Carbon dating of fossils
One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites.
When a creature dies, it ceases to consume more radiocarbon while the C-14 already in its body continues to decay back into nitrogen.At high geomagnetic latitudes, the carbon-14 spreads evenly throughout the atmosphere and reacts with oxygen to form carbon dioxide.Carbon dioxide also permeates the oceans, dissolving in the water.It is naturally unstable and so it will spontaneously decay back into N-14 after a period of time.It takes about 5,730 years for half of a sample of radiocarbon to decay back into nitrogen.Research has been ongoing since the 1960s to determine what the proportion of in the atmosphere has been over the past fifty thousand years.
The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.
The amount of carbon-14 gradually decreases through radioactive beta decay with a half-life of 5,730 years.
So, scientists can estimate the age of the fossil by looking at the level of decay in its radioactive carbon.
This is how carbon dating works: Carbon is a naturally abundant element found in the atmosphere, in the earth, in the oceans, and in every living creature.
C-12 is by far the most common isotope, while only about one in a trillion carbon atoms is C-14.
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).