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.
出处
《矿床地质》
CAS
CSCD
北大核心
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
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
geochemistry fluid inclusions fluid immiscibility Yangzhaiyu gold deposit Xiaoqinling gold district