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thorium-lead dating

thorium-lead dating A radiometric dating method based on the radioactive decay of 232Th, to yield 208Pb + 6He4, with a half-life (see DECAY CONSTANT) of 13 900 million years. The minerals used include sphene, zircon, monazite, apatite, and other rare U/Th minerals. The method is not totally reliable and is usually employed in conjunction with other methods. In most cases the results are discordant as a result of lead loss. The ratio of 208Pb: 232Th compared with 207Pb: 235U ratio is particularly useful. The Th-Pb system can also be interpreted by means of isochron diagrams similar to those used in the rubidium-strontium method.

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"thorium-lead dating." A Dictionary of Earth Sciences. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

"thorium-lead dating." A Dictionary of Earth Sciences. . Encyclopedia.com. (August 19, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/thorium-lead-dating

"thorium-lead dating." A Dictionary of Earth Sciences. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/thorium-lead-dating

thorium–lead dating

thorium–lead dating A radiometric dating method based on the radioactive decay of 232Th, to yield 208Pb + 6He4, with a half-life of 13 900 million years. The method is not totally reliable, in most cases because of lead loss, and it is usually employed in conjunction with other methods.

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"thorium–lead dating." A Dictionary of Ecology. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

"thorium–lead dating." A Dictionary of Ecology. . Encyclopedia.com. (August 19, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/thorium-lead-dating-0

"thorium–lead dating." A Dictionary of Ecology. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/thorium-lead-dating-0