The geochemistry of radiogenic strontium

The important influence that the radioactive decay of the radio-elements uranium and thorium has had on the geochemical distribution of lead is now well appreciated, but little is known about the possible geochemical implications of the radioactivity of rubidium. Like its alkali metal homologue potassium, rubidium is β radioactive and slowly disintegrates into a stable isotope of strontium: small quantities of strontium have therefore been accumulating in various minerals since the earth's crust first consolidated. This paper will describe firstly, the abundance of radiogenic strontium in the earth's crust as a whole, and secondly, the distribution of radiogenic strontium in various minerals and rocks, in particular those which are of igneous origin.