Methods of Age Datin1

Methods of Age Datin1 - lived radioactive isotope pairs...

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Methods of Age Dating French physicist Antoine Henri Becquerel (1852-1908) discovered radioactivity in 1896. He shared the 1903 Nobel Prize in Physics for this work, along with Pierre and Marie Curie . Later recognition of isotopic decay sequences is now used as a way to place numerical dates on rock samples. New Zealand physicist Ernest Rutherford (1871-1937), in 1903, suggested the use of radioactivity to determine the age of a rock. Rutherford also worked out the concept of half-life . Radioactive decay is the process where unstable nuclei are spontaneously transformed into another element. A half-life is the amount of time needed for one-half of a radioisotope to decay into its stable end (or daughter) product. By measuring the various isotopes in a sample, geologists can calculate the age of the specimen. Long-
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Unformatted text preview: lived radioactive isotope pairs have half-lives in millions or billions of years. The U-Pb series isotopes are used to date ancient igneous intrusive rocks such as granite. Likewise, Rb-Sr isotope ratios can be applied to ancient rocks and meteorites. Fine-grained volcanic rocks, such as bentonite and basalt, are dated by the ratios of K-Ar. There are several types of radioactive decay that are used in geology. Alpha radiation (sometimes known as an alpha particle) releases two protons and two neutrons (the alpha particle). This large, slow-moving particle is similar to the nucleus of a helium atom. Beta decay releases a fast-moving electron from a neutron in the nucleus. Electron capture occurs when a proton has captured an electron and becomes a neutron....
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