Match the type of metamorphic rock (lower case letters) with the tectonic envior
ID: 156092 • Letter: M
Question
Match the type of metamorphic rock (lower case letters) with the tectonic enviorment ( Upper case letter). In other words Right the appropriate upper case letter (A,B, or C) after the type of metamorphic rock (a,b, or c)
a. Medium-pressure/Medium temperature metamorphic rock
b. High-pressure/low-temperature metamorphic rock
c.Low-pressure/high-temperature metamorphic rock
A. Mid levels of typical continental crust
B. Near contact of pluton in upper continental crust
C. Subduction zones (specifically subduction complexes)
Explanation / Answer
1. C->b
This type of metamorphism occurs at subduction zones. Here, high pressures result when one plate is submerged under the mantle. Temperatures remain relatively low because the crust that forms the upper part of the subducting plate is cool, having been close to the Earth's surface. As the plate subducts, it actually cools the mantle. The subducting plate reaches high pressures faster than it heats to high temperatures, and this pressure is enough to cause metamorphism.
2.
B->c
some metamorphic rock forms at high temperatures with low pressures. This occurs near hot intrusions of magma from the mantle into the crust. Rock that is in contact with these intrusions undergoes contact, or thermal, metamorphism. This heat causes minerals to react with each other, which produces new minerals.
3.
A->a