College of Earth Sciences��Jilin University��Changchun 130061��China

Daheishan super-large molybdenum deposit of Jilin is one of the porphyry molybdenum deposits in central Asia--Hinggan Mongolian orogenic belt�� The ore bodies are yielded in the Yanshanian granodiorite porphyry and unequal particle granodiorite��and closely related with Toudaogou metamorphic volcanic rocks of Lower Paleozoic�� The research on fluid inclusions showed that the samples mainly developed gas-liquid two-phase inclusions and daughter minerals-bearing three-phase inclusions in Daheishan deposit�� The ore-forming fluids reflected a continuous evolution process��forming gas-liquid two-phase aqueous inclusions and daughter minerals-bearing three-phase inclusions in early-middle stage��and the homogenization temperatures between 300 �� �� 460 �� and fluid salinity between 1. 7 wt% �� 49. 92 wt% NaCl eqv�� In this stage��the fluids underwent decompression and boiling action and resulted in laege-scale mineral precipitation��which was also the main mineralization stage�� In later stage��gasliquid two-phase aqueous inclusions were developed mixing with meteoric water�� The homogenization temperature is 196. 5 �� �� 300 �� and fluid salinity is 1. 7 wt% �� 7. 1 wt% NaCl eqv��belonging to H2O-NaCl system�� Fluid boiling action was the main mechanism of metal sulfides precipitate�� The Daheishan molybdenum deposit formed in the continental marginal arc environment��