Sedimentary Characteristics,Provenance Indication And Climate Response Of Core S05-2 Sediments In The Mud Area Of Inner Shelf In The East China Sea Since 4.9 Ka

In this study,through the corresponding sediment particle size test experiment,clay mineral analysis experiment,element analysis test experiment and AMS14C dating experiment,the data results of sediment samples were obtained,so as to analyze and judge the source of sediment and its deposition.The response and record of sediments to East Asian monsoon,paleo-environment and paleoclimate since4870a BP are analyzed by referring to relevant geological and environmental climate records.Silt is the main component of pore S05-2 sediments,followed by clay,with the lowest sand content.According to the particle size parameters,the particle size is relatively coarse,the hydrodynamic environment is strong,and the sorting is poor.Illite,chlorite,kaolinite and montmorillonite are the main clay mineral components.Combined with the dating results,it is found that in the 4.9ka-4.3ka BP stage,the material of Taiwan rivers and Yangtze rivers is the main source of sediments;in the 4.3ka-3.7ka BP period,the material inflow from Taiwan rivers into the sea continues to influence,and the transport volume of the Yangtze and Yellow rivers into the sea begins to increase;2.4 ka BP up to now,the source of material is the continuing material of the Taiwan River into the sea,mixing the material of the Yangtze River and the Yellow River into the sea.Select Rb/Sr and Sr/Rb ratio,particle size sensitive component analysis,montmorillonite/kaolinite ratio as substitute index,combined with reference to Greenland ice core GISP2?¹⁸O,Donggedong stalagmite?¹⁸O and Huguangyan Malang Lake magnetization Rate and other climate data,divided into four monsoon fluctuation intervals,4.9ka-3.6ka BP:the intensity of the winter monsoon in the eastern part of China is frequent;3.6ka-2.5ka BP:the fluctuation of the monsoon is relatively stable;2.5ka-2.0ka BP:The fluctuation of the monsoon is obvious and the duration has increased;2.0ka BP-today:There is a relatively obvious monsoon enhancement period,but the overall tends to be stable.Among them are 10 obvious cooling events.