SHRIMP U-Pb Zircon Dating of the Quartz-Orthoclase Diorite Porphyrite from the Tonglushan Orefield in Eastern Hubei Province and Its Geological Implication

Located in the northwestern part of the Echen-Daye-Ruichang metallogenetic belt in the middle and lower reaches of the Yangtze River,the Tonglushan Cu-Au(Fe)deposit occurs in the northwestern segment of the Yangxin quartz-orthoclase diorite porphyrite and lies in 4th-7th Members of the Lower Triassic Daye Group.The porphyrite as the parent rock of Cu-Au(Fe)mineralization is closely related to the deposit.Zircon SHRIMP U-Pb age of(146±1)Ma(95% confidence,MSWD=1.2)shows that the porphyrite was formed in the Late Jurassic-Early Cretaceous period.According to the fact that contact metasomatic mineralization took place simultaneously with the crystallization of mineralized intrusion,it is concluded that the Tonglushan skarn type Cu-Au(Fe)deposit was also formed in the Late Jurassic-Early Cretaceous period.