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三江成矿带北段治多-玉树地区已显示出较大的铜多金属矿成矿潜力。在已有研究成果的基础上,结合详细的野外调查和室内研究,对三江北段治多-玉树地区新发现的典型铜多金属矿床的地质特征、成因类型和成矿构造环境进行了综述。这些矿床普遍赋存于中酸性火山岩中,空间上具“火山碎屑岩-矿体-热水沉积岩”的分布特征。矿体多为层状、似层状,且矿石品位较高。对比研究表明,治多-玉树地区铜多金属矿床地质特征与四川呷村矿床和日本“黑矿”矿床相似,成矿流体可能系岩浆水和海水的混合流体;成矿物质可能源于岛弧岩浆作用,并含有热液交代围岩所萃取的金属元素。研究结果表明该区以火山岩为赋矿围岩的铜多金属矿床应归属为VHMS型,成矿构造环境可能与晚三叠世甘孜-理塘洋向南俯冲的大洋岛弧-大陆边缘岛弧环境有关。
The northern section of the Sanjiang metallogenic belt has a large copper-polymetallic ore-forming potential, which is much more than that of the Yushu region. Based on the existing research results and the detailed field investigation and laboratory studies, the geological characteristics, genesis types and metallogenic tectonic environment of the newly discovered copper polymetallic deposits in the Zhiduo-Yushu area of the north of Sanjiang are summarized. These deposits generally occur in moderately acidic volcanic rocks and have spatial distribution of “pyroclastic-ore body-hydrothermal sedimentary rock”. Ore mostly stratified, like layered, and ore grade higher. The comparative study shows that the geological characteristics of the Zhiduo-Yushu copper-polymetallic deposit are similar to those of the Qiongcun deposit in Japan and the “black ore” deposits in Japan, and the ore-forming fluid may be a mixed fluid of magmatic water and seawater. The ore-forming materials may be derived from Island arc magmatism, and contains hydrothermal fluid to replace the surrounding rock extracted metal elements. The results show that the copper polymetallic deposits characterized by volcanic rocks as the host rocks belong to the VHMS type. The metallogenic tectonic setting may be related to the occurrence of the oceanic arc-continental marginal island arc subducted southward from the Garzê-Litang Ocean in the Late Triassic Environmentally relevant.