简介:TheYangtzeRiveristhelargestriverinChina,about6,300kilometreslongwithadrainageareaandpopulationaccountingfor18.8percentand33percentrespectivelyinChina.AimingatincreasingforestandvegetationareasonthemiddleandupperreachesoftheYangtzeRivertocontrolwaterandsoilerosion,theChinesegovernmentin1989decidedtocommenceaconstructionprojectfortheprotectionoftheforestsystemonthemiddleandupperreachesoftheYangtzeRiver.Theprojectcovers645counties(citiesanddistricts)in13provinces,
简介:<正>WiththerecentannouncementofthewaternowrisingbehindthemassiveThreeGorgesDam(SanxiaBa),IwasremindedofmyjourneydowntheLongRiveratatimewhenthedamwasunderconstructionandthemanycommunitiesalongtheriverstillexistedastheyhaddoneforhundredsofyears.TodaytheregionisattheheartofChina’smodernisationdriveandwillplayWiththerecentannouncementofthewaternowrisingbehindthemassiveThreeGorgesDam(SanxiaBa),IwasremindedofmyjourneydowntheLongRiveratatimewhenthedamwasunderconstructionandthemanycommunitiesalongtheriverstillexistedastheyhaddoneforhundredsofyears.TodaytheregionisattheheartofChina’smodernisationdriveandwillplay
简介:ThecharacteristicsoftheTriassicsequencesdevelopedintheLowerYangtzeareadisplaysomegreatchangesinbothenvironmentandclimate.Thechangeofenvironmentwasatransitionfrommarinetocontinentviaalternatingenvironments.Thechangeofclimatewasatransitionfromtropic(torrid)towarmandwetclimateviasubtropicdryclimate.Thetypevariationsofthesequenceswerefromthemarinesequencestothecontinentalsequences,correspondingtothechangesofenvironmentsandclimates.Sequence1isatypeⅡofsequenceofmixedclasticandcarbonatesediments;sequence2isatypeⅠofsequenceofcarbonateplatform;sequence3isatypeⅠofsequenceofcarbonatetidalflat-saltlagoon,sequence4isatypeⅡofsequenceoflacustrinewithinmarinelayers,andsequence5isasequenceoflacustrine-swamp.Thedevelopment,distributionandpreservationofthosesequencesrevealthetectoniccontrolsandtheirchangesinthebackground.ThecollisionbetweentheYangtzeplateandtheNorthChinaplatewasagreatgeologicaleventinthegeologicalhistory,butthetimingofthecollisionisstilldisputed.However,thecharacteristicsofTriassicsequencestratigraphyandsealevelchangesintheLowerYangtzearearespondedtothiscoliision.ThecollisionstartedatthebeginningofmiddleTriassicandthegreatregressionintheLowerYangtzeareastarted22Maearlierthanthoseintheworld.Thetectonicconditionsoccurredbeforeandduringthecollisioncontrolledthedevelopmentofsequencesandtypechanges.
简介:Theexploitablepotentialofhydropowerresourcesinthe1,800,000km~2Yangtzebasinis197GW,correspondingtoanannualelectricitygenerationof1030TWh,whiletheupperYangtzeupstreamofthecityYichangwithdrainageareaof1,000,000km~2possessesanexploitablepotentialofhydropowerresourcesof170GWor85%ofwhatisinthewholeYangtzebasin,asriverchannelsofthemainstemandtributariesinuppeYangtzepassthroughhighmountains,plateausandhills.
简介:ThehydrodynamicandthesedimenttransportpatternswithintheestuaryoftheYangtzeRiverarecomplexbecauseofinteractionoffluvialandthetidalforces,dependingonfreshwaterdischargeandtidalrange.Basedonthedatameasuredinrecentyears,thispaperdiscussesthecharacteristicsofflowandsedimentmovementintheYangtzeRiverEstuaryandtheirinfluencesontheevolutionoftheestuary.
简介:Theso-called“Yangtze-type”copperdepositsinclude:(1)Cu-bearingmassivepyritebed,(2)Cu-bearingskarnandmagnetite-typeoredeposits,withreplacementCu-vein-typedepositsnearthemetasomaticzone,and(3)mineralizedintrusivebodiesandbrecciapipes,someofwhichareknownasporphyrycopperores(e.g.Chengmenshan).ThistypeoforedepositsisatypicalexampletoverifythepolygenesisofinostofthedepositsinChina,ashasbeenpromotedbyProf.TuGuangchiinviewofthepolycyclicdevelopmentofthegeologicalhistoryinChina.Thispaperiscon-cemedwithonesub-typeofsuchdeposits.
简介:BasedonthebiogeochemicalstudiesonnutrientelementsintheChangjiangestuary,themainresultsandrecentprogressesarereviewedinthispaper,suchasthenutrientfluxesintothesea,themixingbehaviors,thedistributioncharacteristicsandtransportationaswellasthebiogeochemicalbehaviorsofnutrientsintheplumefrontalregion.Theexploringdirectionsandresearchemphasesinthefutureareproposed.
简介:GreendevelopmentisthekeynoteofYangtzeRiverEconomicBelt.Itmustinsistonecologypreferentialandgreendevelopmentwhichisnotonlyrespectationofnaturallawsbutalsotheeconomiclawsandsociallaws.ThearticleusesSWOTanalyticmethodtoanalyzetheinternalandexternalsurroundingsofthegreendevelopmentofYangtzeRiverEconomicBeltonthebasisofgettingaclearunderstandingofitspresentdevelopingstatus.BasedonthisthearticleputsforwardthestrategypatternandpathselectionofgreendevelopmentofYangtzeRiverEconomicBelt.
简介:ThecircumfluencearoundtheJiuduanSandbankisthoroughlystudiedbymeansoftheprinci-pleofleastresistanceinfluiddynamics.ThediversionratiooftheNorthChannelfor1998iscalculated,whichisalmostthesameasthefieldsurveydata.ThenormalandminimumdiversionratiosoftheNorthChannelafterstagesⅠ,ⅡandⅢregulationworksaswellasthefuturephaseareobtained.Thenumeri-calresultsandpredictedvalueareaccurate.
简介:-ThispaperdescribesaradioactivetracerexperimentcarriedoutatthelandwardspoilsiteoftheNorthPassageintheYangtzeEstuaryinJune,1991.Scandium-46wasselectedasthetracer,thetotalactivityreleasedwas179.45GBqandtheamountoftheSandium-46glasswas495g.Thepurposeoftheexperimentwastodeterminethesedimentmovementdirection,path,velocityandtransportrate,andtherefore,toprovidedirectevidenceforusingthelandwardspoilsiteinthefuture.Theexperimentalresultsshowedthatthesedimentmovementwasgovernedbytheebbtidecurrentduringtheperiodofmeanandneaptideswhentheradioactivetracerwasinjectedbothonthefloodandebbtides,andthesedimentmovedfromthereleasepointtothemiddleoftheNorthPassagenearnavigationbuoyNo.269.Thedirecitonofthesedimentmovementwas110°,theparticlevelocitywas758m/d,andthesedimenttransportrateperunitwidthwas47.8m3/md.
简介:MultistagesuperimposeddeformationhasbeendiscussedsystematicallybasedontheprogressofthestratigraphicsequencesofthenortheasternmarginofYangtzeBlock.Thenew-discoveredfirststagedeformationofthosesequencesoccurredfromthemiddleTriassictotheendofearlyJurassictogetherwithdevelopmentofregionalfolding,whichwasresultedfromthedeepdetachmentshearingtendingtowardNW-WNW.Thefoldsdiptoeastandfalldowntowardwest,andweresuperimposedbythemainstagefolding.Thereafter,aseriesoffoldsweredevelopedwithaxestrendingtowardnortheast.Consequentlynormalfoldsoccurredonthenormallimbswhileoverturnedfoldontheoverturnedlimbsduringthefirststagefolding.ThedetachmentorthrustwasformedfromlateJurassictoearlyCretaceous.DuetotheupliftingofDabieandtheWannanMountainsinthenorthandsouthsides,thebi-directionalthrustingbeltwasformedbygravityflowingfromtheMountainstowardthecenterofthebasinalongthenorthsideofXuanchengandsouthsideofGuichi.Thedeformationgeodynamicswasdiscussedsimplybasedonthenewlyrecognizedinformationaboutthetectonicevolution.
简介:Throughoneandhalfyearcontinuousin-situmeasurements,thedistributionsandvariationsofsurfaceozoneanditsprecursorsatatypicalmixedagriculturalandmetropolitanarea-Changshu,YangtzeDeltaregion,werestudied.Thepreliminaryanalysisontheconcentrationlevelsandvariationsofsurfaceozoneindicatedtheobviousseasonalanddiurnalcyclesduringtheexperiment.Thehourlyaveragedconcentrationsofsurfaceozonewerehigh,inabout17%oftotalvalidhoursthesurfaceozoneconcentrationexceeded50ppb,andin22daysthehourlyaveragedozoneconcentrationwasgreaterthan100ppb.Therewereabout40%ofthedaysinthatthedailymaximum8-hourozoneconcentrationwasgreaterthan50ppb.Thedayswithdailymaximum8-hourozoneconcentrationgreaterthan80ppbwereabout33daysthataccountedforabout8%oftheobservationaldays.Thevariationsof5-daymovingaveragedozoneconcentrationsdependedbothontheweatherconditionsandonthechangesofozoneinbackgroundatmosphere.Photochemicalprocesshadthesignificantimpactsonozoneproductions.
简介:长江三角洲(UA-YRD)上的城市的凝块在水,土地,生态的环境,地点和交通的方面有一些优点。依靠资源环境库和另外的优点,UA-YRD完成了大开发。基于索引系统和全面评估的模型,自从1978,纸计算UA-YRD的发展水平。从1978~2007,开发水平以0.0333的年度率逐年增加了的结果表演,和开发的进程能被划分成三个阶段,即低速度的开发舞台(19781991),快速的开发舞台(19912000),并且高速度的开发舞台(20002007)。速度分别地是0.0083,0.0356和0.0766。在30年的发展期间,外国经济活动在开发有最大的效果,由交通,工业经济活动和电信列在后面(有序)。另外,不同驱动力在不同阶段有不同效果。纸建议更多的注意应该对高速度的发展阶段和重要驱动力被给予驾驶它的发展。同时,资源和环境的限制不应该被忽视,长有效的机制需要被证实在UA发展,资源利用和环境保护之中支撑和谐开发。一些比较研究应该着急地被执行有效地支持并且支持UA的持续开发,特别向进化,驱动力和braking力量。