本文選題：巖石地球化學(xué) + 流體包裹體　； 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：豫西廟嶺金礦床位于熊耳山金多金屬礦集區(qū),是一構(gòu)造蝕變巖型金礦床。該金礦床賦存于近南北向斷裂中,礦化類型主要為微細(xì)浸染狀黃鐵礦化蝕變巖型,次為石英黃鐵礦脈型和石英多金屬硫化物脈型;圍巖蝕變有鉀長石化、硅化、絹云母化、黃鐵絹英巖化、綠泥石化、綠簾石、螢石化、碳酸鹽化。運(yùn)用LA-ICP-MS鋯石U-Pb測(cè)年、巖石地球化學(xué)、流體包裹體、同位素等手段,查明廟嶺金礦區(qū)花崗斑巖的特征與成因、成礦流體的類型、性質(zhì)、來源與演化、成礦物質(zhì)的來源以及礦床成因。廟嶺金礦床熱液成礦過程可劃分為四個(gè)成礦階段:黃鐵礦石英階段(Ⅰ)、石英黃鐵礦階段(Ⅱ)、石英多金屬硫化物階段(Ⅲ)和石英碳酸鹽階段(Ⅳ)。礦區(qū)內(nèi)白家凹花崗斑巖脈的LA-ICPMS鋯石U-Pb年齡為157Ma,形成于晚侏羅世;巖石地球化學(xué)及同位素特征顯示,花崗斑巖屬高分異的I型花崗巖,是下地殼部分熔融的產(chǎn)物,形成于古太平洋板塊向歐亞板塊俯沖的弧后陸緣伸展環(huán)境;其成巖年齡比成礦年齡(117Ma)早40Ma左右,故推測(cè)花崗斑巖與金成礦作用無關(guān)。黃鐵礦的稀土元素組成兼具燕山期花崗巖和賦礦圍巖地層的稀土元素特征,顯示廟嶺金礦床成礦物質(zhì)來源于太古界太華群,且萃取了部分地層物質(zhì);稀土元素具明顯銪異常、而鈰無明顯異常,表明成礦流體具弱還原性;黃鐵礦的微量元素特征總體上反映了黃鐵礦的熱液成因,與巖漿其后熱液關(guān)系密切,同時(shí)后期演化過程中與圍巖發(fā)生了交代作用。流體包裹體綜合研究表明,成礦流體為巖漿流體,由早期的中溫、中-低鹽度、還原環(huán)境下的H2O-Na Cl-CO2體系,向晚期的低溫、低鹽度的H2O-Na Cl體系演化。C-H-O同位素組成表明,成礦流體可能來源于燕山期巖漿期后熱液,到演化后期有大氣降水的加入。Pb同位素組成顯示廟嶺金礦床成礦物質(zhì)來自于下地殼,混入部分地幔物質(zhì)。Au元素來自早白堊世巖石圈拆沉作用導(dǎo)致殼幔混源巖漿,在巖漿期后熱液流體中以Au(HS)和HAu(HS)2形式遷移;流體的沸騰、混合以及與圍巖地層的水-巖反應(yīng)改變了成礦流體的物理化學(xué)環(huán)境,促使Au沉淀富集成礦。
[Abstract]:Miaoling gold deposit, located in Xiong'ershan gold polymetallic deposit, is a structural altered rock type gold deposit. The gold deposit occurs in the near north-south fault, and the mineralization type is mainly micro-disseminated pyrite altered rock type, followed by quartz pyrite vein type and quartz polymetallic sulphide vein type, and the wall rock alteration includes potassium feldspar, silicification, sericite, etc. Yellow sericite lithotization, green mud petrifaction, verdanite, fluorinization, carbonization. By means of LA-ICP-MS zircon U-Pb dating, geochemistry, fluid inclusions and isotopes, the characteristics and genesis of granitic porphyry, the types, properties, sources and evolution of ore-forming fluids in Miaoling gold deposit are investigated. The origin of the ore-forming materials and the genesis of the deposits. The hydrothermal metallogenic process of Miaoling gold deposit can be divided into four metallogenic stages: pyrite quartz stage (鈪，

本文編號(hào)：2101480