GLG 111 Exam 2

At what type of plate tectonic boundary would you expect tensional forces to occur? A. divergent B. convergent C. transform

A. divergent

In a structural dome, the oldest rock layer is located where? A. in the center of the bull's-eye. B. at the edge of the bull's-eye. C. cutting across the bull's-eye.

A. in the center of the bull's-eye.

Rocks of which composition will melt at the highest temperature? A. mafic B. intermediate C. felsic D. All of these will melt at the same temperature.

A. mafic

Which mineral will crystallize at the lowest temperature? A. quartz B. muscovite C. olivine D. pyroxene E. All of these will crystallize at the same temperature.

A. quartz

Which type of metamorphism is produced along convergent plate boundaries? A. regional B. contact C. shock D. Metamorphism does not occur along convergent plate boundaries.

A. regional

Which is the most likely parent rock of quartzite? A. sandstone B. shale C. limestone D. granite E. gabbro

A. sandstone

Well-rounded sediment suggests sediment has been . A. transported a long distance B. transported a short distance C. not transported at all D. has nothing at all to do with the distance of transport

A. transported a long distance

The presence of large amounts of igneous rocks composed of small mineral crystals is suggestive of what process occurring in the past? A. volcanic eruptions B. earthquakes C. floods D. landslides

A. volcanic eruptions

Where is the most likely location for molten rock to cool and minerals to form quickly? A. in Earth's crust B. at Earth's surface C. in Earth's core D. in Earth's mantle

B. at Earth's surface

Weathering that results in the transformation of one mineral into a different kind of mineral is referred to as weathering. A. physical B. chemical C. metamorphic D. magical

B. chemical

Which type of metamorphism is produced near magma chambers? A. regional B. contact C. shock D. Metamorphism does not occur along convergent plate boundaries.

B. contact

At what type of plate tectonic boundary would you expect compressional forces to occur? A. divergent B. convergent C. transform

B. convergent

Well-sorted quartz sand clasts were most likely deposited: A. in a reef environment. B. in a beach or dune environment. C. in a mountain stream. D. at the base of a mountain cliff (talus slope).

B. in a beach or dune environment.

The primary difference between felsic and mafic igneous rocks is: A. crystal size. B. mineral composition. C. cooling rate. D. depth of formation.

B. mineral composition

The occurrence of conglomerate, sandstone, and mudstone with asymmetrical ripples, mudcracks, and root traces suggest a environment. A. desert B. river and floodplain C. deep ocean D. reef

B. river and floodplain

Which of the following features would indicate an igneous rock cooled quickly? A. large mineral crystals B. small mineral crystals C. dark-colored minerals D. light-colored minerals

B. small mineral crystals

What kind of fault is produced by purely compressional stress? A. left-lateral strike-slip fault B. thrust fault C. normal fault D. right-lateral strike-slip fault

B. thrust fault

Elements are moved between minerals during metamorphism by which of the following? A. magma. B. water. C. oxygen. D. carbon dioxide. E. Elements are not moved during metamorphism.

B. water

Which is an example of chemical weathering? A. fragmentation of a boulder by freezing and thawing B. rounding of a pebble in a flowing stream C. dissolving limestone by rainwater D. fracturing of a rock during an earthquake

C. dissolving limestone by rainwater

Rocks of which composition will melt at the lowest temperature? A. mafic B. intermediate C. felsic D. All of these will melt at the same temperature.

C. felsic

Which of the following foliated rocks indicate the greatest intensity of metamorphism? A. schist B. phyllite C. gneiss D. slate

C. gneiss

Which is the most likely parent rock of marble? A. sandstone B. shale C. limestone D. granite E. gabbro

C. limestone

Shear stress combined with compressional stress will result in which of the following? A. purely vertical motion. B. purely horizontal motion. C. oblique motion. D. All of the above. E. None of the above.

C. oblique motion.

Which mineral will crystallize at the highest temperature? A. quartz B. muscovite C. olivine D. pyroxene E. All of these will crystallize at the same temperature.

C. olivine

Which assemblage of minerals would indicate the lowest weathering intensity? A. quartz, kaolinite B. quartz, mica, feldspar C. quartz, feldspar, pyroxene, amphibole D. All three assemblages indicate equal amounts of weathering.

C. quartz, feldspar, pyroxene, amphibole

Which type of metamorphism is produced from meteorite impacts? A. regional B. contact C. shock D. Metamorphism is not produced by meteorite impacts.

C. shock

When considering the effects of faulting on the lithosphere, it is clear that normal faults serve to effectively _________. A. shorten and thicken the crust. B. thin and shorten the crust. C. thin and extend the crust. D. shorten and thin the crust.

C. thin and extend the crust.

At what type of plate tectonic boundary would you expect shearing forces to occur? A. divergent B. convergent C. transform

C. transform

How do crystal size and foliation change with increasing intensity of metamorphism? A. Crystal size increases and foliation becomes less coarse. B. Crystal size decreases and foliation becomes coarse. C. Both crystal size and foliation coarseness decrease. D. Both crystal size and foliation coarseness increase.

D. Both crystal size and foliation coarseness increase.

Foliation is produced in metamorphic rocks primarily as a result of ___________. A. heat B. fluids C. confining pressure D. directed pressure

D. directed pressure

Purely tensional stresses associated with a _________ plate boundary will generate a _______ fault. A. convergent; strike-slip B. convergent; normal C. divergent; reverse D. divergent; normal

D. divergent; normal

The occurrence of limestone and fossil coral suggest a environment. A. desert B. river and floodplain C. deep ocean D. reef

D. reef

Which fault type can produce vertical repetition of rock layers? A. left lateral B. right lateral C. normal D. reverse

D. reverse

Biological sediment includes: A. quartz. B. sand. C. pebbles. D. shells.

D. shells

Felsic igneous rocks contain more ____________ and are in color compared to mafic igneous rocks. A. iron; darker B. iron; lighter C. silica; darker D. silica; lighter

D. silica; lighter

What kind of cooling history do porphyritic textures indicate? A. slow B. fast C. instantaneous D. slow then fast E. fast then slow

D. slow then fast

Metamorphism occurs as the result of increased heat from . A. Earth's interior B. magma C. Sun D. fossil fuels E. A and B

E. A and B

As sediment is weathered and transported: A. angular grains become rounded. B. feldspars are weathered to clay minerals. C. particle size becomes smaller due to abrasion. D. quartz fraction increases as other minerals are winnowed out. E. All of the above.

E. all of the above

Through compaction and cementation, sediment particles _______ . A. are squeezed closer together. B. are bonded by new mineral growth. C. decrease in volume. D. decrease in porosity. E. all of the above.

E. all of the above

Which of the following conditions promotes ductile flow (vs. brittle behavior)? A. deep crustal depth B. soft rock types (e.g., gypsum) C. higher temperature D. slower deformation E. compression (vs. tensional stress) F All of the above.

F. all of the above

What is an unconformity? a. a chronological gap in the geologic record b. a period of deposition c. a sedimentary layer with variable thickness d. a sequence of deformed rocks

a. a chronological gap in the geologic record

Which of the following is an erosional surface that separates two sets of sedimentary layers with non-parallel bedding planes? a. angular unconformity b. cross bed c. disconformity d. nonconformity

a. angular unconformity

Which mineral can be dated with both Potassium 40 and Rubidium 87? a. biotite b. quartz c. zircon d. gypsum

a. biotite

Which of the following radioactive isotopes has the shortest half-life? a. carbon 14 b. potassium 40 c. rubidium 87 d. uranium 238

a. carbon 14

The study of the layers in sedimentary rocks is known as ________ . a. stratigraphy b. paleontology c. sedimentation d. geochronology

a. stratigraphy

Which of the following instruments is used to precisely measure isotopes for radiometric dating? a. electron microprobe b. mass spectrometer c. Geiger counter d. petrologic microscope

b. mass spectrometer

An undeformed sedimentary layer is _________ than the layer above and ________ than the layer below. a. younger, younger b. older, younger c. younger, older d. older, older

b. older, younger

A rock formed with 1000 atoms of a radioactive parent element, but contains only 250 radioactive parent atoms today. If the half-life for the radioactive element is 1 million years, how old is the rock? a. 250,000 years b. 750,000 years c. 2 million years d. 4 million years

c. 2 million years ago

Radiometric dating is possible if a rock contains a measurable amount of ________. a. daughter atoms b. parent atoms c. both daughter and parent atoms d. either daughter or parent atoms

c. both daughter and parent atoms

The study of faunal succession allows ________. a. absolute dating of fossil bearing strata b. correlation of marine fossils with modern mammals c. rocks to be correlated from different outcrops d. reconstruction of paleogeography

c. rocks to be correlated from different outcrops

Which of the following radioactive isotopes has the longest half-life? a. carbon 14 b. potassium 40 c. rubidium 87 d. uranium 238

c. rubidium 87

Which of the following is the best statement of the principle of original horizontality? a. igneous intrusion form horizontal layers b. metamorphic isograds are horizontal before deformation c. sediments are generally deposited as horizontal layers d. most igneous, metamorphic, and sedimentary rocks in the earth's crust form horizontal layers

c. sediments are generally deposited as horizontal layers

The geologic time scale is divided into eras, periods, and epochs derived from the relative ages of fossils. What marks the boundaries of these intervals? a. zones of metamorphic rocks that display high-grade metamporhism b. igneous rock layers that have been dated radiometrically c. angular unconformities d. abrupt disappearances of old life forms and appearance of new ones

d. abrupt disappearances of old life forms and appearance of new ones

Which of the following is used by geologists to determine the relative ages in a rock sequence? a. cross-cutting relations b. fossils c. stratigraphy d. all of the above

d. all of the above

Which of the following isotopes could be used to date very old (3 billion year old. rocks? a. uranium 238 b. potassium 40 c. uranium 235 d. all of the above

d. all of the above

Which of the following can change the rate of radioactive decay? a. changes in temperature b. changes in pressure c. chemical reactions d. none of the above

d. none of the above

Radiometric dating is least useful for dating _________ rocks a. basaltic b. granitic c. metamorphic d. sedimentary

d. sedimentary

The principle of superposition states that _________. a. a fault is younger than the rock that cuts it b. sediments are deposited as essentially horizontal layers c. the present is the key to the past d. undisturbed sedimentary layers get progressively younger from bottom to top

d. undisturbed sedimentary layers get progressively younger from bottom to top

A stratigraphic succession is a vertical set of strata __________. a. bounded above and below by igneous and/or metamorphic rocks b. that is unique to a specific area c. that represents a repeating set of events, such as recurring flood and debris flows d. used as a chronological record of the geologic history of a region

d. used as a chronological record of the geologic history of a region

Which of the following materials might be dated using carbon 14? a. granite b. iron ore c. sandstone d. wood

d. wood