材料期刊网

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CO2三相包裹体为主,CO2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CO2,成矿流体为CO2-NaCl-H2 O体系;盐度为2%~10%,密度为0.54~0.94 g/cm3,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 contai-ning hornblende biotite,and the ore bodies are controlled by the NW-striking secondary faults of Majiayao-Shang-zhuangtou 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 liq-uid-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/cm3 );The ore-forming temperature is concentrated in between 280℃and 340℃,ore-forming pressure between 68 MPa and 124 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.