【作者】 赵凯；

【导师】 杨立强；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2014， 博士

【摘要】 哀牢山造山带是三江特提斯构造域的重要组成部分，经历了完整的多旋回演化历程，发生了巨量规模的金属工业聚集，形成了我国最重要的喜马拉雅期造山型金矿带，是研究复合造山带中碰撞造山型金矿成因机制理想选区。论文通过对金矿带内四个典型金矿矿床地质和成矿作用地球化学研究，获得如下主要成果。（1）野外及岩相学观察表明，金矿化对围岩并没有选择性；矿体主要受北西向次级构造控制；矿化样式主要为破碎带蚀变岩型与石英硫化物脉型；围岩蚀变具多期多种类型、范围窄、分带不明显；矿物组合相对简单，黄铁矿与石英是主要的载金矿物。（2）EMPA和LA-ICP-MS研究表明，浅部地层为墨江与长安金矿提供了大量成矿物质，而老王寨与大坪金矿成矿物质则主要来自于深部；成矿期载金黄铁矿主体为变质热液成因，高Ni含量指示有幔源物质的混入；老王寨与长安载金黄铁矿Au与As含量呈正相关，电感耦合等离子质谱输出信号图谱平坦，说明Au主要以[Au, As]2-、[Au(As,S3)]2-等络合物在热液中运移，并以类质同象的形式替代[S2]2-进入黄铁矿晶格；而在墨江与大坪金矿，金主要以裂隙金形式存在。（3）流体包裹体研究表明，成矿流体具中低温、中低盐度、富含CO2的特征，为H2O-NaCl-CO2-ΣS体系的还原性流体；从大坪→老王寨→墨江→长安，主成矿期流体均一温度与CO2含量逐渐降低；老王寨金矿成矿流体温度、压力的快速降低，使得流体中CO2过饱和，引起相分离作用；流体沸腾和硫化作用是金的主要沉淀机制。（4）C-H-O-S-Pb同位素与黄铁矿LA-ICP-MS分析表明，区域成矿流体主要为深源流体，以中-下地壳变质流体为主，伴有幔源流体的加入，成矿深度较浅的矿床存在大气降水的混入；成矿物质具有多来源特征，主要来源于中下地壳，并存在幔源物质的混入，浅部地层也提供部分成矿物质。（5）区域地质与各金矿床成矿作用的异同表明，从大坪→老王寨→墨江→长安，成矿深度依次降低，成矿系统中地壳浅部物质所占比率逐步升高，并依此建立了哀牢山金矿带造山型金矿成矿模型。更多还原

【Abstract】 The Ailaoshan orogenic belt is an important part of the Sanjiang Tethys. It hasundergone multiple cycles of evolution with innumerable metallic deposits,comprising the most important Himalayan orogenic gold belt. It is also an idealdistrict of investigating the origin of orogenic gold deposits. Based on field geologyand geochemical research of the ore-forming processes of the four typical golddeposits in the Ailaoshan gold belt, the main achievements are summarized below:(1) Based on field geology and petrographical observations, the disseminatedmineralization and quartz-vein mineralization occur commonly in all wall rocks. Theore bodies are controlled by the NW-trending subsidiary structures. The wall-rockalterations occurred at multiple stages with a variety of types, narrow in space with noobvious zoning. Pyrite and quartz are the main gold-hosting minerals.(2) Based on the EMPA and LA-ICP-MS results, the shallow strata provideabundant ore-forming materials for Mojiang and Changan gold deposits, whereas theore-forming materials of the Laowangzhai and Daping deposits are mainly sourcedfrom the deep. The gold-bearing pyrite in the mineralization stage formed frommetamorphic fluids. The high Ni content indicates partial contribution from themantle. The gold and arsenic contents of pyrite from Laowangzhai and Changandeposits show positive correlations and smooth LA-ICP-MS profile, indicating thegold migrates mainly as complexes of [Au, As]2-、[Au(As,S3)]2-in the ore-formingfluids, and as the isomorphism replacing [S2]2-in the lattice. However, gold aremainly in the form of crack gold in Mojiang and Daping gold deposits.(3) Based on the fluid inclusion study, the ore-forming fluids have lowtemperature, low salinity, and CO2-rich characteristics and belong to reducing fluidsof H2O-NaCl-CO2-ΣS system. From Daping, through Laowangzhai, Mojiang toChangan, the main mineralization homogenization temperature of fluid and CO2content decreased. The remarkable decrease of temperature and pressure of theLaowangzhai deposit results in supersaturation of CO2and phase separation. Fluidboiling and vulcanizing are the main precipitation mechanism of gold. (4) The C-H-O-S-Pb isotopes and LA-ICP-MS analyses of pyrite show that theore-forming fluid are mainly made up of deep metamorphic fluid from themedium-lower crust and mantle fluid. Atmospheric water is evolved in the shallowdeposits. The ore-forming materials are multiple sourced, mainly from themedium-lower crust with mixing of the mantle material. The wall rocks also providesome of the ore-forming material.(5) The similarities and differences between regional geology and themineralization of these gold deposits indicate that from Daping through Laowangzhai,Mojiang to Changan deposit, the metallogenic depth becomes shallower in sequence,the proportion of shallow crust material in the metallogenic system graduallyincreased. Based on these, this study established the model of orogenic goldmetallogenesis in the Ailaoshan gold belt.更多还原