High-Resolution Geochemical Records in the Inner Shelf Mud Wedge of the East China Sea and Their Indication to the Holocene Monsoon Climatic Changes and Events

The inner shelf mud wedge (ISMW) located in the East China Sea (ECS) is the fine-grained sedimentary area with high sedimentation rate and has provided an ideal study area for understanding the East Asian Summer Monsoon (EASM) evolution during the Holocene. In this paper, we presented the high-resolution geochemical data of the sediments from the core MD06-3040 in the ISMW of the ECS determined by X-ray fluorescence core scanning (XRF-CS) analysis, a high-resolution, continuous, and multi-element method. Geochemical and factor analysis results reveal that the variations of elemental compositions (Al, Si, K, Ti, Fe), the elemental ratios of Al/Zr, Ca/Ti and Rb/Sr, and the factor scores (F1) are correlated with the changes of the EASM during the period of 6000–1300 cal yrBP. The higher values of geochemical compositions indicating the terrigenous inputs implied the intensification of anthropogenic activities after 1300 cal yrBP. Meanwhile, the significant decrease of most geochemical compositions and the F1 factor scores during 4500–3500 cal yrBP and 1700–1500 cal yrBP, within the dating errors, coincided with the weak EASM events (presumably drought and cold events). The spectral analysis results of K concentrations, Al/Zr ratios and F1 factor scores show the millennial and centennial climatic fluctuations, which are consistent with other marine sedimentary records in the adjacent areas. All the findings show that the geochemical compositions of sediments from core MD06-3040 are influenced by the EASM evolution, the variable El Niño/Southern Oscillation (ENSO) and the local oceanic thermohaline circulation (e.g., Kuroshio Current). These results are greatly helpful in uncovering the forcing mechanism of the monsoonal climate in the east China over the Holocene and also contribute to the understanding of EASM variability.