焦家金矿带构造控矿模式

发布时间：2018-01-20 16:12

  本文关键词： 构造变形 显微构造 构造控矿模式 数值模拟 焦家金矿带 胶东　出处：《中国地质大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：胶东是全球重要的黄金产地,也是中国探明金资源量最多的地区,其中焦家金矿带已探明金资源量1000吨,其内金矿床(体)严格受焦家断裂带及其下盘次级断裂/裂隙控制,构造控矿模式是亟待深入研究的关键问题。为此,论文通过典型剖面构造-蚀变-矿化岩相填图、露头尺度构造解析、载金矿物黄铁矿微区原位技术和3D有限元数值模拟方法,从区域→露头→矿物多尺度系统剖析金矿床(体)分布规律与不同级别、序次和型式的控矿构造的关系,以揭示焦家金矿带构造控矿规律和巨量金活化富集的构造控制机理,构建其构造控矿模式,为新的勘查部署提供理论依据。主要取得以下认识:(1)焦家断裂带空间结构可细分为断裂核(主断裂面、断层泥、片理化和糜棱岩化带)、破碎带(碎裂岩、构造热液脉群、密集节理和劈理带)和弱变形带(稀疏节理带)。(2)焦家断裂带经历了5期构造变形:D1主要表现为成矿前NE向韧性剪切带;D2为成矿前韧-脆性构造活化;D3为成矿期韧-脆性变形(伴随强烈的水岩反应和大规模金成矿作用);D4为成矿期脆性变形,主要表现为岩/矿石的脆性破裂和热液脉体(如石英-硫化物脉和方解石脉)的充填;D5为成矿后脆性变形。(3)识别出四类黄铁矿,可见金通常发育于黄铁矿脆性变形形成的裂隙和晶隙间或破裂-愈合的裂隙内,以裂隙金为主,兼有包裹体和晶隙金,并发育纳米金粒,可能是黄铁矿显微-超显微变形的位错中不可见金的再活化和再富集而形成。(4)断裂面擦痕所反映的断裂运动学和动力学特征具有复杂的二元结构,既有正断层活动特征,也有逆断层活动特征,兼有走滑分量。成矿期主体表现为张剪性构造控矿样式(NW向拉张兼有左行走滑分量),是成矿前的主要构造形迹在成矿期构造应力场作用下再活化而形成的。控矿构造应力场3D有限元数值模拟结果显示,成矿前主应变和剪应变的相对高值区,随着成矿期构造再活化或应变能释放是成矿流体聚集和成矿物质沉淀的有利部位。
[Abstract]:Jiaodong is an important gold producing area in the world, and it is also the largest area of proven gold resources in China. The Jiaojia gold belt has been proved to have 1000 tons of gold resources. The gold deposit (body) is strictly controlled by the Jiaojia fault zone and its secondary faults / fissures in the footwall. The structural ore-controlling model is a key problem to be studied in depth. In this paper, through typical section tectonic-alteration mineralized lithofacies mapping, outcrop scale structure analysis, in-situ technique of pyrite microarea and 3D finite element numerical simulation method, the regional analysis is carried out. 鈫扥utcrop. 鈫扵he relationship between the distribution law of gold deposits (bodies) and the ore-controlling structures of different grades, order and pattern is analyzed in order to reveal the structural ore-controlling law of Jiaojia gold deposit belt and the tectonic control mechanism of huge amount of gold activation and enrichment. Construct its tectonic ore-controlling model to provide a theoretical basis for new exploration and deployment. The main knowledge is as follows: 1) the spatial structure of Jiaojia fault zone can be subdivided into fault core (main fault surface, fault gouge). Schistatic and mylonized zones, broken zones (cataclastic rocks, tectonic hydrothermal vein groups). The dense joints and cleavage zones) and the weak deformation zone (sparse joint belt, Jiaojia fault zone) experienced five tectonic deformation stages: 1: D1, mainly showing NE ductile shear zone before mineralization; D2 was activated by pre-metallogenic ductile-brittle structure; D _ 3 is ductile brittle deformation during metallogenic period (accompanied by strong water-rock reaction and large-scale gold mineralization); D _ 4 is a brittle deformation in metallogenic period, which is mainly characterized by brittle fracture of rock / ore and filling of hydrothermal veins (such as quartz-sulfide vein and calcite vein). Four types of pyrite were identified by D5 as post-metallogenic brittle deformation. The visible gold is usually developed in the cracks formed by the brittle deformation of pyrite and the intergranular gap or the fracture and healing fissure, mainly in the fissured gold. There are inclusions and intergranular gold, and nanocrystalline gold particles are developed. It may be that the reactivation and reenrichment of invisible gold in the micro-ultramicro deformation of pyrite formed the fracture kinematics and dynamics characteristics of the fracture surface, which reflect the complex binary structure. Both normal fault activity and reverse fault activity, as well as strike-slip component. The main ore-forming stage is characterized by tension-shearing tectonic control style and left strike-slip component. The result of 3D finite element numerical simulation of the ore-controlling tectonic stress field shows that the relative high value region of the principal strain and shear strain before mineralization is obtained. With the tectonic reactivation or strain energy release during metallogenic period, the ore-forming fluid accumulates and the ore-forming minerals are precipitated.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.51
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本文编号：1448840