Term
| Uniformitarianism and an example |
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Definition
gradual change
example: erosion |
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Term
| Catastrophism and an example |
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Definition
unexpected, sudden
example: astroid, comet |
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Term
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Definition
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Term
| What are the three types of studies of Paleontology? |
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Definition
Invetabrate- no backbone animals
Vertabrate- backbone animals
Paleobotanists- plant fossils |
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Term
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Definition
| determining age of rock by comparing it with another one |
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Term
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Definition
| Younger rocks are on top of older ones |
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Term
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Definition
| Contains all known fossils and rock formations on Earth |
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Term
| How is the geologic column formatted? |
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Definition
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Term
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Definition
| Cut across rock to assign relative ages to layers |
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Term
| How do you know if rock has been disturbed? |
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Definition
| If the rocks aren't horizontal |
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Term
| What are examples of features? |
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Definition
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Term
| What are examples of how rocks are disturbed? |
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Definition
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Term
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Definition
| Surface that represents a missing part of the geologic column |
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Term
| What are two things that create unconformities? |
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Definition
Nondeposition- supply of sediments cut off
Erosion |
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Term
| Disconformities; where are they found, and how do they happen? |
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Definition
Found where parrallel layers are missing.
Rock is uplifted, eroded & deposited somewhere else, deposition continues & buries eroded surface. |
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Term
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Definition
| Found where horizontal sedimentary rock layers lay about an eroded surface of older intrusive igenous or metamorphic rock. |
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Term
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Definition
Found between horizontal layers of sedimentary rock & layers of rock that have been titled or eroded.
(Tilted/folded layers eroded before horizontal layers formed above them) |
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Term
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Definition
| Atoms in the same element that have the same number of protons, but different number of neutrons |
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Term
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Definition
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Term
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Definition
| Radioactive isotopes break down int ostable isotopes of the same or other elements. |
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Term
| How do scientists figure a rock's age by looking at radioactive decay? |
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Definition
| They use relative amounts of stable and unstable isotopes in an object to determine it's age. |
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Term
| What sometimes happens as the result of radioactive decay? |
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Definition
| Some neutrons convert into protons and an electron is released. |
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Term
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Definition
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Term
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Definition
| Stable isotope due to radioactive decay |
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Term
| How can we figure out how old a rock is by comparing father and daughter isotopes? |
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Definition
| The more daughter isotopes there are in an object, the older it is. |
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Term
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Definition
| Absolute age based on ratio of parent and daughter material |
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Term
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Definition
| Process of establishing the age of an object by determining the number of years it has existed. |
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Term
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Definition
| Time that it takes for one half of a radioactive sample to decay |
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Term
| How did archaeologists find out how long ago people lived on The Effigy Mounds, and how long ago did they live there? |
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Definition
| They dated bones, etc. to determine people lived there from about 2,500-600 years ago. |
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Term
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Definition
| Potassium-40, an isotope, decays to argon and calcium. Geologists measure argon as the daughter material. |
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Term
| When is the Potassium-Argon Method mainly used? |
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Definition
| When the rock is older than 100,000 years. |
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Term
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Definition
| Uranium-238, a radioactive isotope, decays in series of steps to become lead-206. |
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Term
| In the Uranium-Lead Method, what happens with the rock that is older? |
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Definition
| The older the rock is, the more daughter material, lead-206, there will be in it. |
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Term
| How old does the rock have to be to use the Uranium-Lead Method? |
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Definition
| More that 10 million years old |
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Term
| Rubidium-Strontium Method |
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Definition
| Unstable, parent isotope rubidium-87 forms the stable daughter isotope strontium-87. |
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Term
| How old does the rock have to be to use the Rubidium-Strontium Method? |
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Definition
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Term
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Definition
| stable carbon-12 & 13 and radioactive carbon-14 combine with oxygen to form CO2---taken in by plants (plant is alive=constant carbon-14 & 12 ratio continually taken in) Animals that eat the plants have same ratio of carbon isotopes. As animal dies, amount of carbon-14 & 12 decrease. Decrease measured in a lab. |
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Term
| What is the half-life of carbon-14? |
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Definition
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Term
| How old must rock be to be measured by the Carbon-14 Method? |
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Definition
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Term
| What is the half-life of Potassium-40? |
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Definition
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Term
| What is the half-life of Uranium-238? |
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Definition
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Term
| What is the half-life of Rubidium-87? |
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Definition
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