Uranium to lead dating
The three main parameters that have to be set are the original amount of uranium and lead in the sample, the rate at which uranium and lead enter and leave the sample, and how much the rate of decay changes.Uranium-lead dating uses four different isotopes to find the age of the rock.The four isotopes are uranium-235, uranium-238, lead-207, and lead-206.The process of dating finds the two ratios between uranium-235 and lead-207; and uranium-238 and lead-206.
The half-lives of the cascade from uranium-235 to lead-207 has been been extrapolated to about 704 million years and the cascade form uranium-238 to lead-206 has been calculated to about 4.47 billion years.
For Uranium-Lead dating to work, scientists have to make three assumptions.
These assumptions are that the system being dated is a closed system; at the beginning of the time period, there are no daughter isotopes present; and the rate of radioactive decay stays the same through the whole time period.
Uranium-Lead dating is a radiometric dating method that uses the decay chain of uranium and lead to find the age of a rock.
As uranium decays radioactively, it becomes different chemical elements until it stops at lead.