Gold Ore-forming Fluids and Metallogeny in the Jiaodong Peninsula, Eastern China

Gold deposits in the Jiaodong Peninsula occur as gold-bearing quartz veins and disseminated- and stockwork-style ores adjacent to fault zones. Most of the gold deposits comprise a paragenetic sequence of stage I quartz-(minor) pyrite, stage II pyrite-quartz-gold, stage III quartz-base metal sulphide minerals and stage IV quartz-carbonate. Fluid inclusion studies show that the ore-forming fluids of the gold deposits are consistent in the Peninsula, with similar mineralizing temperature and pressure conditions. Ore-forming fluids are characterized by a composition of H2O-CO2-NaCl +/- CH4. The optimum mineralizing temperatures and pressures are 170 - 335 degrees C and 0.7 - 2.5 kbar. Rb-Sr, Ar-Ar isochron ages and hydrothermal zircon SHRIMP U-Pb dating place the gold mineralization event at 120 +/- 10Ma. Gold deposits in the Jiaodong Peninsula are formed in the same mineralizing-geodynamic association, and are related to a Mesozoic tectonic transition in the eastern North China craton.