The POTASSIUM-ARGON Method of Geological Age Determination

摘要: The development of the potassium–argon method for dating minerals is discussed. decay scheme radioactive potassium-40 examined. results 11 recent counting experiments have been averaged and give a mean value 29.4 ± 2.7 beta emissions per second gram potassium. Averaging 15 previous determinations rate gamma gives branching ratio 0.090 ± 0.038 with above rate. This in close agreement 0.089 suggested by us paper on basis two determinations.Methods measuring radiogenic argon content potassium are discussed use at this laboratory described detail. Yield runs grain size carried out reported. Potassium–argon ages calculated four perthites lepidolites. These excellent best available obtained other methods.