Question

4. Metamorphic rocks​

Answer 1

Answer:

Metamorphic rocks arise from the transformation of existing rock to new types of rock, in a process called metamorphism. The original rock is subjected to temperatures greater than 150 to 200 °C and, often, elevated pressure, causing profound physical or chemical changes. 

Answer 2

Answer:

Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors.