Last Interglacial Age for aeolian and marine deposits and the Nahoon fossil human footprints, Southeast Coast of South Africa

Three hominid footprints preserved as casts were found in 1964 in Pleistocene aeolianites of the Nahoon Formation near East London, South Africa. Dating of the footprint-bearing aeolianite proved a lengthy and problematic task. Previous age estimates included a radiocarbon age of 29,090−390+410 years BP [Deacon, H.J., 1966. The dating of the Nahoon footprints. South African Journal of Science 62, 111–113], an infrared stimulated luminescence (IRSL) age of 144 ± 4 ka, a thermoluminescence age of 236 ± 8 ka (TL) and a luminescence subtraction age based on the IRSL and TL estimates of 75 ± 9 ka [Vogel, J.C., Wintle, A.G., Woodborne, S.M., 1999. Luminescence dating of coastal sands: overcoming changes in environmental dose rate. Journal of Archaeological Science 26, 729–733]. Thus there was no consistency among the ages derived using different dating methods. Here we describe optically stimulated luminescence (OSL) dating of quartz grains from a new set of samples collected from the footprint-bearing aeolianite and from associated geological formations. We also re-assessed the dose rate parameters for the sample for which TL and IRSL ages were reported and analysed the OSL signal from this sample. The new OSL dating yielded a coherent series of ages consistent with the stratigraphy as well as global and local sea level history. The indicated footprint age of 124 ± 4 ka thus relates to an important period of modern human evolution.