Lecture 9: Metamorphic Rocks Flashcards
When do Metamorphic changes occur?
When a rock is subjected to new temperatures and pressures
What are the 3 types of Metamorphism?
- Contact
- Burial
- Regional
What occurs in Contact metamorphism?
Hot magma rises to the surface of the crust and heats adjacent cooler rocks
What occurs in Burial metamorphism?
Sediment is buries and accumulates under moderate temperatures
What occurs in Regional metamorphism?
Rock is buried deep into the crust and elevated pressures and temperatures cause is transform
What are the rocks that Shale transforms into in metamorphism?
Shale➡️ Slate➡️ Phyllite➡️ Schist➡️ Gneiss
What in the rock changes with Metamorphism?
Texture and Minerals
What is Metasomatism?
When hot fluids produced during metamorphism that contain dissolved ions react with rocks and change their chemical composition
What is usually seen in Isograds?
Highest grade minerals are usually surrounded by low grade minerals
What is Foliation?
When pressure causes the minerals in a rock to alight causing a certain orientation
What is an example of a foliated rock?
Gneiss
What is an example of a non-foliated rock?
Marble
What changes with rocks in Metaorphism?
Texture
Crystal size
Mineralogy
What are some of the reasons that some rocks don’t have foliation?
- They are not composed of materials that naturally align
* The rocks were not subjected to regional metamorphism
What are some examples of Non-foliated rocks?
Quartzite
Marble
Granulite
