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Thus, pupal case radiocarbon content would serve as a decay-resistant proxy for the tissues, yielding the year of death.The spike in atmospheric carbon-14 levels during the 1950s and early 1960s makes this approach possible, but it also means it will have a limited period of utility because the amount of carbon-14 in the atmosphere is slowly returning to its natural level.The researchers found that if they assumed tooth enamel radiocarbon content to be determined by the atmospheric level at the time the tooth was formed, then they could deduce the year of birth.
Barring any future nuclear detonations, this method should continue to be useful for year-of-birth determinations for people born during the next 10 or 20 years.
Everyone born after that would be expected to have the same level of carbon-14 that prevailed before the nuclear testing era.
Carbon-14 has a half-life of 5,730 ± 40 years— during the succeeding 5,730 years.
Because carbon-14 decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon.
Now, new applications for the technique are emerging in forensics, thanks to research funded by NIJ and other organizations.
In recent years, forensic scientists have started to apply carbon-14 dating to cases in which law enforcement agencies hope to find out the age of a skeleton or other unidentified human remains.
All the people whose tissues were tested for the study were residents of the United States.
Atmospheric dispersion tends to create uniform levels of carbon-14 around the globe, and researchers believe that these would be reflected in human tissues regardless of location.
However, more testing is needed to confirm that belief. 269, March 2012NCJ 237722 Philip Bulman is a writer and editor at NIJ.
Danielle Mc Leod-Henning is a program manager and physical scientist at NIJ.
The researchers wanted to find out if they could identify a person's year of birth or year of death using precise measurements of carbon-14 levels in different post-mortem tissues.Tags: Adult Dating, affair dating, sex dating