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

Question

Quizplus · Accepted Answer

Blueschist is a metamorphic rock that forms at high pressures (around 12-15 kilobars) and relatively low temperatures (200-500°C) associated with the subduction of oceanic crust and sediments. It is characterized by the blue minerals glaucophane and lawsonite, and often forms in conjunction with eclogite facies rocks. Mylonite forms under high temperatures and pressures as a result of ductile deformation. Migmatite is a type of rock that forms when a metamorphic rock partially melts, and it is not associated with specific pressures or temperatures. Sillimanite bearing marble is a type of metamorphic rock that forms under lower pressures and higher temperatures than blueschist.

A ________ Forms at Very High Pressures but Relatively Low