Metamorphic Rocks

These flashcards cover the key concepts related to metamorphic rocks, including definitions and characteristics of various types of metamorphism and metamorphic rocks.

Metamorphic Rocks

Rocks formed from igneous, sedimentary, or other metamorphic rocks due to changes caused by temperature and pressure without melting.

Metamorphism

The process that causes changes in minerals, texture, and sometimes chemical composition deep within the Earth.

Recrystallization

The process where original stable minerals grow larger under heat and pressure.

Chemical Breakdown

The process where unstable minerals break down and new stable ones form.

Rotation

The reorientation of minerals due to high pressure.

Agents of Metamorphism

Heat, pressure, and chemically active fluids that cause textural and mineralogical changes.

Low-Grade Metamorphism

Weak metamorphism where the original rock slightly changes state.

High-Grade Metamorphism

Strong metamorphism that completely changes the rock, losing its original identity.

Contact Metamorphism

Metamorphism occurring when rocks are heated by nearby magma due to temperature increases from molten material.

Dynamic Metamorphism

Metamorphism occurring along fault zones where rocks are broken and crushed by crustal movements.

Regional Metamorphism

Large-scale metamorphism during mountain building, where rocks experience increased pressure and temperature.

Foliation

Layered or banded texture caused by minerals aligning in parallel due to pressure.

Slaty Cleavage

Low-grade metamorphism where shale becomes slate; splits into flat slabs.

Schistosity

Texture formed under higher temperature and pressure where mica grains grow larger, forming schist.

Gneissic Texture

High-grade metamorphic texture where minerals segregate into light and dark bands.

Non-Foliated Rocks

Metamorphic rocks without layered or banded textures, e.g., marble.

Slate

Fine-grained foliated rock formed from low-grade metamorphism of shale; breaks into thin sheets.

Schist

Strongly foliated rock that splits into thin flakes or slabs; formed from stronger metamorphism of shale.

Gneiss

High-grade metamorphic rock formed from shale or granite; exhibits a banded appearance.

Marble

Coarse, crystalline, non-foliated rock formed from metamorphism of limestone.

Quartzite

Very hard, non-foliated metamorphic rock formed from metamorphism of quartz sandstone.