摘要
Thereexistintermediatetointermediate-acidshoshoniticrocksdatedat26.3-36.7MaintheEarlyTertiaryextensionalbasinsalongtheNEflankoftheDali-JianchuansectionoftheHonghe-Ailaoshanleft-lateralstrike-slipductileshearzone,wheresomehigh-andmedium-highgrademetamorphosedmaficenclaveshavebeenfound.AccordingtotheP-Tconditionsandmineralassemblagecharacteristics,theenclavesaregroupedintothreetypes:type-Ⅰ,garnetdiopsidite,formedatlowercrustorinthetransitionalsectionbetweenthemantleandthecrustwiththemetamorphicconditionP=(10.47-11.51)×108PaandT=771-932℃;type-Ⅱ,garnet-anddiopside-bearingamphibolite,formedatthedepthofmiddletolowercrustwiththemetamorphiccondition:P＝(6-10)×108PaandT=780-830℃;type-Ⅲ,metamorphosedgabbro,formedatrelativelyhigherlevelsthantheabove2typeswithlowermetamorphiccondi-tion.Type-Ⅰandtype-ⅡenclaveshadexperiencedadecompressionalretrogrademetamorphismcausedbytectonicelevationassociatedwiththemetasomatismofSiO2,Na2O-richfluidphasewiththenewequilibratedtemperatureatT=761-778℃.Geochemicalevidenceindicatesthatbothdeep-derivedmaficenclavesandhostrockshavesimilarEMⅡproperties,whicharerelatedtotheinvolvementofsubductedmaterials.Thesustainingsubduction,compressionandstrike-slipductileshearingbetweentheIndiaplateandtheYangtzecratonarethemainconstraintsonthesubcontinentalmantleproperties,interactionbetweencrustandmantle,andtheformationandevolutionofalkali-richmagma.
出版日期
2003年01月11日（中国期刊网平台首次上网日期，不代表论文的发表时间）
