Radiometric dating is based on
The ratio of the parent to daughter then can be used to back-calculate the age of that rock. The reason we know that radiometric dating works so well is because we can use several different isotope systems (for example, Uranium-Lead, Lutetium-Halfnium, Potassium-Argon) on the same rock, and they all come up with the same age.This gives geologists great confidence that the method correctly determines when that rock formed.Obviously, if the substance you are measuring is contaminated, then all you know is the age since contamination, or worse, you don't know anything, because the contamination might be in the opposite direction - suppose, for example, you're looking at radio carbon (carbon 14, which is produced in the atmosphere by cosmic rays, and which decays into nitrogen).
A mass spectrometer is an instrument that separates atoms based on their mass. This is an enormous branch of geochemistry called Geochronology. It is an accurate way to date specific geologic events.For example, the element Uranium exists as one of several isotopes, some of which are unstable.When an unstable Uranium (U) isotope decays, it turns into an isotope of the element Lead (Pb).
Search for radiometric dating is based on:
Uranium eventually decays into lead, and lead does not normally occur in zircon, except as the radioactive decay product of uranium.