UPCAT Earth Science Complete Practice Test 2025

During metamorphism, rocks are subjected to high temperatures and pressures, which can lead to the recrystallization of their minerals, effectively transforming their structure and composition. Metamorphic rocks are specifically defined as rocks that have undergone this metamorphic process, characterized by changes such as new mineral formation, changes in texture, and increased hardness.

While igneous and sedimentary rocks can also metamorphose and become metamorphic rocks, the direct process of recrystallization is primarily associated with the transformation of existing rocks into metamorphic varieties. Thus, the understanding is that it is metamorphic rocks that are the result of this recrystallization process when subjected to a metamorphic environment, and they carry the evidence of the changes that occurred during this transformation.

The other types of rocks can become metamorphosed through processes that include recrystallization but are not themselves defined by the process. While they can lead to the formation of metamorphic rocks, they are not classified as metamorphic until they have experienced the requisite conditions that induce metamorphism.