potassium-argon dating

[ puh-tas-ee-uhm-ahr-gon ]

noun

, Geology.

1. a method for estimating the age of a mineral or rock, based on measurement of the rate of decay of radioactive potassium into argon.

potassium-argon dating

noun

1. a technique for determining the age of minerals based on the occurrence in natural potassium of a small fixed amount of radioisotope ⁴⁰K that decays to the stable argon isotope ⁴⁰Ar with a half-life of 1.28 × 10 ⁹years. Measurement of the ratio of these isotopes thus gives the age of the mineral Compare radiocarbon dating rubidium-strontium dating

potassium-argon dating

1. A method of radiometric dating , involving analysis of the ratio of potassium 40 (a radioactive isotope of potassium) to argon (the product of radioactive decay of potassium 40) in a given sample.

Word History and Origins

Origin of potassium-argon dating¹

First recorded in 1965–70

Example Sentences

Using a method known as potassium-argon dating, Zinjanthropus was determined to be 1.75 million years old.

From Time Magazine Archive