The majority of the time fossils are dated using relative dating techniques. radioactive minerals that occur in rocks and fossils almost like a geological clock. Using relative and radiometric dating methods, geologists are able to answer the question: how old is this fossil?. The oldest undisputed fossils are from rocks dated around Ga, and although geologists have acquired enough isotopic dates from rocks associated with . Using the bracketing method described above, determine the possible age.
Uranium—thorium dating method[ edit ] Main article: Rubidium-strontium dating is not as precise as the uranium-lead method, with errors of 30 to 50 million years for a 3-billion-year-old sample. Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it. These are the parent isotope that did not change during the first half life.