READING QUESTIONS: Metamorphic Rocks
NAME________________________
GEOL 131
DUE: Tuesday, February 9th
Winter 2016
47 pts
All answers should be in your own words.
What is Metamorphism? (p. 102-103)
1. What is meant by the statement “Every metamorphic rock has a parent rock”? (2 pts) ______________
__________________________________________________________________________________
2. Which of the following are aspects of a rock that can change during metamorphism? (Circle all that
apply).
a. Mineral composition
b. Chemical composition
c. Texture
d. None of the above
3. Define metamorphic grade.(2 pts) ________________________________________________________
__________________________________________________________________________________
What Drives Metamorphism? (p. 103-106)
4. List the four agents of metamorphism. (2 pts)
a. ___________________________________
b. ___________________________________
c. ___________________________________
d. ___________________________________
5. Why is heat the most important agent of metamorphism? (2 pts) _______________________________
_________________________________________________________________________________
_________________________________________________________________________________
6. How are confining pressure and differential stress different? (Mark one answer.)
a. Confining pressure is greater in one direction than others; differential stress is equal in all
directions
b. Differential stress is greater in one direction than others; confining pressure is equal in all
directions
c. Differential stress is produced in tectonic plate collisions; confining pressure is produced by
burial
d. Confining pressure is produced in tectonic plate collisions; differential stress is produced by
burial
e. A and C
f. B and D
g. B and C
h. A and D
i. These two kinds of pressure are essentially the same
7. What role do chemically active fluids play in metamorphism? (2 pts) ____________________________
___________________________________________________________________________________
___________________________________________________________________________________
8. EXTRA CREDIT: List the three sources of water for chemically active fluids. (3 pts)
a. ___________________________________________________________________
b. ___________________________________________________________________
c. ___________________________________________________________________
Metamorphic Textures (p. 106-109)
9. Define foliation. (2 pts) _______________________________________________________________
___________________________________________________________________________________
10. Match each of the following foliations with the correct picture on the next page. Write the letter of your
answer on the line beneath the picture. (3 pts)
a. Slaty cleavage
b. Schistosity
c. Gneissic banding
_______
______
______
11. Name and describe the three ways in which the mineral grains in a rock develop preferred orientation.
(5 pts)
a. ____________________________________________________________________________
____________________________________________________________________________
b. ____________________________________________________________________________
____________________________________________________________________________
c. ____________________________________________________________________________
____________________________________________________________________________
12. Define nonfoliated texture. ____________________________________________________________
13. What type of environment does nonfoliated texture typically develop in? (2 pts) _________________
__________________________________________________________________________________
_________________________________________________________________________________
Common Metamorphic Rocks (p. 109-112)
14. The rocks slate and phyllite are similar in appearance. How might you distinguish them from each other?
(2 pts)
____________________________________________________________________________________
____________________________________________________________________________________
15. Match the rocks slate, phyllite, schist, and gneiss to the correct descriptions of their textures and grain
sizes. (2 pts)
a. Slate
Coarse-grained; banded foliation
____
b. Phyllite
Very fine-grained; smooth flat surfaces
____
c. Schist
Medium- to coarse-grained; scaly foliation with abundant mica
____
d. Gneiss
Fine-grained; wavy foliation and glossy sheen
____
16. Name one way in which marble and quartzite are similar, and two ways they are different. (3 pts)
a. Same: ________________________________________________________________
b. Different: _____________________________________________________________
_____________________________________________________________________
Metamorphic Environments (p. 112-115)
17. In which type of metamorphism does differential stress play a major role?
a. Subduction zone
b. Burial
c. Hydrothermal
d. Contact
e. None of the above
18. List two metamorphic rocks that are produced by hydrothermal metamorphism. (2 pts)
a. ________________________________________
b. ________________________________________
19. What is a metamorphic aureole? (2 pts) __________________________________________________
__________________________________________________________________________________
20. Besides heat, which of the other three metamorphic agents plays the most important role in
hydrothermal metamorphism? ________________________________________________
21. Which tectonic plate boundary is associated with regional metamorphism?
a. Subduction zone
b. Continental collision
c. Divergent
d. All of the above
22. List five metamorphic rocks commonly produced by regional metamorphism. (5 pts)
a. _____________________________________
b. _____________________________________
c. _____________________________________
d. _____________________________________
e. _____________________________________