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11 Cards in this Set
- Front
- Back
Events that are listed in order, but without specific time and date.
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Relative Time
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Events that are listed in order with specific time or date.
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Absolute Time
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In undisturbed strate, the layer on the bottom is oldest, and layers above are younger.
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Law of Superposition
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Sediments are generally deposited as horizontal layers.
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Law of Original Horizontality
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Igneous intrusions, are younger than the rock they cut through.
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Cross-Cutting Relationships
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What is an example of relative dating?
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Law of superposition
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What is an example of absolute dating?
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Radioactive dating
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Radioactive isotopes change into daughter isotopes at known rates, allowing the assignment of dates to rocks.
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Radioactive dating
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What are the two types of geologic time?
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Absolute and radioactive
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What is a half-life?
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The amount of time needed for 1/2 of a radioactive parent isotope to decay into a daughter isotope
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How old is the Earth?
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4.6 billion years
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