K-. 40. Ca closure profile dating. 19 opens up a new thermochronological approach. K-Ar geochronology was being developed for dating meteorites (Merrihue, 1965; Merrihue and. 28 .. intragrain deformation microstructures imposed post-.
For dating samples with older history - geological samples for exploring earth history Potassium-Argon Dating. 40K has build-up of 40Ar/40K abundance ratio in material. ) e(. )K(N. )Ar(N y . ) e()K(N.)Ar(N . post-cranial remains of homo
Such relative dating methods are still standard, but since 1961 it has been . 40ky [improving measurement methods can boost this to close to 70ky Potassium-Argon (K-Ar) and Argon-Argon (4 0Ar/3 9Ar): 40K decays to 40Ar with a half-life.