Potassium argon dating animation
Buried bones absorb chemicals, such as uranium and fluorine, from the surrounding ground and absorb more of these chemicals the longer they remain buried.The rates of absorption depend on a number of factors which are too variable to provide absolute dates.This newer method converts a stable form of potassium (potassium-39) into argon-39.Measuring the proportions of argon-39 and argon-40 within a sample allows the age of the sample to be determined.This relatively new technique was developed in order to achieve more accurate dates than those obtained from the potassium-argon method.
It is initially formed in the molten rock that lies beneath the Earth’s crust.
Fossils and other objects that accumulate between these eruptions lie between two different layers of volcanic ash and rock.
An object can be given an approximate date by dating the volcanic layers occurring above and below the object.
Only one sample is required for this method as both the argon-39 and argon-40 can be extracted from the same sample.
In special cases, bones can be compared by measuring chemicals within them.