Authentic Classroom Explanation by IAS Monk

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📌 Question

Which of the following are the evidences of the phenomenon of continental drift?

I. The belt of ancient rocks from Brazil coast matches with those from Western Africa.
II. The gold deposits of Ghana are derived from the Brazil plateau when the two continents lay side by side.
III. The Gondwana system of sediments from India is known to have its counterparts in six different landmasses of the Southern Hemisphere.

Select the correct answer using the code given below:
(a) I and III only
(b) I and II only
(c) I, II and III
(d) II and III only

✅ Correct Answer: (c) I, II and III

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🎯 Theme of the Question

Physical Geography | Geomorphology | Continental Drift | Palaeogeography

This is a classic UPSC question blending NCERT fundamentals + geological reasoning + palaeoclimatic evidence.

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🧠 Classroom Explanation

The Continental Drift Theory, proposed by Alfred Wegener (1912), argues that present-day continents were once joined together as a single landmass called Pangaea and later drifted apart.

UPSC tests whether you can recognise multiple independent lines of evidence supporting this theory.

Let us verify each statement.

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🟢 Statement I

The belt of ancient rocks from Brazil coast matches with those from Western Africa.

✔️ Correct

• Radiometric dating shows ~2000 million-year-old rock belts
• Rock type, age, and structure on:
  • Eastern Brazil coast
  • Western African coast
    match almost perfectly
• This matching is impossible by coincidence across an ocean

📌 This is called Geological Matching Evidence

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🟢 Statement II

The gold deposits of Ghana are derived from the Brazil plateau when the two continents lay side by side.

✔️ Correct

• Ghana has rich placer gold deposits
• But no source rocks are present locally
• The matching gold-bearing veins exist in Brazil
• Logical conclusion:
  • Gold was deposited when Africa and South America were joined
  • Later separation stranded deposits on opposite sides

📌 This is Economic–Geological Evidence of drift

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🟢 Statement III

The Gondwana system of sediments from India has counterparts in six Southern Hemisphere landmasses.

✔️ Correct

• Gondwana sediments found in:
  • India
  • Africa
  • Antarctica
  • Australia
  • Madagascar
  • Falkland Islands
• Presence of glacial tillite at the base indicates:
  • Common palaeoclimate
  • Shared geological history

📌 This is Palaeoclimatic + Sedimentary Evidence

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🧮 UPSC Elimination Logic

• I ✔️ (Rock belt matching)
• II ✔️ (Gold source logic)
• III ✔️ (Gondwana sediment continuity)

👉 All three statements are correct
✔️ Option (c)

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🧠 Memory Hook

“R–G–G Rule of Continental Drift”

• R → Rocks (Brazil–Africa)
• G → Gold (Ghana ← Brazil)
• G → Gondwana sediments (India to Antarctica)

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🔍 Curiosity Corner

Why was Wegener initially rejected?

• He proved drift, but
• Could not explain mechanism
  Later explained by:
• Plate Tectonics
• Sea-floor spreading
• Mantle convection currents

UPSC often links:

Continental Drift → Plate Tectonics (conceptual evolution)

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📘 Enrichment Note

Types of Continental Drift Evidence UPSC loves:

1. Geological (rock belts)
2. Palaeontological (fossils like Glossopteris)
3. Palaeoclimatic (glacial tillite)
4. Economic (minerals, coal, gold)
5. Geometrical (coastline fit)

This question smartly combines three categories in one.

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🎯 Prelims Strategy Insight

• Continental Drift questions are low-risk, high-return
• NCERT-based explanations dominate
• Always assume:
  • Multiple evidences → UPSC prefers “All correct”

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🧩 One-Line Ready Recall

Continental Drift is proved by rocks, minerals, sediments, fossils, and climate — not by coastlines alone.

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🧭 IAS Monk Whisper
When continents speak through rocks and gold, geography becomes history written in stone.