High-northern-latitude forcing modulated fluvial-aeolian interplay during the Last Glacial Period in the Mu Us Desert, northern central China

Substantial stratigraphic evidence from the Late Quaternary at orbital-and millennial-scales indicates that the formation and evolution of aeolian-sand landscapes results from the interaction between regional aeolian and fluvial-lacustrine activity. In many deserts (sandy lands) across the planet, fluvial-aeolian interplay at the glacial-interglacial scale since the Late Quaternary has been responsive to monsoonal precipitation, and linked to atmospheric CO2 and periodic variations in insolation. However, the patterns of fluvial-aeolian interplay and their relationship with climate change are not always consistent over a given timescale during the Late Pleis-tocene. The paucity of studies on fluvial-aeolian interplay in the Mu Us Desert (MUD) during the Last Glacial Period (LGP) hinders our understanding of the relationships between the dynamics of aeolian and fluvial-lacustrine landscapes and their drivers. Here, based on a comprehensive field survey and stratigraphic dating of a typical fluvial-aeolian sequence in the MUD, we synthesized the chronology of fluvial-lacustrine and aeolian strata during the LGP. Our results show that extensive development of a fluvial-lacustrine environment in the MUD during the LG mainly occurred during the late Last Glacial Maximum (LGMa, 20.1-18.4 ka BP) and Bolling/ Allerod interstadial (14.8-12.6 ka BP), while thicker aeolian sands extensively accumulated during the Heinrich Stadial 2, Heinrich Stadial 1, and Younger Dryas periods. However, the development of fluvial-lacustrine en-vironments showed considerable spatial heterogeneity, mainly occurring on the southern and eastern margins of the desert, while they were extremely rare in the central and western parts of the desert owing to strong wind erosion. Comparisons with other high-resolution geological records from the Asian monsoon region reveal that the fluvial-aeolian interplay in the MUD during the LGP was highly consistent with the evolution pattern of the East Asian summer monsoon (EASM) on the millennial-centennial scale, and indicate that the development of fluvial-lacustrine environments was mainly controlled by an increase in monsoonal precipitation during strengthening of the EASM. Consistency with other broad changes at high latitudes in the Northern Hemisphere suggests that fluvial-aeolian interplay during the LGP in northern Chinese deserts, as represented by the MUD, was mainly controlled by changes in high-northern-latitude ice volume and the Atlantic Meridional Overturning Circulation.

Automated summary

Substantial evidence from the Late Quaternary indicates that aeolian-sand landscapes are formed and evolved through the interaction between regional aeolian and fluvial-lacustrine activity. Fluvial-aeolian interplay in many deserts is responsive to monsoonal precipitation and linked to atmospheric CO2 and variations in insolation. However, the patterns of this interplay and its relationship with climate change are not always consistent during the Late Pleistocene. Studies on fluvial-aeolian interplay in the Mu Us Desert during the Last Glacial Period are lacking, hindering our understanding of the dynamics of aeolian and fluvial-lacustrine landscapes. This study provides a comprehensive analysis of fluvial-lacustrine and aeolian strata in the Mu Us Desert during the Last Glacial Period, revealing the spatial and temporal patterns of their development and their relationship with changes in climate.