Question

Off the coast of the Pacific Northwest in the United States, the Pacific plate is being pushed underneath the North American plate in a subduction zone, caused by plate tectonics. As the rock from the Pacific plate is pushed under the North American plate, it is subjected to high temperatures and pressures. Which rock will be created from this process?

Answer 1

Answer:

Metamorphic rocks

Explanation:

When two oceanic plates collide, it occurs oceanic convergence. The thicker and older plate subduces under the other plate. As the thicker plate descends, it is heated and melted and its materials are incorporated into the mantle. The fast subduction originates magma. In the western Pacific crust is old and thick, and hence it submerges easier in the mantle.

Metamorphism provokes structural and mineralogic reordering in an original preexisting rock, under the influence of factors such as temperature and pressure, which are two of the most important and influencing ones.

This physic-chemical processes usually occur in deepness, many times related to plates movement and subduction processes. The sharped temperature rising might be caused by magma injection or by a deep placement or the original rock in a subduction zone.

According to the metamorphism processes, there are different kinds of metamorphic rocks. Metamorphic rocks that are the product of subduction event, belong to "regional metamorphism" which includes a huge area, and among this classification, "underground metamorphism" is associated with plates subduction, with a range temperature among 400-600ºC.