Paleoclimatic Records From Northern Slope Of South China Sea Since The Marine Isotope Stage 5

As the largest marginal sea of China,South China Sea(SCS)have relatively high rate of sediment accumulation by the input of river transport.Meanwhile,consider ofthe SCS is located in the area of East Asian Monsoon,the terrigenous supply is affect by monsoon.The SCS(slope)sediments not only record the response to the globalclimate change,but also stack the region provenance and circumstance information,which makes the SCS became the ideal place to investigate the regional response andits driving force.In this paper,we choose the slope sediments(core ZHSl48PC)in Northern South China Sea (NSCS)for investigating the correlative research and analysis of paleoceanography and discussing the paleoclimate records as well as cycle variation in the climate proxy indicator of SCS since the Marine Isotope Stage(MIS)5.Detailed conclusions are shown below:1.Using the planktonic foraminifera Oxygen isotope curve to establish the agemodel of the core of past 1 35.36ka BP.It rum out the bottom of core located in thestage of Marine Isotope Stage 6.The deposition rate during glacial period wasgenerally higher than interglacial period,especially the MIS2 which was the highest.Millennium scale rapid climate change events were recorder in this sediments.Thespectrum analysis ofOxygen isotope shows that the climate change was influenced bythe precession cycle and semiprecession cycle ofMilankovitch astronomical theory.2.The grain size ofthis core are more stable,with silt and clay-based.O.5⁴μm ofclay fractions,as one of the four sensitive grain size fractions of sediment grain sizedata,can be used as the alternative indicators of the East Asian Summer Monsoon.Onthe contrary,16-63μm ofparticle component can be used as the alternative indicatorsof the East Asian Winter Monsoon.Moreover,4¹ 6μm and>63μm of particlecomponent effectively indicate the transmission ofterrigenous nutrients,which ma.yberelated to the increase of precipitation by strengthened EASM.3.The sediments is characterized by enrichment of ligh rare earth elements(LREE).REE distribution patterns of NASC-normalized of different segmmentsediments are more consistent and expressed as the enrichment of LREE distributionpattern,which shows the sediments basically have the same provenance.The resultsof discriminant function indicate the provenance is mainly from the Pearl River andTaiwan Strait Spectral analysis of the main factor of REE reveal the provenance iscontrolled by the change of sea level.4.Most major elements of this core sediments exist a positive correlation with each other．Geochemical analysis of sediments shows that Si and Al do not exist asurplus situation,even have some losses,Ti can represents the terrigenous,Ba includeboth the Ba—terrigenous and Ba—biogenic．Ni,V,Ba,Cr,Mn,Zn and Cu are relativewith physical and chemical changes of source,Ti,S and Zr can denote the terrigenouscomposition,Sr and P denote the bioclastic components,SiO₂ and Al₂O₃ may relectthe detrital clay component．5．The comparison of chronology of oxygen isotope and volcanic glass contentof core sediments show the volcanic eruption information were detected in thetransitional period of MIS,which reflect the volcanism does have an impact on theclimate change．Different component of volcanic galss in different segment of coresediments may related to the different transmission distance by the height andintensity of volcanic eruption or the distance from volcanic source to the depositionstations．...