Metamorphic Rocks

Question 1

What is metamorphism

Answer 1

metamorphic rocks formed by transformation of pre-existing rocks under influence of high temps + pressure

Question 2

what are the 2 types of metamorphism

Answer 2

contact metamorphism
regional metamorphism

Question 3

Define contact metamorphism

Answer 3

pre-existing rock heated under uniform pressure
heated by intrusion of magma

Question 4

Define regional metamorphism

Answer 4

pre-existing rock heated under differential stress (uneven pressure)
Regionally metamorphosed rocks have squashed or foliated appearance

Question 5

Foliation in contact metamorphism

Answer 5

Pressure is uniform
- grains fo platy material + elongate material + amphibole retain random orientation

Question 6

Foliation in regional metamorphism

Answer 6

occurs where 2 lithospheric plates are pressing against one another
- platy/elongate minerals line up to produce foliated texture

Question 7

Define bedding (stratification)

Answer 7

a sedimentary characteristic, produced by arrangement of sediment in horizontal layers

Question 8

Define foliation

Answer 8

uniquely metamorphic characteristic, produced by alignment of platy/elongate minerals

Question 9

What is metamorphic grade

Answer 9

describing relative temperature + pressure conditions under which metamorphic rocks form
Increase intensity in metamorphism
- increase size of mineral grains + development of distinct foliation

Question 10

Increase metamorphism of SHALE

Answer 10

Shale -> Slate -> Phyllite -> Schist -> Gneiss

Question 11

Is foliation more noticeable w/ increasing metamorphic grade?

Answer 11

Yes, this is due to the increasing degree of alignment + size of platy/elongate grains