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34 Cards in this Set
- Front
- Back
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During metamorphism, the ______ of a rock may change.
a. mineralogy b. texture c. chemical composition d. mineralogy, texture, and chemical composition |
mineralogy, texture, and chemical composition
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What type of metamorphism is caused by high temperature and high pressure
imposed over a large volume of crust? a. metasomatism b. contact c. regional d. cataclastic |
regional
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WWhat type of metamorphism is caused by igneous intrusions?
a. burial b. contact c. regional d. cataclastic |
contact
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Metamorphic rocks:
a. often contain fossils b. commonly are layered c. are rarely found associated with convergent plate boundaries d. none of the above |
commonly are layered
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Which of the following metamorphic rocks forms by subduction of oceanic crust?
a. amphibolite b. eclogite c. hornfels d. granulite |
eclogite
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In what plate tectonic setting(s) does regional metamorphism occur?
a. divergent plate margins b. transform plate margins c. convergent plate margins d. all of these |
convergent plate margins
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Which of the following sequences describes the metamorphic changes in shale with increasing pressure and temperature?
a. schist → gneiss → slate b. gneiss →slate → schist c. slate → schist → gneiss d. gneiss → schist → slate |
slate → schist → gneiss
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The principle of superposition states that _______.
a. sediments are deposited as horizontal layers b. the present is the key to the past c. undisturbed sedimentary layers get younger from bottom to top d. a fault that cuts a sedimentary rock is younger than the rock |
undisturbed sedimentary layers get younger from bottom to top
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Fossils became abundant in the geologic record about ______ years ago.
a. 540 million b. 250 million c. 65 million d. 10 thousand |
540 million
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Which of the following varies the rate of radioactive decay?
a. a change in temperature b. a change in pressure c. a change in humidity d. none of these |
none of these
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Which of the following radioactive isotopes is the most useful for dating very
young (<10,000 year old) wood and charcoal. a. rubidium-87 b. carbon-14 c. potassium-40 d. uranium-238 |
carbon-14
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Human beings (Homo Sapiens) evolved during which geologic era?
a. Cenozoic b. Mesozoic c. Paleozoic d. Precambrian |
Cenozoic
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An unconformity is _______.
a. a layer of sedimentary rock b. an erosional gap in the geologic record c. a layer of rock with very unusual fossils d. a period of deposition |
an erosional gap in the geologic record
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Which of the following sequences is written correctly from oldest to youngest?
a. Cenozoic, Paleozoic, Mesozoic b. Mesozoic, Cenozoic, Paleozoic c. Paleozoic, Mesozoic, Cenozoic d. none of these |
Paleozoic, Mesozoic, Cenozoic
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Lord Kelvin's estimate for the age of the earth:
a. was too high because he did not know about convection in the mantle, which increases the rate at which the earth cools b. was too low because he did not know that the decay of radioactive elements in the earth produces heat c. was too high because he overestimated the initial temperature of the earth d. was too low because he assumed a thermal conductivity for rock that was too high |
was too low because he did not know that the decay of radioactive elements in
the earth produces heat |
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A rock formed with 2,000 atoms of a radioactive parent element, but contains
only 500 radioactive parent atoms today. If the half-life for the radioactive element is one million years, how old is the rock? a. 250,000 years old b. 500,000 years old c. 1,000,000 years old d. 2,000,000 years old |
2,000,000 years old
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A grain of feldspar crystallized from a rhyolitic magma and incorporated 8000
atoms of a radioactive element with a half-life of 20 million years. At a later time, this rock underwent regional metamorphism that caused all of the daughter atoms produced by decay of the parent to be driven out of the crystal. If the mineral originally crystallized 100 million years ago and the metamorphic event occurred 60 million years ago, how many daughter atoms are present in the crystal today? a. 7750 b. 1750 c. 2000 d. 6000 |
1750
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Dinosaurs became extinct at the end of the _______Era.
a. Cenozoic b. Mesozoic c. Paleozoic d. Precambrian |
Mesozoic
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When the age of an igneous rock is determined by radiometric dating, we are
dating the amount of time since _______. a. the Earth formed b. the rock crystallized from a melt c. the rock was exposed at the Earth's surface d. all of the radioactive elements decayed |
the rock crystallized from a melt
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Which of the following has been cited as evidence of a large impact at the end of the Cretaceous?
a. the presence of large amounts of the element rubidium in the clay layer marking the Cretaceous/Tertiary boundary b. tidal wave deposits around the Pacific Ocean c. the fact that the mammals survived into the Tertiary but not the dinosaurs d. grains of shocked quartz in the clay layer marking the Cretaceous/Tertiary boundary |
grains of shocked quartz in the clay layer marking the Cretaceous/Tertiary boundary
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Relative age dating:
a. determines how many years ago a geologic event took place b. has not been used since radioactive dating was developed c. can only give the sequence in which geologic events took place d. none of the above is true |
can only give the sequence in which geologic events took place
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Which of the following was cited by scientists from Dartmouth as evidence that the Mesozoic /Cenozoic extinctions were caused by a long period of volcanic
eruptions? a. the presence of spherical grains in clay layers above and below the Mesozoic/ Cenozoic boundary. b. the presence of large volcanoes of roughly late Cenozoic age. c. the presence of lava flows at many places on earth where the Mesozoic/ Cenozoic boundary is exposed d. the lack of a 65 my old impact crater. |
the presence of spherical grains in clay layers above and below the Mesozoic/
Cenozoic boundary. |
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Which of the following may have contributed to the Mesozoic/Cenozoic mass
extinction? a. global cooling b. global warming c. wildfires d. all of the above |
all of the above
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The division of the geologic time scale into eras is based on:
a. past changes in the earth's climate b. changes in life on earth c. the presence of iridium layers d. none of the above |
changes in life on earth
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Clastic sedimentary rocks are classified primarily on the basis of:
a. color b. type of bedding c. mineral composition d. particle size |
particle size
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A rock composed of clay-sized sediment is called a ______.
a. sandstone b. limestone c. diagenite d. shale |
shale
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An outcrop of rock contains a sandstone which is overlain by a siltstone.
Assuming that both of these layers were deposited by a river, which of the following statements is true? a. the siltstone layer is older than the sandstone layer b. the sandstone was deposited by a slow-moving river c. the water began to flow slower after the sandstone was deposited d. the sandstone is better sorted than the siltstone |
the water began to flow slower after the sandstone was deposited
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In which of the following sedimentary rocks would it be easiest to determine the type of rocks from which the sediment was derived?
a. sandstones b. mudstones c. conglomerates d. shales |
conglomerates
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A sandstone contains well-sorted, coarse sand grains. Which of the following is
the most likely environment of deposition for this sedimentary rock? a. deposited by a fast-moving stream b. deposited by a slow-moving stream c. deposited by wind d. deposited by a glacier |
deposited by a fast-moving stream
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The evidence that the Mediterranean Sea was once a desert is:
a. the presence of the Nile River b. the existence of thick evaporite deposits in the sediments making up the sea floor c. the large waterfall currently seen at the Straits of Gibraltar d. the presence of thick clastic sediments that were deposited on the sea floor |
the existence of thick evaporite deposits in the sediments making up the sea floor
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You find a clastic rock that is well-sorted and contains many large, angular
cobbles. Which of the following statements concerning this rock is true? a. it was probably deposited by a glacier b. the source area for the grains was close by c. it was probably deposited in a large lake d. all of the above are true |
the source area for the grains was close by
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Compaction and cementation in clastic rocks refers to:
a. the closing of pore spaces in loose sediments and their subsequent filling by new minerals b. transformation of organic matter to various forms of coal c. the processes by which graded bedding and cross bedding are formed d. none of the above |
the closing of pore spaces in loose sediments and their subsequent filling by
new minerals |
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Sediments deposited by which of the following would have the largest grain size?
a. glacier b. fast moving stream c. fast moving wind d. slow moving stream |
glacier
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Limestones are sedimentary rocks made of biogenic sediments. They are
deposited in regions: a. where the water is cool and clear b. near the North and South Poles c. near the equator where the water is warm d. that often contain lots of evaporite minerals |
near the equator where the water is warm
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