Metamorphic Rocks: Understanding the Process

What is the metamorphic process that takes place if a rock composed of clay and quartz transforms into a rock with garnet and mica?

A. Phase change

B. Recrystallization

C. This scenario is impossible

D. Neocrystallization

Answer:

D. Neocrystallization

Metamorphic rocks arise from the transformation of existing rock into new types of rock in a process called metamorphism. The original rock, known as the protolith, is subjected to high temperatures and pressure, causing significant physical or chemical changes. During this process, the rock remains mainly in the solid state but gradually recrystallizes into a new texture or mineral composition. The protolith can be an igneous, sedimentary, or existing metamorphic rock.

Metamorphic rocks make up a substantial portion of the Earth's crust and constitute 12% of the Earth's land surface. They are classified based on their protolith, chemical and mineral composition, and texture.