After death the amount of carbon-14 in the organic specimen decreases very regularly as the molecules decay.
Two chert artifacts from the region near Luxor, Egypt have yielded concentrations of cosmogenic (super 10) Be that allow calculation of nominal exposure ages of 326,000 and 304,000 years.
Green plants absorb the carbon dioxide, so the population of carbon-14 molecules is continually replenished until the plant dies.
Carbon-14 is also passed onto the animals that eat those plants.
By examining the object's relation to layers of deposits in the area, and by comparing the object to others found at the site, archaeologists can estimate when the object arrived at the site.
As explained below, the radiocarbon date tells us when the organism was alive (not when the material was used).But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.Until this century, relative dating was the only technique for identifying the age of a truly ancient object.One outcome from this study is that performing chemical residue identification earlier in the method sequence using non-destructive and non-contaminating methods would guide the choice of residue treatment and improve reliability of age determination.Radiocarbon dating is one of the most widely used scientific dating methods in archaeology and environmental science.We found the alkaline surfactant Decon 90 is a useful solution for removal of skin scales and fabric fibre but has limited effect on graphite contamination introduced by pencil lead.