简介：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.

简介：为了预测北部湾盆地福山凹陷勘探深度下限,根据测井孔隙度、实测孔隙度等资料,研究了福山凹陷异常高孔带的分布和成因。结果表明,福山凹陷纵向上发育4个异常高孔带（Ⅰ-Ⅳ）,其深度范围分别为900~1700m、1800~2850m、2850~3500m、3500~4200m,对应的孔隙度分别为20%~36%、12%~27%、8%~28%、5%~23%;第Ⅰ、Ⅱ、Ⅲ高孔带的成孔机制,是干酪根脱羧形成的有机酸溶蚀储集层中的长石和碳酸盐胶结物形成次生孔隙,第Ⅳ高孔带主要由黏土矿物转化过程中产生的无机酸溶蚀储集层形成;福山凹陷储集层中的岩屑主要为石英岩,具有良好的抗压实性能和护孔作用;福山凹陷储集层含油气的孔隙度下限为10%,勘探深度下限为4100m,对应于异常高孔带消失、致密砂岩出现的深度。