摘要
马家窑金矿床位于华北板块东缘胶北隆起区,栖霞—蓬莱成矿带上。赋矿围岩为新太古代的片麻状中细粒含角闪黑云英云闪长岩,矿体受马家窑—上庄头断裂构造的NW向次级断裂构造控制。主要对区内Ⅱ号脉中Ⅱ-1号矿体主成矿阶段的流体包裹体进行岩相学、显微测温和单个包裹体激光拉曼分析。结果表明:矿石中的包裹体类型是以气液二相包裹体和含CO_2三相包裹体为主,CO_2包裹体和单液相包裹体为次的4种类型,矿石中的包裹体普遍富含CO_2,成矿流体为CO_2-NaCl-H_2O体系;盐度为2%~10%,密度为0.54~0.94 g/cm^3,具有低盐度和低密度的特点。成矿温度集中在280~340℃,成矿压力范围为68~124 MPa,成矿深度为6.67~9.26 km。结合流体包裹体氢氧同位素分析以为,马家窑金矿床的成矿流体主要是幔源流体,后期有少量岩浆流体的参与。综合研究表明,马家窑金矿床成因类型为中高温热液脉型金矿床。
Majiayao Gold Deposit is located on the Qixia- Penglai metallogenic belt in Jiaobei uplift region at the eastern margin of North China plate. The host rock is the Neo-Archaean gneissic medium-fine-grained tonalite containing hornblende biotite,and the ore bodies are controlled by the NW-striking secondary faults of Majiayao- Shangzhuangtou faults. Study is focused on the petrography,microthermometry and laser Raman spectroscopy of individual inclusions of OrebodyⅡ- 1 in VeinⅡ. The research shows that the fluid inclusions in ores primarily take the form of gas-liquid two-phased inclusions and three-phased inclusions containing CO2,and secondarily CO2 inclusions and liquid-phase inclusions,making up 4 types in total. The inclusions in the ore are generally rich in CO2. The ore-forming fluids belong to a CO2- NaCl- H2 O system with low salinity（ 2 % to 10 %） and density（ 0. 54 g / cm3 to 0. 94 g / cm-3）;The ore-forming temperature is concentrated in between 280 ℃ and 340 ℃,ore-forming pressure between 68 MPa and124 MPa,and ore-forming depth between 6. 67 km and 9. 26 km; Based on previous researches on fluid inclusions and analyses of hydrogen and oxygen isotopes,the paper takes that the ore-forming fluids of Majiayao gold deposit derived mostly from mantle fluids and in the late period there was a small amount of magmatic fluids involved. According to comprehensive study,the deposit belongs to a medium-high temperature hydrothermal vein type gold deposit.
出处
《黄金》
CAS
2016年第4期18-24,共7页
Gold
基金
山东省财政资金项目[鲁勘字(2009)066号]
关键词
流体包裹体
矿床成因
马家窑金矿床
山东栖霞
fluid inclusion
deposit genesis
Majiayao Gold Deposit
Qixia City of Shandong Province
