秦岭造山带西段八方山-二里河Pb-Zn矿区硅质岩的微组构分析及其意义  

Microfabric Characteristics of Cherts of Bafangshan-Erlihe Pb-Zn Ore Field in the Western Qinling Orogen

作　　者：李红中[1,2,3] 杨志军[1,2,3] 周永章[1,2,3] 古志宏[1,2,3] 马占武[1] 吕文超[1,2,3] 何俊国[1,2,3] 安燕飞[1,2,3] 李文[1,2] 王强[1] 

机构地区：[1]中山大学地球科学系,广东广州510275 [2]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074 [3]中山大学地球环境与地球资源研究中心,广东广州510275

出　　处：《地球科学（中国地质大学学报）》2009年第2期299-306,共8页Earth Science-Journal of China University of Geosciences

基　　金：国家重点基础研究发展计划(No.2006CB4035008);国家自然科学基金项目(No.40573019);地质过程与矿产资源国家重点实验室课题;地质过程与矿产资源国家重点实验室科技部专项经费资助

摘　　要：硅质岩是造山带内广泛发育的一类岩石,该岩石的组成以SiO2为主,具有较高的稳定性.对于经历过造山作用、成矿作用和重结晶作用等影响的硅质岩,其宏观组构和微观组构特征可以很好地反映它所遭受到的改造.秦岭造山带西段八方山-二里河Pb-Zn矿的宏观及微观组构特征分析表明:该区硅质岩具有明显的热水沉积特征.由于受到压扭性和张性两种性质的应力作用,矿区在宏观上形成了东西向压扭性断裂和北北东、北北西两组张性断裂,微观上形成了微裂隙、微褶皱和压扁拉长的石英颗粒.矿区岩石发生了明显的变质作用,除应力作用造成的动力变质作用外,还发生了其他类型的变质作用和重结晶作用.硅质岩中微量碳酸岩矿物的存在以及应力作用对矿床的形成具有非常重要的意义,特别是其可以为金属硫化物热液提供运移的通道和沉淀成矿的空间.With high stability, chert is widely distributed in the orogens, whose major composition is SiO2. Affected by the orogeny, metallogenesis and reerystallization, the metamorphic processes can be well revealed by the megatectonics and microfabric characteristics. The study of the megatectonics and microfabric ore field in the western Qinling orogen reveals that there are obvious characteristics of the cherts of Bafangshan-Erlihe Pb-Zn hydrothermal sedimentary characteristics in the cherts. Because of the stresses, two types of which are extensional and compresso-shear, there are megatectonies of compresso-shear faults with EW direction and gapping faults with NNE and NNW directions. What＇s more, there are microfabric characteristics of microcracks and mieroeorrugations and stretched-out grains of quartzs. In the rocks of this ore deposit field, the dynamic metamorphism, metamorphic recrystallization and other kinds of metamorphisms are clearly revealed. The trace carbonate minerals and the stress are both important to the metallogenesis of this ore deposit, which provide the pathway and space for the metallic sulphide fluids to travel and deposit.

关 键 词：西秦岭 Pb-Zn矿 组构分析 成矿作用 热水沉积 

分 类 号：P588.2[天文地球—岩石学]