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2006 Vol. 17, No. 2

Display Method:
Further Study on Geochemical Characteristics and Genesis of the Boninitic Rocks from Bikou Group, Northern Yangtze Plate
Li Yongfei Lai Shaocong Qin Jiangfeng
2006, 8(2)
Abstract:
Compared with the major and trace elements of typical boninite, the metabasalts collected from the Nanfanba-Miaowanli region in the Bikou block could be treated as boninite characterized by low-Si, low-Ti, low-P, high-Mg# and high Al2O3/TiO2, consistent with geochemical features of boninite. The normal mid-ocean ridge basalt (N-MORB) normalized spider diagram displays fairly depleted high field strong elements (HFSE) (Zr, Y, Ti). Enriched refractory elements (Cr, Co, Ni) as well as light rare earth elements (LREE)-depleted chondrite-normalized REE distribution patterns suggest the boninitic magmas are derived from an extremely depleted mantle wedge in the presence of a hydrous fluid, meanwhile signifying the source region had previously undergone a high degree partial melting process yielding primary magmas with enriched large ion lithophile elements (LILE). In addition, almost all the samples in the Nb-Zr-Y and Ti-Zr-Y discrimination diagrams were plotted in the island arc basalt (IAB) field. Coupled with the island arc tholeiitic (IAT) basalt in the study region, therefore, the geochemical characteristics of the studied rocks indicate the meta-basalts probably occurred in a fore-arc subduction setting. This conclusion may be of great significance for the further study of the tectonic background of the Bikou volcanism.
Preliminary Study on the PGE Geochemistry of the Permian Basalts in the Jinping Area
Nian Hong, Shen Wei, Zhang Xueshu
2006, 8(2)
Abstract:
TodiscloseandstudythemagmagenesisofthePermianbasaltsintheJinpingarea,thePGEandAucontentsofthePermianbasaltsintheJinpingareawereassayedbyuseoftheICP-MSmethod.ThePGEdatashowrelativelystrongdifferentiationofbasalticmagmaincomparisonwiththeprimitivemantle.Theprimitivemantle-normalizedpatternisaleft-dippingcurveofthePd-Ptenrichedtype.ThePd/IrratiosofthePGEofthePermianbasaltsintheJinpingareaarehigherthanthoseoftheprimitivemantleandtheupperprimitivemantleandthechondritemeteorite.ThePd/IrratiosexhibitgreatsimilaritywiththatoftheEmeishanbasaltsasawholesuggestingasimilarmaterialsource.Itisconcludedthattheyarederivedfromthebasalticmagmaoftheuppermantlesourcewithalowermeltingdegree,whichsharesthesimilarmagmamaterialsourcewiththeEmeishanPermianbasaltsasawhole.
Sedimentary Characteristics and Reservoir Prediction of Paleogene in the East Part of Kuqa Foreland Basin
Yan Detian, Wang Hua, Wang Jiahao, Wang Qingchen
2006, 8(2)
Abstract:
sedimentary systems are developed in the area: an oxidative salty wide shallow lacustrine system, a fan delta system and an evaporitic bordersea system. (2) The configuration and evolution of the depositional systems of the Paleogene in the Kuqa foreland basin were predominantly determined by foreland tectonism. Vertically, the Paleogene sedimentary sequence can be divided into three parts: the lower, middle and upper depositional system tracts. The lower and upper tracts commonly consist of progradational or aggradational sequences, while the middle part is usually comprised of a set of aggradational to transgressive third-order sequences. Laterally, the sedimentary systems in the east part of the Kuqa foreland basin spread from east to west as a whole, and the sedimentary facies obviously vary from south to north. The sand bodies of the delta front facies are excellent gas reservoirs, characterized by rather thick, extensive and continuous distribution, high porosity and permeability, and just a few barrier beds.
Evaluation of Two Absolute Radiometric Normalization Algorithms for Pre-processing of Landsat Imagery
Xu Hanqiu
2006, 8(2)
Abstract:
Inordertoevaluateradiometricnormalizationtechniques,twoimagenormalizationalgorithmsforabsoluteradiometriccorrectionofLandsatimagerywerequantitativelycomparedinthispaper,whicharetheIlluminationCorrectionModelproposedbyMarkhamandIrishandtheIlluminationandAtmosphericCorrectionModeldevelopedbytheRemoteSensingandGISLaboratoryoftheUtahStateUniversity.Relativenoise,correlationcoefficientandslopevaluewereusedasthecriteriafortheevaluationandcomparison,whichwerederivedfrompseudo-invariantfeaturesidentifiedfrommultitemporalLandsatimagepairsofXiamenandFuzhouareas,bothlocatedintheeasternFujianProvinceofChina.Comparedwiththeunnormalizedimage,theradiometricdifferencesbetweenthenormalizedmultitemporalimagesweresignificantlyreducedwhentheseasonsofmultitemporalimagesweredifferent.However,therewasnosignificantdifferencebetweenthenormalizedandunnormalizedimageswithasimilarseasonalcondition.Furthermore,thecorrectionresultsoftwoalgorithmsaresimilarwhentheimagesarerelativelyclearwithauniformatmosphericcondition.Therefore,theradiometricnormalizationproceduresshouldbecarriedoutifthemultitemporalimageshaveasignificantseasonaldifference.
Classification and Extraction of Urban Land-Use Information from High-Resolution Image Based on Object Multi-features
Kong Chunfang, Xu Kai, Wu Chonglong
2006, 8(2)
Abstract:
Urbanlandprovidesasuitablelocationforvariouseconomicactivitieswhichaffectthedevelopmentofsurroundingareas.Withrapidindustrializationandurbanization,thecontradictionsinland-usebecomemorenoticeable.Urbanadministratorsanddecision-makersseekmodernmethodsandtechnologytoprovideinformationsupportforurbangrowth.Recently,withthefastdevelopmentofhigh-resolutionsensortechnology,morerelevantdatacanbeobtained,whichisanadvantageinstudyingthesustainabledevelopmentofurbanland-use.However,thesedataareonlyinformationsourcesandareamixtureof“information”and“noise”.Processing,analysisandinformationextractionfromremotesensingdataisnecessarytoprovideusefulinformation.Thispaperextractsurbanland-useinformationfromahigh-resolutionimagebyusingthemulti-featureinformationoftheimageobjects,andadoptsanobject-orientedimageanalysisapproachandmulti-scaleimagesegmentationtechnology.Aclassificationandextractionmodelissetupbasedonthemulti-featuresoftheimageobjects,inordertocontributetoinformationforreasonableplanningandeffectivemanagement.Thisnewimageanalysisapproachoffersasatisfactorysolutionforextractinginformationquicklyandefficiently.
Landslides at Qingjiang River in the Downstream Area of Shuibuya Dam Site, China
Kallen D, Xiang Wei, Ehret D, Rohn J
2006, 8(2)
Abstract:
ToenhancethegeneralknowledgeoflandslidesinChina,theDAAD(GermanAcademicExchangeService)isfinancinganinvestigativeproject.Aspartofthisproject,attheQingjiangRiver,a10km2areadownstreamoftheShuibuyadamsitewasgeologicallyandgeotechnicallymappedtogatherinformationconcerninglandslidesandtheircorrelationtolithology,slopeanglesandtexture.Thegeologicalmappingcontainedthecharacterizationofthelithologicalunits.Thecharacterizationoftheshapeoflandslidesandtheclassificationofrocksintounitswithsimilargeotechnicalbehavioriscontainedinthegeotechnicalmap.SamplesweretakenandinvestigatedusingX-raydiffractiontoidentifytheclaymineralsandgeotechnicalteststodeterminetheeffectiveshearangleandcohesionofrocksandsoils.Geotechnicalmappingshowedacloseconnectionbetweenlithology,slopeangleandtextureconcerningtheoccurrenceoflandslides.MostlandslidesoccuronthenorthernbankoftheQingjiangRiverwherethedipangleofthebeddingisnearlyparalleltotheslope,resultinginpotentialandeffectiveslideplanes.Onthesouthernbankonlysporadicandsmalllandslidesoccurbecausethebeddingisantipodaltotheslopeangle.Thispilotworkisabaseforfurtherandmoredetailedinvestigationsinthisarea.
Modeling the 3D Terrain Effect on MT by the Boundary Element Method
Ruan Baiyao, Xu Shizhe, Xu Zhifeng
2006, 8(2)
Abstract:
Anumericalmethodisputforwardinthispaper,usingtheboundaryelementmethod(BEM)tomodel3Dterraineffectsonmagnetotelluric(MT)surveys.Usingvectorintegraltheoryandelectromagneticfieldboundaryconditions,theboundaryproblemoftwoelectromagneticfieldsintheupperhalfspace(air)andlowerhalfspace(earthmedium)wastransformedintotwovectorintegralequationsjustrelatedtothetopography:onemagneticequationforcomputingthemagneticfieldandtheotherelectricalequationforcomputingtheelectricalfield.Thetopographyintegralisdecomposedintoaseriesofintegralsinatriangleelement.Fortheintegralinatriangleelement,wesupposethattheelectromagneticfieldinitisthestackoftheelectromagneticfieldinthehomogeneousearthandthetopographyresponsewhichisaconstant;sothecomputationbecomessimple,convenientandhighlyaccurate.Bydecompositionandcomputation,eachvectorintegralequationcanbecalculatedbysolvingthreelinearequationsthatarerelatedtothethreeCartesiandirections.ThematrixoftheselinearequationsisdiagonallydominantandcanbesolvedusingtheSymmetricSuccessiveOver-Relaxation(SSOR)method.TheapparentresistivitycurveofMTontwo3DterrainscalculatedbyBEMisshowninthispaper.
Interpreting Dual Laterolog Fracture Data in Fractured Carbonate Formation
Deng Shaogui Wang Xiaochang Zou Dejiang
2006, 8(2)
Abstract:
Theestimationoffracturesiskeytoevaluatingfracturedcarbonatereservoirs.Itisdifficulttoevaluatethiskindofreservoirbecauseofitsheterogeneouslydistributedfracturesandanisotropy.Athree-dimensionalnumericalmodelwasusedtosimulatetheresponsesoftheduallaterolog(DLL)inafracturedformationbasedonamacro-isotropicanisotropicmodel.Accordingly,afastfracture-computingmethodwasdeveloped.First,theapparentconductivityoftheDLLislinearlyrelatedtotheporosityofthefractureandtheconductivityofporefluid.Second,theamplitudedifferenceofthedeepandshallowapparentresistivitylogsismainlydependentonthedipangleofthefracture.ThentheresponseoftheDLLtoaformationwithdipanglefracturesisapproximatelydepictedasafunctionofthebulkresistivityoftherock,theporosityofthefracturesandtheconductivityoffracturefluid.Thisfunctioncanbeusedtocomputetheporosityoffracturequickly.TheactualdatashowthatthefractureparametersdeterminedbytheDLLcloselycoincidewiththeformationmicroimagerlog.
Logging Data High-Resolution Sequence Stratigraphy
Li Hongqi, Xie Yinfu, Sun Zhongchun, Luo Xingping
2006, 8(2)
Abstract:
Therecognitionandcontrastofbedsetsinparasequenceisdifficultinterrestrialbasinhigh-resolutionsequencestratigraphy.Thisstudyputsforwardnewmethodsfortheboundaryidentificationandcontrastofbedsetsonthebasisofmanifoldloggingdata.Theformationofcalcareousinterbeds,shaleresistivitydifferencesandtherelationofreservoirresistivitytoaltitudeareconsideredonthebasisoflogcurvemorphologicalcharacteristics,coreobservation,castthinsection,X-raydiffractionandscanningelectronmicroscopy.Theresultsshowthatthethicknessofcalcareousinterbedsisbetween0.5mand2m,increasingonweatheringcrustsandfaults.Calcareousinterbedsoccuratthebottomofadistributarychannelandthetopofadistributarymouthbar.Lowerresistivityshale(4-5Ω?m)andhigherresistivityshale(>10Ω?m)reflectdifferencesinsedimentfountainorsedimentmicrofacies.Reservoirresistivityincreaseswithaltitude.Calcareousinterbedsmaybeasymbolofrecognitionfortheboundaryofbedsetsandisochronouscontrastbedsets,andshaleresistivitydifferencesmayconfirmthestackrelationandconnectivityofbedsets.Basedonthis,ahigh-resolutionchronostratigraphicframeworkofXi-1segmentinShinanarea,Junggarbasinispresented,andtheconnectivityofbedsetsandoil-watercontactisconfirmed.Inthischronostratigraphicframework,thegrowthorder,stackmodeandspaceshapeofbedsetsarequalitativelyandquantitativelydescribed.
Determination and Application of the Sharp Degradation Point of Concrete under Environmental Actions
Zhou Xiwu Wei Jun Luo Xin
2006, 8(2)
Abstract:
Tostudythesharpdegradationpointofconcretedurability,damageatthecharacteristicfailurepointunderloadswasfirstobtainedbytheapplicationoftheone-dimensionalstress-strainrelationshipofSaenz.Thenbasedontheprinciplethatdamageatthecharacteristicfailurepointsubjectedtoloadsisequaltothedamageinaccordancewiththecharacteristicpointofconcretedurabilityunderenvironmentalactions,thesharpdegradationpointofconcretedurabilitywasdetermined.Theresultswereappliedtothecaseofconcretesufferingfreeze-thawactions.Goodaccordancebetweenexperimentalresultsandforecastedresultsindicatedthereliabilityofthismethod.
Numerical and Experimental Study of Free Vibration Characteristics of a Cable-Stayed Bridge
Zi Jianmin Wang Yuanhan Zhu Hongping
2006, 8(2)
Abstract:
Themainaimofthisstudyistounderstandthedynamicbehaviorofacable-stayedbridge,usingbothnumericalandexperimentalanalysis.Athree-dimensionalfiniteelementmodelforthebridgewasdevelopedforthefreevibrationanalysisandtheambientvibrationpropertiesofthebridgeweredeterminedthroughfieldtesting.Theexperimentalandnumericalresultsofnaturalfrequenciesandtheassociatedmodeshapeswerecompared,andthehighaccuracybetweenthemshowsthatthe3Dmodeliscapableofapproximatelyrepresentingthedynamicbehaviorofthebridgeandtheuseofambientvibrationsurvivesinfuturetestingofthebridge.Thesedynamiccharacteristicscanbeusedasthebasisforupdatingthefiniteelementmodelandalsoforglobaldamagedetection.
Structural Geochemical Study of the Yuxi Fold-Thrust Belt in the Southern North China Plate
Li Wenyong, Xia Bin, Li Dongxu
2006, 8(2)
Abstract:
TheYuxifold-thrustfracturebeltispartofthegiganticfold-thrustfracturebeltthatextendsNWinthesouthernNorthChinaplate.ThecontentsofmajorelementsoftectoniteswereanalyzedbyICP-AES.Theanalysisofchemicalcompositionsandnewstressmineralsindicates:extendingfromthesurroundingcountryrockstothecenterofthefracturebelt,theFe2O3contentgraduallyincreaseswhiletheFeOcontentgraduallydecreases;regularincrease,decreaseorpeakchangesareshownforchemicalcompositionslikeSiO2,Al2O3,Fe2O3,MgO,CaO,FeO,lossonignition,TiO2,K2O,Na2O,etc..Newstressmineralsaredevelopedforthesouthbranchandfewforthenorthbranch.Thecharacteristicsofchemicalcompositionsandnewstressmineralsofthethrustfracturedemonstratethatthefracturebelthasundergoneaprocessfromaclosedreducingenvironmentalsystemtoarelativelyopen,oxidizingenvironmentalsystem,andcompressivefractureshaveresultedfromcompressioninthelatestagesofevolution,andthedynamothermalmetamorphismandthrustingintensitiesaredifferentbetweenthesouthandnorthbranchesofthebelt,whichisstrongforthesouthbranchbutrelativelyweakforthenorthbranch.
Carbonate Diagenesis Controlled by Glacioeustatic Sea-Level Changes: A Case Study from the Carboniferous-Permian Boundary Section at Xikou, China
Zhang Haijun, Ding Lin, Wang Xunlian, Wang Lei
2006, 8(2)
Abstract:
Theplatform-faciescarbonaterocksoftheCarboniferous-PermianboundarystrataarewelldevelopedandoutcroppedinXikou,ZhenanCounty,ShaanxiProvince,China.ThecarbonatediagenesisintheCarboniferous-PermianboundarysectionatXikoucontainsmanyprocesseswithconspicuouseffects,includingmicritization,cementation,mechanicalandchemicalcompaction,neomorphism,anddissolution.Basedonmineralogicalcompositionandmicrofabrics,thediageneticenvironmentsaredistinguishedintomarine,nearsurfacemeteoricandburialenvironments.DetailedpetrographicalobservationofabundantthinsectionsintegratedwithpreviousstudiesonsequencestratigraphyrevealsthatthecarbonatediagenesisintheCarboniferous-Permianboundarysectionisrelatedtotherelativestratigraphicpositionoftherocksinthehigh-frequencycyclesandcontrolledbytheglacioeustaticsea-levelchanges.Therearedistinctivedifferencesindiageneticpatternsbetweenthelowertransgressivesequenceandtheupperregressivesequenceinacyclothem.Thediagenesisinthelowertransgressivesequenceismainlycharacterizedbypressuredissolutionandrecrystallizationofmudstoneandwackstoneinaburialenvironment,andthediagenesisintheupperregressivesequencebycementationandleachingoffreshwaterinameteoricenvironment.
Acyclic Alkanes in the Soil over Heshang Cave in Qingjiang, Hubei Province
Pu Yang, Huang Junhua, Huang Xianyu, Cui Jingwei, Hu Chaoyong
2006, 8(2)
Abstract:
Thereportsthatrelatetothebiomarkersfateandcharacteristicsofthemodernsoilinthekarstareaareverylacking.Byusinggaschromatographymassspectrometry(GC-MS),aseriesofbiomarkerswereidentifiedfromthesoilscollectedoverHeshangcaveinQingjiang,HubeiProvince.Thedistributionofn-alkanesismainlyfromC25toC33incarbonnumber,withamaximumatC31.Theyhaveastrongodd-over-evencarbonnumberpredominance.Thesecharacteristicsrepresentaninputmainlyfromhigherplants.Thelipidparameters,includingCPIh(carbonpreferenceindex),Rh/l(ratiooflower-tohigher-molecular-weighthomologues)andACL(averagechainlength),showcomparabletrendswithdepth,probablyreflectingvegetationchangeandmicrobialdegradation.Seriesofmonomethylalkanesanddiploptenearepresentintheextractableorganicmatter;theymightbederivedfromsoilmicrobes,cyanobacteriainparticular.
Age and General Characteristics of the Calimicrobialite near the Permian-Triassic Boundary in Chongyang, Hubei Province
Yang Hao, Zhang Suxin, Jiang Haishui, Wang Yongbiao
2006, 8(2)
Abstract:
ThecalimicrobialitesofChongyang,HubeiProvince,occurabovethemassextinctionlineintheLatePermianreeffacies.Belowtheboundaryarethespongereeflimestone,crinoidlimestoneandalgae-foraminiferbioclasticlimestoneoftheChangxingFormation.Thecalimicrobialitesaregenerallycomposedofmid-coarsegrainsandmicrolitecalcitewithastructureof“graniphyicfabric”andstromatolite.Thefossilsdiscoveredinthecalimicrobialitesincludeglobularcyanobacteria,ostracods,micro-gastropods,bivalves,fishteethandsomemicro-problematicalfossils.ConodontfossilsofHindeodusparvus,H.typicalis andH.latidentatuswerealsofoundinthecalimicrobialites.Accordingtotheconodonts,thecalimicrobialitesspannedthelatestPermianandearliestTriassicintheChongyangSection.TheupperpartabovethefirstoccurrenceofHindeodusparvusshouldbeattributedtotheearliestTriassic,andthelowerparttotheChanghsingian.Thesedimentarystructure,fossilcompositionandconodontzonationoftheChongyangcalimicrobialitescanbewellcorrelatedwiththecalimicrobialitesfoundinotherareasofSouthChina.