Intro/Metamorphism Flashcards
The process of change or transformation of a pre-existing rock, in the solid state, into another rock due to heat, pressure and chemically active fluids
Metamorphism
A form of metamorphism due to hydrothermal fluids exchanging constituents with an external source.
Metasomatism
What are the different kinds of metamorphism
- Prograde Metamorphism
- Retrograde Metamorphism
- Local Metamorphism
- Regional Metamorphism
A kind of metamorphism where there is an increase in heat and pressure.
Prograde Metamorphism
A kind of metamorphism where there is a decrease in heat and pressure.
Retrograde Metamorphism
A kind of metamorphism that affects areas with less than 100 km².
Local Metamorphism
A kind of metamorphism that affects areas greater than 100 km² and is commonly associated with convergent and divergent plate boundaries.
Regional Metamorphism
Also known as “Protoliths,” are the original rocks from where the produced metamorphic rocks transformed from.
Parent Rock
Enumerate the agents of metamorphism
- Heat
- Pressure
- Chemically active fluids
An agent of metamorphism that provides energy for chemical reactions and recrystallization of minerals.
Heat
An agent of metamorphism that provides stress in equal directions or varying amounts in different directions.
Pressure
An agent of metamorphism that provides and enhances mobility of ions present.
Chemically active fluids
What are the two kinds of pressure?
- Hydrostatic pressure
- Lithostatic pressure
A type of pressure that is also called confining pressure, is a uniform or isotropic form of pressure, where pressure is equal in all directions, which usually produces equant grains and non-foliated texture of metamorphic rocks.
Hydrostatic pressure
A type of pressure also called burying pressure is a non-uniform or anisotropic form of pressure, where pressure is unequal in all directions, which usually produces inequant grains and foliated texture of metamorphic rocks.
Lithostatic pressure
What are the different types of metamorphism?
- Contact Metamorphism
- Hydrothermal Metamorphism
- Dynamothermal Metamorphism
- Burial Metamorphism
- Impact Metamorphism
- Dynamic Metamorphism
A type of metamorphism
-A variable pressure temperature, low metamorphism that develops locally where hot magma intrudes relatively cold, upper crustal country rock.
-What are the products of this metamorphism?
Contact Metamorphism
-Hornfels, metaquartzite, skarn
-A type of metamorphism that results from chemical alteration from circulating fluids within cracks and fissures. Pervasive at ocean-spreading ridges that experience tension, thinning and uplift, causes metasomatism.
-What are the products of this type of metamorphism?
Hydrothermal Metamorphism
-Alteration products, metallic ore deposits
A type of metamorphism
-A regional metamorphism induced by increase in pressure and temperature with non-uniform stress which produces foliated textures, mostly aerially extensive, and dominates convergent margins and associated fold and thrust belts.
-What are the products of this type of metamorphism?
Dynamothermal Metamorphism
-Greenschist, amphibolite, granulite, blueschist, eclogite
A type of metamorphism that results from an increase in lithostatic stress caused by deep burial of rocks and produces non-foliated textures, affects regional subsiding basins that accumulate thick sequences of sediments and volcanic debris, and usually starts at temperatures -150 °C to 300 °C and gradational with diagenesis at depths of about 8 km.
-What are the products of this type of metamorphism?
Burial Metamorphism
-Non-foliated rocks with low temp. mineral assemblages
A type of metamorphism
-A local form of metamorphism generated by explosive volcanic eruptions relatively rare collisions or of extraterrestrial objects with Earth, causing a high strain rate.
-What are the products of this type of metamorphism?
Impact Metamorphism
-“Impactites”, breccias, lamellae, shocked quartz pseudotachylites, coesite, stishovite
A type of metamorphism that is Induced primarily by non-uniform stress in fault zones and shear zones, where the high strain rate is mostly local but extend to a regional scale in large faults or shear zones, and most likely recur in the same fault or shear zone.
-What are the products of this type of metamorphism?
Dynamic Metamorphism
-Cataclasites, pseudotachylites, mylonites
