高级检索

    班−怒成矿带西段切隆铜金矿点成矿物质来源:来自矿石硫化物原位S同位素的证据

    Metallogenic material source of the Qielong copper-gold mineralization occurrence in the western Bangong-Nujiang metallogenic belt: Constraints from in-situ sulfur isotopes of ore sulfides

    • 摘要: 切隆铜金矿点位于班公湖–怒江成矿带西段曲隆地区,矿体主要赋存于晚白垩世二长花岗岩与下拉组大理岩接触带,主要呈脉状、透镜状产出,矿区蚀变以夕卡岩化为主。该矿区稳定同位素研究尚属空白,一定程度上制约了对矿区成矿物质来源及矿床成因的认识。本文对矿石中的斑铜矿、蓝辉铜矿和黄铜矿进行了原位S同位素测试,探讨了切隆铜金矿点的成矿物质来源。结果显示:斑铜矿的δ34SV-CDT值为-0.29‰~2.15‰,均值为1.22‰;蓝辉铜矿的δ34SV-CDT值为-0.52‰~-0.47‰,均值为-0.50‰;黄铜矿的δ34SV-CDT值为0.22‰~1.67‰,均值为1.11‰,指示S同位素组成具有岩浆硫的特征。通过切隆铜金矿点与尕尔穷、嘎拉勒矿床的对比,本文认为切隆铜金矿点与尕尔穷、嘎拉勒矿床具有相似的围岩岩性条件,但其成矿物质源区存在一定的差异。切隆铜金矿点的成矿物质来源于深部岩浆,地层对成矿贡献不大,而尕尔穷、嘎拉勒矿床的成矿物质来源则具有深部岩浆和地层的混源特征。在该区域的后续找矿勘查工作中,要重点关注晚白垩世早期(90 Ma~80 Ma)中–酸性侵入岩发育地区以及侵入岩与地层中碳酸盐岩的接触部位是否存在夕卡岩型矿化。此外,还应重点查明切隆矿区隐伏岩体的侵位情况,以期探获斑岩型矿体。

       

      Abstract: The Qielong copper-gold mineralization occurrence is located in the Qulong area of the western Bangong-Nujiang metallogenic belt. The ore bodies mainly occur in and near the contact zone between the Late Cretaceous monzogranite and marble of the Xiala Formation. The ore bodies occur mainly as vein and lens in shape. The alteration of the host rock is characterized mainly by skarn. Research on the stable isotopes of this mineralization area is lacking, which to some extent hinders further research on the sources of ore-forming materials and the genesis of the Qielong Cu-Au mineralization. This article conducted in-situ S isotope analysis on ore sulfides such as the bornites, digenites, and chalcopyrites, and explored the source of ore-forming materials in the Qielong Cu-Au mineralization occurrence. The results show that the δ34SV-CDT values of bornites range from -0.29‰ to 2.15‰, with an average of 1.22‰; the δ34SV-CDT values of digenites range from -0.52‰ to -0.47‰, with an average of -0.50‰; the δ34SV-CDT values of chalcopyrites range from 0.22‰ to 1.67‰, with an average of 1.11‰, indicating the S isotope compositions have the characteristics of magmatic sulfur. Based on comparative studies on S isotopes between Qielong and the coeval Gaerqiong and Galale deposits, this article suggests that the conditions of surrounding rock lithology of the Qielong copper-gold mineralization occurrence are similar to those of the Gaerqiong and Galale deposits. However, there are certain differences in their ore-forming source regions. The ore-forming material of the Qielong Cu-Au mineralization area originates from deep magma, with little strata contributions to the ore-forming process; whereas, the ore-forming materials of the Gaerqiong and Galale deposits have mixed sources of deep magma and strata. In subsequent prospecting and exploration work in this area, attention should be focused on whether there is skarn-type mineralization in areas where intermediate-acidic intrusive rocks developed in the early Late Cretaceous (90 Ma~80 Ma) and at the contact parts between the intrusive rocks and carbonate rocks in the strata. Furthermore, the emplacement situation of the concealed rock mass in the Qielong copper-gold mineralization occurrence should also be investigated with emphasis, in the hope of discovering and exploring porphyry-type ore bodies.

       

    /

    返回文章
    返回