Multiple protocols - luminescence dating of the Middle Stone Age deposit at Sibhudu rock shelter (South Africa).
Résumé
Sibhudu rock shelter preserves one of the major sequence, over four meters thick, of Middle Stone Age artefacts in South Africa, uncovering pre-Still Bay, Still Bay, Howiesons Poort, and Sibhudan techno-complexes. The first optically stimulated dating chronology performed on single quartz grains indicated ages between 38 to 72 ka (Jacobs et al., 2008, 2017) . While the continuing excavation has uncovered deeper layers, the whole sequence has been re-sampled for optical dating. We applied several protocols on single or multiple grains aliquots of quartz or potassium feldspar grains, including SAR, IR50, pIR-IR290, pIT, and RF , in order to improve and extend the final chronology. Here we show that, other than the RF ages, which overestimate the mean of other age estimates by over 30%, ages for the various protocols are usually within 10% of their mean. Although the excavation has not yet reached bedrock, our results have extended the chronology of Sibhudu back at least until late Marine Isotope Stage 6.