简介:DifferentmodelshavebeenproposedfortheformationandtectonicevolutionoftheSouthChinaSea(SCS),includingextrusionoftheIndochinaPeninsula,backarcextension,two-stageopening,proto-SCSdragging,extensioninducedbyamantleplume,andintegratedmodelsthatcombinediversefactors.Amongthese,theextrusionmodelhasgainedthemostattention.Basedonsimpli?edphysicalexperiments,thismodelproposesthatcollisionbetweentheIndianandEurasianPlatesresultedinextrusionoftheIndochinaPeninsula,whichinturnledtoopeningoftheSCS.TheextrusionoftheIndochinaPeninsula,however,shouldhaveledtopreferentialopeninginthewestsideoftheSCS,whichiscontrarytoobservations.ExtensionalmodelsproposethattheSCSwasabackarcbasin,riftedofftheSouthChinaBlock.Mostofthebackarcextensionmodels,however,arenotcompatiblewithobservationsintermsofeitherageorsubductiondirection.Thetwo-stageextensionmodelisbasedonextensionalbasinssurroundingtheSCS.Recentdatingresultsindeedshowtwo-stageopeningintheSCS,buttheSouthwestSubbasinoftheSCSismuchyounger,whichcontradictsthetwo-stageextensionmodel.Hereweproposeare?nedbackarcextensionmodel.TherewasawideNeotethysOceanbetweentheAustralianandEurasianPlatesbeforetheIndian-Eurasiancollision.Theocean?oorstartedtosubductnorthwardat*125Ma,causingbackarcextensionalongthesouthernmarginoftheEurasianPlateandtheformationoftheproto-SCS.TheNeotethyssubductionregimechangedduetoridgesubductionintheLateCretaceous,resultinginfold-belts,uplifting,erosion,andwidespreadunconformities.Itmayalsohaveledtothesubductionoftheproto-SCS.FlatsubductionoftheridgemayhavereachedfurthernorthandresultedinanotherbackarcextensionthatformedtheSCS.Therollbackofthe?atsubductingslabmighthaveoccurred*90Maago;thesecondbackarcextensionmayhaveinitiatedbetween50and45Ma.TheopeningoftheSouthwestSub
简介:VolcanicrocksinseamountsoftheSouthChinaSeaconsistmainlyofalkalibasalt,tholeiiticbasalt,trachyandesiticpumice,dacite,etc.Inclusionsinthemineralsofthevolcanicrocksaremain-lyamorphorsmeltinclusions,whichreflectsthatthevolcanicrocksarecharacterizedbysubmarineeruptionandrapidcoolingontheseafloor.Furthermore,fluid-meltinclusionshavebeendiscoveredforthefirsttimeinalkalibasaltsandmantle-derivedxenoliths,indicatingaprocessofdifferentiationbetweenmagmaandfluidinthecourseofmantlepartialmelting.Alkalibasaltsandinclusionsmayhavebeenformedinthisnonhomogeneoussystem.Rock-formingtemperaturesoffourseamounsestimatedasfollows:theZhongnanseamountalkalibasalt1155-1185℃;theXianbeiseamountalkalibasalt960-1200℃;tholeiiticbasalt1040-1230℃;theDaimaoseamounttholeiiticbasalt1245-1280℃;andtheJianfengseamounttrachandesticprmice880-1140℃.EquilibriumpressuresofalkalibasaltsintheZhongnanandXianbeiseamountsare13.57and8.8×10^8Pa,respectively.Pyroxeneequilibriumtem-peraturesofmantlexenolithsfromtheXianbeiseamountwereestimatedat1073-1121℃,andpres-suresar(15.58-22.47)×10^8Pa,suggestingadeep-source(e.g.theasthenosphere)forthealkalibasalts.
简介:溶解无机的滋养的元素从在2003年3月在Changjiang(长江)河口的南方经过收集的样品被分析,includingNH_4~+,NO_3~-,NO_2~--)并且PO_4~(3-)。水样品在三个车站在近表面、中间、近底部的深度时时与一个Niskin刺绣花样被收集—A1,A2和A3—在小潮和大潮的二个完全的潮汐的周期期间。结果显示出那1)当PO_4~(3-)显示出一个相反的趋势时,集中ofNH_4~+,NO_3~-和NO_2~-在大潮期间比那些在小潮期间分别地是高一些的,并且各比在涨潮在落潮是更高的,为小潮的任何一个潮汐的周期或春天潮汐的周期;2)营养素的更高的层化在这个区域显然存在与哪个从底部增加了到表面的集中,特别为NH_4~+和NO_3~-;3)所有溶解无机的营养素的变差系数(C.V)价值在潮流和Changjiang流量的不同影响以外从4.06%~36.8%变化了;4)与在水列增加浮游物,PO_4~(3-)的集中在过滤的水里变得更低;并且5)每个潮汐的周期的全部的运输是更,在大潮,比在小潮,和positive,价值显示营养素被出口了到华东海。研究在变化和在theChangjiang河口的南方经过的溶解无机的营养素的网运输将在华东海为红潮的机制的学习提供科学基础。
简介:TheBaobangoldfield,locatedintheareaofHainanIsland,SouthChina,bearsthreegoldde-posits:Tuwaishan,Baoban,andErjia,whichbelongtothewall-rockalterationtype.Intermsofthepetrographydata,fouralterationzonescanberecognizedfromtheore-veinoutwards(1)thesilicificationzone;(2)thesericitizationzone;(3)thechloritizationzone;and(4)thecalcitizationzone.Thegeochemicalkineticsimulationwascarriedoutonsericitizationandchloritization.Resultsofthestudyshowedthattheformationofthealterationzonesisconnectedwiththepropertiesofhydrothermalfluids:theinitialconcentrationofAl(OH)3,thediffusioncoefficientandthevelocityoffluidflow.Thealterationzonesinthisfieldaretheresultofmultipleinteractionbetweenhydrothermalfluidsandwallrocks.
简介:Lepingcoal(includingbarkinite-richcoal)isauniquekindofcoal,whichiswidelydistrbutedintheLatePermianLonganFormation,SouthChina,Inthispaper,ROck-Eval,Py-GCandsimulationexperimentviaanopen-systemwereusedtostudythehydrocarbon-generatingpotential,hydrocarboncomposition.andhydrocarbon-generatingmodelofbarkiniterichcoalsfromtheshuichengcoalfieldofGuizhouProvince,SouthwestChina.Theresultsshowthatbarkinite-richcoalshavehighhydrocarbon-generatingpotential,withS1+S2being211-311mg/g,andcanproducelargeamountsofhydrocorbonatthehigh-maturitystage,mostlywithinthetemperaturerangeof420-450℃(correspondingtoVR01.1-1.5%);barkinite-richcoalisoneofthebetteroilsourcesandlighthydrocarbonandwetgasarethemajorhydrocarboncomponents,whichaccountfor45%and33%ofthetotalhydrocarbons.respectively.ThesecharacteristicsareofimportanceforexploringoilandgasresourcesintheLatepermianLongtanFormationcoals,southwestChina.
简介:ThegeochemistryofthebasicvolcanicrocksatthesouthmarginoftheQinlingorogenicbelt(SMQOB)suggeststhattheywereformedinanintraplatetectonicsetting.TheREEdistributionpatternsshowtheserocksarestronglyenrichedinLREEwithhigh∑REE,andtheirtraceelementsgeochemistryissimilartothatofcontimentalfloodbasalt.AlltheaboveevidencesuggeststhattheCaledonianbasicvolcanicrocksintheSMQOBweretholeiiticbasaltsformedinanintraplatespreading-initialrifttectonicsetting.Thecharacteristicsofregionalgeologyandgeochemistryindicatethattherewasanintraplatespreading-rifttectonicsettingbetweentheSouthQinglingblockandtheYangtzeblockintheCaledonianepoch.ThedynamicspreadinginthisdistrictbeganintheEarlyCaledonianandthentheintraplatespreadinginitialriftswereformedintheLateCaledonian.AsaresultofspreadingoftheTethysandgeodynamicprocessesindeepmantle,theMianlue-HuashanoceanicbasinwasformedbetweentheQinlingblockandtheYangtzeblockinDevonian,andtheQinlingmicroplatewasseparatedfromthenorthernpartoftheYangtzeplate.
简介:这篇论文重新描述奥陶纪前(Pt_3)的特征在从方面ofpetrographic特征,岩石集合,石油化学,REE,痕量元素,铅同位素和大地构造的背景的云南省的Huimin-Manlai区域的变形火山岩。变形火山岩维持blasto-intergranularandblasto-andesitic质地;火山岩被basalt-andesite-daciteassemblage描绘;火山岩是在化学成分的basic-intermediate-intermediate-acid,属于半碱的岩石,与计算碱的系列并且拉斑玄武岩系列共存,并且他们被低TiO_2内容描绘;他们的REE分发模式theLREE丰富是使权利倾向的类型;火山岩在大阳离子元素被充实并且通常在Th充实并且部分在Ti,Cr和P弄空,属于从他们的Pb同位素组成看了的Gondwana类型;石油化学地,数据点主要在岛弧火山岩的地以内掉落。所有这些特征在学习的区域为原来的Tethysan岛弧火山岩的存在提供了新证据。
简介:Geochemical特征上面二叠(P_2)大陆人边缘的弧火山岩被描述,它最近在XiaodingxiandZangli的区域附近基于Yunxian-Lincang花岗石的东方方面以岩石集合,石油化学,REE,痕量元素,Pb同位素,大地构造的环境等等。火山岩集合被basalt-andesite-dacite统治,与次要的粗面岩andecite-trachyte;火山岩系列被计算碱的系列支配,与次要的tholleiite系列和碱的系列岩石;火山岩被高Al_2O_3和低TiO_2描绘,与显示出极其强壮的极性的K_2Ocontents;REE分发模式被LREEenrichment和使权利倾向的类型描绘;痕量元素和大阳离子元素高度被充实,Ti和Cr被弄空,并且P和Nb部分被弄空;Pb作文具有Gondwanatype;石油化学的点主要在岛弧火山岩的地以内掉落,有数据的设计的矛盾大陆人把边缘的火山岩指向南方Lancangjiang带和北方Lancangjiang带的南部的片断。这个大陆人边缘的弧火山岩带和在Changning-Menglian带的海洋山脉和海洋岛火山岩andophiolites,组成海洋山脉火山岩,在对分布式的ophiolite-arcrock-magmatic岩石带,显示Lancangjiang海洋的外壳向东代替ducted。这结果在在Lancangjiang带抑制thepaleo-Tethys的进化是很重要的。
简介:InthispaperanintegratedgeologicalandgeochemicalcomparisonismadeofCarlin-typeandCarlin-like-typegolddepositsintheregionofSouthQinlingwiththeirassociatedhydro-thermalsedimentarylead-zincdeposits,theCarlin-typedepositsintheYunnan-Guizhou-Guan-gxigoldtriangle,China,theCarlingolddeposits,Carlin,westernUnitedStates,andtheMu-runtau-typegolddepositsinUzbekistan.Thecomparativestudyindicatesthattheformationofthesedepositshasanintimatecouplingrelationwiththemechanismofthetectonicmovementofmodernplates.Therefore,thesedepositsbelongtothosethatwereformedintheorogenicstage.Theyhavethefollowingsimilarcharacteristics:theyareallsediment-hosted,occurinatectonicenvironmentofextensionalriftingnatureandshowthecharacteristicsofsyngeneticallymodifiedmineralization.Ontheotherhand,theyalsohavenoticeabledifferences:theyaredifferentinrespecttotheirtectonicsettings,associationandstructureoforogenicbeltsandcomplexityandstrengthofthemodifiedmineralization.Theregionaltectonicevolutionandextensivemineraliza-tioninorogenicbeltsaredifferentexpressionsofthesamecontinentaldynamicprocess.