Consider the following statements regarding tectonic plates:

i. Tectonic plates include the crust and the uppermost mantle of the solid earth.
ii. Tectonic plates are rigid, solid layers about 100 km thick.
iii. Tectonic plates include the crust and the entire mantle.
iv. Tectonic plates are confined to continental land masses only.

Which of the above statements is/are correct?

Question

Consider the following statements regarding tectonic plates:

i. Tectonic plates include the crust and the uppermost mantle of the solid earth.

ii. Tectonic plates are rigid, solid layers about 100 km thick.

iii. Tectonic plates include the crust and the entire mantle.

iv. Tectonic plates are confined to continental land masses only.

Which of the above statements is/are correct?

Quintessence Classes · Accepted Answer

The correct answer is i and ii. Analysis of the Statements:i. Correct: Tectonic plates are composed of the lithosphere, which includes the crust (both continental and oceanic) and the uppermost portion of the mantle that behaves as a rigid solid.ii. Correct: On average, the lithosphere (tectonic plates) is about 100 km thick, though this varies (it is thinner under oceans and much thicker under high mountain ranges). They are rigid and "float" on the semi-plastic asthenosphere below.iii. Incorrect: Tectonic plates do not include the entire mantle. The mantle is nearly 2,900 km deep; the plates only consist of the very top layer. Below them lies the asthenosphere and the lower mantle.iv. Incorrect: Tectonic plates are not confined to land. There are oceanic plates (like the Pacific Plate) and continental plates (like the Eurasian Plate). Most plates actually contain both continental and oceanic crust.

Answer

ii only

Answer

iii and iv only

Answer

iv only

Answer & Explanation

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JKPSC JKAS 2024 Prelims

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