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40 个结果
  • 简介:ObjectiveThenearlyparallelN–S-trendingriftsinsouthernTibetrepresenttheE–WextensionoftheTibetPlateau.MostdatawhichconstrainedtheageoftheextensionaldeformationcomefromisotopicdatingofthedikesprobablyrelatedtotheactivityofthenearlyN–Sfaultingandmicasfromhydrothermalactivityandthelowtemperaturethermochronologyofplateauuplift.Previous

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  • 简介:Recentdramaticadvancesintechnologiessuchascomputer,datamanagement,andcommunicationhaverevolutionizedthewaygeologistscollect,disseminate,andutilizegeosciencedata.Aftersummarizedthecharacteristicsandfusionofgeo-data,severalmajorfielddatacapturesystemsadoptedinNorthAmericahavebeenintroduced.GeoscienceinformationdisseminationanddistributionviathewebtechnologyandGISpackagehavealsobeendiscussed.Inaddition,multisourcesgeo-dataintegrationandtheirapplicationstomineralexploration,geologicalhazardriskassessment,andnationallandresourcesprotectionandutilizationhavebeenaddressedbyconcreteexamples.

  • 标签: GEOSCIENCE DATA field DATA CAPTURE system
  • 简介:Yangjuan-Chuplwa节上的详细conodont分析,Xinmin,PanxianCounty,贵州省,包括四个Anisianconodont地区揭示了一个conodont序列,viz.Nicoraella德语集成通信适配器地区,Nc。kockeli地区,Paragondolella区分。地区和Neogondolellaconstricta地区。这些地区显示上面的Guanling形成从theBithynian由阶层组成到Anisian的Illyrian。Neogondolella的外观压缩一theAnisian/Ladinian边界可能在overlyingYangliujing形成的suggests。Panxian动物志保存withwell的海洋的爬行动物和鱼石块被证明属于conodontNc的更低的部分。在学习区域的kockeli地区。因此,Panxian动物志的年龄能是Anisian的earlyPelsonian。

  • 标签: 牙形石 三叠纪 贵州 动物群 古生物
  • 简介:CART(Constituent-orientedageandresidencetimetheory)andPTM(Particle-trackingmethod)aretwowidelyusednumericalmethodstocalculatewaterage.Thesetwomethodsareessentiallyequivalentintheorybuttheirresultsmaybedifferentinpractice.Thedifferenceofthetwomethodswasevaluatedbyapplyingthemtocalculatewaterageinanidealizedone-dimensionaldomain.Themodelresultsbythetwomethodsareconsistentwitheachotherinthecasewitheitherspatiallyuniformflowfieldorspatiallyuniformdiffusioncoefficient.Ifweallowthespatialvariationinhorizontaldiffusion,atermcalledpseudodisplacementarisingfromthespatialvariationofdiffusioncoefficientlikelyplaysanimportantroleforthePTMtoobtainaccuratewaterage.Inparticular,ifthewaterparticleisreleasedataplacewherethediffusionisnottheweakest,thewateragecalculatedbythePTMwithoutpseudodisplacementismuchlargerthanthatbytheCART.ThissuggeststhatthepseudodisplacementcannotbeneglectedinthePTMtocalculatewaterageinarealisticocean.Asanexample,wepresentitspotentialimportanceintheBohaiSeawherethediffusioncoefficientvariesspatiallyandgreatly.

  • 标签: 水平方向 PTM 位移计算 扩散系数 空间变化 模拟
  • 简介:ThereportednewU-Pbagebysensitivehigh-resolutionionmicroprobe(SHRIMPⅡ)onzirconwasobtainedfromatuffsampleatthebasalDoushantuoFormationintheJiuqunaosection,whichsituatedatthewesternlimboftheHuanglinganticlineintheYangtzeGorgesinZigui,Hubei,SouthChina.Eighteenspotsofzirconswereanalyzedandtheyformtwoclusters:oneincludesthreespots,withaninheritedageof784+15Ma(MSWD=0.05);theotherconsistsof15spotsandgivesaweightedmean^206pb/^238Uageof628.3±5.8Ma(MSWD=0.86).ItisthefirstSHRIMPU-PbzirconageobtainednearlythebaseoftheDoushantuoFormationofEdiacaranandrepresentsamaximumageoftheDoushantuoFormationItalsoformsanageconstraintontheupperlimitageoftheNantuo(Marinoantype)glaciation.

  • 标签: 中国南部 扬子江峡谷 同位素年代测定 冰川作用
  • 简介:TheHezhengareaofGansuProvinceproducesthemostabundantmammalfossilsinChinaaswellasthewholeEurasia,anditalsoproducesotherCenozoicfossilsofdifferentanimalsandplants.Therefore,allofthemarenamedtheHezhengBiota.Mammalsareverysensitivetoenvironmentalchanges,andthustheevolutionofmammalianfaunasintheHezhengareareflectsthestrongupliftoftheTibetanPlateauduringtheLateCenozoic,whichdramaticallyaffectsenvironmentalchanges.IntheHezhengarea,micromammalsarenotveryrich,butsomeofthemstillareimportant.ItisrelativelyuncommonthatthreeprimatesarefoundfromtheMiddleMioceneandtheEarlyPleistocenedeposits.SincetheMiddleMiocene,carnivoreshavebecomeimportantcomponentsintheecosystemoftheHezhengarea,anddominatedintheEarlyPleistocene.TheMiddleMioceneisatimeofhighdiversityforProboscidea,characterizedbyshovel-tuskedelephants.PerissodactylsintheHezhengareaareveryabundant,especiallyLateOligoceneandLateMiocenerhinocerosesaswellastheLateMioceneandEarlyPleistocenehorses.FromtheMiddleMiocene,artiodactylsbecameimportantcomponentsofthemammalianfaunas,especiallybovids.

  • 标签: 甘肃 新生代 哺乳动物 生态系统 生物年代学
  • 简介:Jianglang山位于华南褶层系统,Jiangshan-Shaoxing深破裂地区和Baoan-Xiakou-Zhangcun破裂地区的过渡地区。形成Xiakou盆被土佬归因于拉开差错消沉

  • 标签: 地理学 地形学 发展 理论
  • 简介:Inthisstudy,changesinArcticseaicethicknessforeachiceagecategorywereexaminedbasedonsatelliteobservationsandmodelledresults.InterannualchangesobtainedfromIce,Cloud,andLandElevationSatellite(ICESat)-basedresultsshowathicknessreductionoverperennialseaice(icethatsurvivesatleastonemeltseasonwithanageofnolessthan2year)uptoapproximately0.5–1.0mand0.6–0.8m(dependingoniceage)duringtheinvestigatedwinterandautumnICESatperiods,respectively.Pan-ArcticIceOceanModelingandAssimilationSystem(PIOMAS)-basedresultsprovideaviewofacontinuedthicknessreductionoverthepastfourdecades.Comparedto1980s,thereisaclearthicknessdropofroughly0.50min2010sforperennialice.Thisoveralldecreaseinseaicethicknesscanbeinpartattributedtotheamplifiedwarmingclimateinnorthlatitudes.Besides,wefigureoutthatstronglyanomaloussoutherlysummersurfacewindsmayplayanimportantroleinpromptingthethicknessdeclineinperennialicezonethroughtransportingheatdepositedinopenwater(primarilyviaalbedofeedback)inEurasiansectordeepintoabroaderseaiceregimeincentralArcticOcean.Thisheatsourceisresponsibleforenhancedicebottommelting,leadingtofurtherreductioninicethickness.

  • 标签: 北极海冰 厚度变化 年龄变化 ICESAT 海冰厚度 卫星观测
  • 简介:Globalseismicitycatalogsaresufficientforcharacterizingdoubleseismiczones(DSZs)insubductingslabandfacilitatetoestimatelayerseparationwithoutinconsistentuncertaintiesaslocalcatalogs.PreviousstudieshaveshownthecorrelationbetweenDSZslayerseparationandplateagewhilecorrelationforthoseyoungerthan~60Maissuspicious.ThelackingofDSZswithlayerseparationlessthan10kmfurthermakesitdifficulttopreciselyestimatesuchcorrelation.Thus,weincorporateeightDSZsdatadeterminedthroughlocalseismicityintoglobally-determineddatasetandreexaminesuchcorrelation.Thebestfittingresultsshowthatbothalinearmodelandasquarerootofplateagecanmathematicallyfitthelayerseparationwell.However,itisdifficulttodistinguishthesetwomodelswhenplateageisgreaterthan~20Masincetheirdifferenceislessthan2km.However,ifextrapolationispossible,bothmodelsshouldprovidephysicalinformationthatDSZswillnotformifthereisnosubductinglithosphere.Asaresult,theDSZscannotbeproduceduntiltheoceaniclithosphericagebecomesgreaterthan0.9Mainthesquarerootmodelwhilethelinearmodelgivesamisleadingresult.Assuchthesquarerootmodeldemonstratestherelationshipphysicallybetterthanthelinearone,itstillneedsfurthertestinthefuturewithmoreavailabledata,nevertheless,ourstudymightalsoprovideevidenceforthesuggestionthattheplateageisaprimarycontrolfactoroftheDSZsgeometryaswellasthesubductingprocesswhichdisregardsanylocaltectonicstresses.

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  • 简介:旋转扇子横梁scatterometer(RFSCAT)是被建议的卫星scatterometer的一种新类型约10一以前。然而,类似于另外的旋转scatterometers,相对更大的风检索错误与一行的中间的区域相比发生在天底和外部区域。为有给定的参数的RFSCAT,风方向检索精确性与中间的区域相比在外部区域在约9减少。处理这个问题,为RFSCAT的一个先进的风向量检索算法被介绍。新算法根据检索的风方向偏爱的分发直方图越过整个一行为每个风向量房间位置展示风方向的范围的适应延期。水平2A数据的100条轨道被模仿验证并且评估新算法。检索实验证明新先进算法罐头有效地在天底和RFSCAT一行的外部区域改进风方向检索精确性。在风方向检索的约1.6和9改进为分别地在天底和一行的边点定位的风向量房间被完成。

  • 标签: 旋转扇子横梁 scatterometer 客观功能 弯屈向量检索 偏爱的分发直方图 弯屈方向扩展
  • 简介:Sm-NdandRb-Srwhole-rockisochrondatingofthesamplesofcumulatedgabbro,diabaseandandesiticporphyritefromtheArmantaiophiolite,Xinjiang,yieldedtheagesof561±41(Ma(εNd(t)=6.1)and392±17Ma(87Sr/86Sr)i=0.7041],whichstandfortheagesofcreationandlatermetamorphismoftheophiolites,respectively,ThecreationenvironmentoftheArmantaiophiolitesseemstoaback-arcbasincausedbythesouthwardsubductionofthetheArmantaiophiloitesseemstoaback-arcbasincausedbythesouthwardsubductionofthepalaeo-AsiaOcean.

  • 标签: 钕同位素 锶同位素 新疆 蛇绿岩 成岩时代 等时代年龄
  • 简介:EarlyOrdovicianA-typegranitesinthenortheastern(NE)SongnenBlockNEChinawerestudiedtobetterunderstandthegeodynamicsettingsinthisregion.ThisresearchpresentsnewzirconU-PbagesandwholerockgeochemicaldatafortheEarlyOrdoviciangranitesintheNESongnenBlock.ZirconU-PbdatingindicatesthatthegraniteintheCuibei,Hongxing,andMeixiareasintheNESongnenBlockformedintheEarlyOrdovicianwithagesof471-479Ma.ThegranitesshowgeochemicalcharacteristicsofhighSiO2andK2OcompositionsandlowFeOT,MgO,CaO,andP2O5compositions.TheybelongtoahighKcalc-alkalineseriesanddisplayaweakperaluminousfeaturewithA/CNKvaluesof0.98-1.14.TherockshaveaΣREEcompositionof249.98-423.94ppm,andareenrichedinLREEwith(La/Yb)Nvaluesof2.87-9.87,anddisplayobviousEuanomalies(δEu=0.01-0.29).TraceelementsofthestudiedgranitesarecharacterizedbyenrichmentinRb,Th,U,Pb,Hf,andSm,anddepletionofBa,Nb,Ta,andSr.TheydisplaygeochemicalfeaturesofhighZr+Y+Nb+Cevalues(324-795ppm)andGa/AlratiosconsistentwithA-typegranites.Basedonparticulargeochemicalfeatures,suchashighRb/Nb(7.98-24.19)andY/Nb(1.07-3.43),thestudiedA-typegranitescanbefurtherclassifiedasanA2-typesubgroup.ThisresearchindicatesthattheEarlyOrdovicianA-typegraniteswereformedbythepartialmeltingofancientcrustinanextensionalsetting.LowerSr/Yand(Ho/Yb)Nratiosindicatethatplagioclaseandamphiboleareresidualinthesource,andgarnetisabsent,implyingthatthemagmawasgeneratedatlowlevelsofpressure.Bycontrast,thecontemporaneousgranitesintheSEXing'anBlocksuggestasubduction-relatedtectonicsetting,anditsadakiticpropertyindicatesathickenedcontinentalcrust.WesuggestthatthePaleo-AsianOceanplatebetweentheXing'anandSongnenblockssubductednorthwardduringtheEarlyOrdovician.Meanwhile,theNESongnenBlockwasexposedtoapassivecontinentalmargintectonicsetting.

  • 标签: Early ORDOVICIAN A-TYPE GRANITE Songnen and
  • 简介:从Lombok岛,印度尼西亚,和包围区域的paleotsunami沉积的年龄决心用210在BATAN雅加达的Pb方法。包括paleotsunami沉积,方法假定那捱过沉积的这的基本理论将导致210Pb丰富。这个方法的原则是计算210在到更深埋葬的沉积的从表面的特别沉积间隔的Pb内容累积。结果然后在以前联合起来的年里被变换成年龄或depositional时间。从GawahPudak的paleotsunami沉积的标明日期的结果(S8???

  • 标签: 印度尼西亚 海啸地震 年龄测定 沉积物 鉴定 7级地震
  • 简介:GlobalabruptclimatechangefromMarinoansnowballEarthtogreenhouseEarth,recordedascapcar-bonateoverlainondiamictite,hadshedthefirstlightonCambrianbio-radiation.Themostdocumentedcapcar-bonatesectionsaretypicalwithcomprehensiveδ13Cneg-ativevaluesandubiquitoussedimentarystructures,suchastepee-like,sheet-cracketc.,whichareassociatedwithsuccessiveglacialeustaticvariationcausedbyisostaticreboundinshallow-waterfacies.Herewereportadeep-waterbasinalcapcarbonatesectionwithstrongnegativeδ13CvaluesinthesouthernmarginoftheQinlingOrogen,Heyu,ChengkouCounty,ChongqinginChina,whichconsistsofmassivedolostonewithabundantcarbonaceouslaminae.However,itlacksthesedimentarystructureasmentionedaboveandisoverlainbythin-beddedsiliciousshalesandcherts.AK-bentonitebedwasdiscoveredwithinthebaseofcapcarbonates,about0.7mabovethetopoftheMarinoandiamictite.Magmaticzirconsthatweresep-aratedfromtheK-bentonitebedyieldaSIMSconcordiaU-Pbageof634.14-1.9Ma(lσ,MSWDcE=0.31,ProbabilityCE=1.000,n-=20).TheageisingoodagreementwithpreviouslyreportedTIMSU-PbagesfortheterminationofMarinoanglaciationandprovidesageochronologicalconstraintfortheEdiacaransuccessionsintheQinlingOrogen.

  • 标签: NEOPROTEROZOIC Cap DOLOSTONE K-BENTONITE U-Pb age