A 328.58 m drill core (XK12) was recovered from lacustrine–alluvial sediments in the Xingkai Basin, northeast China, with the aim of obtaining a high-resolution pollen record of East Asian winter monsoon (EAWM) evolution since 3.6 Ma. An index based on the pollen record of thermophilous trees and terrestrial herbs is used as an indicator of winter temperature conditions controlled by the EAWM, at the glacial–interglacial scale. Primary age control was established based on lithostratigraphy and magnetostratigraphy, and then the pollen index was correlated to the LR04 global benthic δ18O record and finally tuned to Earth orbital obliquity to produce a high-resolution astronomical time scale. The pollen record indicates that the EAWM underwent two stepwise enhancements at 2.8 and 1.6 Ma. These events are consistent with paleoclimatic records of mean quartz grain size from the Chinese Loess Plateau, and they are also in accord with the initiation and intensification of Northern Hemisphere glaciation. Our findings suggest that the variability of the EAWM since 3.6 Ma was primarily controlled by changes in global ice volume and climatic cooling.

A 336-cm-long sediment core spanning the last 130 ka was recovered from Lake Xingkai on the northeastern margin of the East Asian summer monsoon domain to reveal the linkage between lacustrine depositional processes and environmental changes. Bayesian end member modeling analysis was conducted to partition and interpret the grain-size distributions of Lake Xingkai sediments. Our results suggest that the sedimentary system is characterized by three end members (EMs). EM1 and EM2, with a modal value of 13 and 10 μm, respectively, indicate the variation of local hydraulic conditions. EM3, with a modal value of 5 μm, reflects the background atmospheric dust loading. High atmospheric dust concentration generally occurred during Marine Isotope Stage (MIS) 5d, MIS 4, and early MIS 3, when the climate in the Asian dust source region was cold and dry. In contrast, low dust concentration prevailed during MIS 2, likely due to the southward shift of the westerlies driven by maximum ice volume in the high latitudes.