三山岛金矿床流体包裹体研究

Study on fluid inclusions in the Sanshandao Gold Deposit

三山岛金矿床位于胶东西北部，属于典型的“焦家式”（破碎带蚀变岩型）金矿床。对矿区内主成矿阶段石英中的流体包裹体进行了岩相学、显微测温、氢氧同位素及单个包裹体成分激光拉曼光谱研究。研究表明，矿石中流体包裹体主要有纯CO2单相包裹体、气液二相包裹体和含CO2三相包裹体3种类型；矿石石英中流体包裹体普遍富含CO2；成矿过程中，流体经历了CO2-NaCl—H2O体系的不混溶作用；成矿流体具有低盐度（3．85％～11．60％）、低密度（0．70～0．96g/cm3）的特点；主成矿温度集中为260～320℃，成矿压力范围为70～110MPa，相应（成矿）深度范围为6．78～8．69km。结合流体包裹体氢氧同位素分析认为，三山岛金矿床成矿流体以地幔流体为主，并有少量的岩浆流体。确定矿床成因类型为为幔源流体参与成矿的中温热液脉型金矿床。

Sanshandao Gold Deposit, located in northwest Jiaodong Peninsula, is a typical ＂ Jiaojia＂ （fractured and altered disseminated） gold deposit. Studies of Petrography, microthermometry,hydrogen and oxygen isotopes and laser Raman microspectroscope have been made on fluid inclusions in quartz of main mineralization stages of Sanshandao Gold Deposit. The results show that there are three types of fluid inclusions, namely pure CO2 single-phase fluid inclusions, aqueous two-phrase fluid inclusions and CO2-bearing fluid inclusions. CO2 is universal in the fluid inclusions in quartz of auriferous ores. The fluids of main mineralization stages should be a CO2 - NaCl - H2O system and fluid immiscibility occurred in the ore-forming process ; The ore-forming fluids have low salinity （3.85 % - 11.60 % ） and low density （0.70 -0.96 g/cm3） ;Mineralization temperature ranges from 260℃ to 320 ℃, mineralization pressure ranges from 70 MPa to 110 MPa,while mineralization depth ranges from 6.78 km to 8.69 km. Associating hydrogen and oxygen isotope analysis of fluid inclusions, the paper takes that Sanshandao gold ore-forming fluids derive mainly from deep mantle fluids, accompanied by a small amount of magmatic fluids. It is determined that the genesis of the deposit is the mesothermal type gold deposits with mantle-derived fluids involved.