Parent daughter ratio radiometric dating
This technique can be applied if the daughter element has at least one stable isotope other than the daughter isotope into which the parent nuclide decays.All forms of isochron dating assume that the source of the rock or rocks contained unknown amounts of both radiogenic and non-radiogenic isotopes of the daughter element, along with some amount of the parent nuclide.Each mineral has different ratios between parent and daughter concentrations.
(See particularly the section on isotope ratio mass spectrometry.) If all data points lie on a straight line, this line is called an isochron.
The advantage of isochron dating as compared to simple radiometric dating techniques is that no assumptions are needed about the initial amount of the daughter nuclide in the radioactive decay sequence.
Indeed, the initial amount of the daughter product can be determined using isochron dating.
Isochron dating is a common technique of radiometric dating and is applied to date certain events, such as crystallization, metamorphism, shock events, and differentiation of precursor melts, in the history of rocks.
Isochron dating can be further separated into mineral isochron dating and whole rock isochron dating; both techniques are applied frequently to date terrestrial and also extraterrestrial rocks (meteorites).