【作者】 戴雪灵；

【导师】 彭省临； 赖健清；

【作者基本信息】 中南大学 ， 地质学， 2012， 博士

【摘要】 大尹格庄金矿位于郯庐断裂东侧,胶西北隆起区东南缘、招平断裂带中段,是胶东地区重要的超大型蚀变岩型金矿之一,具有“深、大、贫”的特点,金矿体赋存于玲珑花岗岩与胶东群变质岩接触带中的招平断裂带中。本论文在充分收集总结前人在胶东研究成果的基础上,通过野外地质调查、区域地质调研、矿床地质剖析、构造地质解析、岩相学研究、主微量元素分析、流体包裹体示踪、稳定同位素分析等多学科理论的交叉和多手段的运用,以陈国达的多因复成理论为指导,以成岩-成矿机理的研究为主线,描绘了大尹格庄金矿多阶段成岩模式和热液对流循环成矿模式。通过对本区出露的各类岩石进行分析认为本区的绿岩基底原岩为基性火山岩+沉积岩,且斜长角闪岩、变辉长岩等基性岩为源自亏损地幔拉斑玄武质岩浆在海相张性环境中喷发而形成；认为玲珑花岗岩为挤压环境中绿岩基底重熔而成,具有富Si、Al、Ba、Sr、Na,贫Mg、Y、Yb、Ti、HREE和正Eu异常、高的Mg#值等特点,为“似C型埃达克岩”,其产出暗示曾有东部高原的存在；郭家岭花岗岩为地壳整体拉薄大地构造背景下形成壳幔混合型花岗岩；闪长玢岩、煌斑岩的产出代表中生代中晚期该区处于整体拉张的大地构造背景,其均为源于富集地幔的高钾—钾质的中—基性岩脉。在研究矿体产状、规模、品位,矿石的矿物成分、结构构造、矿石类型,脉体及矿物的共生组合、穿插关系、包含关系、溶蚀关系,围岩蚀变类型及蚀变分带特征、包裹体测温资料等的基础上将大尹格庄金矿的成矿划分为6阶段。通过研究6个阶段中的流体包裹体的岩相学、类型、温度、压力、盐度、密度及成分特征,认为成矿早阶段至晚阶段包裹体的类型从气相+气液两相+含CO2三相包裹体变为液相+气液两相包裹体,且温度、压力、盐度不断降低,包裹体成份由H2O-CO2-CH4-H2S变为H2O-CO2-CH4-SO2型,成矿环境由还原环境变为氧化环境。氢、氧同位素结果显示大尹格庄金矿的初始成矿流体为地幔+岩浆流体,而晚期则大气水占优势的特征,显示玲珑花岗岩的流体来源较为复杂既有变质水也有幔源水的参与。碳同位素结果同样显示出初始成矿流体主要为深源,晚期不断有其它流体参与的特征；硫同位素特征则显示该区的硫源具有继承性,且矿石的硫同位素范围与郭家岭花岗岩最为相近的特征,暗示其最直接来源为郭家岭花岗岩。铅同位素特征显示古老铅源特征,与S同位素继承性特征一致,且铅同位素落在一条斜率较陡的直线上,意味着其铅源可能为壳幔混合的特点。综合研究了大尹格庄的构控、层控和岩控的特征,并对成矿物质的多源性、成矿流体的多源性、成矿动力的多源性等进行了探讨,重点对成矿流体的性质、运移、沉淀机制进行了分析,系统剖析了“多因复成”的超大型韧性剪切带的典型特征。将地洼阶段的成矿作用归结为“热液对流”多次循环成矿系统,指示深部有巨大的找矿潜力。更多还原

【Abstract】 Dayingezhuang gold deposit, which is located at the southeast margin of the Northwest Jiaodong uplift, and bounded on the middle of Zhaoping fault and on the east of the Tanlu fault, is one of the super-large tectonic alteration gold deposits characterized by "large depth, huge reserve and low grade" This gold orebody occurs in the Zhaoping fault, which is the contact zone of the linglong granite and metamorphic rock of. Jiaodong GroupConsulting the literatures and earliest formal geological survey, and being guided by the polygenetic compound theory of Chen Guoda,, this paper conducts outfield and regional geological survey, ore field geological researches, structure analysis, petrography study, trace element analysis, fluid inclusion tracing, stable isotope analysis and so on, to construct multiphase diagenesis model and hydrothermal convection model for gold deposit in Dayinge county.Investigations on the outcropping rocks in the research area show that the origin of greenstone basement protolith is from mafic volcanic rock and sedimentary rock. And some mafic rocks, like amphibolite and gabbro, is originated from mantle tholeiitic magma erupted in the tensional marin facies, and the Linglong granite from the remelting of greenstone protolith. The linglong granite is bearing abundant Si, Al, Ba, Si and Na, but fewer Mg, Y, Yb, Ti and HREE, positive Eu anomaly, and high Mg#. This is the like C-type adakite, implied from its occurrence there was an eastern plateau in the Mesozoic. The Guojialing granite, the crust-mantle mixed type, was formed under the extensional structural movement. And diorite porphyry and lamprophyre, high potassium-potassic type intermedia-mafic dykes, suggest that Jiaodong area had undergonethe extensional tectonic movement in the late Me sozoic. Subject to the researches on the occurrence, scale, and grade of the orebody, the component of ore, structure, ore types, alteration types and alteration zoning, Dayingezhuang gold mineralization is divided into two periods and six stages. Analysis of fluid inclusions, including petrography, type, temperature, pressure, salinity, density and characteristics of compositions in the six stages, indicate that, from the early to late stage,(1) the inclusions evolve from the gas+vapor-liquid+CO2-bearing vapor-liquid-liquid inclusions to the liquid+vapor-liquid inclusions;(2) temperature, pressure and salinity keep to fall down;(3) the compositions of the inclusions vary from H2O-CO2-CH4-H2S to H2O-CO2-CH4-SO2; and (4) the mineralizing condition changes from reduction to oxidation.The results of hydrogen-oxygen isotope data show that (1) the genesis of ore-forming fluids in the Dayingezhuang gold deposit come from mantle and magmatic fluids at the early stage, then mostly the meteoric water;(2) the fluids in the Linglong granite involve metamorphic and mantle fluids. The test of carbon isotope also shows that the source of ore-forming fluids come from deep-depth, and then converge with other fluids. The results of sulfur isotopes show that the sulfur in the Jiaodong area is inheritable and the sulfur isotope range are the most similar to Guojialing granite, which suggests that the sulfur here apparently comes from Guojialing granite. Lead isotopes also show that the genesis of ancient lead had the identical inheritance as sulfur isotopes, and lead isotopic data plot in a straight line with a relatively steep slope, which indicates that the genesis of the lead might come from the crust and the mantle.This paper synthetically investigates the characteristics of structure-control, strata-control and rock-control, and goes through a deeply discussion on multi-source characteristics of ore-forming materials, fluids and dynamics, especially on the characteristics, transportation, precipitation and mechanisms of ore-forming fluids, and systematically discusses the typical characteristics of super-large plastic shear zone with polygenetic-compound theory.The mineralization of Diwa stage is subject to hydrothermal convectionsystem, which implies that this area may host other potential deposits, especially in its lower part.更多还原