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9 Cards in this Set
- Front
- Back
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Relative Techniques |
Stratigraphy Biostratigraphy Fluorine Dating |
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Chronometric Techniques |
Paleomagnetic Reversals Radiocarbon Dating Potassium/Argon Dendrochonology |
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Stratigraphy |
Superposition: older earth layers will be onbottom (usually) Stratigraphic layers match up in different partsof the world, confirming plate tectonic theory |
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Biostratigraphy |
Site dated by fossils whose age is known from other sites |
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Fluorine Dating |
When animal dies fluorine seeps into the bones Can tell if 2 bones from a site are the same age |
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Paleomagnetic Reversals |
Earth's magnetic field spontaneously reverses every 10,000 to millions of years Lava becomes rock crystals that face direction of magnetic |
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Radiocarbon Dating |
C-14 absorbed during life of organism upon death decays into N-14 at known rate of half life Limited to 75,000 years old or less |
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Potassium-Argon |
Dates volcanic rock by radioactive potassiumK-14 that decays into Argon gas A-14 Thus fossils between can be dated as within arange Thisworks for up to billions of years |
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Dendrochronology |
Ring dating- width of the tree ring depends on available moisture Outer rings are older (Tree age center is like birth?)overlap with inner rings of younger trees |
