Chapter 7 - Earth Materials

Question 1

Metamorphic grade (or fancies) is controlled by:
A) Temperature and pressure during burial
B) Chemical composition
C) Fossil intent
D) Elevation
E) How well a rock scores on a geology exam

Answer 1

A) Temperature and pressure during burial

Question 2

Metamorphism begins at about:
A) 100C
B) 300C
C) 500C
D) 700C
E) 900C

Answer 2

B) 300C

Question 3

The most useful rock material mined by early humans for the production of cutting tools was \_\_\_\_\_\_\_ (produces the best sharp edge).
A) Limestone
B) Chert
C) Sandstone
D) Halite
E) Basalt

Answer 3

B) Chert

Question 4

Chert is a material that forms by _______.
A) Chemical or biochemical precipitation of SiO2 n or just beneath the sea floor
B) Ground-water alteration of felsic volcanic ash
C) Deposition of CaCO2 through chemical precipitation or accumulation of fossil
D) Chemical precipitation of NaCl on the sea floor
E) Both ‘a’ and ‘b’

Answer 4

A) Chemical or biochemical precipitation of SiO2, on or just beneath the sea floor

Question 5

The potassium-argon method of dating the age of ingenious rocks works because:
A) K^40 is lost when a rock melts
B) Ar^40 is lost when a rock melts
C) Both Ar^40 and K^40 are lost when a rock melts
D) K^40 is lost when a magma crystallizes
E) Both K^40 and Ar^40 are formed when a magma crystallizes

Answer 5

D) K^40 is lost when a magma crystallizes

Question 6

Diamonds originate _______ of Earth.
A) In the continental crust
B) In the oceanic crust
C) In the core
D) In the mantle about 200 km or more below the surface
E) In the mantle about 2000 km or more below the surface

Answer 6

A) In the continental crust

Question 7

The fact that minerals grow, analogous to organic growth, is not exactly a common household concept, and yet it is one of the more important things that early geologists came to understand. This growth occurs _______.
A) When a rock melt freezes (solidifies)
B) By precipitation out of water (both above and below ground)
C) Through solid-state ionic diffusion at elevated temperatures
D) By both a and b, but not c
E) By all of a, b, and c

Answer 7

E) By all of a, b, and c

Question 8

Large caldera eruptions occur as a result of:
A) Long-continued lava spattering
B) Contact of magma with ground water
C) Fissure eruptions
D) Violent degassing
E) Mysterious forces at work

Answer 8

D) Violent degassing

Question 9

Island chains like the Hawaii-Emperor chain are thought to be caused by “hotspots” which are the result of _______.
A) Mantle plumes that remain relatively fixed while tectonic plates move over them
B) Mantle plumes that move about chaotically
C) Subduction related volcanism
D) Mid-ocean ridge related volcanism
E) Short-lived mantle plumes

Answer 9

A) Mantle plumes that remain relatively fixed while tectonic plates move over them

Question 10

Shield volcanoes, such as Mauna Loa in Hawaii, are _______.
A) Small cone-shaped volcanoes (5 km in diameter)
C) Very large rounded volcanoes with fairly gentle slopes, many are >50 km in diameter)
D) Spines inside volcanic caldera
E) Vast sheets of lava stacked up one over the other, forming plains or low plateaux

Answer 10

C) Very large rounded volcanoes with fairly gentle slopes, many are >50 km in diameter)

Question 11

Rapidly flowing, Avalanche-like masses of pyroclastic material (and the resulting pyroclastic deposits) are called:
A) Fissure eruptions
B) Flow breccia so
C) Pillow flows
D) Caldera
E) Pyroclastic flows

Answer 11

E) Pyroclastic flows

Question 12

Metamorphism involves:
A) Melting and a complete change of the chemical elements making up the rock
B) A complete change of the chemical elements making up the rock but the rock remains in the solid state
C) Melting and a reorganizing of the chemical elements in the rock to form new minerals
D) A reorganizing of the chemical elements I n the rock to form new minerals but the rock remains in the solid state - (solid-state ionic diffusion)

Answer 12

C) Melting and a reorganizing of the chemical elements in the rock to form new minerals

Question 13

The world's largest batholiths are \_\_\_\_\_ km long.
A) A few
B) About 10
C) Several 10's of
D) Several 100's of
E) Several 1000's of

Answer 13

D) Several 100’s of

Question 14

Based on the sketch that represents rocks seen in a vertical road-cut, which line clearly represents an unconformity?
A) A (igneous stock)
B) B (felsic dike)
C) C (sandstone)
D) D (mafic dike)
E) E (basalt)

Answer 14

C) C (sandstone)

Question 15

Based on the sketch that represents rocks seen in a vertical road-cut, I the lava was dated radiometric ally to have an absolute age of 200 Ma, and the felsic dyke was dated at 250 Ma, then the sandstone bed is \_\_\_\_\_\_\_.
A) Proterozoic
B) Devonian
C) Tertiary
D) Triassic
E) Permian

Answer 15

C) Tertiary

Question 16

Based on the sketch that represents rocks seen in a vertical road-cut, the oldest rock seen in this road cut is the \_\_\_\_\_\_\_.
A) Mafic dyke
B) Felsic dyke
C) Metamorphic rock
D) Lava
E) Igneous stock

Answer 16

C) Metamorphic rock

Question 17

Based on the cross-section sketch, the label Y refers to a \_\_\_\_\_\_\_.
A) Normal fault
B) Thrust fault
C) Anticline
D) Syncline
E) Orogen

Answer 17

B) Thrust fault

Question 18

Based on the cross-section sketch, the structure labelled X is a:
A) Normal fault
B) Thrust fault
C) Anticline
D) Orogen
E) Syncline

Answer 18

E) Syncline

Question 19

Based on the cross-section sketch, prior to erosion, the next youngest geological event was \_\_\_\_\_\_\_.
A) Deposition of red shale
B) Folding
C) Flowage of basalt lava
D) Faulting
E) Intrusion

Answer 19

E) Intrusion

Question 20

Other than in subduction zones, the temperature above which most rocks begin to display ductile behaviour is approximately \_\_\_\_\_\_\_.
A) 100 degrees C
B) 200 degrees C
C) 300 degrees C
D) 500 degrees C
E) 1000 degrees C

Answer 20

C) 300 degrees C

Question 21

Diamonds originate _______ of Earth.
A) In the continental crust
B) In the oceanic crust
C) In the core
D) In the mantle about 200 km or more below the surface
E) In the mantle about 2000 km or more below the surface

Answer 21

A) In the continental crust