A famous French cave has just given up something archaeologists have chased for years, hard dates for prehistoric paintings once thought impossible to date.
Scientists have, for the first time, accurately dated paintings inside Font-de-Gaume, a decorated cave near Les Eyzies in Dordogne in south-western France, according to CNRS. The findings give firm dates for two black images, a bison and a mask-like figure, and show parts of the artwork were created during widely separated periods.
Researchers had long believed many black paintings in the region were made entirely from iron and manganese oxides. Those mineral pigments contain no organic carbon, which meant the art was generally considered impossible to date directly with radiocarbon dating.
To test that assumption, the team analysed the chemical composition of two black figures at Font-de-Gaume using Raman microspectrometry and hyperspectral imaging. Both methods found traces of charcoal in the black pigment, and the charcoal was distributed consistently throughout the black lines of the figures.
According to the researchers, that pattern showed the carbon was part of the original pigment, not contamination left by later graffiti, visitors or tourist activity inside the cave.
After confirming the charcoal, the team received authorisation to remove extremely small samples for carbon-14 dating.
The results dated the bison to between 13,461 and 13,162 calBP, or calibrated years before present. CNRS said the new date places the bison slightly later than previous estimates.
The mask-like figure produced a more complicated result. Samples from separate parts of the image gave three different date ranges: between 8,993 and 8,590 calBP, between 15,981 and 15,121 calBP, and between 15,297 and 14,246 calBP.
Those results suggest the figure includes elements created at very different times. CNRS said that, rather than being the work of a single artist during one visit, the mask may preserve multiple episodes of artistic activity separated by thousands of years.
The study was led by a scientist from the Laboratoire de développement instrumental et de méthodologies innovantes pour les biens culturels at Chimie ParisTech-PSL, CNRS and France’s Ministry of Culture. It was published in the Proceedings of the National Academy of Sciences.
CNRS said the method, combining chemical imaging with highly sensitive radiocarbon measurements, could be used on other prehistoric figures previously considered undatable.
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