Lower Boundary of the Marine Pleistocene in Northern Shelf of the South China Sea

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摘要 AmarinestratigraphicsequenceacrossthePliocene/Pleistoceneboundaryhasbeenfoundinthenorth-erncontinentalshelfoftheSouthChinaSea.ThemarineQuaternarydepositsintheYinggehaiBasinmayex-ceed2,000minthickness,probablyprovidingthebestsectionforstudyingthelowerboundaryofthemarinePleistoceneinSouthChina.TheverticalsuccessionwithplanktonicforaminifersandnannofossilsrevealedinboreholesinthebasinhasbeenwellcorrelatedwiththatintheinternationalstratotypesectionofthePliocene/PleistoceneboundaryatVrica,Italy,resultingintheacquirementofabiostratigraphicboundaryat1.64Ma.Thisboundary,however,doesnotcoincidewithanyprominentlithologicalpalaeoenvironmentalchangesinthestudyareaandcanhardlybeusedingeologicalpractice.Thereare,incontrast,significantchangesatthelevelofLADofGloborotaliamulticameratasensulatolocatedbelowtheabove-mentionedboundary.Thepercentageofplanktonicforaminifersinthetotalpopulationandpreservationofforaminiferaltestsdisplaygreatchangesatthislevelcorrespondingtoaclearonlapontheseismicprofilesandindicatingadepositionalhiatusatca.2.0-2.5Ma.SincethelevelcanbewidelytracedinthePearlRiverMouthBasinandtheBeibuGulfBasinandwellcorrespondswiththemarkeddepositionalenvironmentalchangesrecordedinthewestPacificandotherregions,itisrecommendedthatthePlio/PleistoceneboundarybedrawnatthelevelofGr.multicameratasensulatoLAD,roughlyconcurrentwiththeGauss/Matuyamaturn.
作者
机构地区 不详
出处 《地质学报:英文版》 1991年4期
出版日期 1991年04月14日(中国期刊网平台首次上网日期,不代表论文的发表时间)
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