本文对库喀阿孜铅-锌-(铜-钨)多金属矿床中距矿体不远处出露的二长岩、花岗闪长岩岩体进行了地球化学研究,以便于了解该多金属矿床的形成背景。研究表明,这些侵入岩主要为一套准铝质、钙碱性系列中一酸性岩石,具有较低的铝饱和指数(A/CNK-0.91~1.05),明显富集LILE和具有低的HFSE/LILE比值,具有弱到中等的负铕异常(8Eu-0.53~0.97);二长岩岩体LA-ICP-MS锆石U_Pb年龄为461.5±3.3Ma。初步认为,这些中酸性岩体为加里东期中期侵位的I型陆缘弧花岗质岩石,与矿区内铅-锌-(铜-钨)多金属矿化无明显关系。
In order to understand the ore-forming background of the Kukaazi Pb-Zn-(Cu-W) polymetallic deposit in the west Kunlun area, a primary geochemical study had been performed on the intrusive monzonite and granodiorite rocks near the polymetallic deposit. It is shown that they are metaluminous calc-alkaline granotoids, with relative low A/CNK values (0.91~1.05), obviously enriched in LILE, low HFSE/LILE ratio, weak to medium Eu nega- tive anomalies (~Eu values vary from 0.53 to 0.97). The LA-ICP-MS zircon U-Pb dating of the monzonite is 461.5 -I-3.3 Ma. Therefore, we believed that these intermediate-acidic intrusives, which emplaced in the middle Caledo- nian period, belong to I-type continental marginal arc granitoids, and have no obvious relationship with Pb-Zn-(Cu- W) mineralization.