GEOGRAPHY & EARTH SCIENCE – CONSOLIDATED NOTES

1. Time & International Date Line

• At 180° longitude (International Date Line), time differs by exactly 12 hours from 0° longitude (Prime Meridian).
• This difference remains constant irrespective of eastward or westward travel.
• When a person crosses the International Date Line eastward, the date advances by one day (e.g., Tuesday → Wednesday).

2. Weathering & Geomorphic Processes

Salt Weathering (Haloclasty)

• Salt weathering is a type of physical (mechanical) weathering.
• It involves expansion of saltsdue to:
  • Thermal action
  • Hydration
  • Crystallization
• Common salts involved:
  • Calcium, Sodium, Magnesium, Potassium, Barium salts
• These salts expand within rock pores, exert pressure, and cause rock disintegration.
• Unlike chemical weathering, no chemical composition change occurs.

River Erosion Processes

• Potholes in riverbeds are formed mainly by abrasion.
• Attrition:
  • Involves collision of rock particles
  • Makes them smaller and rounded
  • Does not directly erode bedrock
• Solifluction:
  • A mass movement process
  • Not related to river erosion

3. Mass Movement Types

• Mudflow:
  • Rapid movement of water-saturated soil and debris
  • Speed can exceed 70 mph
• Slump:
  • Moderate to rapid movement
  • Occurs along a curved surface (rotational movement)
• Creep:
  • Very slow and imperceptible movement
  • Evidenced by tilted fences, curved trees
• Solifluction:
  • Slow seasonal flow in permafrost regions
  • A special type of creep

4. Volcanoes

• Stratovolcanoes:
  • Tall, steep cones
  • Built from layers of felsic lava and ash
  • Characterized by explosive eruptions
  • Reason: High gas content + high viscosity of felsic lava

5. Oceanography & Marine Features

• Ocean Trenches & Location:
  • Cayman Trench → Caribbean Sea (Atlantic Ocean basin)
  • South Sandwich Trench → South Atlantic Ocean
  • Bonin (Izu-Bonin) Trench → Pacific Ocean
  • Kermadec Trench → South Pacific Ocean (near New Zealand)

6. Tides

• Spring Tide ↔ Neap Tide interval: 7 days
• Neap to Neap Tide interval: ~14 days
• Neap Tide Condition:
  • Sun and Moon at 90° (Quadrature)
  • Their gravitational forces partially cancel each other
  • Results in low tidal range

7. Inland Waterways (India)

• NW-100 → Tapi River (Gujarat, Maharashtra)
• NW-10 → Amba River (Maharashtra)
• NW-2 → Brahmaputra River (Dhubri to Sadiya, 891 km)

8. World Physical Geography

Africa

• Lake Victoria → Largest lake (area)
• Lake Tanganyika → Deepest in Africa, longest freshwater lake globally
• Equator divides Africa into two nearly equal parts

Europe

• Mont Blanc → Highest peak of Alps

South America

• Patagonia → Cold desert

9. Grasslands (Regional Names)

• Veld → South Africa
• Downs → Australia
• Campos → Brazil
• Gran Chaco → Northern Argentina
• Llanos → Venezuela

10. Tribes & Countries

• Chin → Myanmar
• Toba → Argentina
• Chakma → Bangladesh
• Maori → New Zealand

11. Important Straits

• Strait of Malacca → Between Malaysia & Sumatra
• Sunda Strait → Between Java & Sumatra
• Strait of Messina → Between Sicily & mainland Italy
• Makassar Strait → Between Borneo & Sulawesi

12. Climate & Monsoon

• Chennai rainfall variability > Mumbai
• Retreating Southwest Monsoon brings rain to Tamil Nadu coast
• Western Disturbances originate from Mediterranean Sea
• MONEX (Monsoon Experiment):
  • International project
  • Under:
    • World Meteorological Organization (WMO)
    • International Council of Scientific Unions (ICSU)

13. Agriculture & Crops (India)

• Coffee Production:
  • Karnataka → ~70% (largest producer)
  • Kerala → ~21% (2nd largest)
  • Andhra Pradesh → Smaller producer (Araku Valley, organic coffee)
• Tea Variety (Assam):
  • Camellia sinensis var. assamica (large-leaved)

14. Passes & Locations

• Likhapani Pass → Assam–Arunachal Pradesh
• Shipki La → Himachal Pradesh
• Chang La → Ladakh
• Lipulekh → Uttarakhand
• Nathu La → Sikkim
• Khunjerab Pass → Ladakh

15. Industrial Locations (Aluminium Industry)

• Vedanta Aluminium Refinery → Lanjigarh (Odisha)
• NALCO Smelter → Angul
• BALCO → Korba
• NALCO (Refinery) → Damanjodi (Koraput)

16. Soil Type

• Thur soil:
  • Local name for saline/alkaline soils in India

17. Rivers (India)

• Chambal River:
  • Origin: Janapao Hills (Vindhyan Range), near Mhow (Madhya Pradesh)

18. Infrastructure (Golden Quadrilateral)

• Delhi – Mumbai → ~1,419 km
• Mumbai – Chennai → ~1,290 km
• Chennai – Kolkata → ~1,684 km
• Kolkata – Delhi → ~1,453 km

19. Regional Agriculture Terms

• Conuco → Venezuela
• Roca → Brazil

20. Location Facts (Japan)

• Hiroshima → Island of Honshu
• Nagasaki → Island of Kyushu

21. Climatic Zones

• Temperate Zone:
  • Lies between 40° to 60° latitude in both hemispheres