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10 Cards in this Set
- Front
- Back
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What is the geologic time scale
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The division of Earth history into blocks of time-eons, eras, periods, and epochs; the time scale was created using relative dating principles. The major units of the time scale were described during the nineteenth century
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What types of subdivisions of the geologic time scale, from longest to shortest expanse of time
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eon, era, period, and epoch
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The eon called the what began about 540 million years ago
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phanerozic
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what eras is the Phanerozoic divided into
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Paleozoic, Mesozoic, and Cenozoic
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Is it true or false that periods such as the Tertiary are characterized by more profound life-form changes that those of eras
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false
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is it true or flase that the Precambrian represents a much longer part of Earth's history than the Phanerozoic
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true
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Why do geologists known so little about Precambrian history
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?
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What is one reason why radiometric dating of sedimentary rocks is rarely accurate
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a
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Circle the letter of one reason why radiometric dating of metamorphic rocks is rarely accurate
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b
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Geologists usually assign numberical dates to sedimentary rock layers by relating them to what rock masses that can be dated
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c
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