were formed around 150 million years ago due to the collision of the Indian Plate with the Eurasian Plate.
• The Indian Plate, once part of Gondwanaland, moved northward.
• The collision caused the sediments deposited in the Tethys Sea to compress, leading to the formation of the Himalayas and the Indo-Gangetic-Brahmaputra trough.
• The Indian Plate’s subduction beneath the Eurasian Plate also led to the formation of features such as the Indus-Tsangpo Suture Zone and the Main Central Thrust.

Formation of the Indo-Gangetic-Brahmaputra Plain

• The rise of the Himalayas and the subsequent formation of glaciers led to the formation of new rivers.
• These rivers deposited large amounts of alluvium, filling the depression and creating the Indo-Gangetic-Brahmaputra Plain.

Lesser Himalayas (Middle Himalayas)

• The Lesser Himalayas lie between the Greater Himalayas in the north and the Siwaliks in the south, running parallel to both ranges.
• They have an elevation ranging from 3,500 to 4,500 meters above sea level.
• Many peaks within this range surpass 5,050 meters and remain snow-covered throughout the year.
• The Lesser Himalayas are more accessible for human interaction, with famous hill resorts like Shimla, Mussoorie, Ranikhet, Nainital, Almora, and Darjeeling located in this region.
• This region consists of famous valleys such as Kashmir, Kangra, Kullu, Katmandu, and Pokhara.

Important Ranges of the Lesser Himalayas

• The Pir Panjal Range, stretching from the Jhelum River to the upper Beas River, is the most significant range in the Lesser Himalayas.
• The Dhauladhar Range is located in Himachal Pradesh.
• The Mussoorie Range and the Nag Tibba Range are located in Uttarakhand.
• The Mahabharat Lekh is situated in Nepal.
• The Dafla, Miri, Abor, and Mishmi hills are found in Arunachal Pradesh.

Formation of Duns (Duars/Dooars)

• The Shiwalik Hills were formed by the accumulation and deposition of conglomerates brought down by rivers.
• These conglomerates obstructed and changed the river courses, forming temporary lakes.
• Over time, the lakes gathered more conglomerates and filled in, leaving behind plains known as duns or doons in the west and duars in the east.

Duars

• The duars are located at the foothills of the eastern Himalayas in Northeast India around Bhutan.
• They are like passes in the Eastern Himalayas near Bhutan.
• The Western duars are located in northern West Bengal and are a portion of the Terai.

Purvanchal (Eastern Hills)

• The Purvanchal is a series of relatively low hills, southward extensions of the Himalayas that run along the northeastern edge of India.
• They exhibit a convex shape to the west and extend from Arunachal Pradesh in the north to Mizoram in the south.
• Most rivers in Nagaland are tributaries of the Brahmaputra River.
• Rivers in Mizoram and Manipur are tributaries of the Barak River, which is itself a tributary of the Meghna River.
• The rivers in the eastern part of Manipur are tributaries of the Chindwin, which is a tributary of the Irrawaddy in Myanmar.
• Manipur has a unique physiography due to the presence of Loktak Lake in the center, surrounded by mountains.
• Meghalaya Plateau, technically a part of the Deccan Peninsula, was separated from the peninsular rock base by the Garo-Rajmahal gap.
• The region has the Garo, Khasi, Jaintia, and Mikir (Rengma) hills.

Regional Hills of the Purvanchal

• The regional hills in the Purvanchal are separated by numerous small rivers.
• The hills are inhabited by numerous tribal groups practicing Jhum cultivation.

Patkai Bum and Naga Hills

• The Patkai Bum hills, composed of sandstone, have elevations ranging from 2,000 to 3,000 meters.
• These hills merge into the Naga Hills, where Saramati (3,826 m) is the highest peak.
• The Patkai Bum and Naga Hills form the watershed between India and Myanmar.

Manipur Hills

• The Manipur hills are located south of the Naga Hills, with elevations generally below 2,500 meters.
• The Barail Range separates the Naga Hills and Manipur Hills.

Mizo (Lushai) Hills

• The Mizo Hills, with elevations of less than 1,500 meters, are located south of the Manipur Hills.
• The highest point is Blue Mountain (2,157 m) in the south.

Highest Peaks in Northeastern States

• Arunachal Pradesh: Kangto
• Nagaland: Saramati (3,841 m)
• Manipur: Mt. Tempu (Esii/ISO)
• Mizoram: Blue Mountain (2,157 m)
• Tripura: Betling Sib (Betlingchip)

Regional Division of Himalayas

• The Western Himalayas include the Himalayan region from the Indus in the west to the Kali River in the east.
• The region is distributed across three states: Jammu and Kashmir and Ladakh, Himachal Pradesh, and Uttarakhand.

Punjab Himalayas

• The Punjab Himalayas include the region between the Indus and Sutlej rivers.
• Predominantly located in Jammu and Kashmir and Himachal Pradesh, it is known as the Kashmir and Himachal Himalayas.
• Major ranges in this section include the Karakoram, Ladakh, Pir Panjal, Zaskar, and Dhauladhar.

Eastern Section vs. Western Section of the Himalayas

• The eastern section of the Himalayas rises abruptly from the plains of Bengal and Oudh, attaining great elevations within a short distance.
• The western Himalayas rise gradually from the plains through a series of ranges.

Important Peaks and their Location

• Namcha Barwa is located at the easternmost edge of the Himalayas in Arunachal Pradesh.
• Nanda Devi, the second-highest peak in India, is located in the Kumaon Himalayas within Uttarakhand.
• The Nokrek Peak is situated in the Tura Range of Meghalaya Plateau.
• The Garhwal Himalayas and Kumaon Himalayas are both located in Uttarakhand.

Specific Information

• Dehra Dun, the largest dun, has an approximate length of 35-45 km and a width of 22-25 km.
• Mount Everest is known as Sagarmatha in Nepal and Qomolangma in China (Tibet).