The Re-Os isotopic system was first developed in the early 1960s, but recently has been improved for accurate age determinations.The main limitation is that it only works on certain igneous rocks as most rocks have insufficient Re and Os or lack evolution of the isotopes.Some techniques place the sample in a nuclear reactor first to excite the isotopes present, then measure these isotopes using a mass spectrometer (such as in the argon-argon scheme).
those that form during chemical reactions without breaking down).
The unstable or more commonly known radioactive isotopes break down by radioactive decay into other isotopes.
Radioactive dating is a method of dating rocks and minerals using radioactive isotopes.
This method is useful for igneous and metamorphic rocks, which cannot be dated by the stratigraphic correlation method used for sedimentary rocks. Some do not change with time and form stable isotopes (i.e.
This technique has become more widely used since the late 1950s.