Altamira symbols up to 40,000 years old? Reaction

The Foundation discussed this article with Dr Jean Clottes, who raised several cautionary points:

'In my opinion one should be very cautious about the sensational results announced, because:
1. that method is new and certainly needs to be tested and refined (see below);
2. they compare Useries dates with radiocarbon dates which were obtained with a different method: it would be necessary to date the same artefact with both methods and see if they concur; this is what Valladas and her team tried to do in 2003 in Borneo and they encountered problems;
3. finally, the relation to Neandertal is pure speculation: there has never been portable art discovered in Neandertal occupation sites and there is no relationship ever established between the Neandertals and a painted rock art site. Until there is, such speculation is entirely gratuitous.'

'Dr. Helene Valladas, who is the best French (and possibly European) specialist on dating, has written this comment, published in Science and with which I fully concur because it is fully scientific':

'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. 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.' ... Bradshaw Foundation

Actualización 19-06-12. Spanish Cave Paintings’ Age Questioned by Archaeologist.
Cave paintings in Spain need to be analyzed further before the works can be confirmed as the oldest known examples in the world, an archaeologist said, casting doubt over a paper published in the journal Science.

A team led by Alistair Pike of the University of Bristol in England said in the paper that paintings at El Castillo cave date back at least 40,800 years. That would make them about 4,000 years older than those at the Chauvet cave in France, meaning the Spanish works could be the only cave art ever found to have been painted by Neanderthals, according to Pike.

The findings at El Castillo need further confirmation, Jean Clottes, who led the research team that appraised the Chauvet works in 1998, said in a telephone interview. Pike’s team used a method based on the radioactive decay of uranium to analyze calcium carbonate crusts formed on top of the paintings. This contrasts with radiocarbon dating employed at Chauvet. The two methods have arrived at conflicting dates in the past, according to Clottes... bloomberg.com