How Are Metamorphic Rocks Formed?

How are metamorphic rocks formed? If you have wondered about the answer to this question, then you don't need to look any further. Just as the name imples, metamorphic rocks start out as some other kind of rock and they are some how substantially changed. The change usually comes from exposure to high heat, high pressure or hot fluids that are rich in minerals. It is also possible for the change to come froma a combination of these factors.

Foliated metamorphic rocks. Foliated metamorphic rocks often form near where there are tectonic plates inside the earth. A huge amount of pressure is comes down on the rock making flatten out.  This pressure is not enough to cause new minerals to form, but it is enough to cause the shape to change and a change in the arrangement of the minerals. The pressure can also cause the minerals to form in to bands. These are the rocks that you can actually see the stripes of different colors.

Nonfoliated metamorphic rocks. Nonfoliated metamorphic rocks form in basins where sedimentary rocks have collected. Down under the rocks there is enough pressure from the build up of materials, and there is also geothermal heat from inside the earth. This changes the make up of these sedimentary  rocks. Since the pressure is not a direct pressure the metamorphic rocks that are formed are nonfoliated, which means that you can't see different bands of colors.

Dynamothermal metamorphic rocks. These types of rocks formed as the mountains built up years and years ago when tetonic plates collided. The erosion that happens over time has exposed the metamorphic rock that formed. As the plates collided, it caused  temperatures to change and built up pressure forming the metamorphic rocks. The magma would also come up and increase the amount of heat and change the formation of the rocks.