Metamorphic Rocks

Sandstone: Quartzite, Metaquartzite

Shale: Phyllite

Slate

Schist

Gneiss

Limestone: Marble

Metamorphism of Sedimentary Rocks

Types of Metamorphism

Contact Metamorphism:The main metamorphic agent is heat.

Progression of metamorphism

Slate

Phyllite Schist

Start with a shale and then hitit with pressure and heat.

You end up with something that is really Gneiss!

Introduction to Metamorphic Rocks

Metamorphism is the solid-state transformation of pre-existing rock into texturally or mineralogically distinct new rock as the result of high temperature, high pressure, or both.

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

+

=

+

Schist

Gneiss

+

=

+

How does Metamorphism Relate to Plate Tectonics?

T and P increase at collisional (convergent) plate boundaries.