四川会理大铜厂铜矿床主要控矿因素分析

发布时间：2018-04-23 12:20

本文选题：砂砾岩 + 铜矿床　；参考：《成都理工大学》2015年硕士论文

【摘要】：四川省会理大铜厂铜矿床是西南地区重要的中型铜矿床,它位于川滇南北向构造带中段的中生代会理断陷盆地南西侧。本文在广泛收集前人资料的基础上,通过实地考察该铜矿床的地层出露、岩性组合、沉积建造、构造特征,深入采矿平硐、中段、矿房、选冶厂、尾矿库获得第一手研究资料,再通过室内的综合分析,深入理解了该矿床的成矿地质背景和矿床地质特征,对成矿的控制因素提出了自己的见解,并对前人的某些观点提出了修改意见。会理大铜厂铜矿床产于中生代上白垩统小坝组下段地层中,岩性为一套河流相碎屑沉积,以中-细砾岩和中-细粒岩屑长石砂岩为主。颜色以紫红色为主,偶夹灰绿色条带。矿区主要褶皱构造为近南北向的青蛙甲背斜和向斜,断层仅见于矿区西北角且规模较小,对矿体基本无影响。矿体剖面上呈层状、似层状产出,向东呈叠瓦状排列;平面上呈莲藕状,延伸方向为近南北向。矿石主要原生金属矿物为辉铜矿和斑铜矿,次生金属矿物主要为孔雀石,矿石结构以它形粒状结构为主,构造主要为浸染状胶结构造,无明显围岩蚀变现象。通过矿石及围岩的常微量元素和硫同位素测试数据发现,矿石和围岩的常微量元素组合及含量拟合度很高,显示成矿物质直接来自围岩;硫同位素组成特点表明硫源以硫酸盐的微生物细菌还原和有机质还原成因为主。作者在研究该矿床主要控矿因素时发现:中生代红盆的煤、铜、盐三色建造对砂岩铜矿的成矿控制作用明显;矿体主要分布于上下隔水层所封闭的高渗透性砂体中;矿床严格受层位控制,小坝组砂砾岩地层为找矿目的层;矿体多产于岩石色调的浅紫过渡接触处;岩石孔隙度、组分粒径、胶结物成分都与矿化关系密切;地下水的性质和渗流方向控制了矿质的沉淀和矿体的展布方向;通过对岩相的分析发现河床滞留相和心滩相沉积形成了有利于后期地下水渗流的岩性组合;此外区域地质演化控制了断陷盆地的形成和成矿物质的来源,断裂打通了流体运移的通道,对成矿流体的形成起到了重要作用。青蛙甲背斜对大铜厂铜矿床后期的矿体改造富集起到了关键作用。最后作者提出该矿床成因为沉积-成岩-改造型砂砾岩型铜矿床,成矿大致经历了成矿前的构造运动阶段、矿源层的沉积阶段、改造成矿阶段和表生氧化四个阶段,并对改造成矿阶段的成矿模式做了简要图解。
[Abstract]:The large Tongchang copper deposit in Huili Sichuan Province is an important medium copper deposit in southwest China. It is located in the south west of the Mesozoic Huili fault depression in the middle segment of the southwestern Sichuan-Yunnan trending tectonic belt. Based on the extensive collection of previous data, this paper has obtained first-hand research data by investigating the strata exposure, lithologic assemblage, sedimentary formation, structural characteristics, deep mining adit, middle section, orehouse, Xuanye factory and tailings reservoir of the copper deposit. Through the laboratory comprehensive analysis, the metallogenic geological background and geological characteristics of the deposit are deeply understood, and the views on the controlling factors of mineralization are put forward, and some opinions of the predecessors are put forward. The Datongchang copper deposit in Huili occurs in the lower member of Xiaoba formation of Upper Cretaceous in Mesozoic. The lithology of the deposit is a set of fluvial clastic deposits, mainly of medium-fine conglomerate and medium-fine-grained lithic feldspathic sandstone. The color is mainly purplish red with grayish green stripes. The main fold structures in the mining area are the frog armour anticline and syncline in the north and south direction. The faults are only found in the northwest corner of the mining area and the scale is small and has no effect on the orebody. The orebody is stratified, like stratiform, imbricate to east and lotus root in plane, extending in the direction of near south to north. The ore is mainly composed of chalcopyrite and porphyrite, the secondary metallic mineral is mainly malachite, the ore structure is dominated by other granular structure, the structure is mainly dyed cemented structure, and there is no obvious wall rock alteration phenomenon. Through the data of trace elements and sulfur isotopes of ore and surrounding rock, it is found that the combination of trace elements and the fitting degree of content of trace elements in ore and surrounding rock are very high, which shows that the ore-forming material comes directly from the surrounding rock. The characteristics of sulfur isotopic composition indicate that the sulfur source is mainly caused by the reduction of sulfate bacteria and the reduction of organic matter. When the authors study the main ore-controlling factors of the deposit, it is found that the coal, copper and salt formations of the Mesozoic red basin have obvious controlling effect on the ore-forming of sandstone-copper deposits, and the orebodies are mainly distributed in the highly permeable sand bodies enclosed by the upper and lower water sealants. The deposit is strictly controlled by the horizon, the gravel strata of Xiaoba formation are the ore-prospecting target layer, the orebody mostly occurs in the light purple transition contact of the rock tone, the porosity of the rock, the particle size of the composition and the composition of the cementation are all closely related to the mineralization. The nature and seepage direction of groundwater control the deposit of mineral material and the direction of distribution of orebody, and through the analysis of lithofacies, it is found that the deposit of retained facies of river bed and the facies of core beach form lithologic assemblages favorable to the late seepage of groundwater. In addition, regional geological evolution controls the formation of faulted basins and the source of ore-forming materials, and the faults open the passage of fluid migration, which plays an important role in the formation of ore-forming fluids. The Yuka anticline plays a key role in the orebody reconstruction and enrichment in the late stage of the Datongchang copper deposit. Finally, the author suggests that the deposit is formed by deposition-diagenesis and remolding sand and conglomerate type copper deposit, which has undergone four stages: tectonic movement stage before mineralization, sedimentary stage of ore source bed, reformation metallogenic stage and supergene oxidation stage. A brief diagram of the ore-forming model in the reformed metallogenic stage is also given.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.41

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