Potassium argon dating wiki
The abundance of Ar is unlikely to provide the age of intrusions of granite as the age typically reflects the time when a mineral cooled through its closure temperature.However, in a metamorphic rock that has not exceeded its closure temperature the age likely dates the crystallization of the mineral.Specifically, its presence in solid rock cannot be explained by other mechanisms.
Potassium-argon dating or K-Ar dating is a radiometric dating method used in geochronology and archeology.
Because argon was able to escape from the rock while it was in a liquid state (molten), this accumulation provides a record of how much of the original Ca being the favored daughter nuclide, its usefulness in dating is limited since a great many decay events are required for a small change in relative abundance, and also the amount of calcium originally present may not be known.
The ratio of the amount of K which was present at the beginning of the elapsed time period.
Although it finds the most utility in geological applications, it plays an important role in archaeology.
One archeological application has been in bracketing the age of archeological deposits at Olduvai Gorge by dating lava flows above and below the deposits.