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32 Cards in this Set
- Front
- Back
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uniformitarianism
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a principle that geologic processes that occured in the past can be explained by current geologic processes.
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catastrophism
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the idea that geologic change happens suddenly.
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paleontology
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the study of fossils
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relative dating
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method for determining if an event or rock is younger or older than others.
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superposition
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a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
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geologic column
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arrangement of rock layers in which the oldest rocks are on the bottom.
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unconformity
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break in the geologic record. when rocks are eroded or when sediment is not deposited for a long time.
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absolute dating
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any method of measuring the age of an event or object in years
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isotope
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an atom of an element that has the same number of protons as another atom of the same element but a different number of neutrons
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radioactive decay
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the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element.
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radiometric dating
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a method of determining the age of an object by estimating the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope.
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half-life
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time needed for half of a sample of a radioactive substance to undergo radioactive decay
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uniformitarianism
|
a principle that geologic processes that occured in the past can be explained by current geologic processes.
|
|
|
catastrophism
|
the idea that geologic change happens suddenly.
|
|
|
paleontology
|
the study of fossils
|
|
|
relative dating
|
method for determining if an event or rock is younger or older than others.
|
|
|
superposition
|
a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
|
|
|
geologic column
|
arrangement of rock layers in which the oldest rocks are on the bottom.
|
|
|
unconformity
|
break in the geologic record. when rocks are eroded or when sediment is not deposited for a long time.
|
|
|
absolute dating
|
any method of measuring the age of an event or object in years
|
|
|
isotope
|
an atom of an element that has the same number of protons as another atom of the same element but a different number of neutrons
|
|
|
radioactive decay
|
the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element.
|
|
|
radiometric dating
|
a method of determining the age of an object by estimating the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope.
|
|
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half-life
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time needed for half of a sample of a radioactive substance to undergo radioactive decay
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fossil
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The remains or traces of an organism that lived long ago that have been preserved in rock
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trace fossil
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a fossilized mark that is formed in soft sediment by the movement of an animal
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mold
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a mark or cavity made in a sedimentary surface by a shell or other body
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cast
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a type of fossil that forms when sediments fill in the cavity left by a decomposed organism
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index fossil
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a fossil that is found in the rock layers of only one geologic age and that is used to establish the age of the rock layers
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geologic time scale
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the standard method used to divide the Earth's long natural history into manageable parts
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eon
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the longest division of geological time
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era
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a unit of geologic time that includes two or more periods
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