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Ali Hamza
Ali Hamza
Mechanical
24 Jan 2019

What are the types of Metamorphic Rocks??

Types of metamorphism

Depending upon the dominance of one or the other of the above agents, the metamorphism has been classified as follows

Thermal metamorphism 

Dynamo-thermal metamorphism 

Cataclastic metamorphism 

Metasomatism

Regressive metamorphism

Metamorphic zones

The degree or intensity of metamorphism generally increases with depth because as the depth increases temperature and pressure also increase. From the earth’s surface downwards there are three metamorphic zones. 

Epizone or upper zone

Mesozone or intermediate zone

 Katazone or lower zone

Grade of metamorphism

The grade of metamorphism varies directly with the amountof heat and pressure to which the rocks have been subjected. 

For example, slate and phyllite which show a low grade of metamorphism, are formed away from the intrusive igneous body, while a high grade metamorphic rock like gneiss, is formed near its margin. 

 The increase in the grade of metamorphism is also accompanied by an increase in grain size. For example, slate and phyllites are fine grained, while schists and gneisses are coarse grained.