A dating method with39Ar

The principles of a dating method based on the cosmic-ray-produced radioisotope³⁹Ar are given. Technical requirements such as background and standard gas samples and gas proportional counting systems are described.With samples extracted from Greenland ice it can be demonstrated that³⁹Ar ages agree with ages obtained by other methods. First results on ocean water samples show that with this isotope valuable information on ocean mixing and circulation can be expected.³⁹Ar results on groundwater samples disagree for some aquifers with conventional¹⁴C ages; possible explanations are discussed, especially underground production of³⁹Ar.