In 1946, Willard Libby proposed an innovative method for dating organic materials by measuring their content of carbon-14, a newly discovered radioactive isotope of carbon. Known as radiocarbon dating, this method provides objective age estimates for carbon-based objects that originated from living organisms.

How far back can radiocarbon date?

The work combines thousands of data points from tree rings, lake and ocean sediments, corals and stalagmites, among other features, and extends the time frame for radiocarbon dating back to 55,000 years ago — 5,000 years further than the last calibration update in 2013.

How far back can Seriation dating go?

Currently there are chronologies dating as far back as 11,000. In the southwest, like at the Dillard site where Time Team America excavated, the master chronology goes back to 322 B.C. But if most trees only live for a hundred years or so, how can a master chronology go so far back in time?