| Abstract:Located in Yunkai Mountains, western Guangdong and controlled by a ductile shear zone, the Hetai deposit is an important gold deposit in S6uth China. Fluid inclusion studies show that ore-forming fluids are of the H2O-CO2-NaCl system, and metallogenic environments are noted for moderate to low temperatures(350～220℃), 1ow salinities(3.50～10.50 wt％NaCl), weak acidity(pH = 4.57～4.17), low fO2(10-35～10-44bar), low fS2( (10.7～10-16 bar) and pressures of 1200～1000 bar. Ore-forming fluids are characterized by K+>Na+，Ca2+＞＞,Mg2+, Cl-＞＞F-, CO2>CH4 and abundant K+, Na+, Cl-, Ca2+ and Mg2+, Ore-forming fluids, derived mainly from metamorphic and magmatic waters, changed gradually in composition from the ductile shearing phase through the gold-quartz stage of the brittle deformation phase to the gold-quartz-sulfide stage. The conversion from ductile deformation to brittle deformation resulted in the mineralization and concentration of gold in the ore district. Great gold-hunting potentiality exists in Yunkai area, where Hetai type” gold deposits, “quartz vein type” gold deposits and “sediment-metamorphic type” gold deposits might be further discovered. The eastern part of the No.11 orebody might extend to a depth of some -400 m and plunge laterally towards the Houjing deposit. Mineralization is poor in the depth of the No.12 orebody of the Houjing deposit and between the Gaocun and the Yunxi deposit; nevertheless, the depth of the No.9 orebody of the Yunxi deposit seems rather promising. |
