东昆仑三叠纪斑岩成矿系统及成矿模式

    Metallogenic system and metallogenic model of Triassic porphyry deposits in the East Kunlun orogenic belt

    • 摘要:
      研究目的 古特提斯构造演化在东昆仑造山带引发了重要的斑岩岩浆-成矿作用,形成了复杂多样的矿化类型和丰富的矿产资源,目前,尚未对斑岩成岩成矿时代、成矿特征开展系统的梳理和总结。为提高对东昆仑地区斑岩型矿床成矿系统及成矿模式的认识,
      研究方法 在收集前人资料的基础上,进行了致矿斑岩、斑岩型矿床时空分布、成矿类型及成矿规律总结,以及古特提斯构造演化与斑岩成矿过程关系研究。
      研究结果 东昆仑地区致矿斑岩及斑岩型矿床处于昆北岩浆弧和昆中岩浆弧,形成时代集中在236~218 Ma之间,主要形成了斑岩型铜矿、斑岩型钼矿、斑岩型铜钼矿、斑岩型铜金矿、斑岩型铜锡矿5种类型,已发现的矿体主要产于斑岩体顶部或边部不同方向的次级构造破碎带内,断裂构造是最主要的控矿因素。与斑岩成矿系统有关的矿化类型包括斑岩型、矽卡岩型、隐爆角砾岩型和浅成低温热液脉型,其中,浅成低温热液脉型银铅锌矿规模常达到大型—超大型。
      结论 研究认为,同碰撞造山早期俯冲板片断离引起软流圈地幔上涌,诱发富集地幔的局部熔融和后碰撞伸展阶段岩石圈拆沉引起软流圈上涌,底侵的幔源岩浆将大量成矿物质带入地壳,使被流体交代发生富集作用的新生下地壳重熔,是诱发斑岩矿床成矿最主要的动力学背景。据此建立了与中—酸性斑岩岩浆侵入活动有关的斑岩型-矽卡岩型-隐爆角砾岩型-浅成低温热液脉型矿床深部成矿动力学模型和浅部成矿模式。

       

      Abstract:
      Objective The PaleoTethys tectonic evolution triggered important porphyry magma−mineralization in the East Kunlun orogenic belt, resulting in strong magmatic activity, complex and diverse mineralization types and endowment mineral resources. At present, a systematic review and summary of the diagenetic and mineralization ages and mineralization characteristics of porphyry have not yet been carried out.In order to enhance our understanding of the mineralization system and mineralization model of porphyry−type deposits in the Eastern Kunlun area.
      Methods On the basis of collecting previous data, this paper summarizes the spatial and temporal distribution, metallogenic types and metallogenic rules of ore−producing porphyry and porphyry type deposits, and studies the evolution of paleo−Tethys structure and porphyry mineralization process.
      Results The ore−producing porphyry and porphyry deposits in East Kunlun area are located in the northern and central Quinqueinian magmatic arcs, and their ages are concentrated between 218 Ma and 236 Ma. Mainly formed porphyry Cu, porphyry Mo, porphyry Cu−Mo, porphyry Cu−Au, porphyry Cu−Sn deposit five types, the discovered ore bodies are mainly located in the top or side of the porphyry tectonic belt, the structure is the most important ore−controlling factor, the size of the porphyry−related low−temperature vein type Ag−Pb−Zn mineralization often reaches large−super large.
      Conclusions It is considered that the most important dynamic background for the mineralization of porphyry deposits is the partial melting of mantle enrichment induced by asthenosphere mantle upgassing caused by subduction plate fragmentation in early cocollision orogeny and the partial melting of new crust and thickened lower crust induced by asthenosphere upgassing in post−collision extension stage. The metallogenic model of porphyry type, skarn type, cryptoexplosive breccia type and epithermal vein typedeposit was established.

       

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