These fossil beds lead to the formation of the

These fossil beds lead to the formation of the -...

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These fossil beds lead to the formation of the Geologic time scale , the names of each period deriving from the locality where the characteristic formation was found. The major divisions (eons, eras) are defined by the presence or absence of fossils: proterozoic , phanerozoic (visible life or animals). Geological dating is often problematic because geologists use fossils to date rocks and biologists use rocks to date fossils. A measure independent of stratigraphy and fossil remains is necessary. With the discovery of
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Unformatted text preview: radioactive decay it became apparent that one could use the ratio between the parent isotope and the daughter product (e.g., U238 decays through several steps to Pb206). By measuring the amount of isotope and daughter product and knowing the half life of the isotope one can estimate the absolute age of a rock formation. Problems: when the daughter material escapes and hence produces an inaccurate estimate. Additional tests with different isotopes can corroborate one another....
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