For Radiocarbon Dating we have terms and definitions in 5 topics. The topics are Anthromorphemics, Anthropology, Archaeology, Atmospheric Chemistry and Geologic.

Radiocarbon Dating (Anthromorphemics)

An absolute dating method based on the radioactive decay of Carbon-14 contained in organic materials.

Radiocarbon Dating (Anthropology)

An absolute dating method based on the radioactive decay of Carbon-14 contained in organic materials.

Radiocarbon Dating (Archaeology)

Using the known half-life of Carbon-14, the amount of undecayed carbon-14 is used in order to determine the age of an artifact.

Radiocarbon Dating (Atmospheric Chemistry)

Establishing the relative age of various materials with the use of carbon-14. This involves measuring the amount of 14C and of 12C and comparing the measured ratio to the one established by the production of 14C in the upper atmosphere by cosmic rays. When an organism is alive the 14C/ 12C ratio in its biomass is constant (because of constant atmospheric 14C production, difussion to the lower atmsophere, absorption by organisms, and because of constant 14C radioactive decay) but when the organism dies the ratio begins to change--at a very predictable rate. Therefore knowing the carbon-14/carbon-12 ratio now in some artifact gives a very good measure of how long the carbon has been "dead." The object however must obviously have organic material either in it or on it for this method to work. Also the lenth of time one can "look back" is limited because the amount of carbon-14 must be detected with some certainty for the age to be known with confidence, and the longer the sample has been dead the less 14C is present because it is continually decaying. [New Scientist; v274; 18; 1996.] [Scientific American; v150; 24; 1996.] [Bowman, Sheridan, Radiocarbon dating--Interpreting the past. British Museum Press; 1995.]

Radiocarbon Dating (Geologic)

The age of organic material determined by the amounts of carbon isotopes 12, 13 and 14. The ratio of 12 to 14 is about the same in all living things but when a plant or animal dies, no more carbon is taken on. Carbon 12 and 13 are stable isotopes and the amounts remain the same even in dead material. Carbon 14 is an radioactive isotope that decays radioactively until none is left; . Thus, the ratio records the time elapsed since death. Since carbon 14 decays relatively rapidly, the method is only reliable for the last 40,000 years. See radiometric age.

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