Metamorphic Rocks Quiz: Test Your Knowledge of Metamorphic Rock Formation

Study Notes

Geology defines three high-level rock categories: Igneous, Sedimentary, and Metamorphic rocks.

Metamorphic rocks are defined as rocks that have changed from their original form due to heat, pressure, and chemical reactions.
A key point in the definition of metamorphic rocks is that they do not melt during the transformation process.
The two most common types of metamorphism are contact metamorphism and regional metamorphism.

According to the principles of thermodynamics, all things try to reach a state of lower energy or equilibrium.

Metamorphic rocks form when a preexisting rock, called the protolith, experiences metamorphism.
The protolith can be any type of rock, and it undergoes changes in mineral composition, structure, or texture due to heat, pressure, and chemical reactions.
Examples of common protolith and resulting metamorphic rock include:
- Limestone → Marble
- Shale → Slate
- Basalt → Eclogite

Contact metamorphism occurs when magma intrudes into a rocks, causing a localized change in temperature and pressure.
This type of metamorphism is characterized by a distinct change in crystal structure, such as the transformation from limestone to marble.
Contact metamorphic rocks are distinguished by their distinctive mineral assemblages and textures.
The primary heat source for contact metamorphism is the magma.

Regional metamorphism occurs when rocks are subjected to increased pressure and temperature over a large area, such as during mountain-building events.
This type of metamorphism is characterized by a gradual change in mineral composition and structure over a large area.
Regional metamorphic rocks are distinguished by their widespread distribution and uniform mineral assemblages.
The formation of regional metamorphic rocks is caused by the movement of tectonic plates.
Regional metamorphism occurs on a much larger scale than contact metamorphism.