Each original isotope, called the parent, gradually decays to form a new isotope, called the daughter.
Each isotope is identified with what is called a ‘mass number’.
It is based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.
It is the principal source of information about the absolute age of rocks and other geological features, including the age of the Earth itself, and it can be used to date a wide range of natural and man-made materials.
There are two basic approaches: relative age dating, and absolute age dating.
The zircon is then dated using Uranium-Lead radiometric dating.
U-Pb dating measures the amount of decay from unstable uranium isotopes, to stable lead isotopes.
Zircon is a perfect mineral to use, since it contains both uranium and thorium in its structure.
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