An example of radiometric dating
If a series of zircon samples has lost different amounts of lead, the samples generate a discordant line.
Finally, ages can also be determined from the U–Pb system by analysis of Pb isotope ratios alone. Clair Cameron Patterson, an American geochemist who pioneered studies of uranium–lead radiometric dating methods, used it to obtain one of the earliest estimates of the age of the Earth.
There are three main assumptions that must be made to accept radiometric dating methods.
These must be accepted on faith in uniformitarian and naturalistic frameworks.
Fission tracks and micro-cracks within the crystal will further extend this radiation damage network.
These fission tracks act as conduits deep within the crystal, providing a method of transport to facilitate the leaching of lead isotopes from the zircon crystal.