黄金坪金矿床地质地球化学特征及成因探讨

发布时间：2018-06-01 12:29

本文选题：大渡河 + 地质特征　；参考：《成都理工大学》2015年硕士论文

【摘要】：大渡河流域金成矿带是我国西南地区发现的一条重要的金成矿集中区。矿区位于扬子地台西缘康滇地轴北端,龙门山褶皱带和巴颜喀拉造山带相接处。已发现多处岩金矿床,构成了著名的康定大渡河“金谷”。大渡河金成矿带处于多组大断裂交汇部位,自震旦纪以来直至当今地质构造活动依然活跃。经历多阶段多期次的岩浆活动,构造运动,成矿条件十分优越,找矿潜力巨大。黄金坪金矿床地处大渡河流域金成矿带中段,为区内产于基底中的典型金矿床。区内岩浆活动频繁,皱褶、断裂十分发育。该矿床发现较早(1983年),并一直都在开采中。但因为受气候、地理位置等自然条件限制,近年来较少有专家学者对该矿床的成矿地质背景,成矿条件、成矿物质来源及矿床地球化学特征研究。因此本人结合矿物岩石学、地球化学等相关专业知识,在前人已总结的成果基础之上,较系统地研究了矿床的地质地球化学特征,探讨了成矿物质的来源及其成矿条件。黄金坪金矿床成矿流体在早期受挤压后期拉张贯入断裂或者裂隙中,属典型的石英脉型金矿床。含金石英脉在空间上与辉绿岩岩脉密切相伴,并捕获了大量辉绿岩或者硅质岩,时而捕获,时而相互平行。金属矿物主要为黄铁矿,毒砂、方铅矿、闪锌矿,含有少量磁铁矿。结合野外地质观察及室内鉴定对黄金坪石英闪长岩挑选锆石U-Pb测年,获得成岩年龄723Ma左右,与金成矿年龄相差甚远。含金石英脉ESR测得的年龄分别为50.5±5.0Ma、16.7±1.6Ma、4.9±0.4Ma。其中16.7±1.6Ma的含金石英脉为主要含金石英脉,石英闪长岩与金成矿年龄相差甚远。结合野外地质观察及室内鉴定,对黄金坪金矿床的岩石学特征、常量元素地球化学特征、稀土元素和微量元素地球化学特征、同位素地球化学特征进行的研究表明,金成矿形成于造山环境。石英流体包裹体表明矿床成矿流体温度属于中低温,黄铁矿S同位素分析获得成矿流体中的S来自地幔。
[Abstract]:The Dadu River Basin gold metallogenic belt is an important gold mineralization concentration area discovered in southwest China. The mining area is located at the northern end of the Kangdian axis on the western margin of the Yangtze platform, where the Longmenshan fold belt meets the Bayan Kara orogenic belt. A number of rock gold deposits have been discovered, forming the famous "Golden Valley" of the Dadu River in Kangding. The Daduhe gold metallogenic belt is located at the intersection of many large faults and has been active in geological tectonics since the Sinian. It has experienced multi-stage and multi-stage magmatism, tectonic movement, excellent metallogenic conditions and great prospecting potential. The Jinping gold deposit is located in the middle section of the gold metallogenic belt in the Dadu River basin and is a typical gold deposit occurring in the basement. Magmatic activity in the area is frequent, folds and faults are well developed. The deposit was discovered earlier (1983) and has been under exploitation. However, due to the limitation of climate, geographical location and other natural conditions, few experts and scholars have studied the metallogenic geological background, metallogenic conditions, ore-forming source and geochemical characteristics of the deposit in recent years. Therefore, based on the related knowledge of mineral petrology and geochemistry, and on the basis of the previous achievements, I have systematically studied the geological and geochemical characteristics of the deposit, and discussed the source of the ore-forming material and its metallogenic conditions. The ore-forming fluid of the Jinping gold deposit is a typical quartz vein type gold deposit. The auriferous quartz vein is closely associated with the diabase vein in space and captures a large number of diabase or siliceous rocks which are sometimes captured and sometimes parallel to each other. Metal minerals are mainly pyrite, arsenopyrite, galena, sphalerite, containing a small amount of magnetite. Combined with field geological observation and laboratory identification, the U-Pb dating of zircon selected from Jinping quartz diorite shows that the diagenetic age is about 723Ma, which is far from gold mineralization age. The age of gold-bearing quartz vein determined by ESR is 50.5 卤5.0 Ma, 16.7 卤1.6 Ma, 4.9 卤0.4 Ma, respectively. Among them, 16.7 卤1.6Ma gold-bearing quartz vein is the main gold-bearing quartz vein, and the age of quartz diorite and gold mineralization is very different. Combined with field geological observation and laboratory identification, the petrological characteristics, geochemical characteristics of major elements, geochemical characteristics of rare earth elements and trace elements, and isotopic geochemical characteristics of the Jinping gold deposit are studied. Gold mineralization was formed in orogenic environment. The quartz fluid inclusions indicate that the ore-forming fluid temperature of the deposit belongs to the middle and low temperature, and the S of the ore-forming fluid derived from the mantle is obtained by S isotope analysis of pyrite.
【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】：P618.51

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