Structure and Physiography — Class 11 Geography

India's landforms have evolved over about 4,600 million years through endogenic and exogenic forces and the northward movement of the Indian plate. Geologically, India has three divisions: the Peninsular Block, the Himalayas and other Peninsular Mountains, and the Indo-Ganga-Brahmaputra Plain. The Peninsular Block is an ancient, rigid mass of gneisses and granites, while the young, weak and flexible Himalayas are tectonic in origin and dissected by youthful rivers. Physiographically India is divided into six divisions: (1) the Northern and North-eastern Mountains (the Himalayas, about 2,500 km long, and the north-eastern hills); (2) the Northern Plain, formed by alluvium of the Indus, Ganga and Brahmaputra, with the Bhabar, Tarai, Bhangar and Khadar belts; (3) the Peninsular Plateau (Deccan Plateau, Central Highlands and North-eastern Plateau), with the Western Ghats higher and more continuous than the Eastern Ghats and Anaimudi (2,695 m) its highest peak; (4) the Indian Desert (Marusthali) west of the Aravalis; (5) the Coastal Plains (the submerged western coast and the emergent eastern coast with deltas); and (6) the Islands (the Andaman and Nicobar groups in the Bay of Bengal, including Barren Island, India's only active volcano, and the coral Lakshadweep and Minicoy in the Arabian Sea). (Refer to the map in the NCERT textbook.)