低硫化型与高硫化型浅成低温热液金矿蚀变特征与成矿关系的对比研究  

Comparison of Hydrothermal Alteration Characteristics of Low Sulfidation and High Sulfidation Epithermal Gold Deposits and Their Relation with Mineralization

作　　者：杨永胜[1] 吴春明[1] 吕新彪[2,3] 高荣臻[2] 李春诚[2] 邢伟伟[4] 

机构地区：[1]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [2]中国地质大学(武汉)资源学院,湖北武汉430074 [3]中国地质大学成矿过程与矿产资源国家重点实验室,湖北武汉430074 [4]河北省区域地质矿产调查研究所,河北廊坊065000

出　　处：《地质与勘探》2015年第4期655-669,共15页Geology and Exploration

基　　金：中央高校基本科研业务费专项资金(编号:CUGL120296)资助

摘　　要：文章对浅成低温热液金矿床特征产物、蚀变分带、蚀变类型演化的成因及蚀变形成的主控因素进行了总结。与矿质沉淀在同一机制下形成的特征岩相和蚀变保存了成矿过程的重要信息,是有效的勘查标志。低硫化型中热液爆破角砾岩、刃片状方解石/石英、细粒梳状石英及具快速冷却无序结构的冰长石,是沸腾作用的产物,而沸腾同时控制金沉淀;高硫化型中蚀变以孔洞状石英、硫酸盐及粘土化等酸性淋滤产物为特征,流体酸性性质主要源于岩浆酸性挥发分在液相中的解离及SO2的歧化或氧化反应,孔洞状硅化岩是主要赋金部位,受孔洞或裂隙控制的自形石英及其中的金矿化,它不同于岩浆酸性气水相与大气水为主流体混合形成的酸性淋滤蚀变及浸染状金矿化,而可能是由源于较深部岩浆单相流体(直接从熔体中出溶或与卤水相分离出来)浓缩形成的低温液相流体产生的。由绢英岩化到中级泥化的连续分带蚀变,有利于低硫化型金成矿;而由高级泥化到中级泥化的连续分带蚀变,对高硫化型金成矿有利。流体和围岩的性质、物理化学梯度以及水岩比是控制热液蚀变最主要的因素。初始流体酸碱成分对于形成的蚀变矿物组合具有决定性作用。低硫化型金成矿流体受地热系统驱动,初始富钾低酸性物质在低水岩比条件下形成以岩石缓冲为主的中碱性矿物组合;位于浅部岩浆-热液系统中或较深部岩浆气水,经过收缩或吸收大气水而形成高硫化型成矿流体,初始高酸性贫钾物质在高水岩比条件下形成流体主导的中酸性矿物组合。This paper reviews genesis of typical products,alteration zoning,evolution of alteration types and main controlling factors of alteration in epithermal gold deposits. Typical lithofacies and alteration formed by the same mechanism of ore material precipitation which bear lots of important information of the mineralization process,which are also effective exploration marks. Hydrothermal explosive breccia,bladed calcite or quartz,fine grained comb quartz,and adularia with disordered structure formed under rapid cooling conditions are products of fluid boiling,which also controlled gold precipitation in low-sulfidation epithermal gold deposits. Alteration in high-sulfidation epithermal gold deposits is characterized by vuggy quartz,sulfation,and clayization which are caused by acid leaching. Acidic properties are mainly originated from magmatic acidic volatile dissociation,and disproportionation or oxidation reaction of SO2 in liquid phase fluid. Euhedral quartz was controlled by holes or fractures in vuggy silicified rock,in which gold orebody formed in a way different from that generated by magmatic acid gas fluid mixing with meteoric water with acid leaching alteration and disseminated gold mineralization,instead probably generated by a kind of low temperature liquid phase fluid which contracted from deep magmatic single-phase fluid（ directly exsolution from melt or separation from hypersaline phase fluid）. Continuous zoning from phyllic to intermediate argillic alteration is favorable for low-sulfidation epithermal gold mineralization,while continuous zoning from advanced argillic to intermediate argillic alteration is favorable for high-sulfidation epithermal gold mineralization. Physical and chemical gradients between fluid and wall rock,individual properties,and cumulative water / rock mass ratios are important factors controlling hydrothermal alteration. The initial m（ K^＋/ H^＋） of magmatic-hydrothermal fluid which largely is dictated by magma composition,plays a crucial role in the formation of

关 键 词：浅成低温热液金矿 低硫化型 高硫化型 热液蚀变 成矿作用 

分 类 号：P618.51[天文地球—矿床学] P611.13[天文地球—地质学]