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Carbon 14 dating bomb curve
Carbon-12 accounts for ~99.8 % of all carbon atoms, carbon-13 accounts for ~1% of carbon atoms while ~1 in every 1 billion carbon atoms is carbon-14.
“Related techniques help to answer questions of where.” Samuel Wasser, of the University of Washington, led collection of ivory samples from large stockpiles seized by law enforcement officials between 20.
Alerted by contacts in law enforcement, officials in the seizing country or from internet monitoring, Wasser collected some samples himself and directed colleagues in sampling the rest.
Wasser says seizing countries were helpful and cooperative.
“They really appreciate the collaborative effort,” he says.
As plants took up this radioactive carbon, the heightened carbon-14 signature was preserved in the plants and transferred to animals.
As elephants grow new material at the base of their tusks, the ivory contains the carbon-14 signature of the plants the elephant had recently eaten.Nearly all of the analyzed ivory had a lag time of around 2-3 years, suggesting that the shipments did not come from stockpiles or from old sources, but rather that large shipments of ivory are likely composed of recently poached pieces.“This work demonstrates that little or no ‘old’ ivory, like that held in government stockpiles, is ending up on the black market, which is good news for the security and monitoring of those stockpiles,” Chesson says.But demand in North American and European markets have slowed over the same time period, Cerling says.“It really became unacceptable for people to buy ivory.” Despite progress, elephants are still killed at alarming rates.Allen Family Foundation, and from Save the Elephants’ and Wildlife Conservation’s “Elephant Crisis Fund.” The full study can be found here.Three isotopes of carbon are found in nature; carbon-12, carbon-13 and carbon-14.Because radioactive carbon-14 levels have been slowly declining since the 1960s, scientists can use the carbon-14 signature in a bone, tusk or tooth to determine, within about a year, when the material was formed.Chesson says that forensic scientists have used the so-called “bomb carbon” signature to estimate the ages of human remains in cold cases and to track the transit time of cocaine from South America to the United States.Radioisotope analysis Cerling and his colleagues applied a forensic science method to objectively estimate the age of samples in seized ivory shipments—radiocarbon dating.Aboveground atomic testing in the 1960s doubled the concentration of radioactive carbon-14 in the atmosphere.