【作者】 贾福聚；

【导师】 秦德先；

【作者基本信息】 昆明理工大学 ， 矿产普查与勘探， 2010， 博士

【摘要】 老君山成矿区位于云南省的东南部,以盛产锡、锌、钨、银著称。在1380km2的范围内已探明曼家寨特大型矿床一处,铜街、新寨、南秧田大型矿床三处,辣子寨、水洞厂、南当厂、戈岭、老寨中型矿床五处,以及一系列小型多金属矿床(点)二十余处,是滇东南多金属成矿带(个旧—薄竹山—老君山)的重要组成部分。本文以喷流沉积和成矿系列理论做指导,主要进行了老君山成矿区地层、矽卡岩与花岗岩的岩石学、岩石化学、地球物理、地球化学分析；矿床地质特征、矿石矿物学和组构学研究；岩(矿)石的微量元素、稀土元素、稳定同位素地球化学等方面的研究工作。在系统分析研究区成矿机理的基础上,完成了成矿系列的划分；并总结了老君山成矿区有利的成矿地质因素、建立了成矿模式及找矿模型。在全面分析研究区地层、构造、花岗岩及地球物理、地球化学特征与成矿的关系的基础上,总结了成矿规律,完成了成矿远景评价。论文的研究成果与创新主要体现在以下几个方面：(1)老君山成矿区以老君山为中心,加里东期为扬子地台前缘海盆凹陷中心,沉积厚度较大,加里东晚期开始隆起,海西构造阶段总体上隆,周围局部残存浅海,在早中泥盆世部分地区沉积了碳酸盐岩和砂泥岩,燕山构造阶段沿隆起核心形成陆壳改造重熔花岗岩并部分上升侵位,最终形成弯隆构造格局。(2)老君山地区经历了多期地质作用,区内变形变质作用极其复杂,围绕老君山花岗岩体由外到内以次形成了绿片岩相带、角闪岩相带、混合岩相带三个变质相带。本文结合变质岩的形态产状特征、矿物岩石学特征及岩石化学特征,进行了变质原岩恢复,证明老君山成矿区含矿矽卡岩、角岩、石英岩等变质类岩石的原岩为一套海底火山—喷流沉积岩石。研究区矽卡岩传统上划分为复杂矽卡岩和简单矽卡岩(角岩)两类,作者认为复杂矽卡岩距花岗岩体较近,由火山—喷流沉积—叠加改造作用形成；简单矽卡岩(角岩)分布在距岩体较远的区域,由火山—喷流沉积—改造作用形成。岩(矿)石同位素测年结果显示,印支期是老君山地区变形变质作用的峰期。(3)在老君山成矿区发现了火山—喷流沉积及其若干证据：①多金属硫化物矿体呈层状分布,且与围岩呈渐变过渡关系、互层状产出,含矿地层层位稳定,单层延长可达数十公里；②岩(矿)石的结构、构造中发现了大量的变余斑状结构、变余间粒结构、柱状变晶结构,变余气孔、杏仁构造、鲕状构造、结核状构造等,为喷流沉积型矿床的特征结构、构造；③矿石铅同位素测年结果主要为早加里东期、印支期,早于燕山期花岗岩侵入阶段,与花岗岩成矿理论相矛盾；④对硫化物矿石及矽卡岩进行了岩石化学分析,大量样品点投影在火山岩区域。证明了老君山地区早加里东期火山—喷流沉积作用的存在,喷流沉积层位集中在下寒武统冲庄组和中寒武统田蓬组,是多金属硫化矿床的集中产出地层。(4)老君山成矿区矿床的形成是一个复杂的地质演化过程,主体层状多金属硫化物矿床属多源、多成因的复生矿床,大致经历了三个阶段：即火山—喷流沉积阶段→区域变质阶段→岩浆岩热液叠加阶段。在海底火山—喷流沉积阶段形成了分布广泛的多金属硫化物沉积层,在区域变质阶段喷流沉积物质普遍受到变质,老君山花岗岩体为铝过饱和型陆壳重熔花岗岩,岩体中成矿元素丰富,不但形成了多处伟晶岩矿床,对周边大型多金属硫化物矿床的形成也具有一定的叠加改造作用。(5)以成矿演化的观点,结合不同矿床的主导成矿因素,在老君山成矿区厘定了3大成矿系列。在空间分布上以花岗岩为中心由内向外依次为：Ⅲ、燕山晚期花岗岩伟晶—气成高温热液成矿系列；Ⅱ、加里东早期火山喷流沉积—印支期变质—燕山期花岗岩热液叠加改造成矿系列；Ⅰ、加里东早期火山喷流沉积—印支期区域变质成矿系列。归纳了各成矿系列所包含的矿床类型,并结合典型矿床详细研究了各系列矿床的矿体产出特征、岩(矿)石结构、构造特征及地球化学特征。(6)老君山多金属成矿区众多矿床为多来源、多期叠加成矿模式,是早加里东期火山—喷流沉积、印支期区域变质作用和燕山期花岗岩叠加改造共同作用的结果。(7)老君山成矿区控矿规律：①地层、岩相控矿特征明显,花岗岩体以外几乎所有的多金属硫化物矿床(点)均分布在寒武系,下寒武统冲庄组和中寒武统田蓬组是主要赋矿地层,在由下部碎屑岩相带向上部大理岩相过渡的层位有利于矿体产出。②文山—麻栗坡、马关—都龙深大断裂控制着矿床的分布,在老君山穹窿体周围形成的一系列断裂、裂隙往往成为后期脉状矿体的赋存部位。③老君山成矿区地层受到了强烈的变形变质作用,绿片岩相带是主要的矿床产出相带,矽卡岩是主要赋矿岩石。④燕山期花岗岩控制了气成高温热液矿床的形成,并与多金属硫化矿床紧密相依。更多还原

【Abstract】 Laojunshan Metallogenic Belt is in the Southeast of Yunnan province, it is famous for the abundant ore resources of tin, zinc, ungsten and silver. In which one giant large scale (Man jiazhai) deposit, three large scale(Tongjie, Xinzhai and Nanyangtian) deposits, five medium scale(Lazizhai, Shuidongchang, Nandangchang, Gel ing, and Laozhai) deposits, and more than twenty other ore deposits (points) were proven. Laojunshan Metallogenic Belt is an important part of the southeastern metallogenic belt(Gejiu, Bozhushan and Laojunshan)of Yunnan.This dissertation was guided by the theories of exhalative sedimentary mineralization and metallogenic series, the petrology, petrochemistry and geothemistry of the stratum, skarn and granite were analysised; the geological characteristics of the deposits, the mineralogy, texture and structure of the ores were studied; the microelement, rare earth element and stable isotope of the rocks and ores have been studied. On the basis of examining the relationship between the metal mineralization and strata, structure, granites and geophysics, geochemical, metallogenic regularities were summarized. Based on analyses of metallogenic mechanism, metallogenic series were formed. Ore-forming Geological Conditions were analysed, the metallogenic model and prospecting model were established, ore formation prospect evaluation was given. The main research findings and new viewpoints achieved in this dissertation are as follows:(1)Laojunshan metallogenic belt with the central of Laojunshan mountain, as a front seabasin of Yangtze platform during Caledonian epoch, with thicker sedimentary cover, During late Caledonian epoch the belt was gradually uplift, and was integral uplift during Hercynian, only shallow sea left in the belt. The sequence of Early and Middle Devonian strata, mainly carbonate, sandstone and mudstone. Crust remelting granites formed in the central of the uplift belt during Yanshanian, and the dome like shape was formed during the same period.(2)The region has a complex geological structure and strong metamorphism, metamorphic lithologies include greenschist, amphibolite and migmatite. Based on the petrographic and mineralogical characteristics of metamorphic rocks, and the petrochemical characteristics, that the metamorphic rocks are marine volcanic exhalation-sedimentary origin. There are two kinds of skarns:complex skarn and simple skarn. Complex skarns are close to the granite, that were formed by volcano-exhalative-sedimentation-superimposition and reformation. Simple skarns are far from the granite, that were formed by volcano-exhalative-sedimentation-reformation. According to the isotopic dating, Indo-chinese epoch was the peak metamorphic period of Laojunshan Metallogenic Belt.(3)There are some evidences of volcanic exhalation-sedimentary:①Polymetallic sulfide orebodies are beded, have a gradual transitional contact and interbeded with the wall rocks, the ore-bearing strata occur steadily, and the along strike can be length up to more than 10 kilometres.②Blastoporphyritic texture, intergranular texture, crystalloblastic texture and vesicular structure, amygdaloidal structure, oolitic structure, nodule structure are widespread in the belt.③Isotopic dating of ore-forming events showed that Early caledonian and Indosinian period were the main mineralization stages in Laojunshan Metallogenic Belt, earlier than Yenshanian granite intrusion period, which is in contradiction with granitic genesis.④REE patterns and La/Yb—REE diagram showed the marine volcanic exhalation-sedimentary origin of the skarns and ores. The volcanic exhalation-sedimentary deposits are mainly occurred in Lower cambrian chongzhuang formation and middle cambrian tianpeng formation. (4)The ore generation process is experienced multi-period metamorphism and complex geological evolution process, that could mainly divide into three mineralization stages:Volcanic exhalation-sedimentary stage→Regional metamorphic stage→magmatic hydrothermal superimposition stage. During volcanic exhalation-sedimentary stage, source beds were formed in the sedimentary strata, and most of the source beds were skarnized in regional metamorphic stage, Laojunshan granite belongs to aluminium supersaturation and continental crust remelting type. The granites are rich in ore-forming elements, not only formed many pegmatite deposits nearby, but also the magmatic pneumato-hydrothermal effects are superimposed on preexisting polymetallic sulfide deposits.(5)Three metallogenic series are classified in Laojunshan metallogenic belt. From center to perimeter:Ⅲ. Granitic superimposed metallogenic series of the late Yanshanian epoch,Ⅱ.Volcanic exhalation sedimentary in early Caledonian—regional metamorphism in Indo-chinese epoch—granitic superimposed in late Yanshanian epoch metallogenic series,Ⅰ. Volcanic exhalation sedimentary in early Caledonian—regional metamorphism in Indo-chinese epoch metallogenic series. The deposit types devided, the occurrence of ore bodies, texture and structure of the ore bodies and the wall rocks, and geochemical characteristics of each metallogenic series was studied.(6)The metallogenic models of Laojunshan metallogenic belt were mainly multiple sources and multistage superposition, the formation of ore belt may result from the combination of the volcanic exhalation sedimentary of early Caledonian, the regional metamorphism of Indo-chinese epoch and the granitic superimposed of late Yanshanian epoch.(7)The ore-controlling regularities:①Almost all of the polymetallic sulfide deposits were formed in the Cambrain stratum, lower Cambrian chongzhuang formation, middle Cambrian tianpeng formation and middle Cambrian longha formation were the main ore-hosting stratas in the belt, Lithofacies changes zone from clastic to marble had the favorable condition for the ore formation.②Nearly all of the deposits are restricted between Wenshan-Malipo fault and Maguan-dulong fault, and fault system around the tectonic dome always have good condition for the mineralization of vein ore bodies.③Ore-bearing rocks of the belt always associated with high-grade metamorphism, greenschist is one of the most important ore-bearing facies belts, skarn is one of the most important ore-bearing rock types.④Yenshanian granite was the source of rich metal-bearing fluids that formed hypothermal deposits in the belt, and also important for the polymetallic sulfide deposit.更多还原