The technique can, however, provide the relative ages of bones from the same site.
This problem is now reduced by the careful collection of samples, rigorous crosschecking and the use of newer techniques that can date minute samples.
Volcanic rocks – such as tuff and basalt – can be used in dating because they are formed at a particular moment in time, during an eruption.
This relatively new technique was developed in order to achieve more accurate dates than those obtained from the potassium-argon method.
The older method required two samples for dating and could produce imprecise dates if the argon was not fully extracted.
Argon is gas that gradually builds up within rocks from the decay of radioactive potassium.
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.This damage is in the form of tiny marks called fission tracks.When volcanic rocks and minerals are formed, they do not contain fission tracks.The age of volcanic rocks and ash can be determined by measuring the proportions of argon (in the form of argon-40) and radioactive potassium within them.