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LoginPetrology Tulane University Prof. Stephen A. Nelson Radiometric Dating Prior to the best and most accepted age of the Earth was that proposed by Lord Kelvin based on the amount of time necessary for the Earth to cool to its present temperature from a completely liquid state. Although we now recognize lots of problems with that calculation, the age of 25 my was accepted by most physicists, but considered too short by most geologists. Then, in , radioactivity was discovered. Recognition that radioactive decay of atoms occurs in the Earth was important in two respects: It provided another source of heat, not considered by Kelvin, which would mean that the cooling time would have to be much longer. It provided a means by which the age of the Earth could be determined independently. Principles of Radiometric Dating. Radioactive decay is described in terms of the probability that a constituent particle of the nucleus of an atom will escape through the potential Energy barrier which bonds them to the nucleus. The energies involved are so large, and the nucleus is so small that physical conditions in the Earth i.
Internet Explorer is no longer supported. Try downloading another browser like Chrome or Firefox. If you already have an account, Sign in. Radiometric dating measures the decay of radioactive atoms to determine the age of a rock sample. It is founded on unprovable assumptions such as 1 there has been no contamination and 2 the decay rate has remained constant.
By Sid Perkins. October 5, at am. But the second is powerful, too. It helps place the object in its proper archaeological, geologic or cosmological context. Up until a century or so ago, researchers studying rocks and the fossils they contain could answer the age question only vaguely if at all.
Radiometric dating calculates an age in years for geologic materials by measuring the presence of a short-life radioactive element, e. The term applies to all methods of age determination based on nuclear decay of naturally occurring radioactive isotopes. Bates and Jackson To determine the ages in years of Earth materials and the timing of geologic events such as exhumation and subduction, geologists utilize the process of radiometric decay.
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