C 14 dating controversy

27 Nov

“Seldom has a single discovery in chemistry had such an impact on the thinking in so many fields of human endeavour,” one of Libby's colleagues wrote at the time, according to the Nobel Foundation.

Today, carbon dating is used so widely as to be taken for granted.

The Lamont-Doherty scientists conducted their analyses on samples of coral drilled from a reef off the island of Barbados.

The samples represented animals that lived at various times during the last 30,000 years. Alan Zindler, a professor of geology at Columbia University who is a member of the Lamont-Doherty research group, said age estimates using the carbon dating and uranium-thorium dating differed only slightly for the period from 9,000 years ago to the present.

''But at earlier times, the carbon dates were substantially younger than the dates we estimated by uranium-thorium analysis,'' he said.

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One such indicator is the uranium-thorium dating method used by the Lamont-Doherty group.Dating Subject to Error But scientists have long recognized that carbon dating is subject to error because of a variety of factors, including contamination by outside sources of carbon.Therefore they have sought ways to calibrate and correct the carbon dating method.Scientists across countless disciplines rely on it to date objects that are tens of thousands of years old. An analysis by Heather Graven, a climate-physics researcher at Imperial College London, finds that today's rate of fossil-fuel emissions is skewing the ratio of carbon that scientists use to determine an object's age.Combustion of fossil fuels is “diluting the fraction of atmospheric carbon dioxide containing radiocarbon,” Graven told , the large amount of carbon dioxide in the atmosphere will make new organic material appear to be 1,000 years old based on today’s carbon-dating models.