简介：ThispaperprovidesasyntheticreviewofresearchesonMeishanSectionD,theGlobalStratotypeSectionandPointofthePermian-TriassicBoundary(PTB).Thehistoryofresearch,geographicandgeologicalsettingofthesectionarebrieflyintroduced.Changhsingianto'Griesbachian'conodontandammonoidzonations,themostperfectPermo-Triassiczonationsovertheworld,arepresented,withashortdiscussionontheageofOtoceras.TheChanghsingianto'Griesbachian'strataaresubdividedintothree3rdordersequences,andthesedimentarystructureofeachsequenceisindicated.ThepaperpresentsacorrelationoftheChanghsingianto'Griesbachian'magnetostratigraphyoftheMeishansectionwiththegeneralscale,andinformedthenegationofashortmagneticreversalatthePTBsuggestedbyZhuandLiu(1999).Recentdevelopmentsofchemostratigraphyofδ13Candδ34Sareintroduced,especiallythediscoveryofmorethanonenegativeδ13CexcursionsacrossthePTB.Twoimportantmolecularresearchesrevealtheprofoundchangesatthebaseofeco-system,themicrobialcatastrophy,andtheeuxinicconditionsinthephoticzoneduringthePermian-Triassicsuperanoxicevent.ThepaperreportsthechangesindatingtheageofPTBsince2001.Accordingtorecentachievements,theageofvolcanogenicclaybed25,14cmbelowthePTB,isnowsetat252.4±0.3Ma.Adiscussionontheeventostratigraphyconcludesthat,althoughthereisamajoreventepisodeatbeds25-26,theeventsacrossthePTBatMeishanaremulti-episodicandcommencedpriortotheEventBeds25-26,thusthepossibilitythatthemassextinctionwasmainlyinducedbyanexterrestrialimpactislargelyexcluded.

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简介：PointbarsarewelldevelopedontheYellowRiverdelta,amongwhichtheShengliIpointbaristhemosttypical.Thepointbar,beingabout4kminlengthandseveraltenstomorethan100metersinwidth,islocatedonthesouthsideoftheShengliBridgeinKenliCounty,Dongying,Shandong.Itisatypicalfine-grainedpointbarwithsilt,whichispredominant,someclayandminorplantdebrisandclayboulders.TheShengliIpointbarhascomplicated3-Dstructures.Firstly,inaplaneview,itcomprisesmainlyeightsedimentaryunits,baredge,barridge,barplatform,barplain,barchannel,bargully,barpondandbarbay,developingsidebysideandsuperimposedonebyoneinacomplexway.Secondly,itsverticalstructuresareverycomplexduetothepartialsuperimpositionofthe8sedimentaryunits.Besideshydatogenesis,veryintensivewinderosion,eolian,iceandmeltwateractionsarealsovisibleontheShengliIpointbar.Thecomplexformismadeevenmorecomplicatedbecauseoftheaboveco-actions.

简介：TheGSSPoftheTortonianStage,whichperdefinitionmarksthebaseoftheTortonianand,hence,theboundarybetweentheSerravallianandTortonianStagesoftheMiddleandUpperMioceneSubseries,hasrecentlybeendefinedandratifiedbytheIUGS.Theboundarystratotype-sectionisMontedeiCorvi(Italy)wheretheTortonianGSSPisnowformallyatthemid-pointofthesapropelofsmall-scalesedimentarycycleno.76,closetothelastcommonoccurrences(LCOs)ofthecalcareousnannofossilDiscoasterkugleriandtheplanktonicforaminiferGlobigerinoidessubquadratusandassociatedwiththeshortnormalsubchronC5r.2n.TheGSSPlevelcoincidescloselywithoxygenisotopeeventMi-5andtheassociatedglacio-eustaticsea-levellow-standofsupercycleT3.1andconcurrentdeep-seahiatusNH4,andisdatedastronomicallyat11.608Ma.TheMonteGibliscemisectionisacceptedasanauxiliaryboundarystratotypebecausethebetterpreservationofthecalcareousmicrofossilsinthissectionenablesquantitativeanalysesandtheconstructionofastableisotoperecord.

简介：FollowingtherecommendationoftheInternationalCommissiononStratigraphy(16votesYes[94%],1abstention,2votesnotreceived),theGlobalboundaryStratotypeSectionandPoint(GSSP)forthebaseoftheTuronianStageoftheCretaceousSystemisdefinedasthebaseofbed86oftheBridgeCreekLimestoneMemberoftheGreenhornLimestoneFormationatthewesternendoftheDenverandRioGrandeRailroadcutnearthenorthboundaryofthePuebloReservoirStateParkRecreationArea,westofPueblo,Colorado,USA.ThisGSSPhorizonisalsoexposedandprotectedintheadjacentstaterecreationarea.ItcoincideswiththefirstoccurrenceoftheammoniteWatinocerasdevonense,isinthemiddleofaglobalpositiveexcursioninCarbon-13isotopes,andisbracketedbywidespreadbentonitesthathaveyieldedagesof93to93.5Ma.

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简介：FollowingtheunanimousrecommendationoftheInternationalCommissiononStratigraphy,theGlobalboundaryStratotypeSectionandPoint(GSSP)forthebaseoftheCenomanianStageisdefinedatalevel36metresbelowthetopoftheMarnesBleuesFormation,alevelthatcorrespondstothethefirstappearanceoftheplanktonicforaminiferanRotaliporaglobotruncanoidesSigal,1948,onthesouthsideofMontRisou,eastofRosans,Haute-Alpes,France,whereitcanbeplacedinthecontextofaseriesofsecondarymarkerlevelsbasedonnannofossils,planktonicforaminifera,ammonites,andanornateδ^13Ccurve.

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