The results, if correct, include the earliest ever reported date for cave art: A red disk from El Castillo Cave, on the Pas River in northern Spain, clocked in at a minimum of 40,800 years.The disk, part of a larger composition that includes dozens of other disks and some 40 stencils of human hands, could be older, depending on how soon after it was painted the calcite layer formed.
Now dating experts working in Spain, using a technique relatively new to archaeology, have pushed dates for the earliest cave art back some 4000 years to at least 41,000 years ago, raising the possibility that the artists were Neandertals rather than modern humans.
Dating expert Thomas Higham of the University of Oxford in the United Kingdom calls it "a very convincing study," adding that "it is just possible that a Neandertal hand was involved," in making the red disk.
But he still thinks it most likely that modern humans made the art, because the dates still correspond most closely to the time when was first entering Europe.
The Pike team has not taken into account several potential problems with U-series dating, adds Helene Valladas of the Laboratory of Climate and Environmental Sciences in Gif-sur-Yvette, France, who led the dating at Chauvet.
She says it's possible that some of the uranium in the calcite has been washed out by later water flows, which would increase the thorium/uranium ratio and make the ages seem older than they really are.