LAUSR

Abstract Sauvet et al. (in press) present a partial description of the Uranium-series or 230Th/234U dating method, which leads them to criticize this dating tool and claim that this method provides “an extremely wide range of uncertainty providing a weak base upon which to build scientific reasoning”. In this comment, we discuss three concepts introduced by these authors that could lead to a misunderstanding of the method and its application in the archaeological community and in the scientific debate about rock art chronology. The first misconception concerns the claim that “speleothems stopped during much of the Upper Palaeolithic”. A brief review of the literature demonstrates that this affirmation is not quite exact as a large number of studies document speleothem growth in Europe and circum-Mediterranean regions (as well as in other regions) during the upper Paleolithic. Secondly, Sauvet et al. claim that when age corrections are applied due to the possible presence of initial 230Th, the ages should be considered with caution or they should be rejected. However, this is not entirely correct, as this detrital fraction can be determined using several methods (and not merely assumed to be a “mean earth value”). Thirdly, with respect to their claim that “Loss of uranium or input of 230Th leads to anomalously old ages and sometimes to the impossibility to calculate an age when 230Th/234U > 1”, we present a classical figure of 230Th/234U evolution vs 234U/238U that can be drawn using the U-series equations demonstrating that 230Th/234U ratios can in fact be >1 and permit a valid age determination.