How can Stone Age graves be dated?

If organic material such as plants, animals or humans are to be dated, the carbon 14 method can be used. Carbon 14 is a radioactive isotope, which is part of the earth’s biological cycle. All living things absorb carbon 14 throughout their life. Carbon 14 is radioactive and it decays constantly, becoming smaller and smaller over time. When an organism dies it stops absorbing carbon 14. By measuring the amount of carbon 14 remaining in an organism, we can estimate how old it is. Such a measurement is never completely precise and this is why a +/- is shown after the date.