Radiocarbon dating cost
In short, all parts of the carbon cycle were seen to be invaded by the isotope carbon-14.
Invasion is probably not the proper word for a component that Libby calculated should be present only to the extent of about one atom in a trillion stable carbon atoms.
Radioactive carbon thus was visualized as gaining entrance wherever atmospheric carbon dioxide enters—into land plants by photosynthesis, into animals that feed on the plants, into marine and fresh waters as a dissolved component, and from there into aquatic plants and animals.With correction for radioactive decay during the intervening years, such old samples hopefully would show the same starting carbon-14 level as exists today. His conclusion was that over the past 5,000 years the carbon-14 level in living materials has remained constant within the 5 percent precision of measurement.A dating method was thus available, subject only to confirmation by actual application to specific chronologic problems.It is clear that carbon-14 dates lack the accuracy that traditional historians would like to have.
There may come a time when all radiocarbon ages rest on firmer knowledge of the sample’s original carbon-14 level than is now available.
In the context of carbon-14 dating, this departure from the present-day level means that samples with a true age of 8,200 years would be dated by radiocarbon as 7,500 years old.