Using the various types of radioisotope decay as clocks does not produce consistent results, nor are those results verifiable by observational evidence. If these methods do not properly date rocks of known ages—some less than a century old—how can we trust them to date rocks of unknown ages? Last month we discussed dating methods using rare-earth elements REEs , a group of seventeen metallic elements—i. The Sm- Nd model has a problem the previous models we have discussed do not have—i. Furthermore, the index isotope Nd alpha decays to Ce with a half-life of approximately 2.
Samarium—neodymium dating is a radiometric dating method useful for determining the ages of rocks and meteorites , based on radioactive decay of a long-lived samarium Sm isotope to a radiogenic neodymium Nd isotope. Neodymium isotope ratios together with samarium-neodymium ratios are used to provide information on the source of igneous melts, as well as to provide age information. It is sometimes assumed that at the moment when crustal material is formed from the mantle the neodymium isotope ratio depends only on the time when this event occurred, but thereafter it evolves in a way that depends on the new ratio of samarium to neodymium in the crustal material, which will be different from the ratio in the mantle material. Samarium—neodymium dating allows us to determine when the crustal material was formed.
The Mythology of Modern Dating Methods: Why Million/Billion Year Dates are Not Credible
Radiometric dating , radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon , in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. Together with stratigraphic principles , radiometric dating methods are used in geochronology to establish the geologic time scale. By allowing the establishment of geological timescales, it provides a significant source of information about the ages of fossils and the deduced rates of evolutionary change. Radiometric dating is also used to date archaeological materials, including ancient artifacts.
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