Fossil record radiometric dating
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 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.
It is initially formed in the molten rock that lies beneath the Earth’s crust.
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.
This technique is, however, useful for providing relative dates for objects found at the same site.
Another useful chemical analysis technique involves calculating the amount of nitrogen within a bone.