Physical Features of India

Major Physiographic Divisions

The Physical Features of India can be classified into the Himalayan Mountains, The Northern Plains, The Peninsular Plateau, The Indian Desert, The Coastal Plains and The Islands are physiographic divisions. 

1. The Himalayan Mountains

• Himalayan Mountains are Fold Mountains and these are geologically young Mountains. These folded mountains stretch over the Northern borders of India.
• Himalayan mountains stretch from the West to the East direction starting Indus River in the West and Ending at the Brahmaputra River in the East.
• The Himalayan Mountains are the most rugged mountains in the world, they are 400 km thick (Width) in Kashmir and 150 km in Arunachal Pradesh.
• Altitudinal Variations are greater in the east Himalayan mountains than in the west. The Himalayas consist of three parallel ranges in their Longitudinal extent.

The number of Valleys that lie in between these ranges

1. Northern Most range is called Great Himalayas or Himadri, This range will have the most prominent peaks of the Himalayas. The average height would be 6000 metres
2. South to Great or Himadri there’s a rugged mountain range which is called Himachal or Lesser Himalaya. The altitude varies between 3700 to 4500 metres

• Pir pandal range is the longest as well as Important
• Dhauladhar and Mahabharat ranges are also prominent ones
• This range consists of famous hill stations like Kulu Valley in Himachal Pradesh, Kashmir Valley and Kangra Valley

3. The Outer Himalayas consist of Shiwaliks- They are of width 10-50km and 900 to 1000 metres altitude. These ranges consist of the Sediments brought by the rivers from the main Himalayan ranges which are farther north

• Valleys between Lesser Himalayas and Shiwaliks are called “Duns”-Dehradun, Kotli Dun, Patli Duns

Apart from Longitudinal variations Himalayas are divided according to the regions that are based from west to east. These rivers are demarcated by the river valleys

1. Punjab Himalayas-which lies between Indus and Sutlej (also known as Kashmir and Himachal Locally from west to east)
2. Kumaon Himalayas-which lies between Sutlej and Kali River
3. Nepali Himalayas- Which lies between Kali and Teesta river
4. Assam Himalayas – which lies between Teesta and Dihang river

The Brahmaputra marks the eastern boundary above Dihang Gorge. Beyond Dihang Gorge Himalayas bend to the south so they are called “Purvanchal”

Purvanchal Comprises of Patkai hills, Naga Hills, Manipur hills and Mizo Hills

2. The Northern Plain

• Northern Plains formed by three major river systems namely- Indus, Ganga and Brahmaputra and their tributaries.
• This plain is formed of alluvial soil; these depositions are of huge amounts which lay foothills of the mountains. Spreads over 7 lakh Sq. Km and its hugely populated dense area.
• This part of India is an agriculturally productive area because of the adequate rains as well as fertile lands.
• Rivers coming from the northern side do a lot of depositional work which results slower in speed.
• Speed-slowed rivers form small lakes along their way out which are called riverine islands.
• The rivers in their lower course will split into numerous channels due to deposition and these are called Distributaries.

Northern Plain is divided into three Parts

1. Punjab Plains- The western part of the Northern plains is called the Punjab Plains, most of these are in Pakistan. These are formed by the Indus River and its tributaries
2. Ganga Plains-It extends between Ghaggar and Teesta rivers
3. Brahmaputra Plain-West Bengal to the east particularly in Assam

3. The Peninsular Plateau

           

Peninsular Consists of Old crystalline rocks, igneous rocks as well as metamorphic rocks. The Peninsular Plateau has formed breaking and drifting of Gondwana Land and becoming the oldest Landmass. The plateau has broad and rounded shallow valleys, this plateau consists of two broad divisions.

• Vindhyan range is bounded by the Satpura Range on the South and Aravalli to the Northwest
• The rivers flowing in this region are Chambal, Betwa, and Ken from southwest to Northeast
• Plateaus that present in this region are- Bundelkhand, baghelkand and chotanagpur

• Satpura range occupies a big chunk in the north and Kaimur hills and Maikal ranges are in the eastern part
• The Deccan Plateau is higher at the west and gentler at the eastern side and on the eastern side Karbi are angling Plateau, North Cachar hills and Meghalaya
• It’s separated by a valley called Chotanagpur Plateau
• Three prominent Hill ranges from West to east are Garo, Khasia, and Jhantia Hills

Deccan Trap-Peninsular plateau is filled with black soil and it’s a distinctive Feature. Volcanic eruptions have been denuded and eroded resulting in the formation of black soil this is called Deccan Trap.

Aravalli hills bordered the northwest margins of the peninsular plateau. 

• Telangana Plateau is Located in the north of river Krishna. It is a part of the Deccan Plateau. 
• Karnataka Plateau: Consists of iron ore, Babaduan hills and South to Deccan lava region. 
• Dandakaranya Plateau:  It is a part of Chattisgarh and Odisha. Largely inhabited by Gond tribes. Rocks of the Archean period and the Indravati and Mahanadi rivers flow through this region. 
• Shillong Plateau: Garo, Khasi and Jantia Hills. Mawsynram is located here-highest rainfall a rainfall-receiving area in the world. 

4.  The Indian Desert

The Indian desert lies towards the west of the Aravallis. This region receives very low rainfall below 150mm per year, streams appear in the rainy season and soon they disappear.  Barchans cover a Large Portion but Longitudinally dune covers more on the border of India and Pakistan. Luni is the Prominent river in this region. 

5. The Coastal Plains

The peninsular plateau is stretched with Coastal strips running alongside the Arabian River in the west and the Bay of Bengal in the east. 

• The western coast is in between the Arabian Sea and Western Ghats
• The northern part of the coast is called Konkan
• The Central Stretch is called Kannad plain
• The southern stretch is called Malabar Coast
• Plains along the Bay of Bengal are wide and level
• In the Northern part it is called Northern Circar
• The Southern Part is called the Coromandel coast
• Lakes-Chilika, Mahanadi, Godavari, Krishna and Kaveri

6. The Islands

The group of islands are Composed of Small coral islands, earlier they were known as Laccadive, mini clay and amending

• In 1970 they named it a Lakshadweep
• Karavatti is the administrative place for Lakshadweep
• These islands have rich varieties of flora and fauna
• The Pitti island is unhabituated but has a birding sanctuary

Islands located in the Bay of Bengal are called Andaman and Nicobar Islands. These are bigger and numerous

7. Important Points

• Coral polyps are short-lived microscopic organisms that secrete calcium carbonate and they live in colonies.
• Chilika Lake is the biggest saltwater lake in India and it lies in the state of Odisha to the south of the Mahanadi delta.
• Majuli is the largest inhabited riverine island in the world and it is in the Brahmaputra region. 
• Rivers after descending from mountains deposit pebbles in a narrow belt parallel to the slopes of Shiwaliks called Bhabar, all the streams disappear in the Bhabar belt.
• Streams and rivers re-emerged and formed a wet swampy marshland called Terai
• Alluvial soils are rich in the Northern plains these are called hangars. Younger deposits of floodplains are called Khadar. 
• Indus tributaries- Jhelum, Chenab, Ravi, Sutlej, Beas.