Mesozoic–Cenozoic Volcanic Cycle and Volcanic Reservoirs in East China

There are widespread Mesozoic-Cenozoic terrestrial volcanic activities in East China, and they produced favorable geologic factors for the volcanic reservoirs. To reveal the spatio-temporal evolution of regional volcanisms and their tectonic setting, we subdivide Mesozoic-Cenozoic volcanic activities into 6 volcanic cycles (Ⅰ-Ⅵ), and summarize the temporal-spatial distribution, rock association and tectonic setting of each cycle. The Cycle I forms a post-orogenic intraplate bimodal volcanic association. The cycles Ⅱ and Ⅲ include arc volcanic associations formed in compressional and extensional subduction environments, respectively. The Cycle Ⅳ contains a post-orogenic arc bimodal association. The Cycle Ⅴ is a basaltic association of tholeiite series under initial rift setting, and the Cycle Ⅵ is basaltic association of alkaline series under typical rift setting. The volcanic strata between each cycle are bounded by regional unconformity. The above 6 volcanic cycles correspond to 6 sequential stages of tectonic evolutions from the Early Jurassic post-orogeny, the Mid-Jurassic-Cretaceous subduction of the paleo-Pacific Plate to the Cenozoic marginal rifting. According to the geological characteristics of volcanic reservoirs in different volcanic cycles, it is put forward that the Cycle Ⅴ is the major formation period of volcanic reservoirs in East China and should be the focus of exploration, and that the volcanic reservoirs of the Cycle Ⅳ are also worthy of attention.