Complex pluton is spatially associated with several granitic intrusions at different ages. Researching on complex plutons contributes to a better understanding of the formation and distribution of granitoid rocks with different ages, and their relationship with tectonic development. In this study, we focus on the Qingyang-Jiuhuashan complex pluton, which is the most typical and largest complex pluton in South Anhui Province, and study on its geological, chronological, geochemical characteristics. The zircon LA-ICP MS U-Pb dating results shows four emplacement stages for this pluton: Stage I granodiorite (143. 3 +/- 1. 0Ma), Stage II monzogranite (137. 6 +/- 1. 5Ma), Stage III K-feldspar grnaite (131. 3 +/- 1. 2Ma) and StageN granite porphyry (132. 0 +/- 2. 0Ma). All the intrusions show high calc-alkaline and metaluminous to peraluminous characters. From the early stage to late stage, the evolution trend among four intrusions are more alkaline and higher K, Si content and lower Ca, Mg, Fe contents. The different rock attributes of this pluton were derived from a same primal magma chamber, then they rose along the same path and emplaced to the same or adjacent space, and formed the complex pluton, which is the main mechanism for petrogenesis of the complex plutons in this area. The magmatic source of early-stage granodiorite and monzogranite were generally derived from partial melting of lower crust metamorphic rocks, and then more mantle materials were injected into the primal magma and formed the late-stage K-feldspar graniteand and granite porphyry with highly fractional crystallization. The petrogenetic discriminative indicators shows that the formation of early-stage granodiorite and monzogranite is related to subduction of the ancient Pacific Plate, while the late-stage K-feldspar and granite porphyry were emplaced under an intraplate environment, suggesting a transformation from extrusion environment related to the subduction of the ancient Pacific Plate to the intra-plate lithospheric extension environment in this area.
