Radiocarbon dating
Description
A method used to estimate the age of carbon-containing materials. Radiocarbon dating was discovered by Willard Libby in 1947 (Nobel prize in chemistry 1960). It is based on the measurement of the proportion of the isotope carbon-14 in the total carbon content of the concerned material. Carbon 14 is a naturally occurring radioactive carbon isotope produced by the interaction of cosmic rays (neutrons) with the stable nitrogen 14 present in the earth atmosphere. It is assumed that the proportion of carbon 14 in living plants and animals is in equilibrium with that of the atmosphere due to continual carbon dioxide exchanges with the air. Once the plant or animal dies and no new carbon 14 is assimilated by the plant or animal, the existing carbon 14 concentration decreases at a rate proportional to its radioactive decay. The radioactive period of carbon 14 is 5730 y. Two measurement methods of carbon 14 content are currently used for dating purposes:
- Liquid scintillation, for which each measured sample must have a mass of about 10 to 100 g
- Ion acceleration coupled with a mass spectrometer (AMS), a much more sensitive method, for which each measured sample can have a mass of about 1 to 20 mg
Precise radiocarbon dating is checked and correlated with the measurement of materials of exactly known age like tree rings. The method is imprecise for dating recent materials (less than 500 y before present)but is well adapted and precise for dating ancient and prehistoric materials up to 50000 years old. Radiocarbon dating is been used to determine the ages of of wood, charcoal, seeds, pollen, foraminifers, textiles, bones (carbonized or not), teeth, ivory, hair, leather, basketwork, peat, shells, coral, any archaeological organic remains
Synonyms and Related Terms
carbon-14 dating; radiometric dating; datation par le carbone 14 (Fr.); Kohlenstoff 14 Altersbestimmung (Deut.)
Physical and Chemical Properties
Carbon 14 has a half life(radioactive period) of 5730 years.
Resources and Citations
- C.Tuniz, J.R. Bird, D. Fink & G.F. Herzog. Accelerator Mass Spectrometry: Ultrasensitive analysis for global science. CRC Press, Boca Raton FL (1998)
- R.E. Taylor, O. Bar-Yosef, Radiocarbon Dating - An Archaeological Perspective, 2nd Edition, Left Coast Press, Walnut Creek CA (2014)
- T. Higham and T. E. Levy, The Bible and Radiocarbon Dating: Archaeology, Text and Science, Acumen Publishing, Durham (UK) (2012)
- S. Bowman, Radiocarbon Dating, University of. California Press, Berkeley CA (1990)
- Radiocarbon Web-Info, Radiocarbon Laboratory, University of Waikato (New Zeeland)
- Oxford Radiocarbon Accelerator Unit, Research Laboratory for Archaeology and the History of Art, Oxford (United Kingdom)
http://c14.arch.ox.ac.uk/embed.php?File=webinfo.html
- CEDAD – Lecce (Italy)
http://www.cedad.unisalento.it/en/research.php
- CEA – Saclay (France)
http://www.cea.fr/jeunes/themes/la-radioactivite/l-essentiel-sur-la-datation-au-carbone-14
- Beta Analytic, Miami FL (United States)