Ch-2: Complete Notes & Solutions

Ch-4: Distribution of Oceans and Continents

Continents dharti ka 29 per cent area cover karte hain aur baaki oceanic waters hain.. Ye continents hamesha se apni jagah badalte rahe hain..

1. Continental Drift Theory

• History: 1596 mein Dutch map maker Abraham Ortelius ne pehle bataya ki continents pehle jude hue the..
• Wegener's Theory (1912): Alfred Wegener ne kaha ki saare continents ek single mass the jise PANGAEA (all earth) kehte hain, jo PANTHALASSA (mega-ocean) se gira tha..
• Split: Lagbhag 200 million saal pehle Pangaea tuta—North mein Laurasia aur South mein Gondwanaland bana.,.

2. Evidence for Drift (Saboot)

• Jig-Saw-Fit: Africa aur South America ki coastlines ka perfect match (Bullard ne 1964 mein computer fit dikhaya).,.
• Rocks of Same Age: Brazil aur West Africa ki 2,000 million years purani rocks match karti hain..
• Tillite: Glaciers se bani sedimentary rocks jo India, Africa, Antarctica aur Australia mein ek jaisi hain..
• Placer Deposits: Ghana coast mein gold milta hai par uska source rock Brazil mein hai..
• Fossils: Mesosaurus (chota reptile) ke skeletons sirf South Africa aur Brazil mein milte hain..

3. Forces for Drifting

Wegener ne Polar-fleeing force (rotation ki wajah se) aur Tidal force (Sun/Moon ki attraction) ko zimmedar bataya.. Baad mein Arthur Holmes ne 1930s mein Convectional Current Theory di..

4. Sea Floor Spreading & Plate Tectonics

• Sea Floor Spreading: Hess (1961) ne kaha ki volcanic eruptions se naya lava ocean floor ko push karta hai..
• Plate Tectonics: Earth ki lithosphere 7 major plates aur kuch minor plates (Nazca, Cocos, Arabian) mein banti hai.,.
• Boundaries: Divergent (dur jana), Convergent (takarana), aur Transform (side se nikalna).,.

5. Movement of Indian Plate

India ek bada island tha jo Australian coast ke paas tha.. Tethys Sea ise Asia se alag karta tha.. 40-50 million saal pehle Asia se takrane par Himalayas bane.. Is dauran Deccan Traps (lava outpouring) 60 million saal pehle shuru hua..

--- EXERCISES ---

1. MCQs: (i) c - Abraham Ortelius, (ii) c - Rotation, (iii) d - Antarctica, (iv) c - Distribution of fossils, (v) d - Continent-continent convergence.,,.

2. Short Ans: (iv) Deccan Traps ke formation ke waqt Indian landmass equator ke kafi kareeb tha..

Project: Earthquake se hone wale nuksan (damage) ka collage taiyar karein..

[Diagram: Pangaea]

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Supercontinent
+ Mega Ocean

[Plates]

Pacific, African,
Eurasian, etc..

🗺️ ✨ 🌋

"Ring of Fire".