The essential difference between K-Ar and Ar-Ar dating techniques lies in the measurement of potassium. In K-Ar dating, potassium is measured generally using flame photometry, atomic absorption spectroscopy, or isotope dilution and Ar isotope measurements are made on a separate aliquot of the mineral or rock sample.

What is K-Ar dating used for?

Potassium-argon dating, method of determining the time of origin of rocks by measuring the ratio of radioactive argon to radioactive potassium in the rock. This dating method is based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks; potassium-40 also decays to calcium-40.