Does radiometric dating produce exact results
For example, the decay of potassium-40 to argon-40 is used to date rocks older than 20,000 years, and the decay of uranium-238 to lead-206 is used for rocks older than 1 million years.Radiocarbon dating measures radioactive isotopes in once-living organic material instead of rock, using the decay of carbon-14 to nitrogen-14.Each original isotope, called the parent, gradually decays to form a new isotope, called the daughter.
Kieth and Anderson show considerable evidence that the mussels acquired much of their carbon from the limestone of the waters they lived in and from some very old humus as well.
All radiometric dating methods measure isotopes in some way.
Most directly measure the amount of isotopes in rocks, using a mass spectrometer.
Geologists often need to know the age of material that they find.
They use absolute dating methods, sometimes called numerical dating, to give rocks an actual date, or date range, in number of years.