造山型金矿床成矿作用若干问题研究进展

Latest Advances of Researches on Orogenic Gold Deposits

造山型金矿床是世界上重要的金矿床类型,也是当前国际矿床学研究热点。近年来该类金矿床在成矿流体及成矿物质来源、成矿机理及成矿模式等方面研究取得了重大进展。研究表明:造山型金矿床成矿流体及成矿物质主要为富含水的火山沉积岩在区域变质过程中因脱流体而释放出来的。Au主要以Au[HS]_2^-的络合物形式沿着深大断裂向浅部运移,期间CO_2和H_2S不仅能提高Au在流体中的溶解度,还能使Au在运移过程中不因沉淀而贫化。变质脱流体成矿模式很好地解释了该类金矿床成矿流体及成矿物质的来源、运移和成矿元素的沉淀。水岩反应和压力的瞬时改变是Au发生高效沉淀的主要因素。建议在造山型金矿床研究过程中采用单个流体包裹体成分LA-ICP-MS等先进分析测试技术。

The orogenic gold deposit is one of the most important types of gold deposits in the world,and it is also one of the most popular interests in the international deposit reseaches.Significant advances have been made in the latest decades,including the sources of ore-forming fluids and materials,metallogenic mechanism and model.Studies indicate that ore-forming fluids and materials of orogenic gold deposits are dominantly derived from the released fluids during the process of region metamorphism of the water rich volcanic sedimentary rocks,Au element presents as the complex of Au（HS）2^- and transfers from the deep fracture to the shallow migration.The CO2 and H2S not only improve the solubility of Au in the fluid,but also block Au to precipitate and dilute during migration.Metamorphic defluid metallogenic model can be well used to interpret the origin,transportation and precipitation of the ore-forming fluids of these deposits.The chemical interactions between mineralized fluids and host rocks,and rapid depressurisation are the two significant factors for gold precipitation.At the same time,this paper suggests that the LA-ICP-MS analysis for individual fluid inclusion should be applied to researching the origin of orogenic gold deposits.