Metamorphism Flashcards
What happens to minerals to become more stable?
-minerals RECRYSTALLISE to a more stable form
What is the texture of metamorphic rocks?
- crystalline
- non folded
- metamorphic crystals have random orientation and may cut across sedimentary features
What the key parent rocks in contact metamorphism and what do they change into?
- Imst -> marble (reacts with acid)
- sst -> metaquartzite (doesn’t react with acid)
- shale -> spotted rock (slate)
What does granoblastic mean?
-equal size crystals
What does porphyroblastic mean?
- big and small crystals
- big crystals form first
What changes during contact metamorphism?
Temperature only
What changes during regional metamorphism?
Temperature and pressure
What changes during blueschist metamorphism?
Pressure only
How can you tell the rock has undergone metamorphism for a long time?
Large crystals
What are the key rocks in regional metamorphism?
Slate
Schist
Gneiss
What does foliation mean?
minerals within the rock have aligned within the rocks to create strips along it during metamorphism
What is non-foliation?
The metamorphic rock does not contain minerals that will align itself
