Comments on “ESR dating of the Majuangou and Banshan Paleolithic sites in the Nihewan Basin, North China” by Liu et al. (2014)

Liu et al. (2014) recently published an ESR dating study of two Palaeolithic sites, Majuangou and Banshan, from the Nihewan Basin (China), based on the use of the TieLi paramagnetic centermeasured in optically bleached quartz grains. The authors collected between two and five sediment samples per site and final ESR age results shown in their Table 1 are internally highly consistent for a given site, with a relative scatter (coefficient of variation) varying between 1.3% (BS samples) and 4.3% (MJG-I samples). In addition, these ESR age estimates are overall in good agreement with the previous chronological estimation derived from an interpolation of the sedimentation rate based on magnetostratigraphic data (Zhu et al., 2004): the relative offset of the mean ESR ages for a given site ranges between 9.0% (MJG-I samples) andþ5.5% (MJG-III samples), but 11/ 13 of the ESR age results are consistent at 1swith the expected age, and all of them are consistent at 2s. These excellent results logically lead the authors to conclude that “ESR dating could be effectively applied to establish an independentwhole chronologymodel for the early human sites in the Nihewan Basin to contribute to a better understanding of early human occupation in the high northern latitudes of East Asia“(Liu et al., 2014: 62). Moreover, a previous paper by Liu et al. (2013) presented the results of another ESR dating study, on the Donguttuo Palaeolithic site, also located in the Nihewan Basin, and using a similar methodology. Again, ESR age estimates (n 1⁄4 4) based on the TieLi center were all internally consistent (coefficient of variation 1⁄4 4.1%), and