【作者】 魏浩；

【导师】 徐九华；

【作者基本信息】 北京科技大学 ， 矿业工程， 2014， 博士

【摘要】 黑龙江多宝山斑岩铜（钼）矿床是大兴安岭中北部多宝山-阿尔山铜（钼）成矿带内最大的斑岩型矿床，位于兴蒙造山带的最东端。本文通过对多宝山矿床的精细解剖及矿田内典型矿床的对比研究，理清了多宝山斑岩铜钼矿床蚀变和矿化的关系；明确提出了多宝山斑岩铜钼矿床蚀变-矿化阶段；诠释了早阶段石英脉体缺少高盐度包裹体的成因；约束了流体性质及物化条件；建立了最新的流体P-T演化模式图，再塑了流体演化过程；探讨了成矿物质来源；在提出多宝山矿田多期成矿作用的基础上，建立了新的成矿模式图；概括出找矿勘查模型；开展了区域找矿评价。多宝山斑岩铜（钼）矿床的蚀变-矿化阶段划分为4个阶段：Ⅰ钾硅化阶段、Ⅱ硅化-钼矿化阶段、Ⅲ绢英岩化-铜矿化阶段、Ⅳ碳酸盐石英阶段。各阶段石英中包裹体类型主要有水溶液包裹体、富CO2包裹体、含子晶多相包裹体、纯CO2包裹体。测温结果表明，阶段Ⅰ到Ⅳ均一温度范围分别为245-400℃、260-300℃、200-280℃、125-170℃；盐度分别为6-10%、1.7%-39%、0.1%-24.8%、0.5-12.8%NaCleqv.。阶段Ⅰ到Ⅲ压力分别为110-160MPa,58-80MPa,8-17MPa。早阶段流体总体为H2O-CO2-NaCl体系，晚阶段逐渐演变为H2O-NaCl体系。钼矿化主要和CO2与H2O不混溶作用有关，铜矿化与流体的沸腾和混合作用有关。早阶段包裹体与典型斑岩矿床相比高盐度包裹体很少，主要与燕山期的改造破坏有关，仅有的含石盐子晶包裹体出现在阶段Ⅱ而非钾硅化阶段Ⅰ，可能与阶段Ⅱ的CO2与H2O不混溶过程有关。黄铜矿、黄铁矿δ34S为-4.6~-1.6，成矿物质主要来自深部岩浆房，也有部分硫来自多宝山组或铜山组地层中。阶段I流体D和18O组成分别为-87.2-95.5和7.28.1，阶段III流体分别为-82.2-104.2和2.03.4。总体上含矿热液由岩浆热液演化为岩浆热液加地下水热液。稀土元素特征表明含矿岩体可能与洋壳的俯冲及部分熔融有关，在上升过程中受到了地壳的混染。蚀变-矿化岩石微量元素聚类分析、因子分析表明：①Mo、Bi、Cu、W相关性较好，为矿化的指示元素；②北西向片理化带为斑岩矿化的中心，绢英岩化蚀变与其关系密切，同时还受燕山期片理化构造的影响。年代学数据表明多宝山地区分别在早二叠世（280Ma±）受古亚洲洋俯冲及晚三叠－中侏罗世（200Ma-160Ma）的太平洋俯冲影响至少存在两期矿化。多宝山区域资源预测及综合评价工作中，应用改进的综合地质变量统计法优选出4个铜钼成矿有利异常区，这四处异常区总体上呈北东向排列，基本上与区域构造及岩层走向一致，说明区域构造对铜钼矿化异常控制作用最强，为主要的控矿因素，局部受多宝山矿田北西向构造控制，异常区域排列方向也为北西向，但北西向各异常中心均在北西向异常区域与北东向异常区域叠加处，说明两组构造交汇处为成矿提供了最为有利的条件。更多还原

【Abstract】 The Duobaoshan porphyry Cu(Mo) deposit, located in the eastern part ofXingmeng orogenic belt, is the largest porphyry deposit in theDuobaoshan-Aershan Metallogenic belt on the central and northern Daxinganling.Based on the fine ananlysis of the Duobaoshan porphyry Cu(Mo) deposit andcomparative studies on the typical deposits, this thesis clarified the relationshipbetween alteration and mineralization; clearly put forward thealteration-mineralization stage; explained the reasons for lack of high salinityinclusions within the early stage; constrained fluid properties andphysical-chemical conditions; gave out a new model of fluid evolution; discussedthe ore-forming material source; set up a new metallogenic model after analysedmultistage mineralization; summarized the ore prospecting model; launched theregional prospecting evaluation.Four ore-forming stages are recognized at Duobaoshan deposit:(I) Potassicand silicic stage;(II) Silicification-molybdenum mineralizing stage;(III)Phyllic-copper mineralizing stage; and (IV) carbonate-quartz stage. Fluidinclusions in quartz can be identified as aqueous water, CO2-rich, daughtermineral-bearing and pure CO2.Fluid inclusions of stage (I) are characterized byaqueous, CO2-H2O and pure CO2, with homogenization temperatures of245-400℃, salinities of6-10wt%NaCl eqv., and those of stage II is dominated byaqueous, CO2-H2O, daughter mineral-bearing inclusions, with peakhomogenization temperatures of260-300℃and salinities of1.7~39wt%NaCl eqv.Stage III is also characterized by aqueous and CO2-H2O inclusions, with peakhomogenization temperatures of200-280℃, salinities of0.1-24.8%wt%NaCleqv., whereas stage IV is simply aqueous, with homogenization temperatures of125-170℃, salinities of0.5-12.8wt%NaCl eqv.. Respective trapping pressures forstage I, II, III are110-160MPa,58-80MPa,8-17MPa. The ore-forming fluidgenerally belong to H2O-CO2-NaCl fluid system in the early stage and graduallybecome H2O-NaCl fluid system in the late stage. Mo mineralization is mainlyrelated with CO2-H2O immiscibility, and Cu mineralization is yielded by boilingaction. Compared with typical porphyry deposits, the number of halitecrystal-bearing inclusions are smaller in the Duobaoshan porphyry copper deposit,which is mainly related to the transformation and destruction at Yanshanian. Moreover, the phenomenon that most of the halite crystal-bearing inclusionsappear within stage II instead of stage I suggests possible presence of CO2-H2Oimmiscibility.The34S values of pyrite and chalcopyrite mainly range from-1.6to-4.6permil, suggesting predominantly source of deep magma chamber with lesseramounts of Duobaoshan formation. Hydrogen(D) and oxygen(18O) isotopiccompositions for stage I fluid at the Duobaoshan deposit range from-87.2to-95.5per mil and7.2to8.1per mil, respectively, which are constrained by magmaticfluid. Those for stage III shift evidently toward meteoric water, with the D valuesof-82.2to-104.2per mil and18O values of2.0to3.4per mil, which indicates aevolution process from magmatic hydrothermal fluid to a mixing magmatic andmeteoric fluid. The characteristics of rare earth elements show that Duobaoshangranodiorite and granodiorite porphyry pluton are probably related to the thesubduction and partial melting of ocean crust. Cluster analysis and Factor analysisof trace elements suggest:(1) Mo, Bi, Cu, W have a close correlation, which canbe the indicator elements for mineralization;(2) as the mineralizing center ofporphyry pluton, NW trending schistosity zone where banding phyllic alterationoccur may be influenced by Yanshanian schistosity structure. Geochronologicaldata show that Duobaoshan area are influenced respectively by paleo-asianoceanic subduction at (280Ma±) and by Paleo-Pacific Ocean during the Jurassicperiod (200Ma-160Ma), which lead to at least two mineralizing periods.Druing the work of resource comprehensive evaluation throughout theDuobaoshan area, this thesis applies the improved geological statistics method ofgeological variables to optimize four favorable Cu、Mo mineralizing anomalyareas which occur along NE trending and correspond to regional structures. It isconcluded that NE trending regional structures are the most importantore-controlling Factors. While, NW trending structures also control the location ofthe mineralization. It is thereore the intersection of the two groups of structuresthat are most favorable Cu、Mo mineralizing anomaly areas.更多还原