Geological Divisions and Key Terms
1. Earth’s age: Approximately 4.6 billion years.
2. Forces shaping Earth’s landforms:
o Endogenic Forces: Tectonic forces causing earthquakes and mountain
building.
o Exogenic Forces: Erosion, weathering, and deposition by rivers, wind,
and glaciers.
3. Three Geological Divisions of India:
o Peninsular Block: Stable and rigid.
o Himalayas and Other Peninsular Mountains: Geologically young,
tectonically active.
o Indo-Ganga-Brahmaputra Plain: Formed from sediments of Himalayan
and Peninsular rivers.
4. Key terms related to the Peninsular Block:
o Relict mountains: Aravali Hills, Satpura Range.
o Rift valleys: Narmada and Tapi.
5. Tectonic Movement: The Indian Plate continues to move northward at a rate of
approximately 5 cm/year.
Himalayas and Related Features
6. Longest mountain range in India: The Himalayas, stretching 2,500 km from west
to east.
7. Classification of Himalayas:
o Trans-Himalayas: Karakoram, Ladakh, Zaskar ranges.
o Greater Himalayas (Himadri): Contains the highest peaks.
o Lesser Himalayas (Himachal): Known for hill stations like Shimla,
Mussoorie.
o Shiwaliks: Outer ranges with longitudinal valleys (Duns).
8. Famous Himalayan Peaks (from west to east):
o Nanga Parbat (8,126 m)
o Kanchenjunga (8,586 m)
o Namcha Barwa (7,782 m)
9. Important passes in the Himalayas:
o Zoji La: Great Himalayas
o Banihal: Pir Panjal Range
o Khardung La: Ladakh Range
10. Key Rivers in Himalayan Subdivisions:
o Kashmir Himalayas: Indus, Jhelum, Chenab.
o Darjiling-Sikkim Himalayas: Tista River.
o Arunachal Himalayas: Kameng, Subansiri, Dihang.
11. Other terms to know:
o Karewas: Glacial clay deposits in Kashmir.
o Duar formations: Found in Darjiling and Assam, used for tea cultivation.
Northern Plains and River Features
12. Three Zones of Northern Plains:
o Bhabar: Narrow belt where streams disappear due to coarse sediments.
o Tarai: Marshy and swampy area where rivers re-emerge.
o Alluvial Plains:
Bhangar: Older, less fertile alluvium.
Khadar: Newer, more fertile alluvium.
13. Longest river in India: The Ganga, approximately 2,525 km.
14. Fertile Soils: Found in the Khadar region, which is ideal for crops like rice and
wheat.
15. Key River Features in the Northern Plains:
o Meanders, ox-bow lakes, braided channels, floodplains.
Peninsular Plateau and Features
16. Key features of the Peninsular Plateau:
o Highest peak: Anaimudi (2,695 m) in the Western Ghats.
o Rivers flowing westward: Narmada, Tapi, Mahi, Sabarmati.
o Rivers flowing eastward: Godavari, Krishna, Kaveri, Mahanadi.
17. Distinctive Landforms:
o Black Soil Area: Found in the Deccan Plateau.
o Ravines: Chambal Valley.
o Bhima Fault: Known for seismic activity.
18. Mineral-Rich Plateaus:
o Chotanagpur Plateau: Coal, iron ore.
o Meghalaya Plateau: Uranium, limestone.
Indian Desert (Thar Desert)
19. Features:
o Receives less than 150 mm of rainfall annually.
o Rivers: Luni River and ephemeral streams.
o Landforms: Barchans, mushroom rocks, shifting dunes.
20. Significant Facts:
o Marusthali: Another name for the Indian Desert.
o Fossil evidence: Found at Akal Fossil Wood Park (180 million years old).
Coastal Plains
21. Western Coastal Plain Features:
o Example of a submerged coastline.
o Kayals: Backwaters of Kerala.
o Major ports: Mumbai, Cochin, Marmagao.
22. Eastern Coastal Plain Features:
o Example of an emergent coastline.
o Broad, with major river deltas: Mahanadi, Godavari, Krishna, Kaveri.
o Fewer harbors due to a broader continental shelf.
Islands of India
23. Andaman and Nicobar Islands:
o Ten Degree Channel separates Andaman from Nicobar.
o Barren Island: India’s only active volcano.
o Major peaks: Saddle Peak (738 m), Mount Thuiller (642 m).
24. Lakshadweep Islands:
o Coral atolls.
o Divided by the Eleventh Degree Channel.
o Largest island: Minicoy.
Miscellaneous Facts
25. Famous Lakes in India:
o Dal Lake, Wular Lake (Kashmir)
o Loktak Lake (Manipur)
26. Pilgrimage Sites:
o Vaishno Devi, Amarnath (Kashmir)
o Gangotri, Yamunotri, Kedarnath, Badrinath (Uttarakhand)
27. Tough Trivia Questions:
o Name the rivers forming India's largest delta (Ans: Ganga and
Brahmaputra).
o Identify the volcanic island in India (Ans: Barren Island).
o What is the highest peak in the Andaman and Nicobar Islands? (Ans:
Saddle Peak).
