How does contact metamorphism differ from region metamorphism?

Hint: Metamorphism is the process of mineralogical structural adjustment of pre-existing rocks due to physical and chemical conditions. The word metamorphism has entomological roots in ancient Greek and means “after form”. Metamorphism occurs at temperatures higher than 200°C and pressures higher than 300 MPa which mostly take place during continental collisions or subduction. The increase in temperature and pressure on the rocks is called prograde metamorphism or the grade of metamorphism. A lower grade of metamorphism takes place between the temperatures of 200-320°C and higher grade of metamorphism takes place above 320°C.

Complete answer: Apart from grades, metamorphism can also be subdivided into various types based on the process itself. Here are the basic differences between two such categories.



Note: Based on various processes of metamorphism, two types of metamorphic rocks are formed— foliated and nonfoliated. Examples of foliated rocks are slate, phyllite, schist, gneiss, etc and examples of non-foliated rocks are marble, quartzite, hornfels, anthracite coal, etc.