Lec 6: Metamorphic Rocks

Question 1

Lecture’s goals:

1_ Compare and contrast the different means by which rocks can undergo metamorphism and the various settings where these types of metamorphism occur

2_ Describe the difference between “foliated” and “non-foliated” rocks and list examples of each.

3_ Recognize why engineers must be mindful of metamorphic rocks and their properties.

Answer 1

Lecture’s goals:

1_ Compare and contrast the different means by which rocks can undergo metamorphism and the various settings where these types of metamorphism occur

2_ Describe the difference between “foliated” and “non-foliated” rocks and list examples of each.

3_ Recognize why engineers must be mindful of metamorphic rocks and their properties.

Question 2

Lecture’s goals:

1_ Compare and contrast the different means (3 ways) by which rocks can undergo metamorphism and the various settings where these types of metamorphism occur

Answer 2

Metamorphism means the change form of rocks. Specifically, the description of relative temperature and pressure conditions under which metamorphic rocks form.

3 agents:
1_ heat
2_ pressure
3_ chemically active fluids

Metamorphic grade (low grade to high grade) with depth:
slate -> phyllite -> schist -> gneiss -> granite

Question 3

Lecture’s goals:

2_ Describe the difference between “foliated” and “non-foliated” rocks and list examples of each.

Answer 3

Foliation texture alters with increasing grades of metamorphism
Examples: (low grade-coarse) Sedimentary rock: shale to (high grade-smooth) igneous rock

Foliated rocks: slate (fine-grained, excellent cleavage, results from low-grade metamorphism of shale)

If heat is involved, no foliation (unless there is also pressure)

example of non-foliated metamorphic rocks: quartzite

Question 4

Lecture’s goals:

1_ The various settings where these types of metamorphism occur

Bonus: Which direction was the pressure applied to the rock?

Answer 4

2 types of settings:

1_ contact: due to heat from adjacent rocks.
2_ regional: occurs in the core of subduction zones

Bonus: Perpendicular to the pattern

Question 5

Which of these metamorphic rocks would be best for making a bowling ball?

A: quartzite
B: Slate
C: Schist
D: Phyllite
E: Marble

Answer 5

A: Quartzite

Question 6

Lecture’s goals:

2_ Describe the difference between “foliated” and “non-foliated” rocks.

Answer 6

Non-foliated metamorphic rocks are stronger than foliated rocks