Metamorphic rock

Metamorphic rock is a type of rock that has undergone transformation by heat, pressure, or other natural agencies, such as the colliding of tectonic plates or the impact of meteorites.

Formation

Metamorphic rocks are formed from pre-existing igneous, sedimentary, or older metamorphic rocks. The process of metamorphism involves the mineralogical and structural adjustment of the original rock, known as the protolith, to the physical and chemical conditions imposed at depth in the Earth's crust and mantle. This process is driven by heat and pressure that is sufficient to break the chemical bonds that hold the minerals together.

Types of Metamorphic Rocks

There are two main types of metamorphic rocks: foliated and non-foliated.

Foliated Rocks

Foliated metamorphic rocks are formed within the Earth's crust and tend to have a layered or banded appearance, caused by the alignment of minerals within the rock. Examples of foliated rocks include slate, schist, and gneiss.

Non-Foliated Rocks

Non-foliated metamorphic rocks do not have a layered or banded appearance. Their mineral grains grow and rearrange, but they don't form layers. Examples of non-foliated rocks include marble and quartzite.

Uses of Metamorphic Rocks

Metamorphic rocks have various uses in construction and decoration. For example, marble is widely used in architecture and sculpture, while slate is often used for roofing and flooring.

See Also

• Igneous rock
• Sedimentary rock
• Rock cycle