What type of rock is used for relative dating
Different methods have their own limitations, especially with regard to the age range they can measure and the substances they can date.A common problem with any dating method is that a sample may be contaminated with older or younger material and give a false age.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.
Measuring the proportions of argon-39 and argon-40 within a sample allows the age of the sample to be determined.
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.