学科分类
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3 个结果
  • 简介:Hydrothermalchimneyisaproductofhydrothermalactivityontheseabed.ChimneysamplesdredgedfromJadehydrothermalareainIzenadepressionoftheOkinawaTrough,arecharacterizedbyrelativelyenrichedlightrareearthelements(LREE)andstronglypositiveEuanomalies.87Sr/86Srand143Nd/144Ndofthesesamplesareexactlybetweenthoseofseawaterandofacidicpumice,averagedat0.708928and0.512292,respectively.ThesecharacteristicsimplythatthemainsourceofhydrothermalsulfideatJadeareaispossiblytheundersurfaceacidicrocks.Themineralizingmechanismcanbesummarizedasfollows:LargeamountofmineralizedmaterialwouldbeleachedoutandLREEenrichedhydrothermalsolutionwouldbesubsequentlyproducedasaresultofthermo-chemicalexchangereactionbetweenacidicvolcanicrocksandheatedseawaterthatpenetratedinadvancefromupperwatermass.ThespurtingoutfromtheseabedandquicklycrystallizingintheseawaterofhydrothermalsolutionareresponsiblefortheformationofCu-Znsulfideandbarite-amorphousSiO2mineralsthatarecharacterizedbyenrichedLREEandpositivelystrongEuanomalies.

  • 标签: 稀土元素氧化物 同位素 冲绳
  • 简介:Themajorelements,traceelements,K-ArageandSr-Nd-PbisotopicsystemsoftheCenozoicvolcanicrocksinDaheishanIslandandCishan,Penglai,ShandongProvincearemeasured.Thevolcanicrocks(olivine-nepheliniteandnepheline-basanite)inDaheishanIslanderuptedperiodicallyinanintervalof0.32Ma,from8.72Ma,8.39Ma,8.08Mato7.73Ma.ThevolcanicrocksareallrichinlightREEs.TheyaresimilartotheOIB-typealkalibasaltinthetraceelementsnormalizedmodelbyprimordialmantle:richinhighfieldelementssuchasNbandTa,andimcompatibleelementssuchasCs,Rb,Ba,Th,U.ThevolcanicrocksshowadepletionofKandRbelements.Itissuggestedbythetraceelementsthattheolivine-nepheliniteinDaheishanIslandisoriginatedfromdeepresourcesunderthecontinentalmantle.εNd(0)valuesofthevolcanicrocksinDaheishanIslandandCisbanare5.31~8.51and7.33respectively,suggestingthatthevolcanicrocksarefromthedepletedmantleresources,whichhavehigherSm/NdratiosthantheCHUR.143Nd/144NdratiosofDaheishanIslandolivine-nepheliniteandCishanalkalibasaltsare0.512910~0.513074and0.513014respectively.The87Sr/86SrofDaheishanIslandvolcanicrocksarelowerthanthatofCishan,0.703427~0.703482and0.703895respectively.TheDaheishanIslandolivinenephelinitehasthePbisotopicvaluesasfollows:206Pb/204pb=18.0289~17.9728,207Pb/204pb=15.4358~15.4022and208Pb/204Pb=38.0876~37.9975,lowerthanthoseofCishanbasanite.TheCishanbasanitehas206Pb/204pb=18.2401,207Pb/204Pb=15.5645and208Pb/204pb=38.535.Theauthorssuggestthattheolivine-nepheliniteinDaheishanIslandissimilartotheE-typeMORBorHawaiiOIB,andthealkalibasaltsinCishansimilartotheKerguelenOIB.ThedominantmantlecomponentsofDM+PREMAandperhapsDM(Dupaltype)arethedominantmantlecomponentsforvolcanicrocksinDaheishanIslandandCishan.ThePREMAcomponentplaysanimportantrole.

  • 标签: 岩石学 地球化学 Nd-Sr-Pb同位素系统 火山岩 微量元素 新生代
  • 简介:蔡楚生执导的经典影片《渔光曲》曾在江、浙、沪三地取景,多地根据这一"史实"展开各自文脉传承和旅游宣传,其中个别提法还有待考证。本文通过挖掘原始资料,梳理出完整的影片拍摄行事历,证实影片在浙江的取景地为石浦、沈家门、普陀山,纠正了嵊泗拍摄一说。并对影片拷贝因保存不善而消失的内容作了推断,认为在舟山取景的画面可能在损坏之列。

  • 标签: 《渔光曲》 外景地 考证 电影史 地方文化