14 carbon dating method
There are three carbon isotopes that occur as part of the Earth's natural processes; these are carbon-12, carbon-13 and carbon-14.The unstable nature of carbon 14 (with a precise half-life that makes it easy to measure) means it is ideal as an absolute dating method.In the case of radiocarbon dating, the half-life of carbon 14 is 5,730 years.This half life is a relatively small number, which means that carbon 14 dating is not particularly helpful for very recent deaths and deaths more than 50,000 years ago.Carbon-14 has a half-life of 5,730 ± 40 years— 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.Libby and coworkers, and it has provided a way to determine the ages of different materials in archeology, geology, geophysics, and other branches of science.Some examples of the types of material that radiocarbon can determine the ages of are wood, charcoal, marine and freshwater shell, bone and antler, and peat and organic-bearing sediments.
CARBON-14 IS CREATED (Figure 1a): When cosmic rays bombard the earth’s atmosphere, they produce neutrons.
The other two isotopes in comparison are more common than carbon-14 in the atmosphere but increase with the burning of fossil fuels making them less reliable for study (2); carbon-14 also increases, but its relative rarity means its increase is negligible. After this point, other Absolute Dating methods may be used.
Today, the radiocarbon-14 dating method is used extensively in environmental sciences and in human sciences such as archaeology and anthropology.
It also has some applications in geology; its importance in dating organic materials cannot be underestimated enough.
In 1979, Desmond Clark said of the method “we would still be foundering in a sea of imprecisions sometime bred of inspired guesswork but more often of imaginative speculation” (3).