山东金岭埠南金矿床流体包裹体特征及成因探讨

摘要

Bunan Gold Deposit is located in the northern edge of Jiaolai -Jiaobei uplift and the middle of Zhaoyuan-Laizhou metallogenic belt,controlled by the NE trending Lingshangou-Beijie main fault and a series of secondary ore-controlling structures.The gold orebodies are hosted in NE trending structures and controlled by them. The ores are mainly alteration rocks.The petrography and microthermometry of the fluid inclusions in different metallo-genic stages of Bunan Gold Deposit are studied,and Raman laser analysis of individual inclusion is carried out.The re-sult shows that the fluid inclusions in quartz mainly include Ⅰtype gas-liquid two-phase inclusion and Ⅱtype CO2-containing three-phase inclusion;the homogenous temperature of the ore-forming fluids is 280 ℃ to 320 ℃ and the salinity is 3.76 %to 12.99%;the fluids belong to a NaCl-H2 O-CO2 system which contains small amount of CH4 and N2 .Isochore intersection reveals that the inclusion-capturing pressure of is 54 MPa to 106 MPa and the estimated ore-forming depth is between 5.87 km and 8.52 km.The characteristics of H and O isotopes in fluids indicate that the ore-forming fluids are mainly mantle fluids and contain magmatic water and precipitation.The paper summarizes that Bunan Gold Deposit is a alteration rock type medium-depth orogenic gold deposit.%埠南金矿床位于胶莱胶北断隆北缘，招（远）—莱（州）成矿带中部，受NE向灵山沟—北截主断裂以及一系列次级构造控制。金矿体赋存于NE向构造中，并受其控制，矿石类型以蚀变岩型为主。通过对埠南金矿床不同成矿阶段的流体包裹体进行岩相学、显微测温、单个包裹体激光拉曼分析，结果表明：石英中流体包裹体主要有Ⅰ型气液二相包裹体和Ⅱ型含CO2三相包裹体，成矿流体均一温度为280~320℃，盐度为3.76%~12.99%；流体为NaCl-H2 O-CO2体系，含少量的CH4和N2。通过等容相交法，得出包裹体捕获压力为54~106 MPa，并估算出成矿深度介于5.87~8.52 km。流体H、O同位素特征表明，成矿流体以地幔流体为主，同时存在岩浆水和大气降水的参与。综合分析认为，埠南金矿床属于蚀变岩型中成造山型金矿床。