UPSC Civil Services Examination - Indian
Geography
Chapter 1: Physical Features of India & Geological
Structure
1. The Himalayan Mountains (The Northern Mountains)
Geological Origin: The Himalayas are young, fold mountains formed due to the tectonic
collision of the Indian Plate with the Eurasian Plate during the Tertiary period.
Three Parallel Ranges (North to South):
1. Great Himalayas (Himadri): The most continuous range. Contains the world’s highest peaks
(e.g., Mount Everest, Kanchenjunga). Average elevation is around 6,000 meters. Core is
composed of granite.
2. Lesser Himalayas (Himachal): Highly compressed and altered rocks. Altitude varies between
3,700 and 4,500 meters. Famous for hill stations (Shimla, Mussoorie, Nainital). Includes
important ranges like Pir Panjal (longest) and Dhaula Dhar.
3. Outer Himalayas (Shiwaliks): The outermost range, composed of unconsolidated sediments
brought down by rivers. Altitude varies between 900 and 1,100 meters. The longitudinal valleys
lying between lesser Himalaya and the Shiwaliks are known as Duns (e.g., Dehra Dun, Kotli
Dun).
Regional Divisions (West to East):
o Punjab Himalayas: Between Indus and Satluj rivers.
o Kumaon Himalayas: Between Satluj and Kali rivers.
o Nepal Himalayas: Between Kali and Teesta rivers.
o Assam Himalayas: Between Teesta and Dihang (Brahmaputra) rivers.
Purvanchal (Eastern Hills): Beyond the Dihang gorge, the Himalayas bend sharply to the
south. Includes Patkai hills, Naga hills, Manipur hills, and Mizo hills.
2. The Northern Plains
Formation: Formed by the interplay of three major river systems—the Indus, the Ganga, and
the Brahmaputra along with their tributaries. It is formed of alluvial soil.
Geomorphological Features (North to South):
o Bhabar: A narrow belt (8-16 km wide) parallel to the Shiwalik slopes. Composed of pebbles.
Rivers/streams disappear in this belt due to high porosity.
o Terai: Lies south of Bhabar. It is a wet, swampy, and marshy region where the vanished streams
re-emerge. Highly fertile and historically heavily forested.
o Bhangar: The older alluvium of the plains, forming a terrace above the flood plains. Contains
calcareous deposits locally known as Kankar.
Geography
Chapter 1: Physical Features of India & Geological
Structure
1. The Himalayan Mountains (The Northern Mountains)
Geological Origin: The Himalayas are young, fold mountains formed due to the tectonic
collision of the Indian Plate with the Eurasian Plate during the Tertiary period.
Three Parallel Ranges (North to South):
1. Great Himalayas (Himadri): The most continuous range. Contains the world’s highest peaks
(e.g., Mount Everest, Kanchenjunga). Average elevation is around 6,000 meters. Core is
composed of granite.
2. Lesser Himalayas (Himachal): Highly compressed and altered rocks. Altitude varies between
3,700 and 4,500 meters. Famous for hill stations (Shimla, Mussoorie, Nainital). Includes
important ranges like Pir Panjal (longest) and Dhaula Dhar.
3. Outer Himalayas (Shiwaliks): The outermost range, composed of unconsolidated sediments
brought down by rivers. Altitude varies between 900 and 1,100 meters. The longitudinal valleys
lying between lesser Himalaya and the Shiwaliks are known as Duns (e.g., Dehra Dun, Kotli
Dun).
Regional Divisions (West to East):
o Punjab Himalayas: Between Indus and Satluj rivers.
o Kumaon Himalayas: Between Satluj and Kali rivers.
o Nepal Himalayas: Between Kali and Teesta rivers.
o Assam Himalayas: Between Teesta and Dihang (Brahmaputra) rivers.
Purvanchal (Eastern Hills): Beyond the Dihang gorge, the Himalayas bend sharply to the
south. Includes Patkai hills, Naga hills, Manipur hills, and Mizo hills.
2. The Northern Plains
Formation: Formed by the interplay of three major river systems—the Indus, the Ganga, and
the Brahmaputra along with their tributaries. It is formed of alluvial soil.
Geomorphological Features (North to South):
o Bhabar: A narrow belt (8-16 km wide) parallel to the Shiwalik slopes. Composed of pebbles.
Rivers/streams disappear in this belt due to high porosity.
o Terai: Lies south of Bhabar. It is a wet, swampy, and marshy region where the vanished streams
re-emerge. Highly fertile and historically heavily forested.
o Bhangar: The older alluvium of the plains, forming a terrace above the flood plains. Contains
calcareous deposits locally known as Kankar.
