Here are some USGS Web pages with more information on rubidium-strontium age analysis and Anywhere:
Geochronology
Description of the methods of geochronology used to estimate the dating of rocks and sediments with links to technique, equipment and contacts for a variety of methods.
(Score: 1.000)
Definition:
Determining of the age of a mineral or rock in years based on the ration of radiogenic strontium-87 to rubidium-87 and the known radioactive decay rate of rubidium-87. [Glossary of Geology, 4th ed.]