简介：ThickenedheavyoilsinChinaaregeneticallycharacteristicofcontinenta.Astotheirphysico-chemicalproperties,theseoilsareveryhighinviscosityandlowinsulphurandtraceelementcon-tents.Inthegroupconstituents,theconcentrationsofnon-hydrocarbonsandasphalteneareveryhighbutthoseofsaturatedhydrocarbonsandaromaticsareverylow.Thegaschromatogramsofalkanesshowthattheseheavyoilshavehighabundancesofiso-alkanesandcyclichydrocarbons.Inallthesteroidsandterpenoids,bicyclicsesquiterpenoids,tricyclicditerpenoids,re-arrangedsteranesandgammaceranearestronglybildegradation-resistent.Theformationofheavyoilreservoirsiscontrolledmainlybylatebasinascendance,biodegradation,flushingbymeteoricwaterandoxidationintheoil-bearingformations.Ac-cordingtotheirformationmechanisms,heavyoilreservoirscanbeclassifiedasfourcategories:weatheringanddenudation,marginaloxidation,secondarymigrationandthickeningofbottomwater.Spacially,heavythickoilreservoirsaredistributedregularly:theyusuallyshowsomeparageneticrelationshipswithnormaloilreservoirs.Heavyoilreservoirsoftenoccurinstructuralhighsorinoverlyingyoungerstrata.Theirburialdepthisabout200m.Horizontally,mostofthemaredistributedonthemarginsofbasinsordepressions.

简介：TheearlyMesozoicgranodiorites(ca.165Ma)inthenortheasternHunanProvince(NEH)haveSiO2=65.4-69.65%,K2O/Na2O=0.95-1.38andK2O+Na2O＞6%,A/CNK=0.96-1.13andbelongtometaluminoushigh-Kcalc-alkalineseries.TheyarecharacterizedbyLREEandLILEsenrichment,andHFSEdepletionwithslightlynegativeEuanomalies(Eu/Eu*=0.62-0.90).Theinitial87Sr/86Srratiosareinrangefrom0.711458to0.717461,andεNdvaluesvaryfrom-9.4to-12.3,distinctfromthoseofthecontemporaneousgranodioritesmantle-derivedfromtheSoutheasternHunanProvince(SEH)(87Sr/86Sr(i)=0.707962～0.710396,εNd(t)=-6.98～-2.30).Bycontrast,suchsignaturesareroughlysimilartothoseoftheneighboringotherMesozoicgraniticplutons(Eu/Eu*=0.30-0.70;87Sr/86Sr＞0.710;εNd=-12to-16)inSouthChinaBlock(SCB),whichhavebeeninterpretedastheremeltingproductsofPrecambrianbasement.TheProterozoiclower-middlecrustisanimportantcontributortothepetrogenesisoftheseearlyMesozoicgranodioritesintheNEH.AnintracontinentalextensionsettingispresentinthenortheasternHunanProvinceatthattimeduetothedemandofenoughthermaltransfer.

简介：Resultsobtainedfromthewide-spacedfloodplainsedimentsindicatethattheabundancesofPtandPdinfloodplainsedimentsare0.46ng/gand0.40ng/g,respectively.Threegeochemicalprovinces.Yunnan-Guizhou,Xinjiang-GansuandTibetofPtandPdwithacontentof0.8ng/g,weredelineated.

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简介：Afixedlink(tunnelandbridge,intotal16km)wasconstructedbetweenSwedenandDenmarkduring1995-2000.Aspartofthework,approximately16milliontonnesofseabedmaterials(limestoneandclaytill)weredredged,andabout0.6milliontonnesofthesewerespilledinthewater.Modellingofthespreadingandsedimentationofthespilledsedimentstookplaceaspartoftheenvironmentalmonitoringoftheconstructionactivities.Inordertoverifytheresultsofthenumericalmodellingofsedimentspreadingandsedimentation,anewmethodwiththepurposeofdistinguishingbetweenthespilledsedimentsandthenaturallyoccurringsedimentswasdeveloped.Becausethespilledsedimentstendtoaccumulateattheseabedinareaswithnaturalsedimentsofthesamesize,itisdifficulttoseparatethesebasedpurelyonthephysicalproperties.Thenewmethodisbasedonthegeo-chemicaldifferencesbetweenthenaturalsedimentintheareaandthespill.ThebasicpropertiesusedarethehighercontentofcalciumcarbonatematerialinthespillascomparedtothenaturalsedimentsandthehigherCa/Srratiointhespillcomparedtoshellfragmentsdominatingthenaturalcalciumcarbonatedepositioninthearea.ThereasonforthesedifferencesisthatcarbonatederivedfromrecentshelldebriscanbediscriminatedfromDanienlimestone,whichisthematerialinwhichthemajorityofthedredgingtookplace,onthebasisoftheCa/Srratiobeing488inDanienLimestoneand237inshelldebris.Thegeochemicalrecognitionoftheoriginofthesedimentsprovedusefulinseparatingthespilledfromthenaturallyoccurringsediments.Withoutthisseparation,validationofthemodellingofaccumulationofspilledsedimentswouldnothavebeenpossible.Themethodhasgeneralvalidityandcanbeusedinmanysituationswheretheoriginoragivensedimentissought.

简介：Theresultsof118REEanalysesofLi-FgranitesfromSouthChinaandothercountriesindicatethattherearethreevariationtypesofREEpatterncurveswithdifferentevolutiontrendsfromearlytolatestagesofLi-FgranitecomplexoffromlowertoupperpetrofaciesoftheLi-Fgranitebody;(1)thedecreasing,(2)theincreasing,and(3)thesaltatoryvariationtypes.Thefirstvariationtypeiscalledthepositiveevolutiontype,attributedtocrystallizationdifferentiation.Thesecondiscalledthereversionevolutiontype.whichrepresentsliquidsegreationdominatedbyvapor-liquiddistillation.Thethirdiscalledthesaltatoryvariationtype,whichisformedfromliquidsegregationdominatedbyimmiscibilty,Therefore,theindicaticesofliquidsegregationdominatedbyimmiscibilityarethesaltatoryvariationtypeofREEpatternevolutionandtheseparationofthemainevolutiontrendlineseitherfromthesub-evolutiontrendlinesorfromthecompositionpointsofLi-FgranitesinthediagramsofREE-(La-Yb)NandLa/Sm-La,Theindicatricesofliquidsegregationdominatedbyvapor-liquidfractionaldistillationarethereverstionevolutiontypeofREEpatterncurvesandthemainevolutiontrendlinesofLi-Fgranitesdirectingtotheupperright-handontheREE-La/Yb)NandLa/Sm-Ladiagrams.

简介：Guizhouisoneofthedominatingkarstregions,wherelateriteiswidespread,inChina.Seventy-twolateritesamplesweretakenfromtwelvelateritesectionsinthekarstareasofGuizhouProvince,whicharepossessedoftypicalsubtropicalkarstgeomphologicalandecologicalenvironmentalfeaturesandhaveevolvedcompletelyfromdolostonesandlimestones.Intermsofthemajor,traceandREEdetaforthdsamplesthispaperdiscussesthegeochemicalcharacteristicsoflateriteinthekarstareaswithanattempttodisclosethegeochemicalprocessandevolutionaryruleoflateriteformation.Therehavebeeninvolvedthreeimportantpedogeneticgeochemicalprecessesintheformationoflateriteinthekarstareas:(1)enrichmentofsiliconandaluminumanddepletionofcalciumandmagnesium;(2)enrichmentofironandmanganese;and(3)enrichmentofaluminumanddepletionofsilicon.Duringtheformationandevolutionoflaterite,obviousenrichmentanddifferentiationoftraceelementssuchasCu,Pb,Zn,Ni,Co,Cr,Pb,F,Cl,andAscanbeobserved,butfortherare-earthelements,theirenrichmentisremarkableagainstaweakdifferentiation.TheREEdistributionpatternsinthelateritearesimilartothoseofitsparentalcarbonaterocks.

简介：ThecharacteristicstructuresofthePrecambrianchertsfromtheGusuisection,Guangdong,Chi-na,includebeddedstructure,laminatedstructure,massivestructureandpseudobrecciatedstructure.ThechertischaracterizedbyconsistentlylowabundanceofTiO2,Al2O3andmosttraceelements.Howevver,itisenrichedinBa,As,Sb,HgandSe.InAl-Fe-Mnternarydiagrams,itfallsintothe'hydrothermalfield'.Correspondenceanalysisandfactoranalysisshowthatmanyelementsshowupinthefactorthatrepresentstheleachingofcountryrocksbyhydrothermalsolutions,andaretheverycharacteristicelementassociationfothegeochemicallyanomalousSouthChinabasement.Petrologicandgeochemicalevidencesuggestsahydrothermaloriginforthechert.ThechertmayhavebeenformedinaPrecambrianfiftoranextensionzonedevelopedwithintheYunkaimarginalgeosyncline,withafaultsystemlinkingittoanunknownheatsourceatdepth.

简介：Asequentialextractionmethodforthefractionationofphosphorus(P)inlakesedimentswasusedtoanalyzephosphorusfractionsofsedimentstakenfromthreelarge,shallow,eutrophicfreshwaterlakesofChina-TaihuLake,ChaohuLake,andLongganLake.AllthreelakesarelocatedinthelowerreachesoftheChangjiangRiver(YangtzeRiver).InTaihuLakeandChaohuLake,algaebloomsoccurredeveryyear,whileLongganLakewasamacrophyte-dominatedlake.Resultsshowedthatexchangeablephosphorusfractionsweremuchhigherintheeutrophiclakesedimentsthaninthemacrophyte-flourishinglakesediment.Also,theratioofFe:Pinthesedimentsofthealgae-predominantlakeswasgenerallymuchlowerthanthatinthemacrophyte-predominantlakes.Thus,thegeochemicalfractionsofphosphorusinsedimentshadacloserrelationshipwiththetypeofaquaticvegetation.

简介：ThereoccurabundantchertsintheMesozoicandCenozoicstratainsouthernTibet.Someofthempossesscharacteristichydrothermalstructuressuchaslayered,laminated,massiveandbrecciastructures.RatiosofAl/(Al+Fe+Mn),Co/Ni,Fe/TiandTiO2-Al2O3demonstratethattheiroriginisrelatedtohydrothermalsedimentation.ThechertformationshavecloserelationshipwithSb,Auandpoly-metallicmineralization,andtheore-formingfluidshowstrongcorrelationwithfossilhydrothermalwater.

简介：Thesuper-largePb-ZndepositatFankouisverycomplexinmetallogenicmechanism.Syngeneticbrinesedimentation,hotsubmarinespringeruption-accumulation,syngeneticsedimentation-vadosebrinereplacementhadbeensupposedasthegeneticmodelsbefore.Underthesemodels,syngeneticmineralizationshouldbedominantinoreformation.However,aseriesofgeologicalandgeochemicalpropertiesinvestigatedbyauthorsofthispaperarecontrarytothesemodels.Therefore,theauthorsheresuggestthatthisdepositisatypicalpolygeneticcompoundoredepositwhichsharethepropertiesofmultistagesofgeotectonicevolution,multifactorsofmineralizationcontrol,multisystemofmaterialderivationofmineralization,multimodesofmineralizationandmultitypesofgenesis.

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简介：TheMayangCudeposit,westernHunanisamiddle-scalesandstone-typeCudepositpredominantofnativecopper.Fromanangleofgeologicalintegrativefield,fracturegeochemicalfeaturesarestudidedanddiscussedinthispaper.Infracturestructure,variantregularityandtheratiosofelementcouplesparticipatinginmetallogensisthattheirgeochemicalnaturesaresimilarorstronglycorrelative,revealchanginglawsofmetallogenictemperatureandpressurefieldsandmigratingdirectionofmetallogenicelements.Thetheoreticalstudytalliesmuchbetterwithproductivepractice.Theyaremeaningfultoconductprospectingandexployation.

简介：Aglobal-scaleglaciationoccurredatabout600Maago.Asaresult,theEarthbecamethe'SnowballEarth'.Theglaciationcametotheendabruptlywhenatmosphericcarbondioxideincreasedtosuchanextentastobeabout350timesthemodernlevelbecauseofsubaerialvolcanicdegassing.TherapidterminationofglaciationwouldhaveledtowarmingoftheSnowballEarthandextremegreenhouseconditionswouldhavebeencreated.Thetransferofatmosphericcarbondioxidetooceanswouldgiverisetotherapidprecipitationofcalciumcarbonateinwarmsurfaceseawaters,thusformingthecapcarbonaterocksasobservedworldwidetoday.Regionallypersisting,thinlayersofcarbonaterocksdirectlyandubiquitouslyoverlieProterozoicglacialdepositsalmostoneverycontinent,andarecommonlyreferredtoascapcarbonates.Theirunusuallitho-fabrics,stratigraphicallyabruptbasalandupper-levelcontactsandstronglynegativecarbonateisotopicsignatures(δ13Ccarb.valuesrangefrom-7.0‰-0‰)suggestachemicaloceanographicorigin,thedetailsofwhichremainunknown.Itisproposedthattheseenigmaticdepositsarerelatedtothedestabilizationofgaseoushydrateinterrestrialpermafrostfollowingrapidpostglacialwarmingandfloodingofwidelyexposedcontinentalshelvesandinternalbasins.Theauthorscarriedoutstudiesonthegeochemistry,sedimentologyandpalaeontologyoftheSiniancapcarbonatesinGuizhouandHunanprovinces,includingtheoccurrenceofcapcarbonatesofunusualfabrics,stronglynegativecarbonisotopicsignatures,andalotofbitumennodules.Fromtheresultsitissuggestedthatthecapcarbonateswereformedfromsolidmethaneseepage,anditisinagreementwithKennedy'sviewpoint(2001)thatthecapcarbonatesresultedfromtherapidprecipitationofcalciumcarbonateinresponsetosolidmethaneseepage.

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