【作者】 谭红艳；

【导师】 顾雪祥；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2013， 博士

【摘要】 小兴安岭—张广才岭成矿带位于中亚—兴蒙造山带东段,西伯利亚地块、华北地块和太平洋板块的交汇区域,是经古亚洲洋构造域与滨太平洋构造域强烈叠加而成的复合造山带,具有独特构造演化背景。在两大构造域转换时期,该区发生大规模成岩成矿作用。首先,在成矿相关岩浆岩岩石学和成岩成矿年代学研究基础上,系统划分出矿床成矿系列,并对成矿系列地质地球化学和流体包裹体进行研究,建立了成矿动力学模型。(1)燕山早期与中酸性花岗岩有关的多金属矿床成矿系列(Ⅰ)：包括矽卡岩型、斑岩型和热液脉型及其复合类型矿床。获得相关花岗岩类岩石锆石U—Pb年龄和辉钼矿Re-Os年龄分别为195-175Ma和180-175Ma,结合前人相关研究结果,认为其成岩成矿作用发生于晚三叠世—早侏罗世,其中成岩大致始于T3,成矿于J1,成岩成矿大致结束于172Ma。与成矿相关的花岗岩属钙碱性—高钾钙碱性系列,具有Ⅰ型和A型花岗岩特征,成岩成矿发生于造山期后岩石圈伸展减薄环境。成岩成矿物质主要来自地壳,成矿流体主要来自岩浆,部分来自大气降水。氧化物阶段成矿温度大致为380～500℃,硫化物阶段成矿温度大致为250～360℃,推测的成矿深度为2-3km。包裹体特征显示,在成矿过程中可能发生过不同流体相互混合和流体沸腾作用。(2)燕山晚期与火山作用有关的金银、铅锌矿床成矿系列(Ⅱ)：以浅成低温热液型金矿床为主。获得与之相关流纹岩锆石U-Pb年龄约为110Ma,辉绿玢岩角闪石Ar-Ar年龄约为100Ma,结合前人相关研究结果,认为该成矿系列成岩成矿作用发生于120～100Ma,其中成岩始于120Ma,金成矿年龄为110～105Ma,金成矿稍晚于成岩,辉绿玢岩及与之相关的改造型铅锌矿形成最晚。该成矿系列成岩成矿作用发生于太平洋板块俯冲体制下的地壳加厚构造环境,成岩成矿物质主要来自下地壳或上地幔,成矿流体主要来自大气降水,部分来自岩浆。浅成低温热液型金矿床成矿温度为150～280℃,成矿流体盐度低,成矿深度约为1.2～2.0km。最后,在总结成矿规律基础上,建立了预测模型,并采用综合信息成矿预测方法,对成矿远景进行评价。成矿系列(Ⅰ)分布于早中生代花岗岩带,成矿具同源性、共生性、阶段性、分带性、叠加性、过渡性和互补性。早期为矽卡岩型铁钨锡成矿阶段,晚期为斑岩型钼矿和热液型铜铅锌矿成矿阶段。斑岩型钼矿、矽卡岩型多金属矿和热液脉型铜铅锌矿分别产于岩体内、接触带和外接触带。成矿系列(Ⅱ)分布于晚中生代火山活动带,受裂隙—中心式火山机构控制。共圈定8个成矿远景区,并提出找矿方向。更多还原

【Abstract】 The Lasser Xing’an Range-Zhangguangcai Range metallogenic belt is composite orogen belt superposed by Paleoasia oceanic tectonic domain and circle Pacific tectonic domian, lying in the intersection area among east section of Central Asian-Mongolian-Hinggan orogenic belt and Siberian,North China blocks. In the two tectonic domain transformation period, large-scale mineralization and diagenesis occured.On the basis of study magmatic petrology and diagenesis mineralization chronology, to the division of metallogenic series of ore deposits, to the study of geology and geochemistry and fluid inclusion, establishing the model of metallogenic dynamics.(1) The metallogenic series of intermediate-acid granitoids polymetallic deposit in early Yanshan Period(I):including skarn type, porohyry type, hydrothermal vein type, compound deposit. The zircon U-Pb age of195-175Ma and molybdenite Re-Os age of180～175Ma was obtained from granite, indicating that the suite formed in the Late Triassic-Early Jurassic Epoch, diagenesis in Late Triassic and mineralization in Late Triassic, ended in172Ma. Granitoids related to the mineralization belong to calc-alkaline series to high kalium calc alkalic series, charactered by I and A type, diagenesis and mineralization occurred after orogenic period and lithospheric extension and thinning. Materials source of diagenesis and mineralization comes from crust and the ore-forming fluid is meanly from and magmatic and atmosphere precipitation. The metallogenic temperature of oxide is380～500℃, sulfide250～360℃, depth of2～3km. Fluid inclusion studies that different fluid mixing and boiling during the metallogenic process.(2) In the late Yanshanian, related with volcanism, Au-Ag-Pb-Zn deposit series (II):The epithermal gold deposit. Rhyolite zircon U-Pb age of110Ma and sillite hornblende Ar-Ar age of100Ma, was obtained, indicating that the formed in the120～100Ma, diagenesis in120Ma and gold mineralization in110～105Ma, ended in sillite and releated lead-zinc mine. Diagenesis and mineralization of the metallogenetic series occurred in tectonic environment of the subduction of pacific plate lead to crust thickening, material source of diagenesis and mineralization is from the lower crust or upper mantle and ore-forming fluid is derived meanly from atmospheric precipitation and partly magmatic. The ore-forming temperature of the epithermal gold deposit is150～280℃. The ore forming fluids had very low salinity, depth of1.2～2.0km.Summarizing metallogenic regularities, establishing prediction modles, adopting comprehensive information metallogenic prediction method, this paper evaluates ore-forming prospects. The metallogenetic series (Ⅰ) distributed in granite belt of the early Mesozoic, the character of metallogenic symbiosis stage, homology, superpositon and transitivity. Metallogenic stages of skarn type iron tungsten tin occurred earlier, and late porphyry molybdenum deposit and hydrothermal type copper lead and zinc deposit. Porphyry molybdenum deposit, skarn type polymetallic deposits and hydrothermal type copper lead and zinc deposit come from internal zone, contact zone outer contact zones respectively. The metallogenetic series (Ⅱ) distributed in active belt in the late Mesozoic, controlled by fissure-central volcanic types. The paper outlines8metallogenic prospects and proposes direction of further exploration.更多还原