Response of terrigenous eolian dust sediment composition to the East Asian monsoon evolution in the West Philippine Basin since 50 kaBP

The West Philippine Basin is an ideal area to study the evolution of the East Asian monsoon due to its special geographical location and environmental conditions. However, there are few studies on the source of sediment and its sedimentary evolution in the middle of the basin. Based on the analysis of AMS¹⁴C chronology, grain size and major elements of two columnar sediments (MC09 and MC13) in the middle of the basin, high-resolution records of sedimentology and geochemical deposition were established, the proxy index reflecting the input of Asian eolian dust was extracted, and then the response of sediment composition of the West Philippine Basin to the evolution of East Asian monsoon since nearly 50 kaBP was revealed. Results show that the comprehensive indexes of sediment grain size and element geochemistry could effectively indicate the changes of the East Asian monsoon and the climate in its source region. The variations of sensitive grain size fractions and terrigenous component fractions of major elements in the MC09 and MC13 columnar sediments indicate that the global climate was in a weak warm period and the East Asian winter monsoon was relatively weak from 47 to 26 kaBP. During 26 to 19 kaBP, the East Asian winter monsoon was obviously strong, and the terrigenous component of sediment increased significantly. From 19 to 12 kaBP, the temperature gradually increased and the intensity of the East Asian monsoon decreased, and the sedimentary record fluctuated under the influence of the Younger Dryas event. Since 12 kaBP, the global climate was relatively stable, and the intensity of winter winds in East Asia had weakened slightly. This study provided a reference for understanding the influence of the paleo-environment and paleo-climate changes on the sedimentation in the marginal sea.