- A technique for determining the age of minerals based on the occurrence in natural rubidium of a fixed amount of the radioisotope 87Rb which decays to the stable strontium isotope 87Sr with a half-life of 4.7 ÃÂ 1011 years. Measurement of the ratio of these isotopes thus gives the age of a mineral, for ages of up to about 4 ÃÂ 109 years (noun)
- Geological dating based on the proportions of radioactive rubidium into its decay product strontium; radioactive rubidium has a half-life of 47,000,000,000 years (noun)
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WordNet. Princeton University. 2010.