Question

How does heat and pressure affect metamorphic rocks?

Answer 1

Hint: Metamorphic rocks begin as igneous, sedimentary, or other metamorphic rocks. These rocks get changed when heat or pressure alters the existing rock’s physical or chemical makeup.

Complete answer:
One-way rocks might change during metamorphism by rearrangement of their mineral crystals. When heat and pressure change the environment of the rock, the crystals might respond by rearranging their structure. They will form new minerals that are much stable in the new environment.
Extreme pressure might lead to the formation of foliation, or flat layers in rocks that form as the rocks are squeezed by pressure. Foliation normally forms when pressure was exerted on a rock from only one direction. If the pressure is exerted from all directions, then the rock will not show foliation.
The state of stress, compaction of such grains, cementation and the brittleness of the rocks increases due to the heat and pressure There are two main types of metamorphism:
Contact metamorphism occurs when magma does contact with rock, changing it by extreme heat or say too much temperature. Regional metamorphism occurs eventually when great masses of rock change over a wide area due to the pressure exerted on rocks at the plate boundaries.
Regional metamorphism generally transforms large areas of existing rocks under the tremendous heat and pressure created by tectonic forces.

Note: It is important to note that metamorphism does not cause any complete melting of those initial rocks. It only causes changes to rock either by heat or pressure. The rearrangement of the mineral crystals is the most common way that we notice these kinds of changes.