Luminescence Dating of Late Pleistocene Lacustrine Deposits in Badain Jaran Desert, North China

There are still controversies for the lakes evolution time during late Pleistocene in arid/semiarid north China. Badain Jaran Desert (BJD) features the coexisting of modern lakes in the lowland of megadunes. Also, lots of lacustrine relics could be found distributed widely in the desert, some of them just beside the modern lakes. These lacustrine relics indicated the paleo lakes evolution and the paleo environmental changes in the desert. In this study, one 3.9 m depth lacustrine deposits section was studied in the southeastern BJD which is close to a modern lake Zongzegedan (ZZGD). The deposit ages of the section were obtained by using optical dating with both of quartz and K-feldspar grains. Optically stimulated luminescence (OSL) dating of quartz grains shows that this paleolake was appeared during 65–34 ka, which is in the Marine Isotope Stage (MIS) 3 period, without the saturation of the OSL signals. On the other hand, the high temperature infrared stimulated luminescence (pIR IRSL) dating results from K-feldspar grains show that the paleolake was existed from late MIS 5 to late MIS 4 (86–60 ka) period with also good luminescence characteristics. The further study suggested that the OSL signals from quartz grains in this section show thermal instability, which may lead to the age underestimation. So the reliable age of the existed paleolake should be obtained by using pIRIR signals from K-feldspar, indicated that the relative humid environment in the desert happened at late MIS 5. The paleolake has same position with modern lake in the desert may contain geomorphological indications.