Metamorphism and Metamorphic Rocks

Flashcards covering key concepts from the chapter on metamorphism and metamorphic rocks, including definitions of important terms and processes.

Metamorphism

Changes in rock due to temperatures or pressures different from where they formed.

Parent rock

The original rock type (metamorphic, igneous or sedimentary) that is subjected to metamorphism.

Chemically active fluids

Fluids that can cause changes in mineral composition during metamorphism.

Foliation

The layered or banded texture resulting from directed pressure in metamorphic rocks.

Index minerals

Minerals that indicate the intensity of metamorphism based on their stability at specific temperatures.

Low-grade metamorphism

Metamorphism occurring at lower temperatures, typically near 200°C, exemplified by the mineral chlorite.

High-grade metamorphism

Metamorphism occurring at higher temperatures, around 600°C, exemplified by the mineral sillimanite.

Confining pressure

Uniform stress that applies equal force in all directions, resulting in harder and denser rocks.

Directed pressure

Unequal pressure in different directions that leads to distortion in a rock's structure.

Metasomatism

The process by which the chemical composition of a rock changes due to chemically active fluids.