Class 11 geography chapter

 Chapter: Structure and Physiography

 **Introduction**

   - The Indian subcontinent lies entirely on the northern and eastern hemispheres.

   - It has diverse physical features including mountains, plateaus, plains, and islands.

2. **Geological Structure**

   - **Tectonic Plates**: India is part of the Indian Plate, which collided with the Eurasian Plate leading to the formation of the Himalayas.

   - **Geological Evolution**: The Indian landmass drifted northwards post the breakup of the Gondwana land.

   - **Types of Rocks**: India has diverse rock types like igneous, sedimentary, and metamorphic rocks.

### 3. **Physiographic Divisions**

India can be divided into six physiographic divisions:

   1. **The Himalayan Mountains**

      - Divided into three parallel ranges: the Greater Himalayas (Himadri), the Lesser Himalayas (Himachal), and the Shiwaliks.

      - The Himalayas are young fold mountains with high peaks and deep valleys.

      - Important ranges: Karakoram, Ladakh, Zaskar.

      - Significance: Climate barrier, source of rivers, biodiversity, and tourism.

   2. **The Northern Plains**

      - Formed by the alluvial deposits of the Indus, Ganga, and Brahmaputra rivers.

      - Divided into three sections: Punjab Plains, Ganga Plains, and Brahmaputra Plains.

      - Fertile soil supports intensive agriculture.