Lesson 9: Metamorphic Rocks

Question 1

Metamorphism

Answer 1

Transform

Question 2

Metamorphic grade

Answer 2

the degree that the parent rock changes during metamorphism

Question 3

Metamorphic agents:

Answer 3

1. Temperature
2. Pressure
3. Hot fluids

Question 4

How does temperature and pressure affect metamorphism?

Answer 4

low temperatures and pressures have a low metamorphic grade.
high temperatures and pressure have a high metamorphic grade.

Question 5

Compare the metamorphic textures.

Answer 5

Foliated: when differential stress causes the platy mineral crystals to slide parallel to and past one another
Non-foliated: crystalline texture

Question 6

What are the 4 types of foliated metamorphic rocks?

Answer 6

1. Slate - rock splits into thin sheets
2. Phyllite - wavy and/wrinkled; with a satiny or metallic luster
3. Schist - platy minerals are discernible with the naked eye
4. Gneiss - dark and light bands that does not split as easily as the other foliated rocks

Question 7

What are the 3 types of non-foliated metamorphic rocks?

Answer 7

1. Quartzite - sandy texture
2. Marble - crystalline texture
3. Hornfels - fine-grained

Question 8

What is a protolith?

Answer 8

The original parent rock

Question 9

What are the protoliths of marble?

Answer 9

Limestone
Dolostone

Question 10

What is the protolith of quartzite?

Answer 10

Quartz sandstone

Question 11

What is the protolith of slate?

Answer 11

Shale

Question 12

What is the protolith of phyllite?

Answer 12

Shale

Question 13

What is the protolith of schist?

Answer 13

Shale

Question 14

What is the protolith of gneiss?

Answer 14

Shale

Question 15

What are the metamorphic environments? (5)

Answer 15

1. Contact/thermal metamorphism
2. Hydrothermal metamorphism
3. Burial metamorphism
4. Subduction zone metamorphism
5. Regional metamorphism

Question 16

What is mylonite?

Answer 16

Rocks formed in regions where minerals form a foliated or lineated appearance

Question 17

What is impact metamorphism?

Answer 17

What occurs when asteroids/comets strike the Earth’s surface which produces fused fragmented rock plus glass-rich ejecta that resemble volcanic bombs.

Question 18

A metamorphosed equivalent of a limestone would be a ___.

Answer 18

marble

Question 19

Gneiss _____________.

Answer 19

shows dark and light bands of minerals.

Question 20

A place where rocks are probably being subjected to contact metamorphism.

Answer 20

A mile under St Helens

Question 21

Which of the following metamorphic rocks displays a foliated texture?
a. marble
b. quartzite
c. schist
d. hornfels

Answer 21

c. schist

Question 22

Which of the following is not a useful metamorphic mineral?
a. quartz; used to make glass
b. diamond; used to make saw blades, drill bits, and gemstones
c. graphite; used in lubrication and to make pencil leads
d. garnet; used in abrasives and to make gemstones

Answer 22

a. quartz; used to make glass

Question 23

Which of the following is not an agent of metamorphism?
a. gravity
b. heat
c. pressure
d. fluid activity

Answer 23

a. gravity

Question 24

The original (parent) rock that has undergone metamorphism is called the _____.

Answer 24

protolith

Question 25

Which foliated texture would be most likely to develop in beds of shale with low-grade metamorphism?
a. schistosity
b. fissility
c. gneissic branding
d. slaty cleavage

Answer 25

d. slaty cleavage

Question 26

What is a common parent rock of slate?
a. granite
b. shale
c. limestone
d. conglomerate

Answer 26

b. shale

Question 27

___ ______ produces the greatest quantity of metamorphic rock.

Answer 27

regional metamorphism