| The Bohai Sea is semi-enclosed on three sides surrounded by epicontinental land,which is strongly influenced by deposition on behalf of the Yellow River et al.surrounding rivers. Historically, the Yellow River has been wandering between theYellow Sea and Bohai Sea, it is a major sedimentary events in the Bohai Sea in termsof each relocation, profoundly changed the Bohai Sea deposition process. Based onGeochemistry of surface sediments and core sediments,the inversion from the modernhistory of the state during the deposition of sedimentary evolution can supportunderstanding the role of sources and sinks of the sediments provide scientific.This study,based on system analysis of particle size, major elements and traceelements in combination and variation of surface and core sediments of Bohai Sea,explore the spatial distribution of surface sediments and its influencing factors,revealing the event sedimentology of the Yellow River diversion records in1855,clarifing the effect of Bohai Sea depositional environments around the event.We getthe following main research results:Particle size characteristics of the surface sediments in central and southern Bohaioverall performance of the study area, is fine in the southern part and thick innortheast and northwest, corresponding characteristics of Yellow River,Liaodongshoal and Luan River sediments, respectively.The spatial distribution of Si and Na in surface sediments shows similarcharacteristics and of Al, Fe et.al. have similar distribution; distribution of Cadifferences. V, Cu,et al. five trace elements have similar trends in the spatialdistribution; Sr, Zr and Ba each have its own distribution characteristics.Based on major elements and trace elements, the study area can be clearlydivided into four partitions: The I and the II zone are a low content of Si, Sr, Ba andZr, a high content of Al, Ca and V, Cu and other trace elements are characterized, on the whole source material are mainly Yellow River, but they differences under theinfluence of erosion of.Laizhou Bay Coast and water power environment; in the IIIareas the abnormally high levels of Mn, P, and higher levels of Sr, Ba and Zr ischaracterized,reflects the powerful and significant partial oxidation sedimentaryenvironment in the Liaodong shoal;the IV district with high Si, Al, and relatively lowcontent of trace elements are characterized, representing the source of sediment LuanRiver mainly.The impact on the sedimentary record and environment in central Bohai Sea bythe event of the Yellow River diversion in1855was discussed, through studies of thegrain size characteristics and chemical elements concentrations in3core sedimentscollected from Bohai Sea. Research showed that there were significantly differencesbetween the upper and lower parts in the2cores. They could be divided into twotypes, representing the Yellow River sediments and the terrigenous substance aroundBohai Sea, respectively. The material composition of Class I were closer to the YellowRiver sediments, with finer, better sorting characteristics, and class II were morecoarse, poor sorting, which possible illustrated the land substances surrounding theBohai. The elements of Ni, Zn, Sr, Ba, Zr had significant differences between the twotype sediments, could be used as identification indicators of the Yellow andterrigenous substance surrounding Bohai Sea.This difference is due to the relocationof Huanghe River in1855.After Yellow River diversion, the hydrodynamic force of study area becameweaker, primary productivity was also declined. The sedimentary environment in thestudy area were transfered to delta-delta front with weak oxidation-reductionconditions, from the oxydic shore-shallow environment. |
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