论文部分内容阅读
滩间山金矿区斜长花岗斑岩出露于柴达木盆地北缘构造带,是区内出露较大的斑岩体。利用LA-MC-ICPMS锆石定年方法,测得斜长花岗斑岩锆石的年龄为2 416～336Ma,可分为3组:2 416～2 365,1 797～1 602,358～336Ma。对锆石矿物成因研究表明,第一组和第二组年龄为继承性锆石的年龄,反映其源岩有前寒武纪变质岩或同期岩浆岩的物质;第三组为斜长花岗斑岩的结晶年龄,表明岩体形成于早石炭世,为华力西中期斜长花岗斑岩。岩石地球化学特征表明,岩石属钙碱性系列偏铝质岩石,为I型花岗岩,形成于后碰撞环境。结合锆石的年龄测定数据,认为斜长花岗斑岩物质具有多来源的特点,华力西中期是本区金矿形成的一个重要成矿期。
The plagiogranite porphyry in the Tanjianshan gold deposit is exposed in the tectonic belt along the northern margin of the Qaidam basin, which is a large porphyry body exposed in the area. The zircon dating of the plagiogranite porphyry from 2 416 to 336 Ma was measured by the LA-MC-ICPMS zircon dating method and can be divided into 3 groups: 2 416-2365, 1 797-1 602, and 358-336 Ma. The study on the genesis of zircon minerals shows that the ages of the first and second groups are the ages of the inherited zircons, which reflect that the source rocks are of Precambrian metamorphic rocks or contemporaneous magmatic rocks. The third group is plagioclase The crystallization age of the porphyry indicates that the rock mass formed in the Early Carboniferous, which is the mid-Hypsizonal plagiogranite porphyry. Geochemical characteristics of rocks indicate that the rocks are calc-alkaline series of partial-aluminum rocks, which are type I granites and formed in a post-collision environment. Based on zircon dating data, it is considered that plagioclase granodiorites have multi-source characteristics. The mid-Hurrical period is an important metallogenic stage for the gold deposits in this area.