Metamorphism

Question 1

Regional metamorphism

Answer 1

Formed by intense PRESSURE

Example: Plate collision zone, where pressure exerted deforms the rocks. These rocks often look foliated

Question 2

Contact metamorphism

Answer 2

Formed by intense HEAT

Example: Magma is rising from mantle, rocks surrounding it are being deformed by the intense heat. But not to a point where they melt– NO MELTING! Otherwise these rocks would be igneous rocks.

Question 3

Hydrothermal metamorphism

Question 4

Metamorphism

Answer 4

Change of minerals and/or alignment of minerals in pre-existing rocks (protolith) without melting of the protolith (into magma). High pressure and temp but not to the point of melting (that would form igneous rock)

Question 5

Index Minerals

Question 6

Metamorphism at subductive zones

Answer 6

Pressure high
Temp low (cold, dense, hard oceanic plate, also cold relative to mantle around it)

Question 7

Blueschist facies

Answer 7

Found:
where P high and T low
Ocean-cont have lower temp than cont-cont collision

Color:
Actually blue because of presence of mineral called gluacophane (INDEX MINERAL)

Protolith:
Basalt or gabbro (not eg limestone cuz that is mainly carbon, not enonugh silica)

Fun fact: if found on surface it means the surface you are looking at ancient ocean floor that has been involved in subduction, then has now been lifted up/ (RARE)

Question 8

Eclogite facies

Answer 8

Formed under:
High P and T

Contains:
Garnet (red)
Pyroxene (green)
and sometimes diamonds

Fun fact:
Even more rare than blueschist facies because they are formed even deeper

Question 9

Barrovian Sequence