Radiometric dating allows us to determine Cam girls is for adults only system
A common problem with any dating method is that a sample may be contaminated with older or younger material and give a false age.
This problem is now reduced by the careful collection of samples, rigorous crosschecking and the use of newer techniques that can date minute samples.
It is possible to calculate the age of a sample by measuring the uranium content and the density of the 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.
Argon then starts to re-accumulate at a constant rate in the newly formed rock that is created after the eruption.
This relatively new technique was developed in order to achieve more accurate dates than those obtained from the potassium-argon method.
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.
Sedimentary rocks are rarely useful for dating because they are made up of bits of older rocks.
Only one sample is required for this method as both the argon-39 and argon-40 can be extracted from the same sample.
The rates of absorption depend on a number of factors which are too variable to provide absolute dates.
This technique is, however, useful for providing relative dates for objects found at the same site.
The older method required two samples for dating and could produce imprecise dates if the argon was not fully extracted.
This newer method converts a stable form of potassium (potassium-39) into argon-39.
When volcanic rocks and minerals are formed, they do not contain fission tracks.