Major Physical Divisions of India

1. The Himalayan Mountains
2. The Northern Plains
3. The Peninsular Plateau
4. The Indian Desert
5. The Coastal Plains
6. The Islands

• Himalayas:
  • Includes Himalayas, Purvanchal, Arakan Yoma (Myanmar), Andaman and Nicobar Islands (considered as islands only).
  • Youngest and highly unstable landmass.
  • Prone to tectonic movements.
• Indo-Gangetic Plain:
  • Between Peninsular and Himalayan region.
  • Most youthful and monotonous region.
  • Prone to tectonic forces.
• Peninsular Plateau:
  • Includes entire south India, central India, Aravalis, Rajmahal hills, Meghalaya plateau, Kuchchh-Kathiawar region (Gujarat) etc..
  • Oldest and most stable landmass.
• Great Indian desert:
  • Located in western part of India.
  • Dry, hot, and sandy stretch of land with very little vegetation.
• Coastal Plains:
  • Eastern and Western Coastal Plains.
  • Formed due to consolidation of sediments brought by rivers.
  • Highly stable like Peninsular Plateau.
• Indian Islands:
  • Two major groups – Lakshadweep and Andaman and Nicobar islands.
  • Lakshadweep are a group of atolls occupied by coral reefs with no significant volcanism or tectonic activity in recent past.
  • Andaman and Nicobar islands are a continuation of Arakan Yoma with active volcanoes and tectonically active.

Division of the Himalayas

1. Shiwaliks or outer Himalayas
2. Lesser or Middle Himalayas
3. The Greater Himalayas
4. The Trans-Himalayas – Tibetan Himalayas.
5. The Eastern Hills – Purvanchal: A chain of hills in North-East India.

• The Himalayan Ranges consist of several parallel or converging ranges
• The ranges are separated by deep valleys, creating a highly dissected topography
• The southern slopes have steep gradients, and the northern slopes have comparatively gentler slopes
• Most of the Himalayan ranges fall in India, Nepal, and Bhutan, with the northern slopes partly situated in Tibet (trans-Himalayas) and the western extremity lying in Pakistan, Afghanistan, and Central Asia
• The Himalayas between Tibet and the Ganga Plain is a succession of three parallel ranges
• The Shiwalik Range is also known as Outer Himalayas, located in between the Great Plains and Lesser Himalayas
• The altitude varies from 600 to 1500 meters, and it runs for a distance of 2,400 km from the Potwar Plateau to the Brahmaputra valley
• The southern slopes are steep while the northern slopes are gentle, and the width of the Shiwaliks varies from 50 km in Himachal Pradesh to less than 15 km in Arunachal Pradesh
• They are an almost unbroken chain of low hills except for a gap of 80-90 km, which is occupied by the valley of the Tista River and Raidak River
• Shiwalik range from North-East India up to Nepal are covered with thick forests but the forest cover decreases towards the west from Nepal
• The southern slopes of the Shiwalik range in Punjab and Himachal Pradesh are almost devoid of forest cover. These slopes are highly dissected by seasonal streams called Chos
• Valleys are part of synclines, and hills are part of anticlines or antisynclines.
• The Shiwaliks are known by different names in different areas
  • Jammu Region – Jammu Hills
  • Dafla, Miri, Abor and Mishmi Hills – Arunachal Pradesh
  • The Dhang Range, Dundwa Range – Uttarakhand
  • Churia Ghat Hills – Nepal
• Shiwalik Hills formed by the accumulation of conglomerates (sand, stone, silt, gravel, debris, etc.).
• Conglomerates obstructed the courses of rivers draining from the higher reaches of the Himalayas, forming temporary lakes.
• Temporary lakes accumulated more and more conglomerates, which settled at the bottom.
• When rivers cut their courses through lakes filled with conglomerate deposits, the lakes were drained away, leaving behind plains called ‘duns’ or ‘doons’ in the west and ‘duars’ in the east.
• Dehra Dun in Uttarakhand is the best example.
• Kotah, Patli Kothri, Chumbi, Kyarda, Chaukhamba, Udhampur, and Kotli are other important duns.

Middle or the Lesser Himalaya

• Location: Between the Shiwaliks in the south and the Greater Himalayas in the north
• Runs parallel to both ranges
• Also known as Himachal or Lower Himalaya
• Width: 60-80 km; Length: 2400 km
• Elevations: 3,500 to 4,500 m above sea level
• Snow-covered peaks with elevations of more than 5,050 m
• Steep, bare southern slopes and forest-covered northern slopes
• Middle Himalayas marked by Mussoorie and Nag Tibba ranges in Uttarakhand
• Mahabharat Lekh in southern Nepal is a continuation of Mussoorie Range
• Lower Himalayas represented by Sapt Kosi, Sikkim, Bhutan, Miri, Abor, and Mishmi hills east of Kosi River
• Middle Himalayan ranges more friendly to human contact
• Popular Himalayan hill resorts like Shimla, Mussoorie, Ranikhet, Nainital, Almora, and Darjeeling located here.

• Important ranges of Lesser Himalayas Region
  • The Pir Panjal Range – Jammu and Kashmir (They are to the south of Kashmir Valley)
  • The Dhaola Dhar Range – Himachal Pradesh
  • The Mussoorie Range and The Nag Tiba Range – Uttarakhand
  • Mahabharat Lekh – Nepal
• 
• Important Valleys:
• Kashmir Valley:
  • Location: Between Pir Panjal and Zaskar Range of the main Himalayas
  • Synclinal basin with alluvial, lacustrine, fluvial, and glacial deposits
  • Jehlum River meanders through and cuts a deep gorge in Pir Panjal
  • Few outlets
• Kangra Valley:
  • Location: Himachal Pradesh
  • Strike valley
  • Extends from the foot of the Dhaola Dhar Range to the south of Beas
• Kulu Valley:
  • Location: Upper course of the Ravi
  • Transverse valley

The Great Himalaya

• Name: Trans-Himalayan Range
• Also known as Inner Himalaya, Central Himalaya, or Himadri
• Average elevation: 6,100 m above sea level
• Average width: About 25 km
• Composition: Mainly formed of central crystallines (granites and gneisses) overlain by metamorphosed sediments (limestone)
• Folds in this range are asymmetrical with a steep south slope and gentle north slope, giving “hogback” topography
• Mountain arc convexes to the south like the other two Himalayan ranges
• Terminates abruptly at the syntaxial bends: One in Nanga Parbat in northwest and the other in Namcha Barwa in northeast
• Boasts tallest peaks in the world, most of which remain under perpetual snow
• Sagarmatha (The Goddess of the Sky) – Nepal
• Chomlungma (Mother of the World) – China (Tibet)

• Passes in the Greater Himalayas:
  • Jammu and Kashmir – Burzil Pass; Zoji La [La means pass]
  • Himachal Pradesh – Bara Lacha La; Shipki La
  • Uttarakhand – Thaga La; Niti Pass; Lipu Lekh
  • Sikkim – Nathu La; Jelep La

The Trans Himalayas

• The Trans-Himalayan Ranges lie immediately north of the Great Himalayan range.
• Also called the Tibetan Himalaya because most of it lies in Tibet.
• The Zaskar, the Ladakh, the Kailas and the Karakoram are the main ranges.
• It stretches for a distance of about 1,000 km in the east-west direction.
• The average elevation is 3000 m above mean sea level.
• The average width of this region is 40 km at the extremities and about 225 km in the central part.
• The Nanga Parbat (8126 m) is an important range which is in The Zaskar Range.
• North of the Zaskar Range and running parallel to it is the Ladakh Range.
• The Kailas Range (Gangdise in Chinese) in western Tibet is an offshoot of the Ladakh Range. The highest peak is Mount Kailas (6714 m).
• River Indus originates from the northern slopes of the Kailas range.
• The northernmost range of the Trans-Himalayan Ranges in India is the Great Karakoram Range also known as the Krishnagiri range.
• Karakoram Range extends eastwards from the Pamir for about 800 km.
• It is a range with lofty peaks [elevation 5,500 m and above].
• It is the abode of some of the greatest glaciers of the world outside the polar regions.
• Some of the peaks are more than 8,000 meters above sea level.
• K2 (8,611 m)[Godwin Austen or Qogir] is the second highest peak in the world and the highest peak in the Indian Union.
• The Ladakh Plateau lies to the north-east of the Karakoram Range.
• It has been dissected into a number of plains and mountains {Soda Plains, Aksai Chin, Lingzi Tang, Depsang Plains, and Chang Chenmo}.

Purvanchal or Eastern Hills

• Eastern Hills or The Purvanchals are southward extensions of the Himalayas in the northeast of India.
• The Purvanchal hills run along the India-Myanmar Border from Arunachal Pradesh to Mizoram.
• They are convex to the west and have a comparatively low elevation.
• Patkai Bum hills made up of strong sandstone; elevation varying from 2,000 m to 3,000 m; merges into Naga Hills where Saramati (3,826 m) is the highest peak.
• Patkai Bum and Naga Hills form the watershed between India and Myanmar.
• South of Naga Hills are the Manipur hills, which are generally less than 2,500 meters in elevation.
• The Barail range separates Naga Hills from Manipur Hills.
• Further south, the Barail Range swings to the west into Jaintia, Khasi, and Garo hills, which are an eastward continuation of the Indian peninsular block.
• Jaintia, Khasi, and Garo hills are separated from the main block by Ganga and Brahmaputra rivers.
• South of the Manipur Hills is the Mizo Hills (previously known as the Lushai hills), which have an elevation of less than 1,500 meters.
• The highest point in the Mizo Hills is the Blue Mountain (2,157 m) in the south.
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