【摘要】 西秦岭天水关子镇地区新确定的流水沟变质中基性岩浆杂岩体主要由变质辉长岩-辉长闪长岩-闪长岩组成,地球化学特征显示其形成于岛弧构造环境。变质中基性岩浆杂岩的TIMS法锆石U-Pb同位素年龄为(507.5±3.0)Ma,表明西秦岭北带岛弧型岩浆岩的形成时代为晚寒武世,反映以关子镇蛇绿岩为代表的古洋盆的俯冲作用和形成火山-岩浆岛弧的时限可能为晚寒武世或稍早。更多还原

【Abstract】 The Liushuigou meta-intermediate-basic igneous complex defined recently in the Guanzizhen area, Tianshui City, West Qinling, is mainly composed of metagabbro-metagabbro diorite-metadiorite. Its geochemical characteristics indicate that the complex formed in an island-arc environment. The TIMS single-zircon U-Pb age for the meta-intermediate-basic igneous complex is 507.5±3.0 Ma, which indicates that the formation age of island-arc-type magmatic rocks in the north zone of the West Qinling are Late Cambrian, and that the timing of subduction of the paleo-ocean basin represented by the Guanzizhen ophiolite and formation of the volcanic-magmatic island arc is Late Cambrian to Early Ordovician.更多还原