Study on fluid inclusions of Shawang gold deposit in Haiyang of Shandong

摘要

Shawang gold deposit is a large gold deposit,located in the NE margin of the Jiaolai basin,which is part of Muping-Jimo metallogenic belt in eastern Shandong. It was controlled by the footwall of Guocheng fault zone and secondary faults zone. Aiming to the fluid inclusions in Shawang gold deposit,the authors carry on petrographic,microthermometric and Raman spectroscopic component analyses. The results show that there are four-type fluid inclusions: single phase inclusions,gas-liquid two-phase inclusions,pure CO2 inclusions and three-phase inclusions containing CO2. Ore-forming fluid is characterized by low salinity( 4. 3%--12. 6% NaC l.eqv),low density( 0. 64-0. 97 g / cm3),medium-high temperature( 280℃--320℃),metallogenic pressure with 81--94 MPa,and metallogenic depth as 7. 39--7. 98 km. The fluid experienced immiscibility of CO2-NaC lH2 O system during the metallogenic process. In combination with the analysis of hydrogen and oxygen isotopes in fluid inclusions,it is determined that the Shawang gold deposit is mesothermal vein-type,with participation of mantle-derived water and magmatic water for its genesis.