Uranium-Lead dating

The four isotopes are uranium , uranium , lead , and lead The process of dating finds the two ratios between uranium and lead ; and uranium and lead The radiometric dater then uses the half-life of all four isotopes to find an age range the rock should be in. The half-lives of the cascade from uranium to lead has been been extrapolated to about million years and the cascade form uranium to lead has been calculated to about 4.

This data is compared to a curve called the Concordia diagram.

By study of the decay products of uranium (lead and intermediate radioactive elements that decay to lead) demonstrated to B. B. Boltwood that the lead/uranium ratio in uranium minerals increased with geologic age and might provide a geological dating tool.

Uranium—lead dating facts QR Code Figure 1: Concordia diagram for data published by Mattinson for zircon samples from Klamath Mountains in Northern California. Ages for the concordia increase in increments of million years. Uranium—lead dating , abbreviated U—Pb dating , is one of the oldest and most refined of the radiometric dating schemes. It can be used to date rocks that formed from about 1 million years to over 4. The dating method is usually performed on the mineral zircon.

The mineral incorporates uranium and thorium atoms into its crystal structure , but strongly rejects lead.