Sedimentary Dynamics of the Central South Yellow Sea Revealing the Relation Between East Asian Summer and Winter Monsoon Over the Past 6000 years

Ying Zhong Tang,Tengfei Fu,Zhangxi Hu,Yanping Chen,Shenliang Chen,Guangquan Chen,Xingyong Xu,Wenzhe Lyu

doi:10.3389/feart.2021.689508

Abstract

The mud areas of East Asian marginal seas record considerable information about regional environmental evolution. However, debate continues regarding the relative importance of the major factors in regional sedimentary dynamics, i.e., the East Asian summer monsoon, East Asian winter monsoon, and oceanic circulation. In this study, we investigated the characteristics of grain size from a gravity core obtained in the South Yellow Sea to reveal changes in sedimentary dynamics since 6,000 years BP, and to elucidate the relationship between the East Asian summer monsoon and the East Asian winter monsoon. We found that the mean grain size was in the range of 6.9–7.8 Φ, the sediment was poorly sorted within a small range (1.2, 1.5), and the M values from 4.7 to 6.7 μm and most of the C values from 24 to 65 μm suggested pelagic suspension transport. Results indicated that the intensity of both the East Asian summer monsoon and the East Asian winter monsoon showed a fluctuating trend of decrease after approximately 6,000 years BP, and that the relationship between them was generally anticorrelated. Based on these results, we suggest that positive correlation between the East Asian summer monsoon and the East Asian winter monsoon usually results in the fall or establishment of ancient dynasties in the Central Plains of China and that negative correlation between them is controlled by strong solar radiation. Weakening of solar radiation diminishes its control of the intensity of (and thus the correlation between) the East Asian summer monsoon and the East Asian winter monsoon, at which time the North Atlantic Oscillation plays a modulating role.

Highlights

In recent years, the South Yellow Sea (SYS) has become an area of active research for paleoclimate, sedimentary environment, and marine current/hydrodynamics studies (Kong et al, 2006; Xiang et al, 2008; Zhao et al, 2013; Liu et al, 2014; Yang et al, 2018; Zhang et al, 2018; Wang et al, 2019)
We investigated the characteristics of grain size from a gravity core obtained in the South Yellow Sea to reveal changes in sedimentary dynamics since 6,000 years BP, and to elucidate the relationship between the East Asian summer monsoon and the East Asian winter monsoon
We suggest that positive correlation between the East Asian summer monsoon and the East Asian winter monsoon usually results in the fall or establishment of ancient dynasties in the Central Plains of China and that negative correlation between them is controlled by strong solar radiation

Summary

Introduction

The South Yellow Sea (SYS) has become an area of active research for paleoclimate, sedimentary environment, and marine current/hydrodynamics studies (Kong et al, 2006; Xiang et al, 2008; Zhao et al, 2013; Liu et al, 2014; Yang et al, 2018; Zhang et al, 2018; Wang et al, 2019). As a typical shelf sea, the SYS is an important reservoir of and transportation channel for sediments from the Yellow River, Yangtze River, and some local rivers. It has the largest area of mud in the shelf area of the eastern China Seas, and its sediments are sensitive to changes of sea level and climate (Yang and Youn, 2007). Studies on the sediment sources and current systems of the SYS are linked to the East Asian monsoon (EAM)

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Results

Conclusion