Question
Consider the following statements regarding the Earth's crust :
I. The continental crust is thinner under fold mountains.
II. The mean thickness of ocean crust is \(30\text{ km}\).
III. The Earth's crust is brittle in nature.
Which of the statements given above is/are correct?
The correct answer is
III only
Statement Analysis on Earth's Crust
We will analyze each statement regarding the Earth's crust to determine its correctness.
Statement I: Continental Crust Thickness Under Fold Mountains
- Fact: Fold mountains are formed by tectonic plate collision, causing compression and uplift.
- Analysis: This process generally leads to a thickening of the continental crust beneath the mountain ranges, not thinning.
- Conclusion: Statement I is incorrect.
Statement II: Mean Thickness of Ocean Crust
- Fact: Oceanic crust is typically much thinner than continental crust.
- Analysis: The average thickness of oceanic crust is generally between 5 km and 10 km. A thickness of \(30\text{ km}\) is characteristic of continental crust.
- Conclusion: Statement II is incorrect.
Statement III: Brittleness of Earth's Crust
- Fact: The Earth's crust, as part of the rigid lithosphere, behaves as a brittle material under certain conditions.
- Analysis: This brittleness allows it to fracture and deform, leading to phenomena like earthquakes along faults. Deeper, hotter parts of the Earth behave more plastically.
- Conclusion: Statement III is correct.
Final Conclusion
Based on the analysis, only Statement III is correct.
Therefore, the correct option is the one stating 'III only'.
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Important Questions from Major Domains of the Earth
- Which of the following are associated with composite volcanoes?
I. They result in explosive eruptions.
II. They eject pyroclastic materials.
III. Pyroclastic materials and ashes accumulate near the vent, forming layers.
Select the correct answer using the code given below. - Various landforms observed on the surface of the earth are due to the:
1. differences in the type and structure of the crustal material
2. differences in the land forming processes
3. differential rates of the processes at different places on the Earth's surface
Select the correct answer using the code given below : Which of the following statements with regard to the continental shelf is NOT correct?
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