- Method of determining the age of once-living material, developed by U.S. physicist Willard Libby in 1947.It depends on the decay of the radioactive isotope carbon-14 (radiocarbon) to nitrogen. All living plants and animals continually take in carbon: green plants absorb it in the form of carbon dioxide from the atmosphere, and it is passed to animals through the food chain. Some of this carbon is radioactive carbon-14, which slowly decays to the stable isotope nitrogen-14. When an organism dies it stops taking in carbon, so the amount of carbon-14 in its tissues steadily decreases. Because carbon-14 decays at a constant rate, the time since an organism died can be estimated by measuring the amount of radiocarbon in its remains. The method is a useful technique for dating fossils and archaeological specimens from 500 to 50,000 years old and is widely used by geologists, anthropologists, and archaeologists.
* * *▪ scientific technologyalso called radiocarbon dating,method of age determination that depends upon the decay to nitrogen of radiocarbon (carbon-14). carbon-14 is continually formed in nature by the interaction of neutrons with nitrogen-14 in the Earth's atmosphere; the neutrons required for this reaction are produced by cosmic rays interacting with the atmosphere.Radiocarbon present in molecules of atmospheric carbon dioxide enters the biological carbon cycle: it is absorbed from the air by green plants and then passed on to animals through the food chain. Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food. Once the organism dies, however, it ceases to absorb carbon-14, so that the amount of the radiocarbon in its tissues steadily decreases. Carbon-14 has a half-life of 5,730 ± 40 years—i.e., half the amount of the radioisotope present at any given time will undergo spontaneous disintegration during the succeeding 5,730 years. Because carbon-14 decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon.The carbon-14 method was developed by the American physicist Willard F. Libby (Libby, Willard Frank) about 1946. It has proved to be a versatile technique of dating fossils and archaeological specimens from 500 to 50,000 years old. The method is widely used by Pleistocene geologists, anthropologists, archaeologists, and investigators in related fields.
* * *
Look at other dictionaries:
carbon-14 dating — noun a chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon 14; believed to be reliable up to 40,000 years • Syn: ↑radiocarbon dating, ↑carbon dating • Hypernyms: ↑dating, ↑geological… … Useful english dictionary
carbon-14 dating. — See radiocarbon dating. [1955 60] * * * … Universalium
carbon-14 dating — n. ara gel radiocarbon dating • Etymology: 1955–60 … From formal English to slang
carbon-14 dating. — See radiocarbon dating. [1955 60] … Useful english dictionary
Oxidizable carbon ratio dating — is a method of dating in archaeology and earth science that can be used to derive or estimate the age of soil and sediment samples up to 35,000 years old. The method is considered by some to be experimental, and it is not as widely used in… … Wikipedia
carbon dating — n. a method of establishing the approximate age of carbonaceous materials, such as fossil remains or archaeological specimens, by measuring the amount of radioactive carbon 14 remaining in them: also carbon 14 dating * * * … Universalium
carbon dating — n. a method of establishing the approximate age of carbonaceous materials, such as fossil remains or archaeological specimens, by measuring the amount of radioactive carbon 14 remaining in them: also carbon 14 dating … English World dictionary
Dating methodologies in archaeology — Dating material drawn from the archaeological record can be made by a direct study of an artifact or may be deduced by association with materials found in the context the item is drawn from or inferred by its point of discovery in the sequence… … Wikipedia
Dating methodology (archaeology) — Dating material drawn from the archaeological record can made by a direct study of an artifact or may be deduced by association with materials found in the context the item is drawn from or inferred by its point of discovery in the sequence… … Wikipedia
dating — I In geology and archaeology, the process of determining an object s or event s place within a chronological scheme. Scientists may use either relative dating, in which items are sequenced on the basis of stratigraphic clues (see stratigraphy) or … Universalium