Climate change during the last glacial period on the southeast margin of Badain Jaran Desert, Northwest China

Reconstruction of the desert paleoclimate is important to understand the mechanisms that triggered and/or enhanced climate change. Through optically stimulated luminescence (OSL) dating, grain size, magnetic susceptibility, X-ray powder diffraction (XRD) and geochemical indicators, we provide a well-dated record of a sedimentary outcrop on the southeast margin of the Bardain Jaran Desert, Northwest China, during the last glacial period. Four Qz-OSL ages are obtained, 41.0±34 ka, 54.7±4.4 ka, 59.5±5.0 ka and 66.8±5.8 ka, corresponding to the depths of 35 cm, 70 cm, 150 cm and 200 cm respectively. Indicators like grain size, clay content, magnetic susceptibility, XRD and geochemical index (e.g. Sr, Ba, Sr/Ca) jointly indicate abrupt climate changes at the depth of 35 cm (age, ca. 41.0 ka) and 200 cm (age, ca. 67 ka). Namely, the 280 cm sedimentary outcrop perfectly records a warm wet climate stage, corresponding to the late Marine Isotope Stages (MIS) 4 to the early MIS₃. Besides, there is a trend of grain size increase after around 40 ka BP, which is most likely a signal of wind strength change. Our research supports that enhancing Siberian High pressure system during the late MIS₃ played a key role in NW East Asia climate evolution.