Major Physiographic Divisions of India

1. The Himalayan Mountains
   • Formation:
     • Formed by the collision of the Indian Plate with the Eurasian Plate, causing the uplift of sedimentary rocks.
     • Known as young fold mountains.
   • Characteristics:
     • Extend across northern India, from Jammu and Kashmir in the west to Arunachal Pradesh in the east.
     • Length: Approximately 2,400 km.
     • Width: Varies between 400 km (in Kashmir) to 150 km (in Arunachal Pradesh).
   • Divisions:
     1. Himadri (Greater Himalayas):
        • The northernmost range, with an average height of 6,000 meters.
        • Includes prominent peaks like Mount Everest, Kanchenjunga, and Nanga Parbat.
        • Composed of hard crystalline rocks, perpetually snow-covered, with many glaciers.
     2. Himachal (Lesser Himalayas):
        • Lies south of the Himadri, with elevations ranging from 3,700 to 4,500 meters.
        • Features hill stations like Shimla, Mussoorie, and Nainital.
        • Contains dense forests of oak and pine.
     3. Shiwaliks (Outer Himalayas):
        • Southernmost range, formed by unconsolidated sediments brought by rivers.
        • Height: 900 to 1,100 meters.
        • Features valleys known as ‘Duns’ (e.g., Dehra Dun, Kotli Dun).
2. The Northern Plains
   • Formation:
     • Created by the deposition of alluvium by three major rivers: the Indus, Ganga, and Brahmaputra, along with their tributaries.
   • Characteristics:
     • Area: Around 7 lakh sq. km.
     • Length: About 2,400 km.
     • Width: 240 to 320 km.
     • Extremely fertile and densely populated.
   • Divisions:
     1. Punjab Plains:
        • Formed by the Indus and its tributaries like Jhelum, Chenab, Ravi, Beas, and Sutlej.
        • Lies mainly in Pakistan, with a small part in India.
     2. Ganga Plains:
        • Stretches across Haryana, Delhi, Uttar Pradesh, Bihar, Jharkhand, and West Bengal.
        • Dominated by the Ganga and its tributaries.
     3. Brahmaputra Plains:
        • Located in Assam and the northeastern states.
        • Prone to flooding due to heavy rainfall and river overflow.
3. The Peninsular Plateau
   • Formation:
     • Part of the ancient Gondwana landmass.
     • Made up of igneous and metamorphic rocks.
   • Characteristics:
     • Bounded by the Aravali Hills in the northwest and the Western and Eastern Ghats.
     • Includes the Deccan Plateau and Central Highlands.
   • Divisions:
     1. Central Highlands:
        • Lies north of the Narmada River.
        • Includes the Malwa Plateau and Chota Nagpur Plateau.
     2. Deccan Plateau:
        • Lies south of the Narmada River.
        • Includes the Western Ghats (height: 900-1,600 meters) and Eastern Ghats (height: 600 meters).
4. The Indian Desert (Thar Desert)
   • Location:
     • Western Rajasthan and parts of Gujarat.
   • Characteristics:
     • Sandy terrain with sand dunes.
     • Receives less than 150 mm of rainfall annually.
     • Sparse vegetation, dominated by xerophytes.
5. The Coastal Plains
   • Location:
     • Stretch along the eastern and western coastlines of India.
   • Divisions:
     1. Western Coastal Plains:
        • Narrow and includes regions like the Konkan Coast, Kannad Coast, and Malabar Coast.
     2. Eastern Coastal Plains:
        • Wider and includes deltas of rivers like the Mahanadi, Godavari, Krishna, and Kaveri.
   • Special Features:
     • Lagoons and backwaters, such as Vembanad in Kerala.
6. The Islands
   • Andaman and Nicobar Islands:
     • Located in the Bay of Bengal.
     • Formed of volcanic origin.
     • Known for biodiversity and coral reefs.
   • Lakshadweep Islands:
     • Located in the Arabian Sea.
     • Formed of coral deposits.

Geological History

• Formation of Gondwana Land:
  • India was part of the supercontinent Gondwana.
  • Over millions of years, the Indian Plate drifted northward, colliding with the Eurasian Plate to form the Himalayas.
• Formation of Plains and Plateaus:
  • Rivers deposited sediments to form fertile plains.
  • The plateau was formed due to volcanic activity and subsequent weathering.

Importance of India’s Physical Features

1. Agriculture: Fertile plains support the majority of food production.
2. Natural Resources: Plateaus are rich in minerals.
3. Tourism: Diverse landscapes attract tourists.
4. Transportation and Trade: Coastal plains and islands provide access to ports and trade.