Radiocarbon, or carbon 14, is an isotope of the element carbon that is unstable and weakly radioactive.
A separate issue, related to re-use, is that of lengthy use, or delayed deposition.
These improved field methods were sometimes motivated by attempts to prove that a 14 C date was incorrect.
Contamination is of particular concern when dating very old material obtained from archaeological excavations and great care is needed in the specimen selection and preparation.
Description: The method was developed in the late s by Willard Libbywho received the Nobel Prize in Chemistry for his work in Coal and oil began to be burned in large quantities during the 19th century.