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.
The level of nitrogen gradually reduces as the bone decays.
Absolute dating is not possible with this method because the rate at which the nitrogen content declines depends on the surrounding temperature, moisture, soil chemicals and bacteria.
This relatively new technique was developed in order to achieve more accurate dates than those obtained from the potassium-argon method.
Each volcanic eruption produces a new deposit of ash and rock.Instead, other methods are used to work out a fossil’s age.These include radiometric dating of volcanic layers above or below the fossils or by comparisons to similar rocks and fossils of known ages.The number of tracks increases over time at a rate that depends on the uranium content.It is possible to calculate the age of a sample by measuring the uranium content and the density of the fission tracks.