Jean Combier and Guy Jouve report in L’Anthropologie that the art of Chauvet Cave has been misdated: “New investigations into the cultural and stylistic identity of the Chauvet cave and its radiocarbon dating”. The paper is in French, but here is the English abstract:
The discovery of Chauvet cave, at Vallon-Pont-d’Arc (Ardèche), in 1994, was an important event for our knowledge of palaeolithic parietal art as a whole. Its painted and engraved figures, thanks to their number (425 graphic units), and their excellent state of preservation, provide a documentary thesaurus comparable to that of the greatest sites known, and far beyond what had already been found in the group of Rhône valley caves (Ardèche and Gard). But its study – when one places it in its natural regional, cultural and thematic framework – makes it impossible to see it as an isolated entity of astonishing precocity. This needs to be reconsidered, and the affinities that our research has brought to light are clearly incompatible with the very early age which has been attributed to it. And if one extends this examination to the whole of the Franco-Cantabrian domain, the conclusion is inescapable: although Chauvet cave displays some unique characteristics (like every decorated cave), it belongs to an evolved phase of parietal art that is far removed from the motifs of its origins (known from art on blocks and on shelter walls dated by stratigraphy to the Aurignacian, in France and Cantabrian Spain). The majority of its works are therefore to be placed, quite normally, within the framework of the well-defined artistic creations of the Gravettian and Solutrean. Moreover, this phase of the Middle Upper Palaeolithic (26,000–18,000) coincides with a particularly intensive and diversified local human occupation, unknown in earlier periods and far less dense afterwards in the Magdalenian. A detailed critique of the treatment of the samples subjected to AMS radiocarbon dating makes it impossible to retain the very early age (36,000 cal BP) attributed by some authors to the painted and engraved figures of Chauvet cave.
By far the largest proportion of art in caves of France and Northern Spain is relatively late in time, dating to Magdalenian peoples after 18,000 years ago. But caves were not closed systems, and a number of them have art pieces that date into earlier Solutrean or even Gravettian times.
Every expert agrees that the extensive panels of art in Chauvet are extraordinary. Some believe that they reflect a stylistic tradition of much later people, sharing with caves like Lascaux, Altamira and Font de Gaume. Others have been more willing to accept that the artistic tradition at Chauvet was developed largely independently from the traditions recorded in later caves. These have argued that it is the oldest instance of cave art (called parietal art) in the world.
They have been supported by radiocarbon dating. The dates for charcoal in the Chauvet paintings are more than 30,000 years ago, with four different paintings generating radiocarbon ages between 30,000 and 33,000 years BP. But dating of paintings is a specialized affair. Charcoal is not the best material for dating to begin with, the presence of very thin layers of charcoal in association with damp cave walls, mixed with other pigments, makes matters worse. Combier and Jouve note that some charcoal drawings have given substantially more recent dates than the paintings.
Combier and Jouve favor resolving the discrepancy between these dates by accepting that the paintings involve carbon from charcoal mixed with substances that include carbon from older sources, such as minerals. They base their strongest argument on the similar case of Candamo cave in Spain, where the stable isotope ratio of carbon-13 to carbon-12 in the paintings varies substantially from that expected from wood charcoal. In that case, there is a similar divergence of dates from different figures. The figures with older dates apparently had a diagenesis in which bacteria incorporated older carbon from the cave walls into the pigment samples. Although such an analysis has not been done for Chauvet, the authors advocate examining the radiocarbon samples again with this possibility in mind.
Ultimately, Combier and Jouve reject the stylistic arguments for an Aurignacian age of the Chauvet paintings. They conclude:
We have examined rationally all the statistics that have been presented to justify an Aurignacian age for the Chauvet art, that have hoped to show it as the oldest parietal art in the world, but we found no scientific evidence to justify dates older than the Gravettian, and these relate exclusively to identified charcoal ensuring their reliability. We note that proving a Gravettian age for some drawings still places the Chauvet art as among the oldest in the world, but it is not Aurignacian.
They additionally note that there is widespread evidence for human occupation in the region in Gravettian and later times, but much less evidence for Aurignacian-era occupation. That circumstantial evidence is less persuasive, but it does adjust the prior probability on the calculation as to whether people were more likely to use the cave earlier or later in time.
The paper presents a solid case for skepticism about the age of the Chauvet paintings.
Combier, J and G. Jouve. 2014. Nouvelles recherches sur l’identité culturelle et stylistique de la grotte Chauvet et sur sa datation par la méthode du 14C. L'Anthropologie (in press) doi:10.1016/j.anthro.2013.12.001