2007 Vol. 18, No. 2
Display Method:
2007, 18(2)
Abstract:
Combineddataofphysicalproperty,benthicforaminifera,andstableisotopesfromODPSites1148,1146,and1143areusedtodiscussdeepwaterevolutionintheSouthChinaSea(SCS)sincetheEarlyMiocene.Theresultsindicatethat3lithostratigraphicunits,respectivelycorrespondingto21–17Ma,15–10Ma,and10–5Mawithpositiveredparameter(a*)markingtheredbrownsedimentcolorrepresent3periodsofdeepwaterventilation.Thefirst2periodsshowacloserlinktocontemporaryproductionoftheAntarcticBottomWater(AABW)andNorthernComponentWater(NCW),indicatingafreeconnectionofdeepwatersbetweentheSCSandtheopenoceanbefore10Ma.After10Ma,redparameterdroppedbutstayedhigherthanthemodernvalue(a*=0),theCaCO3percentagedifferencebetweenSite1148fromalowerdeepwatersettingandSite1146fromanupperdeepwatersettingenlargedsignificantly,andbenthicspecieswhichpreferoxygen-richbottomconditionsdramaticallydecreased.Coupledwithamajornegativeexcursionofbenthicδ13Cat~10Ma,theseparametersmaydenoteaweakeninginthecontroloftheSCSdeepwaterbytheopenocean.Probablytheymarkthebirthofalocaldeepwaterduetoshallowwaterwaysorriseofsilldepthsduringthecourseofseabasinclosingfromsouthtoeastbythewest-movingPhilippineArcaftertheendofSCSseafloorspreadingat16–15Ma.However,ittookanother5Mabeforethedissolvedoxygenapproachedclosetothemodernlevel.Althoughtheoxygenlevelcontinuedtostabilize,severalPacificBottomWater(PBW)andPacificDeepWater(PDW)markerspeciesrapidlyincreasedsince~6Ma,followedbyadramaticescalationinplanktonicfragmentationwhichindicateshighdissolutionespeciallyafter~5Ma.Theperiodof5–3MasawthestrongeststratifieddeepwaterinthethenSCS,asindicatedbyupto40%CaCO3differencebetweenSites1148and1146.ApartfromastrengtheningPDWasaresultofglobalcoolingandicecapbuilduponnorthernhighlatitudes,adeepeningseabasinduetostrongersubductioneastwardmayalsohavetriggeredtheinfluxofmorecorrosivewatersfromthedeepwesternPacific.Since3Ma,the
Combineddataofphysicalproperty,benthicforaminifera,andstableisotopesfromODPSites1148,1146,and1143areusedtodiscussdeepwaterevolutionintheSouthChinaSea(SCS)sincetheEarlyMiocene.Theresultsindicatethat3lithostratigraphicunits,respectivelycorrespondingto21–17Ma,15–10Ma,and10–5Mawithpositiveredparameter(a*)markingtheredbrownsedimentcolorrepresent3periodsofdeepwaterventilation.Thefirst2periodsshowacloserlinktocontemporaryproductionoftheAntarcticBottomWater(AABW)andNorthernComponentWater(NCW),indicatingafreeconnectionofdeepwatersbetweentheSCSandtheopenoceanbefore10Ma.After10Ma,redparameterdroppedbutstayedhigherthanthemodernvalue(a*=0),theCaCO3percentagedifferencebetweenSite1148fromalowerdeepwatersettingandSite1146fromanupperdeepwatersettingenlargedsignificantly,andbenthicspecieswhichpreferoxygen-richbottomconditionsdramaticallydecreased.Coupledwithamajornegativeexcursionofbenthicδ13Cat~10Ma,theseparametersmaydenoteaweakeninginthecontroloftheSCSdeepwaterbytheopenocean.Probablytheymarkthebirthofalocaldeepwaterduetoshallowwaterwaysorriseofsilldepthsduringthecourseofseabasinclosingfromsouthtoeastbythewest-movingPhilippineArcaftertheendofSCSseafloorspreadingat16–15Ma.However,ittookanother5Mabeforethedissolvedoxygenapproachedclosetothemodernlevel.Althoughtheoxygenlevelcontinuedtostabilize,severalPacificBottomWater(PBW)andPacificDeepWater(PDW)markerspeciesrapidlyincreasedsince~6Ma,followedbyadramaticescalationinplanktonicfragmentationwhichindicateshighdissolutionespeciallyafter~5Ma.Theperiodof5–3MasawthestrongeststratifieddeepwaterinthethenSCS,asindicatedbyupto40%CaCO3differencebetweenSites1148and1146.ApartfromastrengtheningPDWasaresultofglobalcoolingandicecapbuilduponnorthernhighlatitudes,adeepeningseabasinduetostrongersubductioneastwardmayalsohavetriggeredtheinfluxofmorecorrosivewatersfromthedeepwesternPacific.Since3Ma,the
2007, 18(2)
Abstract:
ThisarticlepresentsSm-Ndandgeochemicaldataonfine-grainedsedimentsofthenorthernmarginfromtheYangtzeblock,China,tounderstandthevariationsofNdisotopiccompositionsandcrustalevolutionhistoryinthisarea.Theresultsareasfollows:(1)NdisotopiccompositionsforclasticsedimentaryrocksoftheMiddle–LateProterozoichaverelativelypositiveNd(t)values(+2.72to+0.69),withNdmodelagesfrom1.38Gato1.55Ga,correspondingtothecontemporaneousvolcanicrocksfromtheXixiang(西乡)Group.Thisindicatesthatthearc-relatedmaterialsfromMiddle–LateProterozoicdominatetheprovenancesoftheMiddle–LateProterozoicperiods.(2)ThegradualdecreaseinεNd(t)duringtheCambrian–CarboniferousperiodsislikelytoreflecttheprogressivelyincreasingproportionoferosionmaterialsfromtheFoping(佛坪)andQinling(秦岭)complexes,correspondingtoagraduallydecreasingtrendintheLa/Thratios.(3)AprominentincreaseintheεNd(t)valueoftheLatePermianstrataprobablyreflectsthesignificantincorporationofthemantle-derivedmaterials.ThetraceelementdataarecomparedwithdataoftheEmeishan(峨嵋山)floodbasalts.ThesedataindicatethatthevolcanicdusthasbeenaddedtotheLatePermianstrataduringtheLatePermian,representedbyperiodsofextremelyhighEmeishanfloodbasaltactivityinthesouth-easternmarginoftheYangtzeblock.
ThisarticlepresentsSm-Ndandgeochemicaldataonfine-grainedsedimentsofthenorthernmarginfromtheYangtzeblock,China,tounderstandthevariationsofNdisotopiccompositionsandcrustalevolutionhistoryinthisarea.Theresultsareasfollows:(1)NdisotopiccompositionsforclasticsedimentaryrocksoftheMiddle–LateProterozoichaverelativelypositiveNd(t)values(+2.72to+0.69),withNdmodelagesfrom1.38Gato1.55Ga,correspondingtothecontemporaneousvolcanicrocksfromtheXixiang(西乡)Group.Thisindicatesthatthearc-relatedmaterialsfromMiddle–LateProterozoicdominatetheprovenancesoftheMiddle–LateProterozoicperiods.(2)ThegradualdecreaseinεNd(t)duringtheCambrian–CarboniferousperiodsislikelytoreflecttheprogressivelyincreasingproportionoferosionmaterialsfromtheFoping(佛坪)andQinling(秦岭)complexes,correspondingtoagraduallydecreasingtrendintheLa/Thratios.(3)AprominentincreaseintheεNd(t)valueoftheLatePermianstrataprobablyreflectsthesignificantincorporationofthemantle-derivedmaterials.ThetraceelementdataarecomparedwithdataoftheEmeishan(峨嵋山)floodbasalts.ThesedataindicatethatthevolcanicdusthasbeenaddedtotheLatePermianstrataduringtheLatePermian,representedbyperiodsofextremelyhighEmeishanfloodbasaltactivityinthesouth-easternmarginoftheYangtzeblock.
2007, 18(2)
Abstract:
TocharacterizethehydrothermalprocessesofEastPacificriseat9o–10oN,sulfidemineralcompositions,textural,andgeochemicalfeaturesofchimneyoreswerestudiedusingoremicroscope,scanningelectronmicroscope,X-raydiffractionanalysis,andelectronmicroprobetechniques.Resultsshowthattherearethreemineralassemblagesforthehydrothermalchimneyores,namely:(i)anhydrite+marcasite+pyrite,(ii)pyrite+sphalerite+chalcopyrite,and(iii)chalcopyrite+bornite+digenite+covellite.Mineralassemblages,zonationalfeatures,andgeochemicalcharacteristicsoftheoremineralsindicatethatorefluidtemperaturechangedfromlowtohighthentolowwithamaximumtemperatureupto400℃.Thechimneyisatypicalblacksmoker.Theinitialstructureofthechimneywasformedbytheprecipitationofanhydrites,andlaterthesulfidesbegantoprecipitateintheinnerwall.
TocharacterizethehydrothermalprocessesofEastPacificriseat9o–10oN,sulfidemineralcompositions,textural,andgeochemicalfeaturesofchimneyoreswerestudiedusingoremicroscope,scanningelectronmicroscope,X-raydiffractionanalysis,andelectronmicroprobetechniques.Resultsshowthattherearethreemineralassemblagesforthehydrothermalchimneyores,namely:(i)anhydrite+marcasite+pyrite,(ii)pyrite+sphalerite+chalcopyrite,and(iii)chalcopyrite+bornite+digenite+covellite.Mineralassemblages,zonationalfeatures,andgeochemicalcharacteristicsoftheoremineralsindicatethatorefluidtemperaturechangedfromlowtohighthentolowwithamaximumtemperatureupto400℃.Thechimneyisatypicalblacksmoker.Theinitialstructureofthechimneywasformedbytheprecipitationofanhydrites,andlaterthesulfidesbegantoprecipitateintheinnerwall.
2007, 18(2)
Abstract:
ManganeseabnormityhasbeenobservedintheHolocenesedimentsofthemudareaofBohaiSea.Onthebasisofgrainsize,chemicalcomposition,heavymineralcontentandacceleratormassspectrometry(AMS)14Cdatingofforaminifer,relationshipsbetweenmanganeseabnormityandsedimentationrates,materialsource,hydrodynamicconditionsareprobed.ManganeseabnormityoccurredduringtheMiddleHolocenewhensealevelandsedimentationrateswerehigherthanthoseatpresent.Sedimentaryhiatuswasnotobservedwhenmaterialsourcesandhydrodynamicconditionswerequitesimilar.Comparedwiththeformerperiod,thelatterperiodshowedadecreaseinreductionenvironmentandaninclinationtowardoxidationenvironmentwithhighmanganesecontent,whereasprovenanceandhydrodynamicconditionsshowedonlyaslightchange.Fromtheaboveobservations,itcanbeconcludedthatcorrelationamongmanganeseabnormity,materialsource,andhydrodynamicconditionsisnotobvious.Redoxenvironmentseemstobethekeyfactorformanganeseenrichment,whichismainlyrelatedtomarineauthigenicprocess.
ManganeseabnormityhasbeenobservedintheHolocenesedimentsofthemudareaofBohaiSea.Onthebasisofgrainsize,chemicalcomposition,heavymineralcontentandacceleratormassspectrometry(AMS)14Cdatingofforaminifer,relationshipsbetweenmanganeseabnormityandsedimentationrates,materialsource,hydrodynamicconditionsareprobed.ManganeseabnormityoccurredduringtheMiddleHolocenewhensealevelandsedimentationrateswerehigherthanthoseatpresent.Sedimentaryhiatuswasnotobservedwhenmaterialsourcesandhydrodynamicconditionswerequitesimilar.Comparedwiththeformerperiod,thelatterperiodshowedadecreaseinreductionenvironmentandaninclinationtowardoxidationenvironmentwithhighmanganesecontent,whereasprovenanceandhydrodynamicconditionsshowedonlyaslightchange.Fromtheaboveobservations,itcanbeconcludedthatcorrelationamongmanganeseabnormity,materialsource,andhydrodynamicconditionsisnotobvious.Redoxenvironmentseemstobethekeyfactorformanganeseenrichment,whichismainlyrelatedtomarineauthigenicprocess.
2007, 18(2)
Abstract:
Lineamentextractionandanalysisisoneoftheroutineworkinmappingmediumandlargeareasusingremotesensingdata,mostofwhicharesatelliteimages.LandsatEnhancedThematicMapper(ETM)of945×1232pixelssubsceneacquiredon21March2000coveringthenorthwesternpartofYunnanProvincehasbeendigitallyprocessedusingERMappersoftware.Thisarticleaimstoproducelineamentdensitymapthatpredictsfavorablezonesforhydrothermalmineraloccurrencesandquantifyspatialassociationsbetweentheknownhydrothermalmineraldeposits.Intheprocessoflineamentextractionanumberofimageprocessingtechniqueswereapplied.TheextractedlineamentswereimportedintoMapGISsoftwareandasuitablegridof100m×100mwaschosen.TheKrigingmethodwasusedtocreatethelineamentdensitymapofthearea.Theresultsshowthatremotesensingdatacouldbeusefultoextractthelineamentsinthearea.Theselineamentsarecloselycorrelatedwiththefaultsobtainedthroughothergeologicalinvestigationmethods.Oncomparingwithfielddatathelineament-densitymapidentifiestwoimportanthighprospectivezones,wherelarge-scaledepositsarealreadyexisting.Inadditionthemaphighlightsunrecognizedtargetareasthatrequirefollowupinvestigation.
Lineamentextractionandanalysisisoneoftheroutineworkinmappingmediumandlargeareasusingremotesensingdata,mostofwhicharesatelliteimages.LandsatEnhancedThematicMapper(ETM)of945×1232pixelssubsceneacquiredon21March2000coveringthenorthwesternpartofYunnanProvincehasbeendigitallyprocessedusingERMappersoftware.Thisarticleaimstoproducelineamentdensitymapthatpredictsfavorablezonesforhydrothermalmineraloccurrencesandquantifyspatialassociationsbetweentheknownhydrothermalmineraldeposits.Intheprocessoflineamentextractionanumberofimageprocessingtechniqueswereapplied.TheextractedlineamentswereimportedintoMapGISsoftwareandasuitablegridof100m×100mwaschosen.TheKrigingmethodwasusedtocreatethelineamentdensitymapofthearea.Theresultsshowthatremotesensingdatacouldbeusefultoextractthelineamentsinthearea.Theselineamentsarecloselycorrelatedwiththefaultsobtainedthroughothergeologicalinvestigationmethods.Oncomparingwithfielddatathelineament-densitymapidentifiestwoimportanthighprospectivezones,wherelarge-scaledepositsarealreadyexisting.Inadditionthemaphighlightsunrecognizedtargetareasthatrequirefollowupinvestigation.
2007, 18(2)
Abstract:
Threekindsoftetrapod-likeZnOnanostructureshavebeensynthesizedsimultaneouslyviapureZnchemicalvapordepositiononsiliconwaferswith(111)orientation(Si(111))at920℃.X-raydiffractionindicatesthatthenanotetrapodsareofwurtzitestructure.Themorphologyandthemicrostructureofthenanotetrapodsareinvestigatedbythescanningelectronmicroscopy.Selectedareaelectrondiffractionshowsthegrowthdirection,andenergydispersiveX-rayspectroscopyrevealstheatomiccompositionratioofZn/O.Thegrowthprocessisbrieflydiscussed.Theopticalpropertyoftheproductswasalsorecordedbymeansofphotoluminescencespectroscopy.
Threekindsoftetrapod-likeZnOnanostructureshavebeensynthesizedsimultaneouslyviapureZnchemicalvapordepositiononsiliconwaferswith(111)orientation(Si(111))at920℃.X-raydiffractionindicatesthatthenanotetrapodsareofwurtzitestructure.Themorphologyandthemicrostructureofthenanotetrapodsareinvestigatedbythescanningelectronmicroscopy.Selectedareaelectrondiffractionshowsthegrowthdirection,andenergydispersiveX-rayspectroscopyrevealstheatomiccompositionratioofZn/O.Thegrowthprocessisbrieflydiscussed.Theopticalpropertyoftheproductswasalsorecordedbymeansofphotoluminescencespectroscopy.
2007, 18(2)
Abstract:
Poly(n-octylacrylate)withuniformpolystyrenegrafts(POA-g-PS)wasobtainedbyradicalcopolymerizationofn-octylacrylate(OA)withPSmacromer,insolution.Thereactivityratioandeffectsofcopolymerizationconditionsongraftingefficiencywerestudied.Thecrudeproductswerepurifiedbyextractionwithcyclohexaneandn-butanolsuccessively.POA-g-PSexhibitedaverygoodcompatibilizingeffectontheacrylicrubber/polystyreneblends.2%–3%ofthegraftcopolymerwasenoughforenhancingthetensilestrengthoftheblends.DSCandSEMdemonstratedtheenhancementofcompatibilityinthepresenceofthegraftcopolymer.
Poly(n-octylacrylate)withuniformpolystyrenegrafts(POA-g-PS)wasobtainedbyradicalcopolymerizationofn-octylacrylate(OA)withPSmacromer,insolution.Thereactivityratioandeffectsofcopolymerizationconditionsongraftingefficiencywerestudied.Thecrudeproductswerepurifiedbyextractionwithcyclohexaneandn-butanolsuccessively.POA-g-PSexhibitedaverygoodcompatibilizingeffectontheacrylicrubber/polystyreneblends.2%–3%ofthegraftcopolymerwasenoughforenhancingthetensilestrengthoftheblends.DSCandSEMdemonstratedtheenhancementofcompatibilityinthepresenceofthegraftcopolymer.
2007, 18(2)
Abstract:
AlloyedternaryCdSxSe1-xnanorodshavebeensynthesizedbythethermaltreatmentofCd2+-dispersedpolyethyleneglycol2000gel(PEG2000)withethylenediaminesolutionofsulfurandseleniuminasealedsystemat180℃for24h,inwhichtheratioofStoSeinthenanorodswascontrolledbyadjustingtherelativeamountsofthestartingmaterials.Basedontheresultsofexperiments,itisfoundthattheCdSxSe1-xnanorodswerealsosynthesizedwithseveralsulfursourcesbythemethod.X-raydiffraction(XRD)showsthatthealloyedternaryCdSxSe1-xnanorodsarehighlycrystalline,andnootherphasewasobservedinthesenanorods.
AlloyedternaryCdSxSe1-xnanorodshavebeensynthesizedbythethermaltreatmentofCd2+-dispersedpolyethyleneglycol2000gel(PEG2000)withethylenediaminesolutionofsulfurandseleniuminasealedsystemat180℃for24h,inwhichtheratioofStoSeinthenanorodswascontrolledbyadjustingtherelativeamountsofthestartingmaterials.Basedontheresultsofexperiments,itisfoundthattheCdSxSe1-xnanorodswerealsosynthesizedwithseveralsulfursourcesbythemethod.X-raydiffraction(XRD)showsthatthealloyedternaryCdSxSe1-xnanorodsarehighlycrystalline,andnootherphasewasobservedinthesenanorods.
2007, 18(2)
Abstract:
Leachingstudiesoflow-gradepyrolusite,containing11.84%Mnwithhighsilicon,werecarriedoutusingsodiumsulfiteasareductantinammoniumsulfatemedium.Variousprocessparametersincludingtemperature,leachingtime,solid-liquidratio,quantityofammoniumsulfate,aswellastheamountofreducingagentwerestudiedindetail.Themanganeseextractionyieldwastheresponseoftheprocess.Temperatureandreagentconcentrationexertedthemostimportantpositiveeffectonthemanganeseextraction.Theoptimizedconditionsshowedthatwhentheamountofreducingagentwasastoichonmetricamount,over90%manganeseextractionandthelowestimpuritieswereachieved,theamountofheavymetalimpuritiesinthemanganeseleachingliquidwaslessthan5mg/L,andalmostnoironandaluminumwereextractedin3mol/Lammoniumsulfateconcentrationat100℃in45min.
Leachingstudiesoflow-gradepyrolusite,containing11.84%Mnwithhighsilicon,werecarriedoutusingsodiumsulfiteasareductantinammoniumsulfatemedium.Variousprocessparametersincludingtemperature,leachingtime,solid-liquidratio,quantityofammoniumsulfate,aswellastheamountofreducingagentwerestudiedindetail.Themanganeseextractionyieldwastheresponseoftheprocess.Temperatureandreagentconcentrationexertedthemostimportantpositiveeffectonthemanganeseextraction.Theoptimizedconditionsshowedthatwhentheamountofreducingagentwasastoichonmetricamount,over90%manganeseextractionandthelowestimpuritieswereachieved,theamountofheavymetalimpuritiesinthemanganeseleachingliquidwaslessthan5mg/L,andalmostnoironandaluminumwereextractedin3mol/Lammoniumsulfateconcentrationat100℃in45min.
2007, 18(2)
Abstract:
ThesizesandmorphologiesofhexagonalphaseZnOcrystalsweresuccessfullycontrolledbyahydrothermalprocessinthepresenceofpoly(acrylicacid)(PAA).ThedosageofNaOHinthisreactionsystemprovedtobecrucialinthegrowthprocess.Withtheincreaseofdosagefrom0.7gto3.0g,themorphologiesoftheZnOcrystalschangedfromnanoplatestomicrorods.Theiropticalpropertieswerealsoinvestigated.
ThesizesandmorphologiesofhexagonalphaseZnOcrystalsweresuccessfullycontrolledbyahydrothermalprocessinthepresenceofpoly(acrylicacid)(PAA).ThedosageofNaOHinthisreactionsystemprovedtobecrucialinthegrowthprocess.Withtheincreaseofdosagefrom0.7gto3.0g,themorphologiesoftheZnOcrystalschangedfromnanoplatestomicrorods.Theiropticalpropertieswerealsoinvestigated.
2007, 18(2)
Abstract:
ThenanometerMnO2hasoutstandingelectrochemicalperformancetheoretically,butitisnotsuitableforactualutilization,whichmayresultincapacitydecreaseandresourcewaste.Inthisstudywehaveutilizedthecharacterizationsofthenanometermaterial,synthesizedatypeofnanometerα-MnO2throughKMnO4andKNO3withhydrothermalmethod,andmixedtheproductsintomicronelectrolyticmanganesedioxide(EMD)toenhancetheelectrochemicalperformanceoftheelectrode.Thecyclicvoltammogramandgalvanostaticaldischargemeasurementsofthesampleswereinvestigated.Itisfoundthatthe50%nanometerMnO2mixedelectrodehasthebestelectrochemicalperformance.TheelectrochemicalperformanceimprovementmechanismofthesamplenanometerMnO2mixedintomicronEMDwasdiscussed.Withtheexistenceofelectrolyte,thenanometerMnO2particlesfilledintotheinterspacesofthemicronEMDparticles,themassandchargetransferconditionsoftheelectrodereactionwereimproved,andtheelectrodepolarizationwasdiminished.
ThenanometerMnO2hasoutstandingelectrochemicalperformancetheoretically,butitisnotsuitableforactualutilization,whichmayresultincapacitydecreaseandresourcewaste.Inthisstudywehaveutilizedthecharacterizationsofthenanometermaterial,synthesizedatypeofnanometerα-MnO2throughKMnO4andKNO3withhydrothermalmethod,andmixedtheproductsintomicronelectrolyticmanganesedioxide(EMD)toenhancetheelectrochemicalperformanceoftheelectrode.Thecyclicvoltammogramandgalvanostaticaldischargemeasurementsofthesampleswereinvestigated.Itisfoundthatthe50%nanometerMnO2mixedelectrodehasthebestelectrochemicalperformance.TheelectrochemicalperformanceimprovementmechanismofthesamplenanometerMnO2mixedintomicronEMDwasdiscussed.Withtheexistenceofelectrolyte,thenanometerMnO2particlesfilledintotheinterspacesofthemicronEMDparticles,themassandchargetransferconditionsoftheelectrodereactionwereimproved,andtheelectrodepolarizationwasdiminished.
2007, 18(2)
Abstract:
ToanalyzethegenesisofSrisotopesingroundwaterofHebeiplain,time-accumulativeeffectof87Sr/86Srratiowasstudied.Itisshownthat87Sr/86Srratioincreaseswiththeincreasingageanddepthofgroundwaterandhasapositivecorrelationto4Heexcandanegativecorrelationtoδ18OandδD.Thegroundwaterisdividedintothreegroupstodiscusstherelationbetween87Sr/86SrratioandSr2+content:①moderateSr2＋contentandhigher87Sr/86Srratio(waterI);②lowerSr2＋contentandhigher87Sr/86Srratio(waterII);and③higherSr2＋contentandlower87Sr/86Srratio(waterIII),thatishotwater.Onthebasisofintegratedanalysis,itwasconsideredthat①theradiogenicSrintheQuaternarygroundwater(Q4–Q1)originatesfromweatheringofsilicaterichinNaandRb,mainlyfromplagioclase;②theradiogenicSrofhotwaterinHuanghuaportisattributedtocarbonatedissolution,withlower87Sr/86SrratioandhigherSr/Naratio;③therechargeareaislaterallyrechargedbythegroundwaterflowingthroughigneousandmetamorphicrocks,withmoderate87Sr/86Srratio.However,theformationmechanismofSrisotopesinTertiarygroundwaterneedsfurtherstudies.
ToanalyzethegenesisofSrisotopesingroundwaterofHebeiplain,time-accumulativeeffectof87Sr/86Srratiowasstudied.Itisshownthat87Sr/86Srratioincreaseswiththeincreasingageanddepthofgroundwaterandhasapositivecorrelationto4Heexcandanegativecorrelationtoδ18OandδD.Thegroundwaterisdividedintothreegroupstodiscusstherelationbetween87Sr/86SrratioandSr2+content:①moderateSr2＋contentandhigher87Sr/86Srratio(waterI);②lowerSr2＋contentandhigher87Sr/86Srratio(waterII);and③higherSr2＋contentandlower87Sr/86Srratio(waterIII),thatishotwater.Onthebasisofintegratedanalysis,itwasconsideredthat①theradiogenicSrintheQuaternarygroundwater(Q4–Q1)originatesfromweatheringofsilicaterichinNaandRb,mainlyfromplagioclase;②theradiogenicSrofhotwaterinHuanghuaportisattributedtocarbonatedissolution,withlower87Sr/86SrratioandhigherSr/Naratio;③therechargeareaislaterallyrechargedbythegroundwaterflowingthroughigneousandmetamorphicrocks,withmoderate87Sr/86Srratio.However,theformationmechanismofSrisotopesinTertiarygroundwaterneedsfurtherstudies.
2007, 18(2)
Abstract:
Onthebasisoftheone-dimensioninfiniteelementtheory,thecoordinatetranslationandshapefunctionof3Dpoint-radiate8-nodeand4-nodeinfiniteelementsarederived.Theyarecoupledwith20-nodeand8-nodefiniteelementstocomputethecompressiondistortionoftheprestressedanchoragesegment.Theresultsindicatethatwhentheprestressedforceactsontheanchorageheadandsegment,thestressesandthedisplacementsintherockaroundtheanchorageheadandsegmentconcentrateonthezonecenterwiththeanchoraxis,andtheydecreasewithexponentialforms.Therefore,thestressesandthedisplacementspindlesareformed.Thecalculatingresultsoftheinfiniteelementareclosetothetheoreticalresults.Thisindicatesthemethodisright.Thisarticleintroducesanewwaytostudythemechanismofprestressedanchors.Theobtainedresultshaveanimportantroleintheresearchoftheanchormechanismandengineeringapplication.
Onthebasisoftheone-dimensioninfiniteelementtheory,thecoordinatetranslationandshapefunctionof3Dpoint-radiate8-nodeand4-nodeinfiniteelementsarederived.Theyarecoupledwith20-nodeand8-nodefiniteelementstocomputethecompressiondistortionoftheprestressedanchoragesegment.Theresultsindicatethatwhentheprestressedforceactsontheanchorageheadandsegment,thestressesandthedisplacementsintherockaroundtheanchorageheadandsegmentconcentrateonthezonecenterwiththeanchoraxis,andtheydecreasewithexponentialforms.Therefore,thestressesandthedisplacementspindlesareformed.Thecalculatingresultsoftheinfiniteelementareclosetothetheoreticalresults.Thisindicatesthemethodisright.Thisarticleintroducesanewwaytostudythemechanismofprestressedanchors.Theobtainedresultshaveanimportantroleintheresearchoftheanchormechanismandengineeringapplication.
