【摘要】 库米什地区火山岩属该区蛇绿岩套的组成部分,形成于晚泥盆世,以中性和酸性岩石为主,火山碎屑岩较发育,具有钙碱性火山岩套的特征。岩套内的沉积夹层具有远海沉积的性质。火山岩岩石化学特征属钙碱性系列;微量元素地球化学证明岩浆起源于消减板块之上的地幔楔形区;稀有元素地球化学特征与安山岩的特征相符。综合分析这些证据发现,该区火山岩形成于弧后盆地环境。更多还原

【Abstract】 The volcanic rocks are the components of ophiolite in the Ku Mishi district, and they were formed during the late Devonian period. The intermediate acidity volcanic rocks are their main typessand the growth of pyroclastic rocks,therefore they belongs to the calculkaline volcanic suite, sedimentary complexes show the characteristics of the pelagic deposit environment.The petrochemistry of the volcanic rocks shows the features of the calcalkaline series, and the trace element geochemistry proves that the magma originated from the mantle wedge above the subducted zone.The features of the rare earth elements are basically the same as those of the erogenic andesites.These evidences testify that it is the best explanation for tectonic environment that the above-mentioned volcanic rocks were formed in the back-arc basin更多还原