- Contact Metamorphism: A type of local, thermal metamorphism caused by the intrusion and extrusion of magmas; takes place in rocks at or near their contact with a body of igneous rock.
- Parent Rock: Rock from which soil, sediment, or other rock is derived.
- Regional Metamorphism: A type of metamorphism that affects an extensive region, as opposed to local metamorphism that is effective only in a relatively restricted area.
Metamorphic Rock Types
Foliated Metamorphic Rocks
As pressure squeezes on a parent rock during recrystallization it causes the platy or elongated minerals within the rock to become aligned, or foliated. Foliated rocks develop a platy or sheet-like structure that reflects the direction that pressure was applied in. Types of foliated metamoprhic rocks include slate, schist, and gneiss. Gneiss found at Antietam National Battlefield, Chesapeake and Ohio Canal National Historical Park, and Harpers Ferry National Historical Park record the ancient beginnings of the Appalachian Mountain belt.