Short note of metamorphic rock

The metamorphic rocks make up a large part of the Earth’s crust and are classified by texture and by chemical and mineral assemblage. They may be formed simply by being deep beneath the Earth’s surface, subjected to high temperatures and the great pressure of the rock layers above it.

Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means “change in form”. The original rock is subjected to heat with temperatures greater than 150 to 200°C and pressure around 1500 bars, causing profound physical and/or chemical change.

 metamorphic rock is a type of rock which has been changed by extreme heat and pressure.

The types of metamorphic rocks depend upon the original rocks that were subjected to metamorphism. Metamorphic rocks are classified into two major types:

(i)foliated rocks 

(ii)non-foliated rocks

Formation of metamorphic rocks : These rocks are formed due to thermal metamorphism.

It is of two types :

(i)Contact metamorphism: In contact metamorphism the rocks come into the contact with hot magma and lava and the rock material is recrystallized under high pressure and temperature.

(ii)Regional metamorphism: In regional metamorphism, rocks under go recrystallization due to deformation caused by tectonic shearing together with high temperature or pressure or both.