河南小秦岭杨砦峪金矿床成矿流体特征  

Characteristics of ore-forming fluid of Yangzhaiyu gold deposit in Xiaoqinling gold district,Henan Province

作　　者：熊索菲[1] 丁振举[1] 姚书振[1] 熊杰[2] 胡新露[1] 何谋春[1,3] 谭满堂[1] 

机构地区：[1]中国地质大学资源学院,湖北武汉430074 [2]广西国土资源规划院,广西南宁530022 [3]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074

出　　处：《矿床地质》2013年第6期1249-1261,共13页Mineral Deposits

基　　金：全国危机矿山接替资源找矿综合研究项目"小秦岭地区金矿床成矿规律总结研究(编号:20089939)";中国地质大学(武汉)教学实验室开放基金(编号:SKJ2011112)共同资助

摘　　要：河南省杨砦峪金矿床位于华北克拉通南缘，是小秦岭地区大型的石英脉型金矿床。据野外观察，成矿过程经历了4个阶段：Ⅰ黄铁矿-石英脉阶段；Ⅱ石英-黄铁矿阶段；Ⅲ石英-多金属硫化物阶段；Ⅳ石英-碳酸盐阶段。包裹体岩相学、显微测温以及激光拉曼显微探针研究显示，该矿床为CO2-H2O-NaCl±CH4流体体系，并且发生不混溶。从第Ⅰ成矿阶段到Ⅳ成矿阶段，流体包裹体的均一温度范围分别是307~407℃，270~320℃，225~272℃和166~226℃，呈现逐步降低的趋势；盐度w（NaCleq）平均值分别为7.3%，7.1%，9.0% 和6.4%。各阶段成矿压力为120~178 MPa，85~140 MPa，75~130 MPa和60~122 MPa，呈现逐渐降低的趋势。流体不混溶作用是导致杨砦峪矿质沉淀的重要原因，其诱因可能与控矿断裂由压扭转为张扭所导致的构造减压有关。Located in the southern margin of the North China Craton, the Yangzhaiyu gold deposit in Henan Province is one of numerous lode gold deposits in Xiaoqinling region. The ore-forming process can be divided into four stages, i.e., Ⅰpyrite-quartz vein stage, Ⅱ quartz-pyrite stage, Ⅲ quartz-polymetallic sulfides stage, and Ⅳ quartz-carbonate stage. Researches based on petrography, fluid inclusion tests and Laser Raman spectroscopic analysis suggest that ore-forming fluids are mainly composed of CO2-H2O-NaCl±CH4. There is an immiscible process in the fluid system. The homogenization temperatures of ore-forming fluids from stageⅠto stage Ⅳ are 307.0~406.8℃,270.3~319.6℃,225.4~272.1℃ and 166.3~226.3℃ respectively, with the corresponding average salinities being 7.25% NaCleqv,7.14% NaCleqv,8.97% NaCleqv and 6.39% NaCleqv. The trapping pressures of fluid inclusions are estimated to be 120~178 MPa, 85~140 MPa, 75~130 MPa and 60~122 MPa for each stage. Fluid immiscibility must have played an important role in ore genesis. The cause of fluid immiscibility might have been related to tectonic decompressing.

关 键 词：地球化学 流体包裹体 流体不混溶 杨砦峪金矿 小秦岭金矿田 

分 类 号：P681.51[天文地球—地质学]