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简介：TwoGSSPs(GlobalStandardStratotypeSectionandPoint)fortheOrdovicianSystemwerededicatedinSwedenon25&26May2003.TheceremonieswerewellorganizedandwellattendedandincludednotonlytheunveilingofformalplaquesdescribingtheGSSPsbutalsothedrivingof“goldenspikes”.

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简介：系统的Ce异例为整个岩石从跨越奥陶纪/志留纪(O/S)的页岩主导、连续、远洋的沉积序列被获得了在Tieshui的边界()Xiushan()，重庆()，华南。越过O/S边界的Ce异例在三间隔被认出，Wufeng()，Guanyinqiao()并且Longmaxi()。计算Ce/Ce*Wufeng形成的价值从0.84～0.96(avg。0.90)。在Guanyinqiao形成，计算Ce/Ce的价值*从0.73～0.85(avg。0.79)。Ce/Ce*价值最高从0.87～0.96的Longmaxi形成范围(avg。0.91)。沿着节，Ce异例的大小总是是否定的，但是在Guanyinqiao形成是更重要的。相对更高的Ce/Ce*在Wufeng和Longmaxi页岩的价值是可能的由于在减少的条件下面扔的沉积。Ce异例显然确实在伴随突出的集体扑灭的缺氧的事件起一些常规作用，并且这个工作为在结束抑制模型提供批评重要性的新数据--奥陶纪缺氧的事件和集体扑灭。

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简介：<正>Chinaisinsevereshortageofpotashreserves,andthebestwayforbreakthroughistomakepotashexplorationinmarinesaltbasins.ErdosbasinissofartheonlyOrdovicianpotashbasinintheworld.TheErdosbasinislocatedwest

简介：TheHuanghuachangsectionnearYichang,southernChinameetstherequirementsofGlobalStratotypeSectionandPoint(GSSP)forthebaseoftheMiddleOrdovicianSeriesandtheyet-to-be-namedthirdstageoftheOrdovicianSystem(orlowerstageofMiddleOrdovicianSeries).TheconodontsuccessionatthesectioniscompleteacrosstheLowertoMiddleOrdovicianseriesboundaryandseveralexcellentphylogeneticlineagesofBaltoniodus,Trapezognathus,Periodon,andMicrozarkodinaarerepresented.ThedefinitionofthebaseoftheMiddleOrdovicianisproposedtobethefirstappearancedatum(FAD)ofBaltoniodus?triangularisinthesection.ItisfollowedcloselybytheFADofMicrozarkodinaflabellum,whichistakenasareasonableproxyfortheboundary.ThislevelapproximatestheboundarybetweenthelowerandupperintervalsoftheAzygograptussuecicusgraptoliteBiozone,andnearlycoincideswiththebaseoftheBelonechitinahenryichitinozoanBiozone.TheproposedGSSPforthebaseoftheinternationalMiddleOrdovicianSeriesislocatedinaroadsideexposureatthebaseofBed(SHod)16,10.57mabovethebaseoftheDawanFormationinthemeasuredHuanghuachangsectionnearYichangCity,southernChina.ThesamefaunalsuccessionisalsorecordedfromtheChenjiahe(formerlyDaping)section,5kmtothenorthoftheHuanghuachangsection.Theproposedboundaryhorizoncanberecognizedandcorrelatedgloballywithhighprecisioninbothrelativelyshallow-watercarbonatefaciesaswellasindeep-watergraptolitefacies.

简介：TheprecisecorrelationoftheOrdoviciansuccessionsindifferentfaciesisdifficultduetothecomplexchangesofthetecto-paleogeographyinSouthChina.Basedonpreviousstudies,theauthorsrecognized103rdgradesequences,i.e.,Osq1toOsq10inascendingorder,bytheintegratedstudyofchronostratigraphy,biostratigraphyaswellastheanalysisonthesedimentaryfacies.TheauthorsareconfidenttocorrelatetheOrdoviciansuccessionspreciselyindifferentfaciesinanisochronousstratigraphicframeworkwiththeapplicationofthemethodofsequencestratigraphyandcorrelation.

简介：EarlyOrdovicianA-typegranitesinthenortheastern(NE)SongnenBlockNEChinawerestudiedtobetterunderstandthegeodynamicsettingsinthisregion.ThisresearchpresentsnewzirconU-PbagesandwholerockgeochemicaldatafortheEarlyOrdoviciangranitesintheNESongnenBlock.ZirconU-PbdatingindicatesthatthegraniteintheCuibei,Hongxing,andMeixiareasintheNESongnenBlockformedintheEarlyOrdovicianwithagesof471-479Ma.ThegranitesshowgeochemicalcharacteristicsofhighSiO2andK2OcompositionsandlowFeOT,MgO,CaO,andP2O5compositions.TheybelongtoahighKcalc-alkalineseriesanddisplayaweakperaluminousfeaturewithA/CNKvaluesof0.98-1.14.TherockshaveaΣREEcompositionof249.98-423.94ppm,andareenrichedinLREEwith(La/Yb)Nvaluesof2.87-9.87,anddisplayobviousEuanomalies(δEu=0.01-0.29).TraceelementsofthestudiedgranitesarecharacterizedbyenrichmentinRb,Th,U,Pb,Hf,andSm,anddepletionofBa,Nb,Ta,andSr.TheydisplaygeochemicalfeaturesofhighZr+Y+Nb+Cevalues(324-795ppm)andGa/AlratiosconsistentwithA-typegranites.Basedonparticulargeochemicalfeatures,suchashighRb/Nb(7.98-24.19)andY/Nb(1.07-3.43),thestudiedA-typegranitescanbefurtherclassifiedasanA2-typesubgroup.ThisresearchindicatesthattheEarlyOrdovicianA-typegraniteswereformedbythepartialmeltingofancientcrustinanextensionalsetting.LowerSr/Yand(Ho/Yb)Nratiosindicatethatplagioclaseandamphiboleareresidualinthesource,andgarnetisabsent,implyingthatthemagmawasgeneratedatlowlevelsofpressure.Bycontrast,thecontemporaneousgranitesintheSEXing'anBlocksuggestasubduction-relatedtectonicsetting,anditsadakiticpropertyindicatesathickenedcontinentalcrust.WesuggestthatthePaleo-AsianOceanplatebetweentheXing'anandSongnenblockssubductednorthwardduringtheEarlyOrdovician.Meanwhile,theNESongnenBlockwasexposedtoapassivecontinentalmargintectonicsetting.

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简介：Diabasbrottet,selectedbytheInternationalSubcommissononOrdovicianStratigraphyandin2002ratifiedbytheInternationalCommissiononStratigraphyastheGSSPoftheSecond(Upper)StageoftheLowerOrdovician,islocatedontheHunnebergMountaininsouthwesternSweden.ThestratigraphicsuccessionrepresentsanoutershelfenvironmentneartheBalticShieldmargin.Theshale-dominated,biostratigraphicallycomplete,richlyfossiliferousboundaryintervaliscompletelyexposedinadisusedquarry.TheGSSPisinthelowerTФyenShale2.1mabovethetopoftheCambrianandismarkedbythefirstappearanceofthegraptoliteTetragraptusapproximatusNicholson.Theboundaryintervalcontainsadiversegraptolitefaunaandbiostratigraphicallydiagnosticconodontsandtrilobitesthatmakeitpossibletodefinetheboundaryintermsofzoneschemesbasedonthesegroups.Inthisrespect,theDiabasbrottetandnearbysectionsareuniqueintheworldamongdescribedlocalitieshavingthisboundaryinterval.BasedontheappearanceofT.approximatus,thebaseoftheSecondStagecanbeidentifiedinmanygraptolitiferoussuccessionsroundtheworldbutthisleveliscurrentlymoredifficulttorecognizepreciselyinsomecarbonatesequencesoutsideBaltoscandia.WeproposetheSecondStagebecalledtheFloanStage.ItisnamedfortheVillageofFlo,whichissituatedabout5kmsoutheastoftheGSSP.

简介：中央煤气的地是在中国的Ordos盆的一块著名的大尺寸的煤气的地。然而，在这气体的奥陶纪水库的主要煤气的来源的鉴定回答遗体思索。根据天然气上的很多geo化学的数据和地质的研究，从奥陶纪的天然气的特征和来源在Ordos盆在中央煤气的领域里捱过外壳水库被学习。结果显示从在中央气体的捱过的外壳水库在Ordos盆回答的奥陶纪的天然气有类似的化学药品和同位素组成到高度成熟、在成熟上的干燥气体。导出煤的气体和油类型气体在Ordos盆在中央煤气的领域里共存。前者从更低的古生代的海洋的碳酸盐主要从含碳二叠的煤措施和后者被导出。当油类型气体可以在Ordos盆主要在中央煤气的领域的北、西方、南部的部分被生产时，导出煤的气体发生在中央煤气的领域的东方部分，这被建议。

简介：ThewesternKunlunorogeninthenorthwestTibetPlateauisrelatedtosubductionandcollisionofProto-andPaleo-TethysfromearlyPaleozoictoearlyMesozoic.ThispaperpresentsnewLA-ICPMSzirconU-PbagesandLu-Hfisotopes,whole-rockmajorandtraceelements,andSr–NdisotopesoftwoOrdoviciangranitoidplutons(466–455Ma)andtheirSilurianmaficdikes(~436Ma)inthewesternKunlunorogen.Thesegranitoidsshowperaluminoushigh-Kcalc-alkalinecharacteristics,with(87Sr/86Sr)ivalueof0.7129–0.7224,εNd(t)valuesof-9.3to-7.0andzirconεHf(t)valuesof-17.3to-0.2,indicatingthattheywereformedbypartialmeltingofancientlower-crust(metaigneousrocksmixedwithmetasedimentaryrocks)withsomemantlematerialsinresponsetosubductionoftheProto-TethyanOceanandfollowingcollision.TheSilurianmaficdikeswereconsideredtohavebeenderivedfromalowdegreeofpartialmeltingofprimarymaficmagma.Thesemaficdikesshowinitial87Sr/86Srratiosof0.7101–0.7152andεNd(t)valuesof-3.8to-3.4andzirconεHf(t)valuesof-8.8to-4.9,indicatingthattheywerederivedfromenrichedmantleinresponsetopost-collisionalslabbreak-off.Combinedwithregionalgeology,ournewdataprovidevaluableinsightintolateevolutionoftheProto-Tethys.

简介：MostofthehinterlandoftheNorthChinaplatformisdevoidofLateOrdovicianstrata.TheBaiyanhuaMountainsectionatShetaiTownisastandardsectionoftheUpperOrdoviciannewlyestablishedinrecentyearsatthenorthernmostmarginoftheplatform.ThisestablishmentdirectlyinvolvedthedeterminationofthenorthboundaryoftheplatformandtheunderstandingofitsevolutionaryListory.TheareaisquitedifferentfromthebinterlandoftheplatforminMiddleOrdovicianrocktypesandsedimentaryenvironments,withtheformercharacterizedbyfrequentslopedepositsandthelatterconsistingalmostentirelyofplatformdeposits.ThepresentpaperfocusesonthepetrographicfeaturesandsedimentaryervironmentsoftheMiddle-UpperOrdovicianstratainthearea,providingfurthertheoreticalsupporttotheestablishmentofthesectionandfil-lingthegapinthisrespect.

简介：ThreemajortypesofOrdovicianintrusive-relatedgold-copperdepositsarerecognizedincentral-westNewSouthWales,Australia:porphyry,skarnandhighsulphidationepithermaldeposits.ThesedepositsaremainlydistributedwithintwoOrdovicianvolcano-intrusivebeltsoftheLachlanFoldBelt:theOrange-WellingtonBeltandtheParkes-NarromineBelt.AvailableisotopicagedatasuggestthatmineralizationofthethreetypesofdepositsisessentiallycoevalwiththeOrdovicianintrusiverocks(480-430Ma).Porphyrygold-copperdepositscanbefurtherdividedintotwogroups.Thefirstgroupisassociatedwithmonzoniteshowingshoshoniticfeatures,representedbyCadiaandGoonumbla.Thesecondgroupisassociatedwithdioriteanddacite,includingtheCopperHillandCargogold-copperdeposits.GoldskarnisassociatedwithLateOrdovician(430-439Ma)monzoniticintrusivecomplexesintheJunctionReefsarea(Sheahan-Grants,Frenchmans,andCor-nishmens),Endeavour6,7and44,BigandLittleCadia

简介：ObjectiveTheYubeiareaislocatedinthemid-eastMaigaitislopeofsouthwesternTarimBasin,China,withanexplorationhistoryofseveralyears.RecentexplorationhaspreliminarilyindicatedthattheOrdoviciancarbonateformationsinthisareahavesomeoilandgaspotential.Carbonatemicrofaciesprovidesmaterialbasisforreservoirdevelopment,sealformationandhydrocarbon

简介：HavingstudiedthebiomarkercompositionandmaturityofdissolvedhydrocarbonsfromOrdovicianformationwaters,theauthorspresentedmoleculargeochemicalevidenceforthecontroversialoriginofnaturalgasesincentralOrdosBasin.ThedissolvedhydrocarbonsinWellShan12andWellShan78arerelativelyhighinabundanceoftricylicterpane,pregnaneseriesanddibenzothiopheneseriesandlowinPr/Ph(＜2)andhopane/steraneratios,indicatingthesourceinputofmarinecarbonates.Incontrast,thedissolvedhydrocarbonsinWellShan81arefreefromtricyclicterpaneandpregnaneseries,withtracedibenzothiopheneseriesandhighPr/Ph(3.27)andhigherhopane/steraneratios,whicharethetypicalfeaturesofterrestrialorganicmatter.Furthermore,WellShan37andWellShan34arebetweenthetwosituations,havingamixedsourceofmarinecarbonateandterrestrialorganicmatter.Thematurityofbiomarkersalsosupportstheabovesuggestions.Theseresultsareconsistentwiththegeologicalbackgroundandsourcerockdistributioninthisregion.

简介：AnoilflowobtainedfromtheMiddleOrdovicianFengfengFormationcarbonatereservoirinthewellKG-3,Kongxiburial-hillzonein1993markedabreakthroughinpetroleumexplorationofthehigh-matureLowerPalaeozoicstrata,NorthChina.BoththeLowermemberoftheFengfengFormationandtheSecondMemberoftheUpperMajiagouFormationintheMiddleOrdovicianaresupposedtobethemainsourcebeds.Oilgenerationpeaksrangefrom1.0%to1.6%inRo,showinga搇ageffect?ofoilgenerationinhigh-maturecarbonatesourcerocksundermulticyclictectonicmovementconditions.TheKongxiburial-hillzoneadjoinsapotentialOrdoviciansourcekitchen.TheKG-3Ordovicianburial-hillreservoirhasundergonetwooilfillingevents,i.e.,anearlyeventintheLateCarboniferous-PermianandamoresignificantlateeventintheearlyEogene.