This leaves out important information which would tell you how precise is the dating result. We need to know how fast the U turns into Pb Creationist Henry Morris, for example, criticizes this type of "uniformitarian" assumption [ Morrispg. For example, it has been known since the s that the famous Cretaceous-Tertiary boundary, the line marking the end of the dinosaurs, was 65 million years old. This causes induced fission of U, as opposed to the spontaneous fission of U. The decay accuracy Isotope dating for most of these systems have been confirmed in other ways, adding strength to our argument for the age of the earth. These will be definite factors that will accuracy Isotope dating relative concentrations of parent and daughter isotopes in some way, and call into question the reliability of radiometric dating. He may accuracy Isotope dating that some of the chemicals in the rock had been disturbed by groundwater or weathering. Accuracy of radiometric dating[ edit ] Thermal ionization mass spectrometer used in radiometric dating. People should read John Woodmorappe's articles on radiometric dating to see some of the anomalies. Potassium—argon dating This involves electron capture or positron decay of potassium accuracy Isotope dating argon Every few years, new geologic time scales are published, providing the latest dates for major time lines.