Week 4           Archaeology

Uranium-lead (U-Pb) dating is the oldest and one of the most refined of the radiometric dating schemes. It works on rocks ranging from about 1 million years old to those over 4.5 billion years (the oldest on Earth), and has precisions in the 0.1-1% range. The method relies on two separate decay chains, the uranium series from 238U to 206Pb, with a half-life of 4.47 billion years and the actinium series from 235U to 207Pb, with a half-life of 704 million years