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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。
The newly-identified Liugutou metamorphic medium-magmatic complex mainly consists of metamorphic gabbro-gabbro diorite in the Guanzizhen area, western Qinling, and its geochemical characteristics show that it is formed in the island arc tectonic setting. The TIMS zircon U-Pb isotopic ages of (507.5 ± 3.0) Ma in the metamorphic medium magmatic complexes suggest that the formation of the northern arc island magmatic rocks in the northern part of the West Qinling is Late Cambrian, The subduction of the paleo-oceanic basin represented by the rock and the time frame for the volcanic-magmatic island arc formation may be Late Cambrian or earlier.