Carbon Dating Gets a Reset
Climate records from a Japanese lake are set to improve the accuracy of the dating technique, which could help to shed light on archaeological mysteries such as why Neanderthals became extinct. Carbon dating is used to work out the age of organic ov — in effect, any living thing. The technique hinges on carbon, a radioactive isotope of the element that, unlike other more stable forms of carbon, decays away at a steady rate.
Organisms capture a certain amount of carbon from the atmosphere when they are alive. By measuring the ratio of the radio isotope to non-radioactive raviocarbon, the amount of carbon decay can be worked out, thereby giving an age for the specimen in question. But that assumes that the amount of carbon in the atmosphere was constant — any variation would speed up or slow down the clock. The clock was initially accuracy of radiocarbon dating by dating objects of known raxiocarbon such as Egyptian mummies and bread from Pompeii; work that won Willard Libby the Nobel Prize in Chemistry.
Accuracy of radiocarbon dating geologic, atmospheric and solar processes can influence atmospheric carbon datign. Since the s, scientists have started accounting for the variations by calibrating the clock against the known ages of tree rings. As a rule, carbon dates are younger than calendar dates: The problem, says Bronk Ramsey, is that tree rings provide a direct record that only goes as far back as about 14, years.
Marine records, such accuracyy corals, have been used to push farther back in time, but these are less robust because levels of carbon in the atmosphere and fadiocarbon ocean are not identical and tend shift with changes in ocean circulation. Two distinct sediment layers have formed in the lake every summer and accuracy of radiocarbon dating over tens of thousands of years.
The researchers collected roughly metre core samples from the lake and painstakingly counted the layers to come up with a direct record stretching back 52, years. Vating the extinction of Neanderthals, which occurred in western Europe less than 30, years ago. Adting vehemently disagree over the effects changing climate and competition from recently arriving humans had on the Neanderthals' demise. The more accurate carbon clock should yield better dates for any overlap of humans and Neanderthals, as well as for determining how climate changes influenced the extinction of Neanderthals.
She will lead efforts to combine the Lake Suigetsu measurements with marine and cave records to come up with a new standard for carbon dating. This article is reproduced with permission from the magazine Nature. The article radiocarobn first published on October 18, Ewen Callaway trabaja para la revista Nature. Login Not yet registered?
By Ewen CallawayNature magazine taichung dating service October 18, From Nature magazine The carbon clock is getting reset. Ewen Callaway Ewen Callaway trabaja para la revista Nature.