吉林省珲春市五道沟钨矿床地质特征及找矿前景分析

发布时间：2018-04-25 19:26

本文选题：矿床地质特征 + 矿床成因　；参考：《吉林大学》2017年硕士论文

【摘要】：五道沟钨矿床位于吉林省珲春市东部,属环太平洋构造岩浆成矿带组成部分。中生代以来多次构造—岩浆活动事件,导致延边地区Cu、Au、W、Mo等多金属成矿作用异常强烈。作者在野外实地调研基础上,通过对研究较为薄弱的五道沟钨矿床的成矿背景、矿床地质特征、矿床地球化学特征等进行的系统研究,分析讨论了矿床成因。进一步总结成矿地质条件,找矿标志和矿化富集规律,为矿区进一步钨矿找矿勘查工作提供理论。矿床地质研究表明:(1)五道沟钨矿床产出于海西晚期花岗闪长岩岩体与五道沟群变质岩接触带之内带和五道沟群杨金沟组和香房子组层间破碎带。(2)矿石矿物主要为白钨矿,伴有少量的磁黄铁矿、黄铁矿、毒砂等;脉石矿物由石英、钠长石、黑云母、阳起石、绢云母、方解石等组成。(3)围岩蚀变有硅化、绢云母化、绿泥石化、钠长石化、阳起石化、碳酸盐化、毒砂、磁黄铁矿化等,其中硅化、钠长石化与白钨矿化密切相关。(4)矿石结构有包裹—乳滴状结构、填隙结构及交代结构等;细脉状构造和浸染状构造。(5)矿床划分为热液期和表生期2个成矿期。其中,热液期由早到晚进一步可划分为3阶段:石英—白钨矿—毒砂阶段→石英—白钨矿—硫化物阶段→石英—方解石阶段阶段,而石英—白钨矿—毒砂阶段和石英—白钨矿—硫化物阶段是主成矿阶段。矿床地质化学特征研究表明:(1)五道沟群各组地层具有钾玄岩系列—高钾钙碱性系列—钙碱性系列特征;(2)海西晚期岩浆岩和印支晚期—燕山早期脉岩显示钙碱性系列造山花岗岩构造环境。(3)主成矿元素W与中低温元素As、Sb、Hg、Ag相伴生,揭示钨成矿具有多期性。(4)矿床地质特征、成矿相关地质体微量元素地球化学特征综合研究表明成矿物质来源具有多源性,五道沟群是矿床成矿物质的主要来源,岩体除提供热源、流体外,亦提供部分成矿物质。五道沟钨矿床具有多期次成矿的特点,成矿时代分别为海西晚期(230~267.8Ma)和印支期—燕山早期(178~197Ma)。成矿流体属中温、低盐度的NaCl-H2O-CO2体系,成矿流体以岩浆水为主,亦有少量大气降水参与。成矿流体减压沸腾作用,破坏了含矿流体的内物理化学体系平衡,使WO42-与Ca2+在适当物理化学条件下和不同赋矿围岩和不同含矿构造空间内形成不同矿化类型的白钨矿。矿床形成机制受控于地层—构造—岩浆成矿系统,矿床成因类型属于层控—岩浆中高温热液叠加改造石英脉型白钨矿床,成岩成矿作用形成于太平洋板块向欧亚板块俯冲的动力学背景。通过对矿床区域和矿区2个尺度的成矿地质条件深入分析,总结其找矿标志,进一步揭示该矿床受“地层—岩体—断裂”联合控制。通过继续开展不同层次的地质勘查工作,在土壤化探异常圈定的2处成矿远景区,有望发现规模更大的矿体。
[Abstract]:The Wudaogou tungsten deposit is located in the east of Hunchun City, Jilin Province, and is a part of the tectonic magmatic metallogenic belt around the Pacific Ocean. Since Mesozoic, many tectonic-magmatic events have resulted in strong polymetallic mineralization in Yanbian area. On the basis of field investigation, the authors analyzed and discussed the genesis of the Wudaogou tungsten deposit through a systematic study of the metallogenic background, geological characteristics and geochemical characteristics of the deposit. The ore-forming geological conditions, ore-prospecting marks and mineralization enrichment rules are further summarized, which provides a theory for further prospecting and exploration of tungsten deposits in the mining areas. Geological study of the deposit shows that the Wudaogou tungsten deposit occurred in the contact zone between granodiorite and metamorphic rocks of the Wudaogou group in the late Hercynian period and the interlayer fracture zone of Yangjingou formation and Xiangjiangformation in the Wudaogou group. The ore minerals are mainly scheelite. Accompanied by a small amount of pyrrhotite, arsenopyrite, etc.; gangue minerals are composed of quartz, albite, biotite, actinolite, sericite, calcite, etc.) the surrounding rock is altered by silicification, sericite, green mud, albite, and actinolite. Carbonation, arsenopyrite, pyrrhotite, etc., of which silicification, albite and scheelite are closely related to the ore structure, such as encapsulated emulsion dripping structure, filling structure and metasomatism structure. The ore deposit is divided into two metallogenic periods: hydrothermal period and supergene stage. The hydrothermal period can be further divided into three stages from early to late: quartz-scheelite-arsenopyrite stage-Scheelite-sulphide stage-quartz-calcite stage. The quartz-scheelite-arsenopyrite stage and the quartz-scheelite-sulfide stage are the main metallogenic stages. The study on the geological and chemical characteristics of the deposit shows that the strata of Wudaogou group have the characteristics of kalitization series, high potassium calc-alkaline series and calc-alkaline series.) the late Hercynian magmatic rocks and the late Indosinian and early Yanshanian dikes show calc-alkaline series. The main ore-forming element W is associated with the moderate and low temperature element As-SbSbSbHgng-Ag. It is revealed that tungsten metallogeny has the geological characteristics of multi-period. The comprehensive study of trace element geochemical characteristics of ore-forming related geological bodies shows that the source of ore-forming material is multi-source, and the Wudaogou group is the main source of ore-forming material. The rock mass provides not only heat source and fluid, but also some ore-forming materials. The Wudaogou tungsten deposit is characterized by multiple stages of mineralization, the metallogenic ages are: late Hercynian 230U 267.8 Maand Indosinian to early Yanshanian 17879 Ma. The ore-forming fluid belongs to NaCl-H2O-CO2 system with medium temperature and low salinity. The ore-forming fluid is dominated by magmatic water and has a small amount of atmospheric precipitation. The depressurized boiling effect of ore-forming fluid destroys the equilibrium of internal physicochemical system of ore-bearing fluid, and makes WO _ 42- and Ca2 form different types of scheelite mineralization in proper physicochemical conditions and in different ore-bearing surrounding rock and different ore-bearing tectonic space. The formation mechanism of the deposit is controlled by the stratigraphic-tectonic-magmatic metallogenic system, and the genetic type of the deposit belongs to the quartz vein type scheelite deposit, which is superimposed by the strata-magma medium and high temperature hydrothermal solution. Diagenesis occurred in the dynamic background of the Pacific plate subducting to the Eurasian plate. Through the deep analysis of the ore-forming geological conditions of two scales in the ore deposit and ore area, the ore-prospecting criteria are summarized, and it is further revealed that the deposit is controlled by the combination of "strata, rock mass and fault". By continuing to carry out geological exploration at different levels, it is expected that a larger ore body will be discovered in 2 metallogenic areas delineated by soil geochemical anomalies.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.67

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