【作者】 薛传东；

【导师】 秦德先； 刘星；

【作者基本信息】 昆明理工大学 ， 矿产普查与勘探， 2002， 博士

【摘要】 个旧矿区以锡铜为主的多金属矿产开发历史悠久，地质研究程度较高。但前人大量的研究工作多注重花岗岩成矿理论及相关模式的建立，认为该区锡多金属矿床主要与燕山期花岗岩成矿作用有关，成矿时间集中在燕山中晚期。本文主要从与花岗岩成矿相冲突的地质事实入手，系统研究和探讨了矿床地质特征、矿石矿物学、岩（矿）石的微量元素、稀土元素、稳定同位素地球化学和流体包裹体等，结合对个旧组地层、玄武岩及花岗岩的岩石学、岩石化学、地球化学及区域地质综合分析研究，获得如下结论： 1、个旧地区为一北尔向的印支期裂陷槽（盆地），中-晚三叠世存在剧烈的裂陷活动，并可与北西侧的广南-邱北、麻栗坡-八布等裂陷槽（盆地）相连通，共同构成一个裂陷带。个旧组（T₂g）、法郎组（T₂f）中碱性玄武岩、玄武质疑灰岩、含火山碎屑碳酸盐岩、硅质岩等的大量多层次产出，也反映本区为拉张裂陷的构造环境。岩石产状和岩石化学等特征表明，区内个旧组中普遍产出的碱性玄武岩(T_2g1β)为陆内拉张构造环境下的产物。 2、区域地层和个旧组实测剖面地层地球化学分析表明，该区富Sn、Cu多金属的前寒武古老基底及寒武系、泥盆系等地层可为矿床形成提供一部分成矿物源；个旧组是矿床的主要赋矿岩系，但不是成矿物源的主要提供者。 3、不同类型矿床的对比研究证实，区内玄武岩中层状Sn、Cu（Zn）多金属矿体是火山沉积成因；而个旧组碳酸盐岩中层状锡石-硫化物型矿床应为海底喷流热水沉积成矿作用的产物，具有明显的同生沉积特征；两者的成矿时代均为中三叠世个旧组同生沉积期，两种成矿作用具有继承性和连续性。层状火山沉积型Cu（Sn）矿体和层状喷流热水沉积型Sn、Cu（Pb、Ag）矿体上往往叠加有与燕山期花岗岩成矿有关的不规则状、脉状Sn、W、Be、Cu、Pb、Ag矿体。同沉积构造和地层是控制火山沉积成矿作用和喷流热水沉积作用发生以及层状矿（化）体的产出的关键因素。要形成大而富的矿床，则须具备早期为火山喷发或热水喷流中心、后期为花岗岩侵位中心的条件。 4、矿石、围岩的微量元素、稀土元素、稳定同位素地球化学研究发现，同生沉积型层纹条带状矿体与细（网）脉状、大脉状矿体具有同一的金属和硫铅来源，且主要来自深部。碱性玄武岩为火山沉积型Sn、Cu矿床的成矿提供了大部分的成矿物源；燕山期花岗岩浆活动主要提供叠加改造成矿的动力和热力条件。 5、全面建立了个旧锡铜多金属矿床的时空结构模型。即：矿床的成矿作用经历了印支期海底火山沉积成矿、喷流热水沉积成矿和燕山中晚期花岗岩叠加改造成矿，并且形成了相应的3个矿床成矿系列，可进一步分为8个矿床式。在空间上，矿床构成“两楼一梯”结构模式，即“下楼”为层状火山-沉积型Sn、Cu（Zn）矿体，“上楼”为层状喷流热水沉积Sn、Cu（Pb、Ag）矿体，“一梯”即受花岗岩叠加-改造而形成的上下贯通的不规则状、（细）脉状型及矽卡岩型Sn、W、Be、Cu、Pb、Ag矿体。由于多期次、多来源和多种成矿作用的叠加成矿，从而形成了超大型矿床。这一模式可为个旧矿区深部及外围地区的找矿提供崭新而有效的找矿思路。 6、在上述矿床结构模型和控矿规律认识的指导下，综合区内矿床生产实际情况，进行了成矿预测。北东东向同沉积断裂、玄武岩层以及花岗岩同时产出的地段是寻找Sn、Cu多金属矿床的有利靶区。值得重视的是，区内火山沉积型Cu（Sn）矿床在空间上与玄武岩的密切依存关系可用于指导找矿，而且在玄武岩受花岗岩交切的某些有利部位可找到403^#矿体式和双竹式Sn、Cu矿床。更多还原

【Abstract】 The Gejiu super-large tin-copper-polymetallic deposit is located on the southeastern Yunnan province, and technically situated on the junction area of Eurasian, Pacific and Indian plates. There are a long history of mineral exploitation and much more high geological researches in Gejiu ore district. But the substantive researches are mainly focus on the minerogenetic theory and related model based on granitic hydrothermal mineralization, and many conclusions have been drawn that the tin-copper-polymetallic deposit is mainly related to Yanshanian epoch granitic mineralization,and the metallogenetic period is medium-later Yanshanian epoch. Based on the geological fact which collides with granitic mineralization,this paper mainly do systemic researches on geologic features, mineralogy, trace elements, rare earth elements, stable isotope geochemistry, fluid inclusions of rock or orebody, and petrology, petrochemistry, geochemistry, regional geological synthetic analyses of the Gejiu strata formation. From that, some conclusions are summarized as follows:The geological environment of Gejiu ore district is a NE-striking fault basin during Indo-Chinese epoch which goes deep and wide smartly in middle-upper Triassic, and it may combine or join NW-striking fault basin named Guangnan-Qiubei and Malipo-Babu into a fault basin belt. The viewpoint also can be supported by the rock types of alkali-basalt, basalt-tuff, carbonatite bearing pyroclastic material, silicolite and so on. The characteristics of petrochemistry and rock occurrence show that the alkali-basalt in Gejiu strata formation was formed in the extensional tectonic setting within continent (T2gi $ ).Geochemical analysis of the regional strata and the section in-place measurements shows that the strata rich in tin and copper of Precambrian basement and Devonian system etc. is the partly mineral source for Gejiu Tin-copper-polymetallic deposit.The Gejiu strata formation is the mainly mineral-hosting rock series, but not the main source for mineralization.Comparison researches on different types of deposits indicate that the bedded tin-copper-polymetallic ore bodies in alkali-basalt have a volcano-sedimentary origin, and the bedded cassiterite-sulfide deposit in carbonate rock of Gejiu formation have a seabed exhalative hydrothermal sedimentary mineralization genesis. There are obvious characteristics of symphitic sedimentary. Their mineralizations occurred both during mid Triassic, the mineralization of latter is successive and successional. The bedded volcano -sedimentary copper (tin) ore bodies and exhalative hydrothermal sedimentary tin, copper (lead, silver) ore bodies are often superimposed by vein tin, tungsten, beryllium, copper, lead, silver ore bodies related to granitic mineralization of Yanshanian epoch. Symphitic sedimentary structures and strata are the key factors for volcanic sedimentary mineralization, exhalative hydrothermal sedimentary mineralization and output of bedded ore body. So if there are huge and rich ore bodies, there must be centers for volcano eruption and exhalative hydrothermal in the forepart and for granitic intrusion in the last stage.It is found that the symphitic sedimentary laminated striped ore bodies and thin(net) vein or thick vein bodies have the same source of metal, lead and sulphur through studying on the trace elements, rare earth elements, stable isotope geochemistry. Furthermore they mainly come from mantle. Alkali-basalt is the main mineral source for volcanic sedimentary tin copper deposit. The Yanshanian epoch granitic magma activity mainly provided drive power and heat for superimposed mineralization.The time-space structure model of Gejiu super-large tin-copper-polymetallic deposit has been set up. There take place three different stages of mineralization, such as seabed volcanic sedimentary stage, exhalative hydrothermal sedimentary stage in Indo-Chinese epoch and granitic superimposed activity stage in the mid-late Yanshanian epoch. So three types of metallogenic series and eight types of deposit models更多还原