Geology And Geochemical Characteristics And Mineralization Potential Estimation Of Bajiatan Intrusion In Luzong Volcanic Basin, Anhui Province

Luzong volcanic basin is located in the LowerYangtze Fault Belt, where is the north margin of Yangtze block. Mugearite, K-rich intrusions and adakite as well as porphyry copper deposit (Shaxi) and volcanic-subvolcanic hydrothermal vein type copper deposits (Bamoshan, Jinbian and Tiantoushan) outcrop in this district. The Bajiatan intrusion, which is sited in the center of the basin, is the main object of this research. Based on the geology and geochemical characteristic of the intrusion, we focus on the intrusion's diagenetic process and magma evolution mechanism. The study shows that the magma activities of Bajiatan intusion can be divided into two stages: the early stage magma activity formed pyroxene monzonite and monzodiorite as enclosures in the main intrusion, the later stage formed monzonite and quartz-bearing monzonite. The later stage of magma activity can be divided into three phases, the early pyroxene monzonite phase, the middle quartz-bearing monzonite phase and late syenite phase. The main diagenesis is fractional crystallization assimilation and contamination. The age of Bajiatan rockbody has been determined to be 135Ma using zircon U-Pb SHRIMP dating, indicating the Bajiatan rockbody formed at time between the Zhuanqiao Cycle and the Shuangmiao Cycle. The genesis of copper metallogenic in Bjiatan intrusion has been discussed. Disseminated pyritization is related to hydrothermal activity, while the nodule-like chalcopyrite and bornite may be formed in the deep and carried to the surface by intrusion. Compared with the Shaxi porphyry copper, the Bajiatan intrusion is thought to be Adakitic rocks. The Bajiatan intrusion has good mineralization potential.