Kiloyear-scale climate events and evolution during the Last Interglacial, Mu Us Desert, China

摘要

The fifth segment of the Milanggouwan stratigraphical section (MGS 5) in the Mu Us Desert provides high-resolution geological information on environmental variations during the Last Interglacial. The analysis of grain content (<50μm), organic content, SiO_2, Al_2O_3, TOFe, and SiO_2-(Al_2O_3 +TOFe) ratios in the MGS 5 suggest that there were 17 kiloyear-scale climate fluctuations in the Last Interglacial, including 9 warm events (W1-W9) and 8 cold events (C1-C8), dominated by the East Asian summer monsoon and winter monsoon respectively. The analysis also suggests that the Eemian interglacial was unstable, with 3 warm events (W7-W9) and 2 cold events (C7-C8), indicating that climate fluctuations affected the East Asian monsoon in the Mu Us Desert during the Last Interglacial. The change cycles and the nature of the kiloyear-scale climate events have a close temporal relationship with the Greenland ice-core oxygen isotope data, suggesting that the climate forming mechanism was affected by polar weather, North Atlantic sea ice, range of the Eurasian ice front, and movement of the Arctic frontal, all of which affect the intensity of the Siberian-Mongolian high pressure region through the movement of the cold air mass.