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中晚元古代碧口群海相火山岩分布于扬子古板块西北缘,本文通过火山岩岩相学及微量元素研究,对该群火山岩的岩浆系列,岩浆作用以及产出地质构造环境等一系列问题进行了论述。碧口群海相火山岩由火山相细碧岩、角斑岩、石英角斑岩及次火山相的钠质辉绿岩组成,岩相学资料表明本区细碧-角斑岩系是由偏富钠的细碧岩浆直接结晶形成,可借用“海底热卤水与岩浆混染”成因模式来说明细碧岩浆成因。火山相细碧角斑岩属钙碱岩浆系列,次火山相钠质辉绿岩属拉斑玄武岩浆系列,它们与产于火山岩系中的超基性岩组成蛇绿岩套,产于岛弧环境,按都城(1975)分类属I类蛇绿岩。该蛇绿岩组合为橄榄拉斑玄武岩浆深部分异序次喷发-侵入的产物。
The Middle-Late Proterozoic Bikou Group marine volcanic rocks are distributed in the northwestern margin of the Yangtze plate. Through the study of volcanic petrography and trace elements, a series of questions such as the magmatic series, magmatism and the geological structure of the volcanic rocks are studied The discussion. The Bikou group marine volcanic rocks are composed of volcanic facies bryophytes, angular porphyry, quartz horn porphyry and subdural sodium diabase. According to petrographic data, the lithospheric-lithic rocks in this area are composed of partial The sodium-rich fine bifurcated magma is crystallized directly and can be explained by the genesis model of “submarine hot brine and magma contamination”. Volcanic facies Bibi corniculate porphyry Ca-alkali magma series, subvolcanic sodium diabase diabase stratigraphic magmatic series, which formed with the ultrabasic rocks in the volcanic rock ophiolite suite, produced in the island arc Environment, according to the capital (1975) is classified as Class I ophiolite. This ophiolite assemblage is the product of the heterogeneously sub-eruptive-intrusion of the deep part of the olive tholeigenic basaltic magma.