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26 Cards in this Set
- Front
- Back
uniformitarianism
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the principle that earth's landforms are being constantly changed by the same geological forces that have been at work since the beginning of time.
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Catastrophism
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the principle that all of Earth's landforms were formed suddenly by catastrophic events
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James Hutton
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created the principal of uniformitarianism in 1795
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superpostion
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the principal that states that rock layers are in order of age, youngest sediment are the topmost layers and older sediment are bottommost layers
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Charles Lyell
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wrote and published the volumes titled Principles of geography
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relative dating
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figuring out whether an object is older or younger than another object
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geologic column
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the ideal sequence of rock layers that contains all rock layers know to man in superpostion and without any unconformities
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absolute dating
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the process of determining the age of an object, such as a rock layer or fossil, by fiquring out the number of years it has existed
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isotopes
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atoms of the same element with the same number of protons but different number of nuetrons
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radioactive decay
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when a radioactive isotopes of one element decay into stable elements of another element
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radiometric dating
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determining the absolute age of a sample based on the ratio of parent material to daughter material
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half-life
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the time it takes for one half of a radioactive sample to decay
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fossil
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naturally preserved evidence of life
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permineralization
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a process in which minerals fill in the pore spaces of an organism's tissues- minerals can also replace the original tissues of the organisms
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petrification
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when organisms tissues are completely replaced by minerals
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trace fossil
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any naturally preserved evidence of an animal's activity
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coprolites
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preserved animal feces
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mold
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cavity in the gorund or rock where a plant or animal was buried, it leaves a cast of the original organism
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cast
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an object created when sediment fills a mold and becomes rock- shows what the outside of the organism looked like
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index fossil
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fossils of organisms that lived for a relatively short, well defined time span
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geologic time scale
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a scale that divides Earth's history into distinct periods of time
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eon
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largest division of geologic time
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era
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second largest division of geologic time
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period
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third largest division of geologic time
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epoch
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fourth largest division of geologic time
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unconformity
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a surface that represents a gap in the geologic time column
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