Rubidium-Strontium Dating

Abstract

That rubidium is naturally radioactive was shown in 1906 by N. R. Campbell and A. Wood, but it was not until 1937 that rubidium-87 was identified as the relevant radioisotope.1--3 Otto Hahn, with E. Walling, a year later discussed the possibility of dating rubidium-bearing minerals through the decay of 87Rb to 87Sr and by 1943 the first age determination had been made by Hahn et al. 4,5 In the 1950s, when mass spectrometers following Nier's design were constructed for the isotope analysis of solids, the Rb-Sr dating method became widely used, the concentrations of these elements being determined by isotope dilution and also as a result of separation by cation exchange chromatography.