CS(P) 2025 Paper -2 (CSAT)

🔆 Indian Passes & Plateaus

📍 Aghil Pass
✅ Location: Between Ladakh (J&K) and Sinkiang (China)
✅ Significance: Important for military movement, part of the Karakoram Range.

📍 Banihal Pass (Jawahar Tunnel)
✅ Location: Connects Banihal town (Doda District) and Qazigund (Anantnag, Kashmir Division)
✅ Significance: Key highway pass on NH44 connecting Jammu and Kashmir.

📍 Baralacha La
✅ Location: Between Keylong (Himachal Pradesh) and Leh (Ladakh)
✅ Significance: Located on the Leh-Manali highway, an important trade route.

📍 Burzil Pass
✅ Location: Connects Srinagar to Gilgit (now in Pakistan-Occupied Kashmir)
✅ Significance: Historically significant for trade.

📍 Karakoram Pass
✅ Location: Between Ladakh (J&K) and Sinkiang (China)
✅ Significance: An ancient trade route on the Silk Road.

📍 Khardung La
✅ Location: Between Leh and Siachen Glacier via Nubra Valley
✅ Significance: One of the highest motorable roads in the world (5,359 m).

📍 Umling La (Uming La)
✅ Location: Ladakh
✅ Significance: Highest motorable road in the world at 5,883 m.

📍 Zoji La
✅ Location: Between Srinagar and Leh
✅ Significance: Important link between Kashmir Valley and Ladakh, often blocked by snow.

📍 Chang La
✅ Location: Between Ladakh (J&K) and Tibet (China)
✅ Significance: One of the highest passes in the world.

📍 Shinkun La
✅ Location: Between Himachal Pradesh & Ladakh
✅ Significance: India has started construction of Nimmu-Padum-Darcha (NPD) route for all-weather connectivity to Ladakh.

📍 Balcha Dhura
✅ Location: Connecting Uttarakhand with Tibet (China)
✅ Significance: High-altitude pass in the Himalayas.

📍 Mana Pass
✅ Location: Between Uttarakhand and Tibet (China)
✅ Significance: Highest motorable pass in Uttarakhand, connects to Tibet.

🔆 Important Trenches

📍 Mariana Trench
• Location: Western Pacific (Near Guam)
• Plates Involved: Pacific Plate subducting under Philippine Plate. Includes the Challenger Deep (10,971m)

📍 Tonga Trench
• Location: South Pacific (Near Tonga)
• Plates Involved: Pacific Plate subducting under Indo-Australian Plate

📍 Kuril-Kamchatka Trench
• Location: Northwest Pacific (Near Russia, Japan)
• Plates Involved: Pacific Plate subducting under Eurasian Plate

📍 Peru-Chile Trench (Atacama Trench)
• Location: Eastern Pacific (Off South America)
• Plates Involved: Nazca Plate subducting under South American Plate

📍 Philippine Trench
• Location: West Pacific (Near Philippines)
• Plates Involved: Philippine Plate subducting under Eurasian Plate

🔆 Oceans (Pacific & Atlantic Oceans)

📍 Japan Trench
• Location: Northwest Pacific (Off Japan)
• Plates Involved: Pacific Plate subducting under Eurasian Plate

📍 Kermadec Trench
• Location: South Pacific (Near New Zealand)
• Plates Involved: Pacific Plate subducting under Indo-Australian Plate

📍 Aleutian Trench
• Location: North Pacific (Near Alaska)
• Plates Involved: Pacific Plate subducting under North American Plate

📍 Middle America Trench
• Location: Eastern Pacific (Off Central America)
• Plates Involved: Cocos Plate subducting under North American & Caribbean Plates

🔷SEAFLOOR SPREADING

🔹 Proposed by: Harry Hess in the early 1960s
🔹 Meaning:
✅ Seafloor spreading is a geological process at oceanic ridges where new crust forms and spreads apart.
✅ It occurs continuously along mid-oceanic ridges (underwater mountain chains).

🔹 Process of Sea-Spreading:
✅ Mid-oceanic ridges are divergent plate boundaries, where tectonic plates move apart.

🔷 Process Explained Step-by-Step

1️⃣ As the plates separate, magma from the asthenosphere rises due to mantle convection.
2️⃣ Magma cools and solidifies on contact with seawater, forming new oceanic crust.
3️⃣ This creates symmetrical magnetic patterns (magnetic anomalies) on both sides of the ridge due to Earth’s magnetic field.

🔆 Ninetyeast Ridge

✅ A linear submarine volcanic ridge running north to south near 90° East longitude.
✅ Formed by hotspot volcanic activity beneath the Indian Ocean.
✅ Linked to the Kerguelen hotspot, which is a moving hotspot, influencing the ridge’s formation and path.
✅ Reference: Nature Article on Kerguelen Hotspot Movement

🔆 Georges and Grand Banks

✅ Georges Bank: Located off the coast of New England, USA.
✅ Grand Banks: Situated off the coast of Newfoundland, Canada.
✅ Among the world’s richest fishing grounds due to the mixing of warm Gulf Stream and cold Labrador Current waters.
✅ Experienced collapse of fisheries in the 1990s, especially cod, due to overfishing.

#geography #fisheries

🔆 Key Takeaways: Madden-Julian Oscillation (MJO) and Indian Monsoon

✅ What is MJO?
• A moving system of winds, clouds, and pressure circulating eastward near the equator.
• Discovered in 1971 by Roland Madden and Paul Julian.
• Crucial for tropical rainfall patterns, including the Indian monsoon.

✅ Structure and Movement:
• Moves eastward at 4–8 m/s, completing a cycle every 30–60 days (sometimes up to 90 days).
• Two phases:
• Active Phase: Brings rainfall and storms.
• Suppressed Phase: Causes below-average rainfall.

✅ Relevance to Indian Monsoon:
• Strongly influences monsoon onset and intensity, especially during active phase.
• Early 2024 monsoon onset (May 24 Kerala, May 26 Mumbai) partly due to strong MJO.

✅ Cyclone and Rainfall Connection:
• Active MJO triggers tropical cyclones, supporting monsoon initiation (e.g., June 2015 had 20 days of rain linked to MJO).

✅ Interaction with El Niño:
• MJO and El Niño may coincide but are not causally linked; both affect rainfall unpredictably.

✅ Geographical Impact:
• Influences weather between 30°N and 30°S; India lies in this zone, making it vulnerable to MJO-driven rainfall variations.

#climate #monsoon

🔆 Key Takeaways: Unseasonal Weather and Urban Flooding Crisis

✅ Unseasonal Weather Patterns:
• Early monsoon in Kerala and Maharashtra, with Mumbai receiving rains 16 days ahead of schedule — earliest in 75 years.
• Reflects growing trend of unpredictable weather events.

✅ Urban Flooding and Infrastructure Stress:
• Mumbai recorded its wettest May in 107 years, disrupting transport and infrastructure.
• Disruptions worsened by unanticipated downpours and incomplete pre-monsoon desilting.

✅ Drainage Infrastructure Deficiencies:
• Despite post-2005 flood initiatives (widened drains, pumping stations), BRIMSTOWAD project remains incomplete.
• Colonial-era drainage designed for 25 mm/hour rainfall is inadequate for current extreme rains.

✅ Encroachment and Mismanagement of Water Bodies:
• River catchments like Mithi encroached by real estate, reducing flood absorption.
• Garbage dumping further weakens water bodies’ capacity.

✅ Pan-India Implications:
• Cities like Bengaluru and Delhi face similar drainage, infrastructure, and encroachment issues.
• Delhi recorded 9x normal May rainfall without matching drainage upgrades.

✅ Governance and Urban Planning Failures:
• Crisis highlights failure despite wealth of cities.
• Urgent need to incorporate climate adaptation and weather management in urban planning.

🔆 National Parks in Assam

📍 List of National Parks (West to East)
1. Raimona National Park
2. Manas National Park (WHS/ TR/ ER/ BR)
3. Orang National Park and Tiger Reserve (NP/ TR)
4. Nameri National Park (TR)
5. Kaziranga National Park (mentioned later)
6. Dibru-Saikhowa National Park (BR)
7. Dehing Patkai National Park (ER)

🔆 Important Lakes of Europe

📍 Lake Ladoga
✅ Country: Russia
✅ Type: Glacial

📍 Lake Onega
✅ Country: Russia
✅ Type: Glacial

📍 Lake Constance
✅ Countries: Germany, Austria, Switzerland
✅ Type: Glacial

📍 Lake Como
✅ Country: Italy
✅ Type: Glacial

📍 Lake Skadar
✅ Countries: Montenegro, Albania
✅ Type: Karst (in a Karst Depression)

#mapping

Drought in Amazon : decline in biomass, big losses and mortality of the largest trees.


The loss of ~ 40% of the total weight of the vegetation and the carbon stored within....

🔆 What 24 Years of Drought Simulation in the Amazon Revealed

✅ About the Project:
• The Esecaflor project (2000–present) is the world’s longest-running drought experiment in a rainforest.
• Located in Caxiuana National Forest, scientists diverted 50% of rainfall using 6,000 plastic panels to mimic long-term drought.

✅ Key Findings:
• After 8 years, the forest showed a sharp decline in biomass and 40% loss in vegetation weight.
• Large trees suffered high mortality, leading to significant carbon release into the atmosphere.
• The Amazon shifted from a carbon sink to a carbon emitter, losing its ability to absorb CO₂.

✅ Why It Matters:
• Forest trees store the equivalent of 2 years of global carbon emissions.
• Cutting or death of these trees due to drought accelerates climate change.
• In extreme dry years (El Niño + climate change), impacts were most severe.

✅ Next Steps:
• Scientists are now observing if the forest can regenerate and return to baseline post-drought.
• The project helps predict future resilience of the Amazon amid changing climate patterns.

#Amazon #ClimateCrisis #ForestDrought #CarbonSink

In snow free areas, the ground reflects 2.2% more sunlight, causing colling effect.

🔆 Key Takeaways: Subtle Vegetation Shifts Made Earth Brighter and Cooler

✅ Satellite data (2001-20) shows snow-free areas reflect 2.2% more sunlight, causing a cooling effect.
✅ Increased brightness mainly due to drying grasses and shrubs replacing darker plants.
✅ These subtle shifts caused 3.9-8.1 times more cooling than land-use changes.
✅ Shrublands and short natural vegetation are the biggest contributors.
✅ Shrinking snow cover accounts for only 14% of the cooling effect.

#ClimateScience #EarthObservation #VegetationChanges
#geography

🔆 Glacier Loss Warning: Only 24% May Survive at 2.7°C Warming

✅ Key Findings:
• At 2.7°C rise, only 24% of glaciers may remain globally
• Limiting to 1.5°C (Paris target) could save up to 54% glacier mass
• Indian glaciers & Hindu Kush: only 25% ice remains at 2°C
• Glacier retreat is faster in South Asia, steepest in Indian sub-regions

✅ Why it Matters:
• Major rivers (Ganga, Indus, Brahmaputra) are glacier-fed
• Melting raises sea levels, threatens millions of lives

✅ Study Used:
• 21 scientists, 8 models, 200,000+ glaciers simulated

Mount Etna : world heritage site since 2013

🔆 Key Takeaways: Mount Etna’s Massive Eruption

✅ Eruption Details:
• Mount Etna, the largest volcano in Europe, erupted explosively on June 1, sending ash and smoke several kilometers into the sky.
• Experts suggest the eruption was triggered by increasing pressure inside the volcano, leading to the collapse of the southeast crater.
• This was categorized as a Strombolian eruption, characterized by bursts of lava, rock, and ash.

✅ Location & Importance:
• Mount Etna, an active volcano on the east coast of Sicily, is Europe’s largest active volcano and a UNESCO World Heritage site.
• The volcano has been active for over 2,700 years and is known for its frequent eruptions.

#MountEtna #Volcano #Eruption #Strombolian #Italy

🔆 Important Deserts

📍 Subtropical Hot Deserts

📍 Great Victoria Desert
✅ Largest Australian Desert
✅ Contains many sand dunes and salt lakes

📍 Great Sandy Desert
✅ Passes through the Pilbara region
✅ An ephemeral river, Rudall, flows through here

📍 Gibson Desert

📍 Simpson Desert

📍 Tanami Desert