Radiocarbon dating

Description

A method used to estimate the age of carbon-containing materials. Radiocarbon dating was discovered by Willard Libby in 1947. It is based on the measurement of carbon-14. Carbon-14 is a naturally occurring radioactive carbon isotope made by the interaction of cosmic rays with nitrogen in the atmosphere. It is assumed that the proportion of C-14 in living plants and animals is constant due to continual carbon dioxide exchanges with the air. Once the plant or animal dies and no new C-14 enters the plant or animal, the existing C-14 concentration decreases at a rate proportional to its decay. The C-14 measurements were formerly made with Geiger counts but now are made using a sensitive mass spectrometers. Radiocarbon dating has been checked with the measurement of materials of known age (tree rings, etc.). It is imprecise for dating recent materials but is good for dating ancient and prehistoric materials up to 70,000 years old. Radiocarbon dating has been used to determine the ages of textiles, bones, vegetable oils, wood, charcoal and lime mortars.

Synonyms and Related Terms

carbon-14 dating; radiometric dating; datation par le carbone 14 (Fr.); Kohlenstoff 14 Altersbestimmung (Deut.)

Other Properties

Carbon-14 has a half life of 5730 years.

Additional Information

° Protsch and Berger, Science, 179:4070 p.235-239, 1973. ° Roy Switzur "Dating Techniques" Building Conservation Directory 2001: Link