What are Metamorphic Rocks

These rocks form under the action of volume, pressure, and temperature (PVT) changes.

Metamorphism happens when rocks are forced down to lower levels by tectonic processes or when molten magma rising through the crust comes in contact with the crustal rocks or the underlying rocks are exposed to great amounts of pressure by overlying rocks.

The materials of rocks chemically modify and recrystallize due to thermal metamorphism.

There are two types of thermal metamorphism

1. Contact metamorphism
2. Regional metamorphism

1. Contact metamorphism
The rocks come in contact with hot intruding magma and lava and the rock materials recrystallize under high temperatures.

2. Regional metamorphism
The rocks experience recrystallization due to deformation caused by tectonic shearing together with high temperature or pressure or both.