Filling the gap: OSL data expanding 14C chronologies of Late Quaternary environmental change in the Libyan Desert

Several decades of geomorphological and archaeological research in the Libyan Desert conducted by the Cologne projects B.O.S. and ACACIA have yielded a wealth of radiocarbon data from archaeological sites and, over the last decade, also 48 OSL ages, mainly from aeolian deposits. This paper focuses on the combination of both data sets in order to obtain a synthesis of Late Quaternary occupational and environmental history in this region. Case studies demonstrate that despite a poorer time resolution of OSL chronologies compared to 14C data, OSL ages can be more consistent with the archaeological context, particularly if the dating of charcoals poses problems due to poor quality or re-deposition.Comparison of data sets from the Egyptian sand seas and from the Wadi Howar (Sudan) shows that in both cases, OSL and 14C data cover complementary time slices. On the regional scale, however, contradictory intervals of aeolian accumulation are documented which can be explained by the different environmental histories. The results accentuate that interpretation of OSL data has to be done in the context of the entire environmental systems including the effective geomorphological processes.