甘肃阳山金矿床成矿流体演化与矿床成因
发布时间：2018-07-22 13:57
【摘要】：甘肃阳山金矿床是我国近几年发现的超大型金矿床。本文基于野外观测和前人总结,对阳山金矿床进行系统研究,确定成矿阶段以及成矿时代,并且进行了流体包裹体显微测温、成分分析和H-O同位素研究,对成矿流体来源与演化和矿床成因进行探讨。1,根据野外工作成果,在总结前人工作的基础上,提出阳山金矿床存在多期次成矿的观点,并对成矿期次进行了划分。阳山金矿床成矿作用可分为沉积成岩期、变质热液期、岩浆热液期和表生氧化期,其中不同热液期又可分为不同阶段。变质热液期又可分为石英-绢云母-黄铁矿阶段、黄铁矿-毒砂-石英阶段、毒砂-黄铁矿-石英阶段以及石英-碳酸盐阶段;岩浆热液期又可分为石英-黄铁矿阶段、自然金-辉锑矿-石英阶段、石英-碳酸盐阶段。2,阳山金矿床两期成矿流体总体上表现为中低温(110℃~380℃)、低盐度(8wt.%NaCl eqv)、低密度。变质热液期成矿流体的均一温度主要集中220℃~320℃,盐度主要集中在2.0~6.6wt.%NaCl eqv,富含CO2。岩浆热液期成矿流体均一温度主要集中在120℃~220℃,盐度主要集中在2.0~6.0wt.%NaCl eqv,富含有机气体。3,成矿流体的H-O同位素结果显示成矿流体来源特征。综合以上流体包裹体特征,早期变质热液期成矿流体来自富矿下地壳地层的变质流体,主要以变质热液为主。晚期岩浆热期成矿流体可能为岩浆热液和大气降水的混合流体。4,综合流体包裹体和H-O同位素研究,我们认为在变质热液期,流体由于压力降低,发生沸腾导致CO2等大量气体逸出,其温度降低,盐度增高,导致Au以络合物的形式被吸附到黄铁矿表面,Au与黄铁矿毒砂一起沉淀。岩浆热液期有机气体的加入和水岩反应,破坏了Au硫氢络合物的平衡,导致大量Au硫氢络合物形式沉淀。
[Abstract]:Yangshan gold deposit is a super-large gold deposit discovered in China in recent years. Based on the field observation and the previous summary, this paper makes a systematic study on the Yangshan gold deposit, determines the metallogenic stage and the metallogenic age, and carries out the fluid inclusion microthermometry, composition analysis and H-O isotopic study. The origin and evolution of ore-forming fluids and the genesis of ore deposits are discussed. Based on the results of field work and on the basis of summing up the previous work, the author puts forward the viewpoint that there are many times of mineralization in Yangshan gold deposit, and divides the times of mineralization. The mineralization of Yangshan gold deposit can be divided into sedimentary diagenesis metamorphic hydrothermal magmatic hydrothermal and supergene oxidation. The metamorphic hydrothermal period can be divided into quartz sericite pyrite stage pyrite arsenopyrite quartz stage and quartz carbonate stage and magmatic hydrothermal stage can be divided into quartz pyrite stage. The ore-forming fluids of the natural gold-stibnite-quartz stage, quartz-carbonate stage and Yangshan gold deposit generally show moderate and low temperature (110 鈩，
本文编号：2137682
[Abstract]:Yangshan gold deposit is a super-large gold deposit discovered in China in recent years. Based on the field observation and the previous summary, this paper makes a systematic study on the Yangshan gold deposit, determines the metallogenic stage and the metallogenic age, and carries out the fluid inclusion microthermometry, composition analysis and H-O isotopic study. The origin and evolution of ore-forming fluids and the genesis of ore deposits are discussed. Based on the results of field work and on the basis of summing up the previous work, the author puts forward the viewpoint that there are many times of mineralization in Yangshan gold deposit, and divides the times of mineralization. The mineralization of Yangshan gold deposit can be divided into sedimentary diagenesis metamorphic hydrothermal magmatic hydrothermal and supergene oxidation. The metamorphic hydrothermal period can be divided into quartz sericite pyrite stage pyrite arsenopyrite quartz stage and quartz carbonate stage and magmatic hydrothermal stage can be divided into quartz pyrite stage. The ore-forming fluids of the natural gold-stibnite-quartz stage, quartz-carbonate stage and Yangshan gold deposit generally show moderate and low temperature (110 鈩，
本文编号：2137682
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