Consider the following statements with respect to the 'asthenosphere'

Consider the following statements with respect to the ‘asthenosphere’ :

1. It extends from the lower crust to the upper mantle.
2. It is the main source of the magma that finds its way to the surface of the Earth during volcanic eruptions.

Which of the statements given above is/are correct?

1 only

2 only

Both 1 and 2

Neither 1 nor 2

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC CBI DSP LDCE – 2023

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Statement 2 correctly identifies the asthenosphere as a major source of magma, while Statement 1 inaccurately describes its location.

The asthenosphere is the highly viscous, mechanically weak and ductile region of the upper mantle, below the lithosphere. It extends roughly from about 100 km to 400 km depth. Statement 1 is incorrect because the asthenosphere is entirely within the upper mantle and does not extend into the lower crust. Statement 2 is correct because partial melting occurs within the asthenosphere due to its temperature and pressure conditions, generating magma that contributes to volcanic activity.

The lithosphere, which comprises the rigid crust and uppermost part of the mantle, floats on the ductile asthenosphere. The movement of tectonic plates (parts of the lithosphere) is facilitated by the plastic flow within the asthenosphere.

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