Ink carbon dating

11 Jan

Radiocarbon dating uses the naturally occurring isotope Carbon-14 to approximate the age of organic materials. Often, archaeologists use graves and plant remains to date sites.Since its conception by Willard Libby in 1949, it has been invaluable to the discipline.It is too soon to know whether the discovery will seriously upset the estimated dates of events like the arrival of human beings in the Western Hemisphere, scientists said.But it is already clear that the carbon method of dating will have to be recalibrated and corrected in some cases.Radiocarbon, or carbon 14, is an isotope of the element carbon that is unstable and weakly radioactive. Carbon 14 is continually being formed in the upper atmosphere by the effect of cosmic ray neutrons on nitrogen 14 atoms.It is rapidly oxidized in air to form carbon dioxide and enters the global carbon cycle.The technology uses a series of mathematical calculations—the most recognizable of which is known as half-life—to estimate the age the organism stopped ingesting the isotope.Unfortunately, the amount of Carbon-14 in the atmosphere has not been steady throughout history.

Because it is radioactive, carbon 14 steadily decays into other substances.Scientists at the Lamont-Doherty Geological Laboratory of Columbia University at Palisades, N.Y., reported today in the British journal Nature that some estimates of age based on carbon analyses were wrong by as much as 3,500 years.Plants and animals assimilate carbon 14 from carbon dioxide throughout their lifetimes.When they die, they stop exchanging carbon with the biosphere and their carbon 14 content then starts to decrease at a rate determined by the law of radioactive decay.