Other experts are less convinced.
Paul Mellars, a professor of prehistory and human evolution at Cambridge University, said he believes the range of radiocarbon dating evidence in the paper suggests ages more like 31,000 or 32,000 years for the charcoal. Contamination by younger material might have skewed some radiocarbon results toward more recent dates, he observed.
Even with the older dates, the paper would be important because it would represent one of the last Neanderthal occupations in Europe, he said.
But paleoanthropologist Richard Klein of Stanford University said it's questionable whether the charcoal fragments really date Neanderthal presence. Neanderthal artifacts appear to be sparsely distributed in the deposit, and their spatial relationship to the charcoal needs to be specified more clearly, he said.
Finlayson said he's comfortable with the 24,000-year figure and called the 28,000-year estimate conservative. There's no evidence of contamination with younger material and chemical analysis argues against it, he said.
As for the Neanderthal artifacts, he said, their location within the excavated site shows they're associated with the dated charcoal. And there aren't any artifacts from modern humans associated with the charcoal, he said.
