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6 Cards in this Set
- Front
- Back
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How is radiometric dating used to establish an absolute time scale ? |
Radiometric isotopes in rocks are unstable and breakdown (decay), which is at a constant rate. This is its half life |
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Describe and explain limitations of radiometric dating |
The actual shortage (scarcity) of radioactive material or they are found in small quantities of some rock forming minerals. (e.g. may involve crushing the rock and picking out the minerals such as zircon/Muscovite from granite) |
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What are the difficulties to obtaining accurate dates for radiometric dating ? |
1) Faulty equipment 2) Contaminated samples 3) differences between individual minerals and whole rock dates |
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What are the problems from obtaining accurate data from sedimentary rocks ? |
1) weathering/erosion break up the closed system 2) loss of gasses allowing argon to escape resulting in a much older rock 3) sedimentary rocks are made up of older rocks. The clasts could have a range of all the older rocks which could be misleading. |
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What are the problems from obtaining accurate data from metamorphic rocks ?
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1) different minerals become closed systems at different temperatures 2) 40K40Ar has a closure temperature of |
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What are the problems from obtaining accurate data from igneous rocks ?
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tyrtyh |
