Quiz 3 Flashcards
METAMORPHIC ROCK
1
Q
Metamorphic Rock Definition
A
-the process of changing the characteristics of a rock by changes in the pressure, and temperature.
2
Q
Characteristics of Metamorphic Rock
A
- doesn’t change rock composition
- Alters minerals and texture
- No Melting, but fluids (think H20) can be important
- Majority is found in Eastern Canada
3
Q
Causes of Metamorphism
A
Increases in:
- Pressure
- Temperature
4
Q
Two Types of Pressure
A
- Confining pressure (uniform pressure)
* Stress (directional pressure, differential pressure)
5
Q
Pressure can cause
A
- Growth or dissolution of crystals
- Change in crystalline structure
- Texture or “fabric”
6
Q
Controls on Metamorphism
A
- Metamorphic grade
- Water
7
Q
Metamorphic Grade
A
- refers to the combination of pressure and temperature
- Low grade < or equal to 10km
- High Grade > or equal to 20km
8
Q
Water’s Affects on Metamorphism
A
- Facilitates mineral growth by easing movement of ions
* When it moves through system, composition can change
9
Q
Kinds of Metamorphism
A
Regional, Catalectic, Burial, Hydrothermal, Burial, Regional & Contact
10
Q
Regional Metamorphism
A
- Widespread (most common)
- Medium to high grade
- Differential pressures -> fabric
- Cores of mountains
11
Q
Cataclactic Metamorphism
A
- High stresses/faulting
- Mechanical crushing and shearing
- Fluid interactions
12
Q
Hydrothermal Metamorphism
A
- Moving hot water
- Metasomatism
- Common near mid-ocean ridges
- Produces important resources
a. Sulfides and ore bodies
b. Origin of life (or refugia…)
13
Q
Burial Metamorphism
A
- Thick sedimentary blanket
- Low grade
- Rocks retain primary structures
14
Q
Contact Metamorphism
A
- High T, low P “halo” around intrusions
- Grade decreases away from intrusion
15
Q
Naming Metamorphic Rocks
A
-Based on minerals, texture and source rock or “protolith”
