Carbon-date | definition of carbon-date by Medical dictionary
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carbon dating A radiometric dating method for determining the age of life forms which have died in the relatively recent past, having a limit of accuracy of about 60,000 years. Carbon dating is the result of cosmic radiation which bombards the Earth’s atmosphere, which constantly produces more 14C isotopes from 14N.
carbon dating the dating of organic remains by measuring the radioactive carbon content. Atmospheric carbon dioxide contains carbon atoms of two types, ordinary carbon 12C and radioactive carbon 14C. Like other radioactive isotopes, 14C decays with age, so that the proportion of radioactive carbon present in, say, peat gives an indication of its age, assuming no more 14C has been incorporated in it since it was a live plant, and also that the amount of 14C in the atmosphere has remained constant. 14C has a HALF-LIFE of 5,570 years and one carbon atom in every million million in the atmosphere is radioactive. Dating organic remains by the use of 14C is a well-used and valuable technique, but not entirely accurate due to variations in atmospheric 14C over long periods of time. Comparisons with tree ring dates (see DENDROCHRONOLOGY have shown errors in the order of 900 years in 5,000.