Metamorphic Rocks
Metamorphic rocks have been changed from a pre-existing rock. Caused by extreme heat and/or pressure.
Regional Metamorphism Caused by extreme pressure and heat. Happens over wide “regions”.
Contact Metamorphism Caused by contact with extreme heat.
Meta. rocks will often have foliation or a distorted structure.
Distorted Structure
Foliation is a “grain” to the rock.
Types of Foliation: Gneissic Foliation- minerals are squished into bands. “Zebra Stripes”
Bands Layers Banding vs. Layers
Schistose foliation- minerals have been squashed into flakes of mica.
Slaty foliation- Rock splits into flat, thin layers.
Take out your Handy Dandy Earth Science Reference Tables Page 7.
Slate Phyllite + = +
Phyllite Schist + = +
Gneiss + = +