Term
|
Definition
alteration of pre-existing rocks by T & P (fluid)
-changes mineralogy, texture &/or chem. composition |
|
|
Term
|
Definition
T increase w/ depth
-T increase average of 30 degrees C, depending on lithosphere thickness |
|
|
Term
Heat Sources
-Contact metamorphism |
|
Definition
Igneous activity
Local-scale events
-Temperature related |
|
|
Term
Pressure Sources
-Regional metamorphism |
|
Definition
Plate tectonic activity
convergent boundaries force rocks to collide
-large scale events, T increase also involved |
|
|
Term
Pressure
-Confining Press
-Directed Press |
|
Definition
most met. rocks form 10-30 km depth (mid-lower crust) P increase ~ 300 bar/km
-applied equally in all directions
- force exerted in a particular direction |
|
|
Term
| High Pressure Metamorphism |
|
Definition
Ultra high P: >28kbar
Depths >30 km
Unusual minerals, including coesite and diamond |
|
|
Term
|
Definition
rock formed near the base of the crust
-large outcrops are known |
|
|
Term
|
Definition
Meteorite Collision
10s-100s kbar
T increase also plays a role due to energy released as heat |
|
|
Term
|
Definition
partially melted country rock
-and unusual high-P minerals (coesite) |
|
|
Term
|
Definition
| As fluid moves upward, it interacts with rocks adding new components |
|
|
