Radiometric dating wikipedia the encyclopedia
Radiometric dating is also used to date archaeological materials, including ancient artifacts.Different methods of radiometric dating vary in the timescale over which they are accurate and the materials to which they can be applied.All ordinary matter is made up of combinations of chemical elements, each with its own atomic number, indicating the number of protons in the atomic nucleus.Additionally, elements may exist in different isotopes, with each isotope of an element differing in the number of neutrons in the nucleus.
In this case, the only atoms of the daughter nuclide present in a sample must have been deposited by radioactive decay since the sample formed.
After an organism has been dead for 60,000 years, so little carbon-14 is left in it that accurate dating becomes impossible.
On the other hand, the concentration of carbon-14 falls off so steeply that the age of relatively young remains can be determined precisely to within a few decades.
This predictability allows the relative abundances of related nuclides to be used as a clock that measures the time from the incorporation of the original nuclide(s) into a material to the present.
The processes that form specific materials are often conveniently selective as to what elements they incorporate during their formation.