【摘要】 郭家沟铅锌矿床位于甘肃省西成矿集区东端,是近年来在西秦岭新发现的超大型矿床,也是寻找厂坝式矿床的重大突破。该矿床的矿体主要赋存于中泥盆统安家岔组生物灰岩、硅化-铁白云石化灰岩以及千枚岩中,明显受层间断裂带的控制。由于其新发现不久,该矿床控矿因素和成因认识尚不清楚。文章在系统成矿地质特征观察的基础上,将成矿期次划分为沉积成矿期和热液成矿期,其中,热液成矿期包括:石英-闪锌矿-方铅矿-铁白云石(菱铁矿)阶段(Ⅰ)、石英-方铅矿-闪锌矿-碳酸盐阶段(Ⅱ)和方解石-硫化物阶段(Ⅲ)。在综合分析该矿床成矿过程与控矿因素的基础上,认为成矿受压扭性逆冲断层相关的断裂构造系统和褶皱构造变形带控制,硅化和铁镁碳酸盐化与铅锌矿化密切伴生,表现出热液交代蚀变矿化为主的特征,矿脉穿切矿区内的花岗岩墙,推测成矿作用发生在三叠纪或者更晚,后生热液成矿作用造成了铅锌的巨量富集。更多还原

【Abstract】 The giant Guojiagou Pb-Zn deposit is located in the east of the Xihe-Chengxian(abbreviated as "Xicheng")ore concentration area in Gansu Province. It is a newly discovered giant deposit in the western Qinling and a major breakthrough in exploration for the Changba-type deposit.The orebodies in the deposit are mainly hosted in the biolithite limestone, silicified and dolomitic limestone as well as phyllite of the Middle Devonian Anjiacha Formation, controlled by the fault zone between phyllite and limestone. As it is a newly discovered deposit, the ore-controlling factors and genesis of the Guojiagou deposit is still unclear. Based on systematical observation of the ore-forming geological characteristics, the authors divided the ore-forming processes into sedimentary metallogenic period and hydrothermal mineralization period, in which the hydrothermal mineralization period includes(Ⅰ) quartz-sphalerite-galena-ankerite(siderite) stage,(Ⅱ) quartz-galena-sphalerite-carbonate stage and(Ⅲ) calcite-sulfide stage. Based on comprehensive analysis of the ore-forming process and ore-controlling factors of the deposit, it is considered that the ore-forming processes were controlled by the torsional thrust fault related to sub-faults between different strata and fold-deformed zones. Silicification and iron-magnesium carbonation were closely related to lead-zinc mineralization, showing the characteristics of hydrothermal alteration and mineralization. In the mining area, the ore veins crosscutting the granite wall indicates that the mineralization occurred during the Triassic or later. It was the epigenetic hydrothermal mineralization that caused the huge amount enrichment of lead and zinc.更多还原