Potassium occurs in two stable isotopes (Ar atoms trapped inside minerals.
These factors introduce error limits on the upper and lower bounds of dating, so that final determination of age is reliant on the environmental factors during formation, melting, and exposure to decreased pressure and/or open-air.
Time since recrystallization is calculated by measuring the ratio of the amount of The quickly cooled lavas that make nearly ideal samples for K–Ar dating also preserve a record of the direction and intensity of the local magnetic field as the sample cooled past the Curie temperature of iron.
The potassium-argon age of some meteorites is as old as 4,500,000,000 years, and volcanic rocks as young as 20,000 years old have been measured by this method.
Potassium–argon dating, abbreviated K–Ar dating, is a radiometric dating method used in geochronology and archaeology.
While this assumption holds true in the vast majority of cases, excess argon can occasionally be trapped in the mineral when it crystallizes, causing the K-Ar age to be a few hundred thousand to a few million years older than the actual cooling age.
Secondly, K-Ar dating assumes that very little or no argon or potassium was lost from the mineral since it formed. it does not bond to any other elements), it can readily escape from minerals if they are exposed to significant amounts of heat for a prolonged period of time.
On the other hand, the abundance of argon in the is relatively small because of its escape to the atmosphere during processes associated with volcanism.
The potassium-argon dating method has been used to measure a wide variety of ages.
Geologists have used this method to date rocks as much as 4 billion years old.
It is based on the fact that some of the radioactive isotope of Potassium, Potassium-40 (K-40) ,decays to the gas Argon as Argon-40 (Ar-40).
Though we know that K-Ar dating works and is generally quite accurate, however, the method does have several limitations.