Sanshandao gold deposit, located in the north west of Jiaodong Peninsula, is a typical highly fractured and altered disseminated gold system. Petrography and fluid inclusion study on the altered wall rocks and gold ores from different depths (more than 2km) of the deposit indicate that the Sanshandao gold deposit is formed of similar gold-bearing fluids, characterized by H2O-CO2-NaCl ± CH4 with homogenization temperature (170 - 330℃) and pressure conditions (50 - 255MPa) during the main gold mineralized stage. The carbon, oxygen, hydrogen and sulfur isotope data show that ore fluids are derived from magmatic origin, most likely sourced from mafic to intermediate dikes. Water-rock interaction led to more crustal fluids with greater input of carbon and sulfur from the crust in the ore fluids. A variety of fluid processes have been responsible for gold precipitation including water-rock interaction and fluid immiscibility caused by cooling and change of mineralizing stress possibly. Additionally, chemisorption' s processes in the interface between the fluid and sulfides may have further enhanced the deposition of the gold, particularly on the surfaces of these sulfide minerals.%三山岛金矿位于胶东西北部,属于典型的破碎蚀变岩型金矿.流体包裹体研究表明该矿床为中温、中低盐度H2O-CO2-NaCl±CH4流体;中深部成矿流体对比研究表明,在纵深超过2000m范围内,成矿流体具有较一致的成矿流体介质条件,主成矿均一温度为170～330℃,成矿压力为50～255MPa.H、O、C同位素表明,深源流体参与了成矿作用,很可能是与金矿床伴生的基性幔源岩浆脱水形成的岩浆水,在地壳浅部遭受到大气降水的混合,而S同位素研究进一步揭示了成矿物质具有多源性,矿区浅表在成矿晚期可能受到了表生硫影响而导致δ34S偏高.水岩反应、成矿应力场转变及表面吸附电化学还原反应等导致金沉淀成矿.
展开▼
