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云南墨江金矿床位于“三江”褶皱带哀牢山板块结合带北段的墨江 -九甲断裂带中。矿体分布于金厂超基性岩体西侧的金厂组烂山段含火山物质的硅质岩、变余粉砂岩和板岩中 ,矿体由含金石英脉、含金硅质岩组成 ,金矿体受层位和岩性控制。在矿区还分布晚于金矿化形成的镍矿体。金镍矿体共同存在于同一矿区 ,矿区围岩蚀变种类多 ,与金矿化有关的围岩蚀变主要有硅化、黄铁矿化等。矿体的空间分布与穿插关系表明 ,金成矿作用开始于晚三叠世以前。含金硅质岩具有沉积作用形成的地质特征 ,其稀土元素、氧、硅同位素地球化学特征与热水沉积作用形成的硅质岩一致 ;含金石英脉的矿物组成、结构和构造特征、稀土元素、硅同位素、微量元素组成与含金硅质岩相似 ,可能与硅质岩具有相似物质来源或形成作用。金矿石中金与镍、铬等元素的相关性很低。推断金矿床成矿作用可能开始于中石炭世含金硅质岩的热水沉积作用 ,在早三叠世以前 ,成矿热液通过充填和交代作用在硅质岩和上部的岩石中形成含金石英脉。后来的区域变质作用、超基性岩自变质作用及镍矿化作用可能使金矿体的金含量提高 ,但没有产生具有工业意义的独立金矿化。
The Yunnan Mojiang gold deposit is located in the Mojian-Jiujia fault zone in the northern segment of the Ailao Mountain plate junction zone of the “Sanjiang” fold belt. The ore body is distributed in the volcanic siliceous rocks, metamorphic siltstones and slate in the Rotary Station of the Jinchang Formation in the Jinchang Formation on the west side of the ultramafic rock mass. The orebodies are composed of gold-bearing quartz veins, gold-bearing silicalite Composition, gold ore subject to lithology and horizon control. Nickel ore bodies formed later than gold mineralization are also distributed in the mining area. The gold-nickel ore bodies coexist in the same mining area. There are many types of wall rock alteration in the ore area. The alteration of the surrounding rock associated with gold mineralization mainly includes silicification and pyrite mineralization. The spatial distribution of orebodies and interspersed relationship show that gold mineralization began before Late Triassic. The gold-bearing silicalites have the geological characteristics of sedimentary formation. The REE, oxygen and silicon isotope geochemical characteristics are consistent with those of the silicic rocks formed by hydrothermal sedimentation. The composition, structure and structural features of the minerals with gold-bearing quartz veins, Elements, silicon isotopes, and trace element compositions are similar to those of gold-bearing cherts, which may be of similar material origin or formation with cherts. Gold in gold and nickel, chromium and other elements of the correlation is very low. It is inferred that the metallogenic process of the gold deposits may start from the hydrothermal sedimentation of the Carboniferous gold-bearing cherts. Prior to the Early Triassic, the ore-forming hydrothermal fluids formed into siliceous rocks and upper rocks by filling and metasomatism Quartz vein. Subsequent regional metamorphism, ultrabasic rock metamorphism and nickel mineralization may increase the gold content of gold ore, but did not produce an independent gold mineralization of industrial significance.