【作者】 林龙华；

【导师】 徐九华；

【作者基本信息】 北京科技大学 ， 矿山地质工程， 2012， 博士

【摘要】 蒙库铁矿床是我国新疆规模最大的铁矿床，构造位置处于晚古生代早期活动陆缘的麦兹火山沉积盆地内，其成因类型长期以来备受争议。本文通过细致的野外调查和室内综合研究，从研究矿床的成矿作用机制入手，在综合分析前人研究成矿背景的基础上，系统研究矿床的构造和变质岩地层之控矿规律，获得对矿床模式的认识、找矿的主要标志和勘查模型，并进行了区域找矿评价。应用的主要方法有矿物地球化学、年代学、爆裂法研究，流体包裹体显微测温、同步辐射X射线荧光微区分析（μ-SRXRF）及激光拉曼（LRM）分析。本文关于成矿作用方面的成果包括：1)明确提出蒙库铁矿床的主要富集成矿期为阿尔泰主碰撞造山-区域变质期，早泥盆世的古海底火山作用下只是形成了铁矿的初始矿源（浸染状贫矿），而造山后期的热液交代主要与铜矿化有关。2)综合应用多种分析手段，对矿石矿物特征、流体特征及成矿物质来源有了较全面的认识。研究结果显示，蒙库铁矿床的磁铁矿氧同位素δ¹⁸O_SMOW=-2‰⁺1.77‰，平均-0.15‰，与沉积变质型铁矿床特征较为接近，而与典型矽卡岩铁矿床有显著差别；磁铁矿稀土含量很低，ΣREE=0.94⁴.46ppm，具有LREE富集的右倾配分模式特征，提示成矿物质来源可能与火山岩有密切联系；δCe值则提示成矿环境从早期到晚期由相对氧化环境转变为相对还原的环境；磁铁矿爆裂法提示有多期成矿作用叠加；激光拉曼研究显示流体成分以H₂O和CO₂为主；同步辐射X射线荧光（μ-SRXRF）微探针研究表明流体中铁族元素以及亲硫元素含量较高，提示流体对成矿的贡献；Sm-Nd同位素年代学研究显示成矿物质可能源自古老陆壳基底；Rb-Sr同位素示踪显示成矿流体具有壳源和幔源混合特征。3)综合成矿地质背景、控矿地质条件、多期成矿作用机制，本文给出了蒙库铁矿床的成矿模式。依据地球化学标志、矿区地球物理资料，结合控矿规律建立了勘查模型，并对矿床成矿远景进行了简要评价，认为矿体向西部随着标高的降低，在铁木下尔衮紧闭向斜的西部转折端深部及构造滑脱部位仍然可能有隐伏矿体赋存。4)首次在阿尔泰地区开展综合地质信息变量统计方法研究，提出该方法在本区开展资源远景评价和靶区优选的思路与工作方法。依据1：20万综合地质信息变量异常、1：20万区域化探资料等，提出了区域内7处有利的找矿远景区。更多还原

【Abstract】 Mengku Iron deposit is the largest iron deposit in Xinjiang, west China,whose’s structural position is located in the Mazy volcanic sentiment basin whichformed in the late Paleozoic active continental margin, but the genesis of Mengkuiron deposit is a conflict for a long period of time. This thesis is mainly aboutstaging the structural and metamorphosed formation ore-controlling regularity andmetallogenic model systematically based on comprehensive analysis ofmetallogenic background, also with evaluation of the regional exploration. Themain analysing method implicated are mineral geochemistry, chronology,decrepitating method, fluid inclusion microthermometer, Synchrotron radiationX-ray fluorescence microanalysis （μ-SRXRF） and Laser Raman spectroscopy.Achievements of metallogenesis study in this thesis are:1) Clearly definingthat the main enrichment and metallogenic period of Mengku iron deposit areAltay main collision orogeny–reginal metamorphose period, the paleo submarinevolcanism of Early Devonian Epoch only formed the initial material resource ofiron （impregnated structural lean element）. The postorogenic hydrothermalmetasomatism mainly related to the copper mineralization;2) Get a relativelycomprehensive consideration about a characteristic of ore mineral, hydrothermalfluid and ore forming material sources based on integrated application of variousanalytical methods. The study result shows that δ¹⁸O_SMOWof magnetite fromMengku iron deposit varies from-2‰to+1.77‰with the average of-0.15‰thatsimilar to sedimentary-metamorphic iron deposits and clearly differs from that oftypical skarn type iron deposits. Content of Rare Earth Elements in magnetite isvery low, the range of ΣREE is0.94ppm to4.46ppm, with the characteristic ofrichen of LEE and right dip rare earth elements patterns which indicate thatsources of metallogenic materialism are closely bound up with volcanic rocks;Value of δCe shows that relatively oxidizing metallogenetic environment turned tobe reducing. Decrepitating of magnetite suggesting overlapping of multistagemetalloginesis. Laser Raman study shows the composition of fluid is mainly ofH₂O and CO₂; μ-SRXRF test shows constent of iron family elements andsulphophile elements in fluid are relativly high, which indicates the contributionof fluid to mineralization; Sm-Nd isotope chronology study indicates the sourceof ore-forming materials is from the ancient continental basement. Rb-Sr radioisotopic tracer study suggesting that charactristics of fluid is the mixed crustand mantle source.3) This thesis gives out a metallogenetic model of MengkuIron deposit based on analyzing the geological background, ore controllinggeological condition and mechanism of multi-stage mineralization, also build upan exploration model based on geochemical marks and geophysical data of theMengku orefield, still evaluated the mineralization prospecting of the Mengkuiron deposit briefly, concluding that blind ore deposit maybe occurs in the deephinge zone, and the detachment structure of Tiemuxiaergun enclosed syncline.4)This thesis applies the geological statistics method of geological variables toevaluate the resource prospecting of Altay area for the first time, raising a thoughtand working method of evaluating resource prospecting and optimizing targetingfor ore prospecting. This thesis also gives out seven prospecting area based ongeological variable’s anomaly of regional geological data and regionalgeochemical data which’s scale is1:200,000.更多还原