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13 Cards in this Set
- Front
- Back
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ways of dating things
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- strat of fossils/cross cutting
-strat of animal bones in ice -tree dendrochrinology -absolue (technology) |
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unconformity
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a period of no deposition and possible erosion
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angular unconformity
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rocks below were tilted or folded before unconformity developed
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nonconformity
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sed rocks overly intrusive igneous rocks and/or metamorphic rocks
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disconformity
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the border between an eroded bed and a new one
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When was snowball Earth?
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Proterozoic
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Cambrian explosion
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explosion of diversity
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radiometric dating
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the sci of datin geologic events in years
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How do geologists obtain a radiometric date?
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-radioactive decay (need a radioactive isotope with a known half life)
-choose minerals with radioactive elements |
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What is the oldest rock? How do we know?
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Zircon, 4.4 Ga, traces of H20 show that Earth cooled off quick!
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When did life appear on Earth, undisputed?
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3.3 billion y a
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Orogeny occurred during the
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Phanerozoic, ex Grenville Orogeny
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Pangea has formed by the end of what era?
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Paleozoic
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