论文部分内容阅读
利用电子探针对冲绳海槽１３３站位玄武岩的斑晶矿物、基质以及斑晶矿物中关晶石包体和岩浆包裹体作了化学主成分分析，结果表明，该站位玄武岩属橄榄玄武岩，岩石中斑晶矿物由培长石、普通辉石、贵橄榄石和磁铁矿组成，尚见有少量外来的脉石英碎块，基质成分由拉长石微晶和玻璃组成．培长石和贵橄榄石中含有玻璃质岩浆包裹体和铬镁尖晶石或铬镁铁尖晶石包体。尖晶石的化学成分证明它是地幔部分熔融成因的．岩浆包裹体代表了一种原生的碱性橄榄玄武岩浆，其化学成分相当于橄榄辉长岩。该站位的玄武岩浆起源于上地幔尖晶二辉橄榄岩的部分熔融，并沿着“碱性橄榄玄武岩浆－粗面玄武岩浆－玄武质粗面岩浆－粗面岩浆”方向演化，每一阶段的岩浆在上升过程中都不同程度地受到地壳物质的同化和混染作用。
The chemical principal component analysis (PCA) was used to analyze the chemical composition of the clinoptilolite inclusions and magma inclusions in the basalts of the basalt in the 133 stations of the Okinawa Trough by means of electronic probe. The results show that the basalts belong to olivine basalts, Porphyrites in the rock are composed of feldspar, pyroxene, peridotite and magnetite. There are also few foreign vein quartz fragments and the matrix composition is composed of labradorite crystallites and glass. Pergite and peridotite contain vitreous magmatic inclusions and chromium-magnesium spinel or chromite-spinel inclusions. The spinel’s chemical composition proves that it is partly melted by the mantle. Magmatic inclusions represent a native alkaline olivine basaltic magma that has the chemical composition equivalent to olive gabbro. The basalt magma originates from the partial melting of the spinel lherzolites in the upper mantle and evolves along the direction of “basic olivine basaltic magmas - crude basalt - basaltic mafic - facies lava” Phase magma in the ascending process are affected to varying degrees by the assimilation and mixing of crustal material.