新疆西准噶尔巴尔鲁克蛇绿岩形成时代及大地构造意义

摘要

新疆西准噶尔地区分布多条蛇绿岩带，通过对巴尔鲁克蛇绿岩中2个辉长岩LA-ICP-MS锆石U-Pb测年，获得比较准确的年龄数据512.3±7.2Ma、521.1±2.8Ma。确定了该蛇绿岩的形成时代为晚寒武世；结合混杂岩带内岩石组合特征及其与中—下泥盆统库鲁木迪组为不整合接触，推断该蛇绿混杂岩带与唐巴勒蛇绿岩带及玛依勒蛇绿岩为同一时代、同一构造带产物，就位时代不晚于早泥盆世。%Severial ophiolite belts are distributed in west Junggar area, Xinjiang. LA-ICP-MS zircon U-Pb dating of two gabbro bodies in the Baerluke ophiolite yielded the age of 512.3 ± 7.2Ma and 521.1 ± 2.8Ma, respectively, which indicate that the ophiolite was formed in Late Cambrian. Combined with characteristics of rock combination in ophiolite and its unconformity contact with middle-lower Devonian Kulumudi Formation, the authors hold that this ophiolitic melange belt and Tangbale and Mayile ophiolite belt were formed in the same epoch and in the same tectonic belt, with the emplacement not later than Early Devonian.