Explain radiometric dating fossils
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.
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.
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.
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 form of uranium usually decays into a stable lead isotope but the uranium atoms can also split – a process known as fission.
During this process the pieces of the atom move apart at high speed, causing damage to the rock or mineral.