东昆仑督冷沟铜钴矿床多期成矿特征及成矿过程探讨

督冷沟铜钴矿床位于近东西向东昆仑构造带东段,其形成于晚古生代岛弧环境,成矿地质作用非常复杂,绿泥绢云母千枚岩为主要赋矿地层,构造变形使矿质运移、富集.根据矿床地质特征、矿物共生关系、矿石矿物结构构造特征以及矿物生成顺序,可将成矿过程划分为热水喷流沉积成矿期、构造变形叠加改造成矿期和表生期.形成的矿石有氧化矿石、硫化矿石及两者混合的混合矿石.通过微量、稀土元素特征分析表明,成矿物质来源最合理的解释是热液流体与围岩发生水-岩交换,应为多源.矿石的稀土元素特征与现代大洋中脊喷流热水沉积的含金属沉积物及其热液稀土元素特征相似,但又有不同,反映了矿石的形成过程较复杂,可能经历了后期的富集改造.

Discussion on Metallogenic Characteristics and Multi-stage Mineralization Process of Dulenggou Copper-cobalt Deposit in East Kunlun,Qinghai Province

Dulenggou copper-cobalt deposit is located in the eastern section of the near EW-trending east Kunlun tectonic belt. Formed in island arc environment of late Paleozoic, the deposit shows very complex mineralization process. Chlorite sericite phyllite is the main ore-hosting formation, structure deformation makes the minerals migrate and enrich. According to the geological characteristics of the deposit, the symbiotic relationship of minerals, texture and structural characteristics of ores and minerals, and the sequence of generation, the mineralization process can be divided into sedimentary exhalative mineralization period, tectonic deformation superimposed mineralization period and supergene period. Mineralized ore includes oxide ore, sulfide ore and mixed ore of the former two. In this paper, trace and rare earth elements analysis shows that the most reasonable interpretation of the mineral source is water and rock exchange between the hydrothermal fluid and surrounding rock, and the minerals should be multi-source. REE analysis shows similar characteristics with the metalliferous sediments from modern mid-ocean ridge and its hydrothermal fluid, but still there are some differences, reflecting that the ore formation process is a bit more complex, which may be caused by later enrichment and transformation.