南岭东段银坑地区W-Au-Ag-Pb-Zn(Cu)复合成矿机理研究

Yinkeng mining area is located in the intersection between Nanling metallogenic belt and Wuyi metallogenic belt, which is characterized by developing largescale W- polymetallic deposits. In addation, there is a set of larege-middle scale magmatic-hydrothermal Au-Ag-Pb-Zn(Cu) polymetallic deposits occurring in this area. Preliminary studies have shown that there is closely temporal-spatial relationship between the two metallogenic series. But little is known about their temporal sequence, the metallogenic mechanism and corresponding geological setting. This proposal will take the Yanqian-Huameiao W deposit and Niuxingba- Liumukeng Au-Ag-Pb-Zn( Cu) deposit of Yinkeng mining area with typical characteristics of superimposed mineralization as an example. Based on its special tectonic position, we will focus on the source and evolution process of magma in Yinkeng mining area, make full use of the Nanling Scientific Dring(NLSD-1)data and systematically conduct the studies of petrology, ore mineralogy, elemental and isotopic geochemistry, and fluid geochemistry. Based on the above, we will try to constrain the spatial, temporal, and probably relationship between the two metallogenic series, as well as subtly depict the evolution of fluid during the process of petrogenis and metallogeny. In turn, we will further discuss its metallogenic mechanism. Finally, a preminary genetic model for the Yinkeng mining area will be proposed. The study of this project is significant to enrich the metallogenic theory associated with granite, as well as to guid to deep ore-prespecting in this region.

银坑矿区位于"南岭成矿带"与"武夷成矿带"的交汇部位，是赣南钨多金属矿集区的重要组成部分。区内不仅发育以岩前-画眉坳为代表的矽卡岩-石英脉型W多金属矿床，还发现了一批大型-中型的Au-Ag-Pb-Zn（Cu）矿床（如留龙、牛形坝-柳木坑）。已有研究显示两类矿床具有密切的时空关系，体现多元素复合成矿的特点，但成矿作用的地质背景、成矿机制以及与岩浆演化的关系等科学问题尚不明确。本申请以银坑地区两类矿床为解剖对象，以岩浆来源及演化过程与多金属成矿关系研究为主线，充分利用正在本区实施的南岭3000m科学钻探资料，系统开展岩石学、矿床学、年代学及同位素地球化学研究，探讨该区两类矿床的时空关系、成岩成矿物质来源、成矿流体演化过程及成因联系，揭示该区多元素复合成矿机理，建立多元素复合成矿作用的矿床模型。该项目的开展，不仅对丰富华南花岗岩成矿理论具有重要意义，而且对该区深部和外围找矿具有重要的指导意义。

江西银坑矿田位于南岭—武夷山—赣东北三大成矿带交汇斜接部位，以同时发育钨多金属矿床（如岩前矽卡岩型、画眉坳石英脉型)和银金铅锌锰矿床（留龙石英脉型、牛型坝破碎带热液脉型和老虎头层控型）组合为特色，是南岭地区最重要的贵多金属找矿远景区之一。本项目系统总结了银坑矿田两类矿床的时空分布规律、成矿期次与控矿要素，开展了矿田构造、岩浆活动、典型矿床，认识到矿田内中高温热液型钨多金属矿床和中低温金银铅锌铜贵多金属矿床分带性在二维平面空间内的存在。通过区内岩浆活动与典型矿床研究，发现两类矿床的形成在时间、空间、物质来源和成矿作用方面均与燕山早期的两套花岗质岩浆活动密切相关，结合南岭科学钻探两类矿化的垂向分带特征，建立了精确的成岩成矿年代学格架，阐明了两类矿化组合在三维空间内的分带性，在成矿时间上的集中性（150～160Ma），是华南中生代两类矿床成矿系列（南岭与花岗岩有关钨锡矿床成矿系列和赣东北与花岗闪长岩有关贵金属成矿系列）在银坑地区时空四维尺度的叠加。由此，确立了银坑地区钨多金属矿与银金铅锌多金属矿在时空三维上存在的成因联系。综合应用深部地球物理探测信息、3000m科学钻探信息和典型矿床研究成果，建立了银坑地区综合成矿模式，反映了南岭东段多期次构造岩浆活动背景下，两类矿化的深部动力学过程，揭示了银坑矿田二层结构的成矿作用叠加的存在。本次工作以南岭银坑地区为典型，重点解剖了南岭大规模花岗质岩浆活动区的成矿规律问题和多矿种的成因联系等复杂科学问题，为区内两类矿化的深部找矿实践取得突破提供了重要的理论依据。