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：Naturalgasisprovidingalargerproportionofprimaryenergy,andwillsoonsurpassoiltobecomethemostimportantfossilfuel.Therearevariousgenetictypesofnaturalgasofwhichthetypethatpyrolysedorcrackedfromhumickerogenaccountsfor70%ofpresentlydiscoveredglobalnaturalgasreserves.Theparentmaterialofhumickerogenishighermulti-cellularplants.InvestigationsofoffshorebasinsinChina,Russia,Indonesia,Bangladesh,Australia,EgyptandNamibiashowthatriver-deltasystemscontainthemajorsourcesofcoal-typegas.Sandandmudcarriedbyriversformdeltasatrivermouthsandfertilesoilofthesedeltasencouragesthelong-termgrowthofhigherplants.Autochthonoushigherplantsandallochthonousterrigenousphytoclastscontributetotheformationofcoal,carbargiliteanddarkmudstone,whicharepotentialparentmaterialsofnaturalgasandthebasisofcoal-typegasgeneration.

简介：

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

简介：

简介：

简介：

简介：

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

简介：

简介：

简介：

简介：

简介：

简介：

简介：