【摘要】：豫西萑香洼金礦是小秦嶺-熊耳山金礦集中區(qū)最具代表性的蝕變巖-石英脈復合型金礦床之一。該礦成礦條件優(yōu)越,找礦潛力較大。本文通過野外調(diào)查與室內(nèi)分析研究,查明了萑香洼金礦礦床地質(zhì)和成礦流體地球化學特征,探討了萑香洼金礦成礦過程。根據(jù)礦石中金屬硫化物類型、礦物共生組合和結構構造特征,可將豫西萑香洼金礦礦石分為蝕變巖型和石英脈型兩種。蝕變巖型礦石具有交代結構,組成礦物主要是鉀長石、黃鐵礦、石英和絹云母。石英脈型礦石具有熱液充填結構,組成礦物主要是石英和黃鐵礦。野外調(diào)查與鏡下觀察發(fā)現(xiàn),萑香洼金礦床的圍巖蝕變和礦化存在明顯的空間分帶,從礦體向兩側依次出現(xiàn)黃鐵絹英巖化帶、黃鐵鉀硅化帶、青磐巖化帶和新鮮圍巖。根據(jù)礦脈穿插關系和蝕變礦物組合,將豫西萑香洼金礦床蝕變礦化過程分為熱液期和表生期,其中熱液期又可進一步分為鉀長石化、石英-黃鐵礦、石英-多金屬硫化物、螢石-多金屬硫化物和碳酸鹽化五個階段。石英-黃鐵礦階段是次要成礦階段,在這一階段形成了石英脈型礦石,而石英-多金屬硫化物階段是最主要的成礦階段,在這一階段形成了最重要的蝕變巖型金礦石。流體包裹體鏡下觀察與分析測定結果表明,萑香洼金礦床礦物流體包裹體主要有Na Cl-H2O、含二氧化碳和含子晶多相包裹體,不同階段成礦流體分別屬于揮發(fā)分-鹽水和氯化鈉-水體系。從早期的鉀長石化階段到晚期的碳酸鹽階段,成礦流體的溫度和鹽度總體上逐漸降低,δ18O和δD逐漸減小,表明成礦流體中的天水熱液逐漸增多。根據(jù)已經(jīng)獲得的礦床地質(zhì)和流體地球化學資料,認為在萑香洼金礦床蝕變礦化過程中,鉀長石化階段的降溫冷卻使金在成礦流體中初步富集,而石英-黃鐵礦階段的脫氣作用、石英-多金屬硫化物階段的水巖反應和螢石-多金屬硫化物階段的流體不混溶作用使金從成礦流體中沉淀出來而形成不同類型金礦石。
[Abstract]:Huanxiangwa gold deposit is one of the most representative altered rock-quartz vein complex gold deposits in the Xiaoqinling-Xiong 'ershan gold deposit concentration area. The ore-forming conditions are superior and the prospecting potential is great. Based on field investigation and laboratory analysis, the geological and ore-forming fluid geochemical characteristics of Huanxiangwa gold deposit are investigated, and the metallogenic process of Huanxiangwa gold deposit is discussed. According to the types of metallic sulphide mineral symbiotic assemblages and structural characteristics Huanghuangwa gold ore can be divided into altered rock type and quartz vein type. Altered rock type ores have metasomatic structure, mainly composed of potassium feldspar, pyrite, quartz and sericite. Quartz vein type ores have hydrothermal filling structure, and the main minerals are quartz and pyrite. Field investigation and microscopic observation show that the wall rock alteration and mineralization of Huanxiangwa gold deposit have obvious spatial zonation, and from the ore body to the two sides, there are yellow iron sericite zone, Huang Tie potassium silicification zone, Qingwangyan zone and fresh surrounding rock in turn. According to the interpenetrating relation of vein and altered mineral assemblage, the alteration and mineralization process of Huexiangwa gold deposit in western Henan is divided into hydrothermal period and epigenetic stage, in which the hydrothermal period can be further divided into potassium feldspar, quartz pyrite, quartz polymetallic sulfide, etc. Fluorite-polymetallic sulphide and carbonation are five stages. The quartz-pyrite stage is a secondary metallogenic stage, in which quartz vein type ore is formed, while quartz polymetallic sulfide stage is the most important metallogenic stage, in which the most important altered rock type gold ore is formed. The results of observation and analysis of fluid inclusions under microscope indicate that the main mineral fluid inclusions in Huanghuangwa gold deposit are Na Cl-H2O, containing carbon dioxide and sub-crystalline polyphase inclusions. The ore-forming fluids in different stages belong to volatile saltwater and sodium chloride-water systems respectively. The temperature and salinity of the ore-forming fluid gradually decreased, and 未 18O and 未 D gradually decreased from the early stage of potash petrifaction to the late stage of carbonate, indicating that the hydrothermal fluid in the ore-forming fluid increased gradually. Based on the obtained geological and fluid geochemical data of the deposit, it is considered that in the process of alteration and mineralization of Huanxiangwa gold deposit, the cooling and cooling of the stage of potassium feldspathitization lead to the preliminary enrichment of gold in the ore-forming fluid, and the degassing of quartz to pyrite stage. The water-rock reaction in quartz-polymetallic sulphide stage and fluid immiscible in fluorite-polymetallic sulfide stage resulted in the precipitation of gold from the ore-forming fluid and the formation of different types of gold ores.
【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P618.51

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