Metamorphic Rocks
What is a metamorphic rock? Rock formed from other rocks as a result of intense heat, pressure, or chemical processes. There are two types of metamorphism, contact and regional.
Contact Metamorphism Occurs when magma comes into contact with rocks. Only rocks extremely close or touching the magma are affected. The heat from the magma can change the structure and mineral composition.
Regional Metamorphism Caused by the movement of 1 tectonic plate against another. This friction causes extreme heat and pressure that can change a rock’s structure and mineral composition. Occurs over wide areas.
Metamorphic Rocks Cascade Peak held up by Cascade River Schist on the middle left. Next right is Mixup Mountain, carved from Magic Mountain Gneiss. Eldorado Peak underlain by the Eldorado Orthogneiss is on the skyline, left. 3 2 1
Foliation Foliation is layering within a metamorphic rock. Foliation is caused by heat and pressure.
Common Foliated Rocks Schist
Gneiss
Slate
Common non-foliated Rocks Marble
Quartzite
Anthracite Coal
Parent Rock Metamorphic Sandstone Granite Limestone Shale Bituminous Coal Quartzite Gneiss Marble Slate or Schist Anthracite Coal