Chronology of the middle palaeolithic open-air site of Combe Brune 2 (Dordogne, France): A multi luminescence dating approach

The Bergerac region of south-western France is well known for its wealth of Middle Palaeolithic open-air sites. However, their chronology remains poorly understood due to the complexity of the deposits and difficulties applying radiometric dating techniques. Combe Brune 2, excavated in 2006 and 2007 by the INRAP (. Institut National de Recherches Archéologiques Préventives), comprises a substantial stratigraphic sequence providing an almost continuous sedimentary record that is unique for the region. Three lithic assemblages were documented in the eastern part of the site and six stratified assemblages in the western part, five of which are concentrated in Unit 7. All the clearly individualised industries portray an unequivocal techno-economic coherence and are dominated by Levallois debitage.Minerals present in the sediments were dated by the Optically Stimulated Luminescence (OSL) using different protocols (Thermal-Transfer: TT-OSL for quartz grains and IRSL and post-IR IRSL for feldspar grains). Heated flints were also dated by thermoluminescence (TL). Dating results obtained from quartz and feldspars grains provide an age of 234±25 ka for Unit 8 at the base of the western sequence, 161±18 to 97.3±12 ka for Unit 7; 63.1±6.5 ka for Unit 4 and a series of ages ranging from 39.2±4.0 to 22.3±2.2 ka for Unit 3. TL ages obtained from heated flints recovered from the base of Unit 7 in the eastern section range from 183±20 to 195±16 ka. These results are in good agreement and are stratigraphically coherent, suggesting that the Early Middle Palaeolithic occupation, the first documented for the Bergerac region, can be placed at the end of Marine Isotopic Stage (MIS) 7 and the beginning of MIS 6.