Potassium argon dating definition
- Uranium-Lead method - Rubidium-Strontium method - Carbon-14 method – also known as carbon dating.
The half-life of carbon-14 is only 5, 730 years so this method is mainly used for dating things from the last 50,000 years Here's how it works.
Thus, the ratio of argon-40 and potassium-40 and radiogenic calcium-40 to potassium-40 in a mineral or rock is a measure of the age of the sample.
The calcium-potassium age method is seldom used, however, because of the great abundance of nonradiogenic calcium in minerals or rocks, which masks the presence of radiogenic calcium.
The proportion of potassium to argon suggests how old the object in question is.
An equation used is t = (1/c)Ln(1 (D/P)) Where c is the decay constant D is number of daughter atoms (number decayed) P is the number of parent atoms (number undecayed) t is the age of the object… Carbon dating is not useful for dating things more than about 50,000 years old.
A volcano explodes over a landscape four million years ago. Potassium, naturally occurring in the lava, is made-up of a mixture of radioactive Potassium-40 and non-radioactive Potassium-39.
During the explosion, Argon gas trapped within the lava is expelled. Over time the radioactive Potassium-40 breaks down into Argon-40 which is trapped in the structure of the hardened lava. The isotope potassium-40 decays into argon-40 at a predictable rate.
One such example is potassium-argon dating, where potassium decays into argon.
Potassium reacts violently with just water while argon is very inert and stable, which is why it remains in the atmosphere as a monatomic element.
Argon and potassium are reversed on the periodic table.
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Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work! This dating method is based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks; potassium-40 also decays to calcium-40.