Origin of Asian dust reconstructed from the Eu anomaly in the Hanon paleo-maar sediment of Jeju Island, Korea

Abstract

Asian dust between the Mongolian Gobi and Taklimakan Desert is dependent on wind system changes in the East Asian winter monsoon (EAWM) or westerly jet. This study investigated the origin of Asian dust, and factors affecting its intensity, through analysis of the Hanon paleo-maar sediment of Jeju Island, Korea, using the Eu anomaly as a dust proxy. Eu anomalies from the pre-Last Glacial Maximum (Late Pleistocene, 32.8–25.9 ka) to the early deglacial period (16.8–14.8 ka) showed low fluctuation (0.82–0.85), indicating that most of the dust originated from the Gobi Desert. During the late deglacial period (14.5–10.2 ka), the Eu anomaly increased to 0.88 on average, which indicated a gradual change in Asian dust origin toward the Taklimakan Desert and a consequently higher Eu anomaly (>0.9) during the Holocene period (after 9.5 ka). The Asian dust proportion was around 50% during the last glacial period (32.8–14.8 ka), but decreased to 30% during the Holocene as the East Asian summer monsoon (EASM) expanded toward north and northeast China. Based on the Eu anomaly, the Asian dust flux associated with the EAWM intensity fluctuated, but was overall greater, during the last glacial period.2