Rubidium–strontium dating

A radiometric dating method that estimates the age of rocks and minerals from the decay of rubidium-87 into strontium-87. Its isochron approach can determine an age without assuming the samples began with the same strontium isotope composition.

Rubidium-87: A naturally occurring radioactive isotope of rubidium that decays to strontium-87. Its decay supplies the time-dependent increase in radiogenic strontium measured by this method.
Radioactive decay: The spontaneous transformation of an unstable atomic nucleus into a more stable configuration. The method’s clock is the steady decay of rubidium-87.
Geochronology: The science of determining the ages and timing of geological events. Rubidium–strontium dating is one tool for establishing geological ages.
Uranium–lead dating: A radiometric dating method that uses uranium isotopes decaying into lead isotopes. Its decay chains and mineral behavior provide a different clock for many of the same rocks.
Strontium-87: A stable isotope of strontium produced by the radioactive decay of rubidium-87. Its abundance relative to stable strontium-86 records accumulated rubidium-87 decay.
Half-life: The time required for half the radioactive atoms in a sample to decay. Rubidium-87’s long half-life makes the method useful for ancient rocks.
Metamorphic rock: Rock transformed in the solid state by heat, pressure, or chemically active fluids. Mineral isochrons can date metamorphism or later isotopic equilibration.
Potassium–argon dating: A radiometric dating method based on radioactive potassium-40 decaying to argon-40. Unlike rubidium–strontium dating, it commonly dates argon retention after cooling.
Isochron dating: A radiometric dating approach that estimates age from a line relating parent-to-daughter and reference-isotope ratios in related samples. Rubidium–strontium dating is a major application of this shared-ratio method.
Radiogenic isotope: An isotope produced by radioactive decay of another nuclide. Strontium-87 becomes radiogenic strontium when formed from rubidium-87.

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