简介:UltrabasicrocksintheMianxian-LueyangophioliticmelangezoneincludeharzburgiteanddunitewhichexhibitLREEdepletionwithremarkablepositiveEuanomaly.ThediabasedikeswarmshowsLREEenrichmentbutslightlynegativeEuanomaly.MetamorphosedvolcanicrockscanbedividedintotwogroupsintermsoftheirREEgeochemistryandtraceelementratiosofTi/V,Th/Ta,Th/YbandTa/Yb.OneisthsMORB-typebasaltwithLREEdepletion,representingthefragmentsofoceaniccrustandimplyinganassociationoftheMORB-typeophioliteandanancientoceanbasinbetweentheQinlingandYangtzeplatesduringtheMiddlePaleozoic-EarlyMesozoicera.Theotercomprisestheisland-arcvolcanicrocksincludingtholeiiticbasaltandalargeamountofcalc-alkalineintermediate-acicvolcanicrock,whichcouldnotbethecomponentoftheancientoceaniccrustbuttheresultofmagmatismatthecontinentalmargin.ThisindicatesthattheMianxian-Lueyanglimitedoceanbasinhadundergoneawholeprocessofdevelopment,evolutionandvanishingfromDevonian-CretaceoustoPermian.AndtheQinlingareahadbeconeanindependentlithosphericmicroplate,onthesouthernsideofwhichtherewereexhibitedthetectoniccharacteristicsofactivecontinentalmarginsduringtheLatePaleozoic-EarlyMesozoic.Thatistosay.theQinlingcannotbesimplyconsideredasaresultofcollisionbetweentheYangtzeandNorthChinaplates.
简介:OurworkingareaissituatedtotheeastoftheBengbuantecliseonthesoutbeastmarginoftheNorthChinageodepression,knownaslateArcheozoicgranitc-green8tonetcrrian.ThelatitudinallincarclosedjSoclinalfoldsformedbytbelatcArcheozoicBengbugroupandthecrustalsurfacerocksoftheearlyProtcrozoicWuhegroup,togethcrwiththemidd
简介:在大陆中国的气候能在西北以及intercross地区在东南和西的区域被划分成季风区域,即,季风来自西南中国是面向的到上面的黄河,诺思中国,和东北中国的极北的边缘的活跃地区。在三个区域,干燥湿的气候变化直接在高原的北方方面上在西藏的高原和西的流动的东方方面上被连接到南方的季风流动的相互作用从对内部十的时间规模内部年度。在为最后一半的三个区域的气候可变性的一些基本特征世纪并且历史几百年在这篇论文被考察。在最后一半世纪,西的流动从Xinjiang在西的区域被发现到诺思中国和东北中国的北部分的与提高联系的夏天降水的一个增加的趋势。在另一方面,沿着长江的夏天降水的一个增加的趋势和沿着季风的夏天降水的一个减少的趋势极北的边缘的活跃地区在东亚与变弱的季风流动被联系。历史的文件在季风区域是广泛地分布式的因为几百年和自然气候代理在非季风区域被构造,当气候代理的二种类型能通常在季风上被发现极北的边缘的活跃地区时。在季风区域,干燥湿的变化中心从一个世纪在诺思中国,更低的长江,和华南之中被改变到另外一个。干燥或湿的异例是第一沿着季风观察了极北的边缘的活跃地区并且变对长江山谷和华南在向南方或向东南关于70年的时间规模。严重干旱事件沿着季风经验丰富极北的边缘的活跃地区在最后5个世纪期间。内部十的干燥湿的变化被自然代理在非季风区域上在几个区域为最后45个世纪描绘。一些问题例如在中国的在干燥湿的政体变化上的全球温暖的影响,在在东北中国的季风和西的流动之间的复杂相互作用,和中国的在整个所有的综合多代理分析,被建议。
简介:在在圣路易斯,的一条城市的溪流的水泥隧道衬里密苏里增加事件水贡献在泛滥期间,弄短搬运时间,并且由于hyporheicflowpaths的混乱在短、季节的timescales上放大geochemical可变性。详细分析浇同位素,主修并且跟踪元素,并且在situ浇为一个单个洪水事件的优秀数据表明baseflow贡献这条特别隧道从在哪儿变化的点下游地由8%仅仅320m升起对unlined排队水泥。然而,另外的自记水位计分离显示baseflow贡献是可变的并且能高得多(平均baseflow增加是16%)。流,显示更大的事件流动部分电的电导率(EC)和在衬里的活动范围的溶质集中是多达25%比的在山峰流动期间降低在unlined隧道。相反,在低流动,溪流EC和溶质期间,在衬里的活动范围的集中由于更多的限制流入更高是多达30%冲淡地下水。在更长的timescales上,EC,溶质集中,混浊,和细菌的负担下游地减少意味着增加的贡献冲淡baseflow。沿着在衬里的隧道的hyporheic地区的表面水和地下水的减少的连接增加城市的溪流的hydrologic和geochemical可变性。
简介:ThemicrostructuresoffaultrocksfromtheWasatchfaultzoneinUtah(USA)havebeenstudiedusingapolarizingmicroscope,ascanningelectronmicroscope(SEM)andanultrahigh-voltageelectronmicroscope(HVHM).Thisfaultzonemayberecognizedasoneawithlonghistoryofseismicactivityaccordingtothemicrostructuralcharacteristicssuchastype,deformationcharacteristics,meltingstructureandsurfacetexturesofthefaultrocks.However,themainfaultnowpresentseemsnottohavebeennoticeablyactivesincethelatePleistocene(Q3),asshownbytheeroded-surfacetextureonthequartzfragmentsinthefaultgouge.Meanwhile,thosefaultssupposedtobestronglyactiveinmoderntimesarebranchingfaultsmuchclosertothebasinsideandarecoveredbytheHolocenesedimentsinthebasin.
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简介:Upwellingcoastalsystemscanbeusedtounderstandhowdissolvedoxygenandbiologicalproductivitycontroltheaccumulationofredox-sensitivemetalsinmarinesediments.Thealuminium(Al),cadmium(Cd),iron(Fe),nickel(Ni),molybdenum(Mo),vanadium(V),totalorganiccarbon(TOC),totalnitrogen(TN)andtotalsulfur(TS)contentsinsurficialsedimentcollectedfromdifferentwaterdepths(30,70,and120m)inthreenorthernChileanbaysinfluencedbycoastalupwellingandoxygenminimumzones(OMZs)weremeasured.Principalcomponentanalysis(PCA),clusteranalysis,andSpearman'srankcorrelationwereusedtoidentifythemechanismsresponsiblefortheredox-sensitivemetalaccumulation.Thecontentofredox-sensitivemetalsandorganiccomponentsinsedimentincreasedwithincreasingwatercolumndepth,whereaslithogenicmetalsdecreased.IntheMejillonesdelSurandCalderabays,theenrichmentfactorsoftheredox-sensitivemetalsshowedenrichmentforallmetalswithdepth.TheCdandVenrichmentsaremainlytheproductofbiogenicflowtotheseabed,andtheMoandNienrichmentsareduetopreservationunderlowsubsurfaceoxygenconditions.Sulfatereductionisnotanimportantmechanismintheaccumulationofredox-sensitivemetalsinthesedimentofthethreebays.ThePCAshowedthatthebehaviorsoftheredox-sensitivemetalsandorganiccomponentsreflectdifferencesintheeffectsoftheOMZinsedimentalongthecoastofnorthernChile,withamoreintenseOMZinMejillonesdelSurbayandweakerOMZsinCalderaandInglesabays.However,thehighdegreeofenrichmentinredox-sensitivemetalsinCalderaBaycanbeattributedtotheintenseactivityoftheminingindustrynearthebay,asituationthatproducesgeochemicalbehaviorsimilartothatobservedinMejillonesdelSurBay.
简介:Fieldinvestigationhasrevealedthatthelarge-scaledextralstrike-slipmovementandtheassociatedtectonicdeformationalongtheRedRiverfaultzonehavethefollowingfeatures:geometrically,theRedRiverfaultzonecanbedividedintothreedeformationregions,namely,thenorth,centralandsouthregions.ThenorthregionliesontheeasternsideoftheNorthwestYunnanextensionaltaphrogenicbelt,whichischaracterizedbythe3setsofrift-depressionbasinsstrikingNNW,NNEandnearN-SsincethePliocenetime,andonitswesternsideistheLanping-YunlongcompressivedeformationbeltofthePaleogenetoNeogene;thedeformationinthecentralregionischaracterizedbydextralstrike-sliporshearing.TheeastYunnanMiocenecompressivedeformationbeltliesontheeasternsideofthefaultinthesouth,andtheTengtiaohetensilefaultdepressionbeltislocatedonitswest.Intermsoftectonicgeomorphology,theaforementioneddeformationisrepresentedbybasin-rangetectonicsinthenorth,linearfaultedvalley-basinsinthecentralpartandcompressive(ortensional)basinsinthesouth.Amongthem,thegreatvarianceinelevationoftheplanationsurfacesonbothsidesoftheCangshan-ErhaifaultsuggestsprominentnormalfaultingalongtheRedRiverfaultsincethePliocene.Fromtheviewpointofspatial-temporalevolution,themainactiveportionofthefaultwasthesouthernsegmentinthePaleogene-Miocene-Pliocene,whichisrepresentedby"tearing"fromsouthtonorth.ThemainactiveportionofthefaulthasmigratedtothenorthernsegmentsincethePliocene,especiallyinthelateQuaternary,whichischaracterizedbyextensionalslipfromnorthtosoutheast.ThesizeofthedeformationregionandthemagnitudeofdeformationshowthattheeasternplateoftheRedRiverfaulthasbeenanactiveplateoftherelativemovementofblocks.
简介:Sm-Ndisotopiccompositionsofeightlamprophyresamples,whichcomefromtheGezhengold-bearingshearzoneonwesternHainanIsland,aremeasured.TheSm-Ndisochronageis495.98±13.14Ma,(143Nd/144Nd)0=0.512094,εNd(t)rangesfrom+1.80to+2.00andTDMfrom982Mato1196Ma(average:1060Ma).Theauthorspointoutthatthewhole-rockSm-Ndisochronage(495.98±13.14Ma)reallyrepresentsthepetrogeneticageoflamprophyreandthetimeofmagmatismduringsubsequentsubduction.
简介:基于确定的数学模型和图形的解释,一个新方法,被用来在一由紫外线光谱技术生产混合很好计算单个地区的生产的贡献,被建立了。标准板用作为X轴作为Y轴和波长人工地提出的样品油的消光系数E被拉。从样品油的紫外分析导致混合的井的曲线被插入到标准板并且比较。在生产混合很好的每个单个地区的比例与接近人工地提出的样品油的曲线的曲线的比例是相同的。在井QHD32-6-3地里,例如并且用这个方法拿A22很好,一个单个地区的生产贡献被计算。Theresult证明Nm4地区是一个主要“贡献者”,Nm4地区的比例是70%,并且Nm1地区的是30%。紫外线光谱技术提供了监视生产贡献的一种新reservoirgeochemical技术,特别为简历降级的重油,而是它有某限制,就取决于GC指纹技术。
简介:TheHuashixiaareaintheMadoiCounty,QinghaiProvince,westernChinaisoneofthemostimportantareasforthestudiesoftheformationandevolutionoftheA’nyemaqenmélangezoneduetothewellexposed,relativelycompletetectonostratigraphicsuccessions.However,thetimingandevolutionaryprocessoftheA’nyemaqenpaleo-oceanhaslongbeenpoorlyunderstood.Recently,weobtainedabundantradiolariansfromthesiliceousrocksoftheMaerzhengFormationofthismélangezoneinHuashixia.Total19speciesin10radiolariangenerahavebeenidentified.TheybelongmainlytotheAlbaillellaria,Spumellaria,Entactinaria,andLatentifistularia.Fourradiolarianassemblagezonesareestablished,including:thePseudoalbaillellarhombothoracata,Pseudoalbaillellascalprata,Ruzhencevispongusuralicus,andFollicucullusbipartitus-Follicucullussp.cf.F.ventricosuszones.RadiolarianfaunalcorrelationssuggestalateArtinskian–earlyKungurianageandlateCapitanian–earlyWuchiapingianageforthefirsttwozonesfromthelowerpartandthelasttwozonesfromtheupperpartsoftheMaerzhengFormation,respectively.AllradiolariansaretypicalofdeepwaterelementslivingindeepoceansinlowlatitudesduringthePermian.Previously,theradiolariansofEarlyCarboniferoustoEarlyPermianageandfusulinidsofEarly–MiddlePermianagehavealsobeenreportedfromtheA’nyemaqenmélangesuccessions.ThecombinationofthenewlyfoundradiolarianswiththepreviouslyreportedfaunalandmicrofloralassemblagesaswellasradiometricagesobtainedfromthesamestratigraphicunitsindicatesthattheA’nyemaqenpaleo-oceanmayhaveopenedinitiallyduringtheEarlyCarboniferous,expandedfromtheEarly–MiddlePermian,reacheditsacmeintheearlyLatePermian,shrunkduringthelatestPermiantoEarlyTriassic,andeventuallywasclosedintheMiddleTriassic.
简介:Althoughseismicgaptheoryplaysanimportantroleinthemed-andlong-termearthquakeprediction,thepotentialriskofthenon-seismicgapinhistoricalearthquakeruptureareaswillneedtobesimultaneouslytakenintoaccountinthestudyofmed-andlong-termearthquakeprediction,duetothetemporallyclusteringornon-linearbehavioroflargeearthquakerecurrence.Inordertoexploretechnicalmethodswhichcanbebasedonobservationaldata,andidentifyhistoricalearthquakerupturezones(includingtheseismicgapinhistoricalandprehistoricearthquakerupturezones),weselecteighthistoricallargeearthquakerupturezoneswithdifferentelapsedtimesonthemid-northsegmentoftheNorth-SouthSeismicBelttomakequantitativeanalysisonthecharacteristicsofmodernseismicityofthesezonesandpreliminarilyexploretheseismicitymethodfordeterminingtheurgencydegreeofpotentialearthquakehazards.Theresultsmainlyshowthatthepvalue,whichreflectstheattenuationofearthquakesequence,andthea-value,whichreflectstheseismicityrate,arestronglyrelatedtotheelapsedtimeofthelatestearthquakeintherupturezone.However,thecorrespondingrelationshipsinsomeruptureareasarenotclearperhapsduetothecomplexfaultstructureandfaultingbehavior.Theb-value,whichrepresentsthestateoftectonicstressaccumulation,doesnoteasilyreflecttheelapsedtimeinformationofdifferentevolutionstages.Theb-valuetemporalscanningshowsasteadyevolutionovertimeinmostoftherupturezones,butintherupturezoneoftheWuduM8.0earthquakeof1879,theb-valueshowssignificantfluctuationswithadecreasingtrendfor20years.Bycomparativeanalysis,weconcludethattherupturezonesofthe1933M7.5Maoxianearthquakeandthe1976M7.2Songpan-Pingwuearthquakearestillinthedecayingperiodofearthquakesequences,andthusdonothavethebackgroundforrecurrenceofM7.0earthquakes.Thelowb-valueMaqusegment,whichislocatedatthenorthmarginoftherupturezoneof
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