Potassium–Argon Ages of the Dartmoor and Shap Granites using the Total Volume and Isotopic Dilution Techniques of Argon Measurement

Abstract

EARLY in 1960, J. L. Kulp and others reported potassium–argon and rubidium–strontium ages for a number of granites from Great Britain and Eire1. The argon measurements were made at the Lamont Geological Observatory by the isotopic dilution technique, and the rubidium–strontium determinations were made at Oxford and Harwell. Some of the rocks examined, including the Shap and Dartmoor granites, had been measured by Mayne et al. 2, using the total volume technique for measuring the argon. There was a serious discrepancy between the potassium–argon measurements reported in these two communications, the results obtained by Kulp et al. being in agreement with the rubidium–strontium data (Table 2).