Abstract
A comparison of the ratio, radiogenic /, found in eight Rb minerals of differing Rb content from the same rock unit has shown this ratio to be constant for a given mineral assemblage. This ratio has been measured on Rb minerals from six rock units for which concordant U-Pb ages ranging from 375 to 2700 million years have also been obtained. From the ratio radiogenic / and the age of the mineral obtained from the U-Pg age, the half-life of R is calculated to be (5.0±0.2)× yr. This lies in the range of values found by direct counting experiments.
- Received 20 March 1956
DOI:https://doi.org/10.1103/PhysRev.103.1045
©1956 American Physical Society