Enhanced drying of the Tengger desert, northwest margin of East Asian summer monsoon during warming interglacials after 500 ka

The arid-semiarid regions face drying threats under global warming, but their future changes in terms of drying or not are controversial. High orbital-scale resolution records spanning across the Mid-Brunhes event in the arid deserts provide a climate analogue since the formation of deserts. However, there was no definite work in the deserts so far. Here, we present the results of a chronological and paleoenvironmental study of a 122.63 m-long core drilled in the largest lake basin in the central Tengger Desert (northern China), located in the northwestern margin of East Asian Summer Monsoon regions. Following comprehensive paleomagnetism analysis, the Matuyama/Brunhes boundary was detected at a core depth of 87.5 m, and the basal age of the core is estimated at ∼940 ka based on orbital tuning. The lithology, grain size, carbonate and total organic carbon content were analyzed to examine the sedimentary facies and reconstruct the paleoenvironmental evolution. Ten relatively humid layers were identified by sedimentary facies, further results confirmed by fine grain size, high carbonate, and total organic carbon content, which generally developed during interglacial and were controlled by the East Asian summer monsoon precipitation during the past 940 ka. Since ∼500 ka, the interglacial climate regime displayed an intensified aridification manifested as shrinking lakes and persistent mobile dunes in the Tengger Desert. We argue that this aridification was caused by the combination of a massive supply of clastic material for the desert and the occurrence of higher potential evapotranspiration during warmer interglacials after the Mid-Brunhes Event. This research finding provides geological evidence for the aridification of the deserts in the East Asian Summer Monsoon margin under global warming.