西昆仑铁克里克成矿带布琼铁（铜）矿床地质地球化学特征与矿床成因研究

发布时间：2018-02-12 17:57

本文关键词： 沉积变质型铁矿矿床地质成矿作用布琼西昆仑　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：新疆西昆仑铁克里克成矿带位于塔里木盆地西南陆缘隆起区,布琼铁(铜)矿床是带内最具代表性的、唯一的成型金属矿床,但是相关研究工作十分薄弱。本文在充分收集相关研究资料成果的基础上,采用野外地质调查和室内分析测试相结合的方法,对布琼铁(铜)矿床开展了矿床地质、岩相学、岩石学、地球化学和年代学等方面的综合解剖性研究,取得的主要认识有:(1)赋矿地层为古元古界喀拉喀什群大理岩、角闪片岩、黑云石英片岩、含石榴石阳起角闪片麻岩及磁铁石英岩,对角闪片岩及黑云石英片岩进行原岩恢复,布琼铁矿床的含矿围岩为一套从安山岩到玄武岩过渡的中-基性火山岩。(2)矿区地层发育呈线性分布的强变形、退变质带,叠加在面状中-深程度区域变质岩之上,变形带中心到周围发育韧-脆性变形及退变质绿泥片岩。(3)铁矿体呈层状、似层状或透镜状,沿单斜地层与围岩整合接触产出。铁矿石构造类型主要有条带条纹状矿石和浸染状矿石,粒状变晶结构和交代结构,矿石矿物主要为磁铁矿,黄铜矿,脉石矿物主要为石英、角闪石,石榴子石,阳起石等。铜矿化和石英-方解石-硫化物脉密切共生,矿化类型主要为黄铜矿化、孔雀石化及蓝铜矿化等;围岩蚀变主要有硅化、方解石化、假象赤铁矿化、绿泥石化、黄铁矿化、方铅矿化等;成矿期次可划分为沉积期、变质期、构造-热液期和表生期。(4)矿体围岩都具有富硅铝,贫钙的特点,高场强元素含量较高,条带条纹状矿石与角闪质围岩的稀土元素配分模式相似,轻重稀土分馏不明显,具有同源性,成矿物质可能来自与海底高温热液和海水;黑云母片岩类围岩与浸染状蚀变岩型矿石的稀土配分模式相似,富集轻稀土、亏损重稀土,可能为受后期构造-热液作用的结果。(5)对铁矿体夹层围岩斜长角闪岩进行LA锆石U-Pb定年,推测布琼铁形成于2000-2350Ma,岩石形成后经历的一期构造-热液事件年龄为749-764Ma。(6)通过围岩地球化学示踪研究,结合前人对铁克里克地区大地构造演化的认识,本文认为布琼BIF形成的构造背景为火山机构控制的弧后盆地,铜矿化与新元古代西昆仑大陆裂解关系紧密,成矿模式可以分为沉积阶段(BIF的形成)、变质阶段(沉积变质型铁矿体形成)、构造-热液阶段(铜矿化的叠加)。
[Abstract]:The Tikrik metallogenic belt in West Kunlun, Xinjiang is located in the southwestern continental margin of Tarim Basin. Buqiong iron (copper) deposit is the most representative and the only formative metal deposit in the belt. However, the related research work is very weak. Based on the full collection of relevant research data, the paper develops the deposit geology and petrography of Buqiong iron (copper) deposit by using the method of field geological survey and laboratory analysis and test. A comprehensive anatomical study of petrology, geochemistry and geochronology shows that the main knowledge obtained is that the ore-bearing strata are Paleoproterozoic Karakash group marble, hornblende schist and black cloud quartz schist, the ore-bearing strata are the Paleoproterozoic Karakash group, the hornblende schist and the black cloud quartz schist. Garnet bearing granodiorite gneiss and magnetite quartzite, as well as hornblende schist and black cloud quartz schist for original rock restoration, The ore-bearing surrounding rock of Buqiong iron deposit is a set of meso-basic volcanic rocks in transition from andesite to basalt. The ductile-brittle deformation and retrograde metamorphic green-mudstone schist are developed from the center of the deformation zone to the surrounding area. The main structural types of iron ore are striped ore and disseminated ore, granular metasomorphic structure, magnetite, chalcopyrite and gangue minerals. Hornblende, pomegranate, actinolite, etc. Copper mineralization and quartz-calcite-sulphide veins are closely associated with each other. The main types of mineralization are chalcopyrite, peacock fossilization and blue copper mineralization, and the wall rock alteration is mainly silicified and calcite. The ore-forming stages can be divided into sedimentary period, metamorphic stage, tectonic-hydrothermal stage and supergene stage. The surrounding rock of the orebody is rich in silicon and aluminum, poor in calcium, and high in content of high field strength elements, and the ore body is characterized by aluminosilicate, pyritization, galena mineralization and so on, and the ore-forming stage can be divided into four stages: sedimentary period, metamorphic stage, tectonic-hydrothermal stage and supergene stage. The REE distribution pattern of striped ore is similar to that of hornblende surrounding rock, but the fractionation of light and heavy rare earth is not obvious, and the ore-forming material may come from high temperature hydrothermal solution and sea water. The rock mass of biotite schist is similar to that of leachate altered rock. It is rich in light rare earth and depleted in heavy rare earth. It is possible that the LA-zircon U-Pb dating of the amphibolite in the interbedded rock mass of the iron ore body may be the result of the late tectonic-hydrothermal interaction. It is inferred that Buqiong iron was formed in 2000-2350 Ma, and the first stage tectonic-hydrothermal event age after rock formation was 749-764Ma.Y6) based on the geochemistry tracer study of surrounding rock, combined with the previous understanding of tectonic evolution in the Tieckrik area, In this paper, it is considered that the tectonic setting of Buqiong BIF is a back-arc basin controlled by volcanic mechanism, and that copper mineralization is closely related to the disintegration of the Neoproterozoic West Kunlun continent. The metallogenic model can be divided into sedimentary stage, metamorphic stage (sedimentary metamorphic iron ore body formation), tectonic-hydrothermal stage (superposition of copper deposit).
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.41;P618.31

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