A ________ forms at very high pressures but moderately low temperatures associated with subduction of oceanic crust and sediments.
A)mylonite
B)migmatite
C)biotite marble
D)blueschist

Question

Quizplus · Accepted Answer

Blueschist forms at depths of 15-30 km during the subduction of oceanic crust and sediments. The high pressure and relatively low temperature conditions of this process result in the formation of the blue mineral glaucophane, which gives blueschist its characteristic color. Mylonite forms as a result of intense shear deformation, migmatite forms from partial melting and recrystallization of rocks under high temperatures, and biotite marble is a metamorphic rock composed of biotite (a dark-colored mineral). None of these processes are associated with the formation of blueschist.

A ________ Forms at Very High Pressures but Moderately Low