Question

Melting by temperature increase is the least common melting mechanism that generates molten rock (magma).  Which of the following best describes this partial melting process?

Group of answer choices

Intrusion of basaltic magma into the continental crust heats and partially melts the continental crust which has a much lower melting temperature than basalt.

Rock is buried and melts as pressure increases

Water released by metamorphic reactions from a subducting plate lowers the melting temperature of the upper mantle above the subduction zone causing partial melting of this upper mantle

Outer core injects into the upper mantle, heating it and causing it to melt

Solid mantle rises and partially melts as pressure decreases

Answer 1

Melting by temperature increase is the least common melting mechanism that generates molten rock. This type of partial melting is best described by the intrusion of basaltic magma into the continental crust heats. It partially melts the continental crust, which has a lower melting temperature than basalt.

These are the processes that cause mantle melting. This can be achieved by decreasing pressure (more dominant), adding volatiles in the system, Increasing temperature (least dominant). The second question has not mentioned specific volatile contents, but it should have mentioned that.