【作者】 万多；

【导师】 王可勇； 孙丰月；

【作者基本信息】 吉林大学 ， 矿产普查与勘探， 2014， 博士

【摘要】 中国山东省胶东地区是我国最重要的金矿富集区之一，拥有大小金矿山百余座。位于胶西北地区的招平断裂带是该区最重要的控矿构造带，而其北段是整个断裂带金矿床产出最集中的地区，尽管目前对招平断裂带北段的尚无比较统一的界定，但该区域金矿床富集并主要受断裂带活动控制的地质事实已经被大家公认。本文将招平断裂带北段的两个NE—NNE向分支断裂：九曲蒋家断裂带和破头青断裂带统一归为招平断裂带北段地区，以他们的交汇部位直至两条断裂带结束部位所控制的5个金矿床为主要研究内容。旨在总结该区金矿床的成因及成矿规律，并利用数字地质模拟软件进行成矿预测。九曲蒋家断裂带由北向南依次分布有大磨曲家金矿床、阜山金矿床、九曲金矿床；破头青断裂带由北向南依次分布有赵家小型金矿、水旺庄大型金矿、东风大型金矿。通过研究发现，该区金矿主要以构造蚀变岩型金矿为主，作为著名的玲珑金矿的分矿之一的九曲金矿属蚀变岩型和石英脉型过渡型金矿。研究区的金矿床虽然各自的矿体产出规模，空间分布形态等不同，总体上属于同一大地构造环境下，同一地质过程对不同地质部位影响的结果。因此各金矿床具有相似的地质特征，出露地层以胶东群老基底变质岩为主，岩浆岩主要为与成矿关系密切的郭家岭花岗闪长岩和玲珑花岗岩。区内金矿床乃至胶西蚀变岩型金矿床普遍分为四个成矿阶段，即黄铁矿—石英阶段；石英—黄铁矿阶段；石英—多金属硫化物阶段和碳酸盐阶段。系统的流体包裹体研究表明，随着成矿作用的进行各成矿阶段流体性质发生明显变化，早期—主成矿期流体主要为中温、低盐度的NaCl-H2O-CO2体系流体，并发生过强烈的相分离作用，成矿流体经历了初始不混溶→强烈不混溶→不混溶减弱的演化过程。流体相分离作用过程中CO2、H2S等挥发组分的大量逸出，导致热液体系物化条件的明显变化，进而破坏含金络合物的稳定性，使金元素及其化合物沉淀、析出。金矿化的强弱与流体相分离的程度直接相关，石英-黄铁矿阶段是本区成矿流体不混溶作用最强烈阶段，同时也是本区金元素沉淀成矿的主要阶段。成矿晚期随着大气降水的不断加入，成矿流体演变为简单的低盐度NaCl-H2O体系，此时由于流体不混溶导致热液中金的大量沉淀而使晚阶段流体中金剩余量较少，金的沉淀、析出也已基本完成，因此该阶段成矿作用亦较弱。流体包裹体H-O、C-O同位素研究结果暗示流体来源于岩浆，通过对比胶东群地层、玲珑花岗岩及郭家岭花岗闪长岩的含金性、S同位素、铅同位素等地球化学参数认为成矿物质主要来源于郭家岭花岗闪长岩。测得金矿区内辉钼矿模式年龄为128.5±1.9Ma～131.1±1.8Ma，郭家岭花岗闪长岩年龄为126～135Ma，略晚于玲珑花岗岩的150～160Ma。结合前人对成矿后脉岩119±7Ma的年龄，认为本区成矿年龄应在119～128Ma。综合分析认为本区成岩成矿作用主要受环太平洋构造域的影响。在受太平洋板块俯冲影响的岩石圈减薄环境下，胶东地区在燕山期发生了多期岩浆活动，与本区金成矿作用直接相关的为郭家岭花岗闪长岩体的侵入活动。早白垩世郭家岭花岗闪长岩就位以后，受构造运动、变形的影响，富含成矿物质的岩浆分异流体及富含地幔物质的成矿流体在构造薄弱部位沉淀、析出金元素，形成金矿床。矿床形成时代为白垩纪。金矿床的产出部位、规模大小和矿石类型严格受断裂蚀变带的形态、规模、空间展布所控制。矿体的空间展布与断裂带基本一致。两条分支断裂沿NE—NNE方向延伸，沿其走向方向，矿体呈减弱→减小→尖灭的整体趋势。构造对金矿的控制作用突出表现在不同规模断裂的多级控矿特征，主干断裂控制着主要矿脉的产出及分布，次级断裂控制着次要矿脉的产出及分布，断裂规模与矿脉（体）规模呈正相关关系。而这种构造控矿规律直接导致矿化空间出现明显的分段富集现象，表现在矿体在矿脉中沿走向和倾向的分布并不是连续的、均匀的，而是存在无矿间隔，呈现尖灭再现的特点。研究区范围在区域1:200000水系沉积物金异常J13、J14高值区，区域重力场、磁场及激电异常中均显示该区具备较好的成矿条件。结合实际地质特征，利用OPIS成矿预测模拟系统对九曲蒋家断裂带和破头青断裂带断面形态、金品位、米克吨值、矿体厚度和蚀变带厚度进行成矿指标趋势模拟可以发现，九曲蒋家断裂带NE端虽处于构造尖灭端，但构造带连续完整，未经后期破坏，其深部各成矿指标趋势模拟高值区套合关系较好，显示较好的成矿潜力，区内104号勘探线至112号勘探线之间，深度范围-800～-1200m，为本文预测靶区。破头青断裂带NE端同样处于构造尖灭端，但被滦家河断裂切割破坏，个别成矿指标趋势模拟虽在断裂带NE端有高值区出现，但彼此套合关系并不理想，该区域近年来的探矿工作也未发现有价值的找矿线索，综合分析认为，破头青断裂带NE端深部成矿潜力很小，不建议投入过多探矿工作。通过现有工程控制数据，结合实际地质特征，利用OPIS系统对阜山金矿207号脉、大磨曲家金矿302号脉和东风金矿171号脉分别进行深部矿体形态模拟，在各成矿指标高值重合部分定位预测靶区。更多还原

【Abstract】 As one of the most import regions with rich gold pool in China, Jiaodong area ofShandong province possesses hundreds different sizes gold mines. The mostsignificant ore-controlling tectonic belt locates in Zhaoping fault at northwest of Jiaodong.However, north side is the major gold deposits producing area in the whole fault belt.Although researchers still have different definitions about north area of Zhaoping fault atpresent, they all admit the geological fact that this area is enriched with gold depositswhich are mainly controlled by fault activities.In this work, two branch faults with NE and NNE directions are unified as north sideof Zhaoping fault, which are Jiuqujiangjia fault and Potouqing fault respectively. Researchwas focused on five gold deposits controlled by the areas from their intersection part totheir ends. Aims of this research are to summarize the causes and metallogenic regularityof gold deposits, and further predict the gold deposits using digital geological simulationsoftware. North to south distributions of Jiuqujiangjia fault are Damoqujia gold deposit,Fushan gold deposit, and Jiuqu gold deposit separately. And for Potouqing fault, they areZhaojia gold deposit, Shuiwangzhuang gold deposit, and Dongfeng gold deposit fromnorth to south.Research turns out that alter rock type gold deposit/mineralization is the main type.And Jiuqu gold deposit, as part of the famous Linglong gold mineralization, belongs to alter rock type and quartz vein type transitional mineralization. In spite of the differencesin respective orebody output scales and spatial distribution, all the gold deposits werecaused by the impacts from different geological parts during the same geological processunder the same tectonic environment. Therefore, all the gold deposits share similargeological characteristics. The outside strata are mainly metamorphic rocks of originalJiaodong group. Magmatic rocks mainly consists of Goujialing granodiorite and Linglonggranite rocks which are closely associated with mineralization. Generally, the golddeposits in researching area or even Jiaoxi alter rock type gold deposits are divided intofour metallogenic stages which are pyrite-quartz, quartz-pyrite, quartz-polymetallic sulfide,and quartz-carbonate respectively.Systematic fluid inclusion studies indicate that characteristics of mineralizing fluidschange obviously during different mineralizing stages. The fluids for pre-andsyn-mineralization are typically characterized by low salinities, mesothermal condition,NaCl-H2O-CO2components and phase separation. The evolution of mineralizing fluidsstarts from initial immiscibility to intense immiscibility, following by decreasingimmiscibility. With the escape of volatile components (CO2, H2S) during the phaseseparation process, the physical and chemical conditions of fluids have changed. Theprecipitation of gold and gold compound is controlled by the stability of gold-bearingcomplex, which is affected by the changing fluid conditions.The extent of goldmineralization is directly controlled by phase separation process. Quartz-pyrite stage inour study area represents the strongest immiscibility, which is corresponded to the maingold mineralization stage. The fluids for post-mineralization, with the mix of meteoricwater, are characterized by low salinities and simple NaCl-H2O components. Because ofthe low concentration of gold in the post-mineralizing fluids, the precipitation of gold islimited.Fluid inclusion, H-O and C-O isotope studies indicate the mineralizing fluids arederived from magma. Comparing the geochemical data (gold components, S, Pb isotopevalues, etc) to Jiaodong stratum, Linglong granite and Guojialing granodiorite, the oreminerals mainly derive from Guojialing granodiorite.The molybdenite model suggests theages ranging from128.5±1.9Ma to131.1±1.8Ma for gold mine. The ages for Linglong granite are150-160Ma, following by the ages of126-135Ma for Guojialing granodiorite.With the constraint of the ages (119±7Ma) from post-mineralization veins, the ages forAu-mineralization are considered to be119～128Ma in our study area. The diagenesis andore-forming processes in our study area are controlled by the Pacific Ocean tectonic field.The lithospheric thinning situation, resulted from the subduction of the Pacific Ocean plate,is favourable for multiple magma activities in Jiaodong area at Yanshanian. The intrusionof the Guojialing granodiorite is responsible for the Au-mineralization in our studyarea.The cretaceous Au deposits formed after the intrusion of the early cretaceousGuojialing granodiorite. The deformation process and structural movement contribute tothe gold precipitation from magma differentiation in fracture zone.The locations, dimensions and ore minerals of gold deposits are directly controlled bythe texture, size and distribution of fractural alteration zone. The distributions of oredeposits and fractural zones are basically consistent.The ore deposits with the trend fromweak to decreasing distribution and to wedge out is following the NE-NNE strikes of twosecondary fractures.The structural control on gold deposits is characterized by multilevelore-controlling. The main fractures controlled the occurrences and distribution of maindeposits, and the secondary fractures controlled the occurrences and distribution ofsecondary deposits. The size of fracture is positively correlative to the dimension of oredeposit.This ore-controlling process contributes to the discontinued concentration of oredeposits. The existence of barren zone along the strikes of veins, showing end to endalignment structures, is correspond to the discontinuity.Our study area lies in the stream sediment with gold abnormity J13、J14area. Theregional gravity field, magnetic field and electricity abnormity all refer to the favorableore-forming conditions in this area. Based on geological setting of our study area, theOPIS ore-forming prediction model is used on Jiuqu Jiangjia and Potouqing fracture zonesin terms of the shape of fracture, grade of gold, thickness of the ore body and the alterationzone. The results indicate potential ore deposits in the deeper area of Jiuqu Jiangjiafracture zone. Even though the northeast Jiuqu Jiangjia fracture zone lies in the tip ofstructure, the fracture zone shows continuity with little destruction in late period. Thepotential ore deposits in our study lie within the No.104prospecting line and No.112 prospecting line, with the depth ranging from800to1200meters.The northeast Potouqingfracture zone lies in the tip of structure as well, and the fracture zone is crosscut byLuanjia River. The interactive relationship is not ideal for ore-forming even withindividual high values. Considering little ore-forming evidences were reported in recentlywork, further mining exploration is not recommended in the deeper part of northeastPotouqing fracture zone.Base on the geologic characteristic and engineering data, using OPIS System modelthe shapes of the ore-bearing vein NO.207in Fushan gold deposit and the ore-bearing veinNO.302in Damoqujia gold deposit and the ore-bearing vein NO.207in Fushan golddeposit respectively. Restrict the forecast scope from the superposition of everyOre-forming parameter.更多还原