Rb-Sr dating relies on correctly measuring the Rb-Sr ratio of a mineral or whole rock sample, plus deriving an accurate One of the major drawbacks (and, conversely, the most important use) of utilizing Rb and Sr to derive a radiometric date is their relative mobility, especially in hydrothermal fluids.
In addition, Rb is a highly incompatible element that, during partial melting of the mantle, prefers to join the magmatic melt rather than remain in mantle minerals. The radiogenic daughter, Sr, is produced in this decay process and was produced in rounds of stellar nucleosynthesis predating the creation of the Solar System.Different minerals in a given geologic setting can acquire distinctly different ratios of radiogenic strontium-87 to naturally occurring strontium-86 (Sr as the parent melt.Conversely, these fluids may metasomatically alter a rock, introducing new Rb and Sr into the rock (generally during potassic alteration or calcic (albitisation) alteration.Rb-Sr can then be used on the altered mineralogy to date the time of this alteration, but not the date at which the rock formed. Development of this process was aided by German chemists Otto Hahn and Fritz Strassmann, who later went on to discover nuclear fission in December 1938.
The utility of the rubidium–strontium isotope system results from the fact that Sr with a half-life of 48.8 billion years.
In this period a number of comprehensive cosmogonies were proposed.
These were long on armchair speculation and short on substantive supporting evidence.
The resulting Rb-Sr ratios and Rb and Sr abundances of both the whole rocks and their component minerals will be markedly different.
This, thus, allows a different rate of radiogenic Sr to evolve in the separate rocks and their component minerals as time progresses.
The Rb-Sr dating method has been used extensively in dating terrestrial and lunar rocks, and meteorites.