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Definitions |
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How old are the oldest zircon minerals on Earth?
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Approximately 4.4 billion years old.
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The smallest time division on the geologic time scale is a(n) _________.
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epoch
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The largest mass extinction event in Earth history took place __________.
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at the end of the Permian
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Which of the following is an erosion surface that separates two sets of sedimentary layers with non-parallel bedding planes?
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Angular Unconformity.
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Which of the following statements about radioactivity is false?
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Energy is consumed during radioactive decay.
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Which of the following radioactive isotopes has the shortest half-life?
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Carbon-14
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What is the youngest rock formation exposed in the Grand Canyon?
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Kaibab Limestone.
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Almost nine-tenths of Earth history occurs during the _________.
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Precambrian.
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In sequence stratigraphy, what is a sequence?
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A series of sedimentary beds bounded by unconformities.
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Geologic correlation of sedimentary rocks bounded above and below by unconformities is called _________.
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sequence stratigraphy
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Which of the following is the best statement of the principle of original horizontality?
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Sediments are deposited as horizontal layers.
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Radiometric dating is least useful for dating __________ rocks.
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Sedimentary.
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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 one million years, how old is the rock?
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2 million years old
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The stratigraphic order of the fossils from animal species is know as the ________.
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Faunal succession.
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During which geologic eon did the amount of oxygen in the atmosphere approach modern levels?
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Protorozoic.
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An undeformed sedimentary layer is ______ than the layer above and ______ than the layer below.
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Older, Younger.
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Which of the following radioactive isotopes is the most useful for dating very young (< 10,000 years old) wood and charcoal?
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carbon 14
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Which of the following materials might be dated using carbon-14?
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Wood.
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If the Earth's history was compressed into a single calendar year, complex organisms (including those with shells) first appeared in _______.
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October.
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Who proposed the theory of evolution?
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Darwin
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Which of the following statements regarding radiometric dating is true?
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Carbon-14 cannot be used to date material more than 100,000 years old.
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Abrupt changes in the faunal succession in the rock record represent __________.
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mass extinction
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Which of the following can change the rate of radioactive decay?
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None of above.
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When did the horizontal, layered sedimentary rocks in the Grand Canyon form?
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Pealeozoic.
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What is an unconformity?
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A gap in the geologic record.
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The principle of superposition states that __________.
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undisturbed sedimentary layers get progressively younger from bottom to top
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When did the oldest rocks, now exposed at the base of the Grand Canyon, form?
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Precambrian.
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A stratigraphic succession is a vertical set of strata ___________.
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used as a chronological record of the geologic history of a region
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When did the Mesozoic era begin?
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251 million years ago
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The study of faunal succession allows_______.
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Rocks to be correlated from different outcrops.
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Which of the following is the smallest division of geologic time?
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Epochs.
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The absolute age of a geologic event in the rock record is __________.
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the number of years that has elapsed between the event and the present day
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Repeated cycles of glaciations have taken place since the beginning of the ________.
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Pleistocene epoch
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Which of the following instruments is used to precisely measure isotopes for radiometric dating?
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Mass Spectrometer.
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Which of the following is in order from the shortest to longest geologic event?
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meteorite impact, life cycle of ocean lithosphere, evolution of continents
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Approximately how fast do plates spread apart?
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2 to 20 centimeters per year
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Which of the following radioactive isotopes could be used to date very old (3 billion years old) rocks?
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uranium-238
potassium-40 uranium-235
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Human beings (homo sapiens) evolved during which geologic era?
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Cenozoic.
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Changes in global temperature over the last 1.8 million years have been calculated by measuring ___________.
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the stable oxygen isotopes in shelly fossils
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Fossils are most common in which rock types?
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Sedimentary.
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A disconformity is ___________.
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An erosional surface between horizontal layers of sedimentary rocks.
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Radiometric dating is possible if a rock contains a measurable amount of ___________.
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both daughter and parent atoms
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Which of the following is used by geologists to determine the relative ages in a rock sequence?
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Cross-cutting, fossils and stratigraphy.
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Which of the following statements is false?
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Dikes are older than the rocks they cross-cut.
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The founder of the principle of the faunal succession is ____________.
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Smith.
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The study of ancient life forms preserved in the rock record is referred to as _________.
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paleantology
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The study of the layers in sedimentary rock is know as _________.
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Stratigraphy.
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How long did the Proterozoic eon last?
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approximately 2 billion years
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When were the Earth's climate, geodynamo, and plate tectonics systems established?
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During the Archean.
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