Valladas says she and her colleagues encountered just such problems when they attempted to compare and crosscheck U-series and radiocarbon dating results from prehistoric cave paintings in Borneo back in 2003.Other researchers say the jury is out on whether prehistoric European cave art became more sophisticated over time.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.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.
"The dating at Chauvet has been confirmed over time" by numerous studies, says Gilles Tosello, an archaeologist at the University of Toulouse in France who has worked at the site since the late 1990s.
Questions have even arisen in cases like the superb renditions of horses, rhinos, and other animals in France's Grotte Chauvet, the cave where researchers have directly radiocarbon dated artworks executed in charcoal to 37,000 years ago.
Other archaeologists have argued that artists could have entered Chauvet much later and picked up charcoal that had been lying around for thousands of years.
Since the Chauvet art was discovered in 1994, many researchers have seen it as evidence that modern humans arrived in Europe from Africa ready, willing, and able to create sophisticated paintings that rival those of much later caves, such as Lascaux in southern France.
The team argues that the new dating, along with similar dates from sites such as Abri Castanet in France, where archaeologists recently dated depictions of female genitalia to at least 37,000 years ago, suggests that the earliest European artists "were less concerned with animal depictions" and more interested in simpler motifs such as "red dots, disks, lines, and hand stencils," as they put it in the paper.