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15 Cards in this Set
- Front
- Back
Relative Dating
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the placing of geologic events in their proper sequence
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Doctrine of uniformitarianism
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Proposed by james Hutton - Physical, chemical, and biological laws that operate today have operated throughout Earth's history
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Principle of Original Horizontality
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Sediment forms in horizontal layers when deposited. if drastic angles exist, some deforming took place
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Law of Superposition
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If any sequence of undeformed sedimentary rocks, the oldest rock is at the bottom and the youngest at the top
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Inclusions
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pieces of one rock unit that are contained within another rock unit.
the rock containing the inclusions is younger than the inclusions themselves |
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Unconformities
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problems with sedimentation where time isn't recorded properly
Unconformity - erosion occurs and layer is erased A GAP IN THE ROCK RECORD |
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Angular unconformity
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horizontal layers top angular layers
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Discomformity
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Abrupt change....erased layer?
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noncomformity
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one layer "spikes" to hit next layer
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Principle of Cross Cutting Relationship
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Whenever a fault of intrusive igneous rock cuts through an existing feature it is younger than the structure it cuts
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Fossil succession
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fossil organisms succeed each other in a definite and determinable order
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Radiometric Dating
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Numerical age of the earth calculated by analyzing radioactive decay
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parent isotope
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radioactive isotopes used to determine radiometric date
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Half-life
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Amount of time it takes for half of the radioactice nuclei in a sample to change to their stable end product
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Daughter Products
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the resulting isotopes from the decay of the parent
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