研究区位于中祁连地块南缘,青海湖南-古雷深大断裂南侧,是祁连成矿带铜镍矿找矿最有利地区.铜镍矿矿体产于同源同期侵入的基性-超基性岩体内,铜镍矿化无论在时间上和空间上都与岩体的侵位密切相关.本次研究对乙什春基性-超基性岩体中的锆石进行了阴极发光(CL)成像观察,结合Th/U比值特征,显示其为岩浆成因；并应用LA-ICP-MS对锆石微区U-Pb年龄进行了测定,获得乙什春含矿岩体中锆石加权平均年龄为(455.1±1.7)Ma,表明其含矿岩体的侵位及矿化作用发生于晚奥陶世,成岩成矿的动力学背景为陆缘裂谷构造环境.%The study area is located at the southern margin of the Middle Qilian, south of the Qinghai Lake-GuLei deep fault belt, which is a favorable area for copper-nickel deposits in Qilian metallogenic belt. Yishichun Copper-nickel ore occurs within the homologous and contemporaneous basic-ultrabasic intrusions, and copper-nickel mineralization is spatially and temporally related to the intrusive rocks. The cathodoluminescence (CL) images and the Th/U ratios of zircons from the basic-ultramafic rocks suggest that zircon crystals are of magmatic origin; The LA-ICP-MS U-Pb dating of these zircons yields a weighted mean age of 455.1 ±1.7 Ma. Therefore, the ore-bearing rock emplacement and copper-nickel mineralization occurred during the late Ordovician, and the metallogenic dynamic process was probably related to an ancient continental margin rifting.
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