焦家金矿床成矿多样性的构造控制机理

Complex regional structure evolution results in the diversity of forming condition and mineralization style of gold deposit, tradition researches of mineral deposits emphasis on ore-forming material source and physical chemistry condition during mineralization, and ignore deep analysis on the major key scientific issues about tectonic style and the permeability structure, which cause same metallogenic system comes up to different explaination of genesis. Jiaojia gold deposit is the place where the name structure fracture zone alternated rock type gold deposit came from, the association of the altered rock-, disseminated/veinlet-, and gold-bearing quartz veins-types mineralization found by a large number of explorations in recent years as well as the huge metallogenic potential in the deep make it a favorite place for the research of the structure controlling mechanism on mineralization diversity. In the connection, this project plan to focus on the tectonic style of mineralization as well as permeability structure which all are scientific issues to carry out a series studies. Firstly, on the base of the explicitation of mineralization spatial structure and composition of fault zone, in order to investigate the ore-forming structure, fault zone structure zone number, average index number and variation index will be checked out. Secondly, to define the permeability structure and its evolution history, SEM-BSE, EBSD microfabric analysis of tectonites in deformation generations and muscovite 40Ar/39Ar dating of syn-tectonic deformation and syn-metallogenic minerals will be performed. Finally, concentrate on simulating the transfer tectonic stress field, the coupling relationship of ore forming structure-its ermeability structure-controlling mechanism on diversified mineralization styles will be revealed, these works will improve theoretical knowledge of mineralization diversity of gold deposits.

复杂区域构造演化造就了金矿床形成条件和矿化式样多样性，传统矿床研究往往侧重成矿物质来源和成矿物理化学条件限定，忽略对成矿构造样式及其渗透性结构这一关键控制因素深入剖析，导致对同一成矿系统提出多种成因解释。焦家金矿床是构造破碎带蚀变岩型金矿命名地，近年来大量工程揭露发现蚀变岩型、细脉浸染型和石英脉型三种矿化样式共生且深部成矿潜力巨大，使其成为研究成矿多样性构造控制机理理想选区。为此，项目拟聚焦该矿床成矿构造样式及其渗透性结构这一科学问题，在明确矿化结构及赋存空间基础上，通过测定断裂带结构指数、平均指数和变异指数，厘定成矿构造样式；通过各构造变形世代构造岩SEM-BSE和EBSD显微组构分析、同构造变形矿物和同成矿白云母40Ar/39Ar定年，厘定断裂带渗透性结构及其演化史；集成开展控矿构造应力场转移模拟，揭示成矿构造样式及其渗透性结构对多种金矿化样式控制机理，深化对金矿床成矿多样性理论认识。

金矿床形成条件和矿化式样多样性导致对同一矿床提出多种成因解释，成矿构造样式及其渗透性结构是控制金成矿多样性的关键因素。焦家金矿床是构造破碎带蚀变岩型金矿命名地，近年来大量工程揭露发现蚀变岩型、细脉浸染型和石英脉型三种矿化样式共生且深部成矿潜力巨大，使其成为研究成矿多样性构造控制机理的理想选区。项目聚焦该矿床成矿构造样式及其渗透性结构这一科学问题，通过剖析焦家金矿区矿化结构和赋存空间以及控矿断裂的几何学和运动学特征，定量化分析断层核和破碎带变形强度，提出焦家断裂为一走滑-伸展断裂带，其走滑和伸展构造活动往复循环的叠加-转换控制焦家金矿床的形成，金矿体赋存于先存的左行走滑焦家断裂系内的里德尔剪切断裂-裂隙网络，为构建矿床成因模式提供理论支撑；通过金云母40Ar/39Ar、LA-ICP-MS锆石U-Pb年代学研究及构造应力场反演模拟，提出在约120Ma区域远应力场由ENE-WSW向伸展转换为WNW-ESE向伸展，同时NE向二长花岗岩的侵入导致局部应力场调整为走滑体制，控制了约119Ma的金矿化；通过区域对比综合分析，提出“断层阀-地震泵吸”复合成矿作用控制焦家金矿床成矿多样性，构建了金成矿多样性的构造控制模式，并用于指导焦家、望儿山和寺庄等金矿床成矿预测，实现了找矿新突破。