Choose the best answer. Magma forms at subduction zones because:

a. The lithosphere is thinned at convergent boundaries allowing hot mantle rocks to melt due to decompression.

b. The Earth is hotter at convergent boundaries.

c. Friction from the subducting plate against the overriding plate melts the rocks.

d. Volatiles released from minerals in the subducting plate lower the melting temperature of hot mantle rocks above them.

Question

Geography

Nathalia Pace

2 February, 08:48

Choose the best answer. Magma forms at subduction zones because:

a. The lithosphere is thinned at convergent boundaries allowing hot mantle rocks to melt due to decompression.

b. The Earth is hotter at convergent boundaries.

c. Friction from the subducting plate against the overriding plate melts the rocks.

d. Volatiles released from minerals in the subducting plate lower the melting temperature of hot mantle rocks above them.

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Answers (1)

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Trace · Answer 1

The correct option is: d. Volatiles released from minerals in the subducting plate lower the melting temperature of hot mantle rocks above them.

Explanation:

Magma is the hot molten or semi-molten natural liquid, present under the surface of the Earth.

The subducting basalt and sediment contains a large amount of surface water and also in the form of hydrated minerals and volatiles.

The subduction of the plate deep into the earth results in greater pressures and temperatures. This causes the slab to release the water present into the overlying mantle wedge. This release of water, lowers the melting temperature of the mantle rock such that it melts. This results in the generation of magma.