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中生代是华北地台金矿床的最重要成矿时期 ,该时期的金矿床与煌斑岩和花岗岩类密切伴生 .煌斑岩以富金和富LILE为特征 ,而花岗岩的金含量则甚低 .金矿床的铅、氢、氧和硫同位素组成高度分散 ,表明成矿物质具有多来源性 .金矿床中的蚀变时间上从早到晚的演化和空间上从下到上的分带为 :由气化 -高温 (30 0℃～ 4 5 0℃ )阶段的钾长石化 ,经 (高 - )中温(2 0 0℃～ 32 0℃ )阶段的黄铁绢英岩化和绢英岩化 ,变为中 -低温 (2 2 0℃～ 15 0℃ )阶段的硅化 .金在钾交代阶段活化转移 ,而在黄铁绢英岩化阶段开始沉淀成矿 .欧亚板块与古太平洋板块之间以及华北板块与华南板块之间在中生代时期的强烈碰撞、挤压和俯冲造成了华北地台金矿床形成的有利构造环境 .俯冲板块俯冲过程中的去气、去碱、去硅和去LILE(包括金 )等作用 ,可形成含金成矿流体 .在俯冲板块进入地幔后 ,含金流体和分熔产物一起上升并交代地幔楔 ,形成能够产生富金煌斑岩浆的富集地幔 .同时 ,仰冲板块中的褶皱、变质、花岗岩的形成、火山作用、煌斑岩侵入、水 /岩反应 ,以及成矿物质的活化转移和交换作用 ,促进了金在有利环境中聚集成矿 .在上述基础上建立了金在俯冲带的成矿模式
The Mesozoic is the most important metallogenic stage of the gold deposits in the North China Platform, where the gold deposits are closely associated with the lamprophyres and granites, and the lamprophyres are characterized by rich gold and rich LILE while the gold content of granites is very low. The highly dispersed isotope composition of lead, hydrogen, oxygen and sulfur in the gold deposit indicates that ore-forming materials have multiple origins.The evolution of the alteration time in gold deposits from morning till evening and spatially from bottom to top are: From the k-fossilization of the gasification-high temperature (30 0 ℃-45 0 ℃) stages to the pyroxenation and sericite alteration of the (high-mid-temperature (2000 ~ 3200) Is silicification at the mid-low temperature (220 ° C-150 ° C), while activation and transfer of gold occurs during the replacement of potassium, and begins to deposit and mineralize during the yellow-silty-sinonitization stage.As the Eurasian and Paleo-Pacific plates and the North China plate Strong crustal, compressional and subduction during the Mesozoic during the Mesozoic from the South China Plateau resulted in the favorable tectonic setting of the gold deposits in the North China Platform.The gas removal, de-alkali removal, silicon removal and LILE (including gold removal) And so on, can form the gold ore-forming fluid in the subduction plate into After the mantle, the gold-bearing fluid and the melt fraction rise together and account for the mantle wedge to form an enriched mantle that can produce gold-rich lamprophyres. At the same time, folds, metamorphism, granite formation, volcanism, Rock intrusion, water / rock reaction, and activation and transfer of ore-forming materials and exchange, promoting the accumulation of gold in the favorable environment mineralization.Based on the above, the establishment of gold in subduction zone metallogenic model