Increasing accuracy for the radiocarbon dating of sites occupied by the first Americans

We re-dated vertebrate fossils associated with the North American butchering sites of Wally's Beach (Canada), La Prele [also known as Fetterman (Wyoming)], Lindsay (Montana), and Dent (Colorado). Our work illustrates the crucial importance of sample chemical preparation in completely removing contaminants derived from sediments or museum curation. Specifically, our work demonstrates that chromatographic methods, e.g. preparative High Performance Liquid Chromatography and column chromatography using XAD resins, are currently the only efficient methods for removing environmental and museum-derived contaminants. These advanced techniques yield demonstrably more accurate AMS 14C measurements that refine the ages of these four sites and thereby contribute to advancing our understanding of human dispersals across North America during the late Pleistocene.