Geol 101: Physical Geology
PAST EXAM QUESTIONS
LECTURE 15: METAMORPHIC ROCKS I
15. Which of the following statements about metamorphism is FALSE?
A. metamorphic rocks form from existing sedimentary, igneous, or metamorphic rocks
B. metamorphism involves melting of existing rocks to form new minerals
C. during metamorphism, existing minerals are transformed into new minerals
D. metamorphism is controlled by pressure, temperature, fluids, and time
E. metamorphic means “change of form”
15. The zone of metamorphism is above the zone of (1)________ but below the zone of (2)_________.
A. (1) diagenesis
(2) partial melting
B. (1) magma
(2) migmatites
C. (1) 150°C
(2) 800°C
D. (1) partial melting
(2) diagenesis
E. (1) molten magma
(2) partial melting
15. Metamorphism of rocks in the crust begins below the zone of sedimentary diagenesis, which extends down to the
depth where rock temperatures reach:
A. 150°C
B. 300°C
C. 500°C
D. 1000°C
E. 1500°C
15. The depth at which metamorphism begins depends on pressure and temperature. The pressure is controlled by
the (1) _______ whereas the temperature is controlled by the (2) ___________.
A. (1) weight of the overlying rocks
(2) geothermal gradient
B. (1) lithostatic pressure
(2) rock type
C. (1) lithostatic stress
(2) radioactive decay
D. (1) differential stress
(2) convection in the mantle
E. (1) depth of diagenesis
(2) isotherms
15. At depths in the crust shallower than about 15 km (~9 mi), rocks undergo (1)________ metamorphism. An
example of a metamorphic rock formed at this grade is (2)__________.
A.
B.
C.
D.
E.
(1) high-grade
(1) high-grade
(1) low-grade
(1) low-grade
(1) low-grade
(2) slate
(2) schist
(2) gneiss
(2) slate
(2) migmatite
15. Which of the following will have no effect on the process of metamorphism?
A. the addition of water to the rocks being metamorphosed
B. the length of time of metamorphism
C. the type of rock that got metamorphosed
D. the pressures and temperatures that the rocks experienced
E. all of the above will have an impact on metamorphism
15. Which of the following statements regarding lithostatic pressure is correct?
A. it is caused by the weight of the overlying rocks
B. it is equal in magnitude from all directions
C. it causes rocks to decrease in volume but it does not change the rock shape
D. all of the above
E. none of the above
15. A foliation develops in a metamorphic rock because:
A. platy minerals always align with each other during any type of metamorphism
B. the original rock that got metamorphosed must have had a foliation in it
C. differential stress causes minerals to align parallel to each other
D. high temperatures during metamorphism always cause minerals to recrystallize with a foliation
E. this is what defines a metamorphic rock in the first place
15. Which of the following statements is true?
A. differential stress is equal in magnitude in all directions
B. a foliation only develops in rocks when stresses are equal in all directions
C. the weight of overlying rocks in the crust produces a lithostatic pressure
D. the weight of overlying rocks in the crust produces a differential stress
E. as lithostatic pressure increases, rocks change both in volume and shape
15. Which of the following metamorphic terms does not belong with the others?
A. foliation
B. schistosity
C. gneissic texture
D. hornfels
E. slaty cleavage
15. Which of the following is NOT a type of metamorphic texture?
A. hornfels
B. schistosity
C. slaty cleavage
D. gneissosity
E. gneissic texture
15. Which of the following types of metamorphic rocks is NOT foliated?
A. hornfels
B. gneiss
C. slate
D. phyllite
E. schist
15. In the lists of metamorphic rocks below, which one shows rocks in the correct order from lowest to highest
metamorphic grade for an initially clay-rich rock?
A. slate - phyllite - schist - gneiss
B. slate - schist - phyllite - gneiss
C. schist - phyllite - slate - gneiss
D. gneiss - slate - phyllite - schist
E. gneiss - schist - phyllite - slate
15. Which of the following metamorphic rocks does not belong in the same list as the others?
A. quartzite
B. greenschist
C. phyllite
D. gneiss
E. slate
15. Metamorphism of limestone produces:
A. granulite
B. hornfels
C. quartzite
D. slate
E. marble