Geological Characteristics and Diagenetic-Metallogenic Chorological Study of the Yuanzhuding Porphyry Cu-Mo Deposit,Western Guangdong Province

The large Yuanzhuding porphyry deposit is Located in the northern margin of the Dayaoshan uplift and in Fengkai County of Guangdong-Guangxi boundary.The Cu-Mo mineralization exists commonly within the Yuanzhuding adamellite porphyry and its outside contact zone.Asteroidal pyrite,chalcopyrite and molybdenite can be viewed within the porphyry body,but industrial Cu-Mo orebodies lay mainly in the outside contact zone and is characterized by ellipsoids mineralization zoning:molybdenum mineralization→copper-molybdenum mineralization→copper mineralization from the porphyry body outwards,which shows that the Cu-Mo mineralization is closely related to the adamellite-porphyry.The authors carried out chronological study of the adamellite-porphyry and orebodies using high decision SHRIMP zircon U-Pb and Re-Os dating technique,yielding 154±2Ma of zircon U-Pb age(95% confidence,MSWD=0.75,N=11) and 155±5Ma of molybdenite Re-Os isochron age(95% confidence,MSWD=0.31,N=8),respectively.These data show that diagenesis and metallogeny of the Yuanzhuding Cu-Mo orefield happened during the late Middle Jurassic period while mineralization occurred in the extensional tectonic setting of South China.