Abstract:Objectives: Volcanic and intrusive rocks serve as important sources of ore-forming materials and fluids in many epithermal gold deposits. The South China Block has experienced strong magmatic-hydrothermal activities during the Mesozoic time, producing a large number of volcanic-intrusive complexes and epithermal gold deposits along the coastal area of Southeast China. This study select the Dongkeng Volcanic Basin, which was less studied, to explore the genetic relationship between its volcanic and intrusive rocks, their magmatic evolution process, and their relationship with gold mineralization. Methods: Based on the field work, we conducted petrological, geochronology, whole-rock geochemistry, and Sr-Nd-Hf isotopes studies of the Dongkeng volcanic-intrusive complex. Results: The Dongkeng Volcanic Basin is composed of various lithological volcanic rocks and coexisting shallow intrusive rocks, including porphyritic granite, porphyritic quartz monzonite, and mafic microgranular enclaves bearing granite veins. The LA-ICP-MS zircon U-Pb dating results show that the volcanic and intrusive rocks in Dongkeng were formed in the Cretaceous (101.0 ± 0.9~97.3 ± 1.2 Ma). All the rocks have consistent Sr, Nd isotopic compositions with ISr values of 0.7085~0.7104 and εNd(t) values of -8.83~-7.34. However, their zircon Hf isotopic compositions are highly variable with εHf(t) values ranging from -14.0 to +3.3. Geochemically, the volcanic-intrusive rocks in Dongkeng Volcanic Basin show high potassium, high alkaline, metaluminous to weakly peraluminous features, and have linear variation in the Harker diagrams, high oxygen fugacity (logfO2=-17.44~-4.18). In chondrite-normalized REE distribution patterns and primitive mantle-normalized trace element spidergrams, all lithologies are enriched in LREEs compared with HREEs, and they have weakly to moderately negative europium anomalies (Eu/Eu* =0.19~0.83) and are enriched in Rb, K, Pb, and depleted in Nb, Ta, Ti. Conclusions: Based on the geochronological and geochemical data, the volcanic-intrusive complex in the Dongkeng Volcanic Basin were generated by mixing of mantle-derived magma and its induced crustal felsic magma in an extensional tectonic setting due to the rollback of subducted Paleo-Pacific plate in the Cretaceous. The magmatic source, crystallization differentiation, and high magma oxygen fugacity are important factors for the formation of contemporaneous gold deposits in the Dongkeng Volcanic Basin.