Then in 2004, geochronologists at Berkeley — Ludwig, Renne, and Roland Mundil, working with Australian geologist Ian Metcalfe — improved the pretreatment of volcanic zircon samples gathered in China. (discovermagazine.com)
In 1998 a Chinese and American group headed by geochronologist Sam Bowring of MIT nailed the date of the Permian extinction at 251 million years ago. (discovermagazine.com)
Those artifacts consist of pigment - stained seashells with artificial holes, presumably for use as necklaces, and seashells containing remnants of pigment mixtures, say geochronologist Dirk Hoffmann of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues. (sciencenews.org)