Metamorphic rocks are formed from pre-existing rocks (called parent rocks) that undergo changes due to heat, pressure, or mineral exchange. This process is called metamorphism, and it typically occurs deep within Earth’s crust, where conditions are suitable for transforming the original rock’s mineral composition, texture, and/or structure. Here’s a summary of how metamorphic rocks are formed:
- Heat: When parent rocks are exposed to high temperatures, the heat can cause minerals to become unstable, break down, and recrystallize into new minerals. This can happen when rocks come into contact with hot magma or lava (contact metamorphism) or when they are buried deep within the Earth’s crust, where temperatures rise due to the geothermal gradient (regional metamorphism).
- Pressure: As rocks are buried deeper within the Earth’s crust, they experience increasing pressure from the weight of the overlying rocks. This pressure can cause minerals to recrystallize and form new, denser structures. In some cases, the pressure can be so intense that it forces the minerals to reorganize and create a foliated or banded texture in the rock.
- Mineral exchange: When parent rocks are exposed to hot fluids, such as water or other volatile substances, the fluids can facilitate the exchange of ions between minerals. This process, called metasomatism, can lead to the formation of new minerals and the alteration
During the metamorphic process, the parent rock’s mineral composition, texture, and/or structure may change, giving rise to a new rock with different characteristics. Examples of metamorphic