Permian in southern Anhui Province has become an important objective interval for shale gas exploration. Once a breakthrough is achieved, it will open a new window for oil and gas exploration in Anhui Province and even the Lower Yangtze region. However, the siliceous source of marine black rock series has been controversial for a long time, and the enrichment accumulation mechanism of organic matter is still unclear. Based on the petrological characteristics, paleontological communities, sedimentary characteristics, organic matter abundance and elemental geochemical characteristics of the Permian marine black rock series of Qixia, Gufeng and Dalong Formations in South Anhui Province, the sedimentary background, siliceous source and organic matter enrichment model are discussed. The results show that Qixia Formation is a typical hydrothermal siliceous rock, Gufeng Formation and Dalong Formation are biogenic-hydrothermal siliceous rocks, a few Dalong Formation is a typical biogenic siliceous rock with weak hydrothermal. Permian belongs to the warm and humid climate of tropical and subtropical zone. Black rock series are deposited in anaerobic-poor oxygen water environment with slow sedimentation rate. The organic matter content is abundance, and the sedimentary water body is generally 100～300 m. The formation of organic-rich black rock series in Qixia Formation and Gufeng Formation is not only controlled by limited-retention hypoxic environment, but also closely related to the role of organisms-blooming nutrient element and minerals and upwelling, which are provided by seafloor hydrothermal activities. The formation of organic-rich black rock series in Dalong Formation and the multi-stage volcanic eruption in Changxing Period brought in a large number of nutrient elements and trace elements, which led to the increase of primary productivity, benthos extinction-prosperity-re-extinction-re-prosperity-extinction, the rapid accumulation of hydrocarbon-generating parent materials and the inseparable relationship with hypoxia environment. In the Early Triassic, the climate was hot and dry, the volcanic activity was frequent, the ecosystem deteriorated rapidly, and the sea-water gradually turned into an oxidizing environment, which was not conducive to the enrichment and preservation of the living creature.
Xu Jinlong Wang Yafei Ge Haiying Shi Yonghong. Genesis and organic matter enrichment mode of the Permian marine black rock series in South Anhui Province[J]. Chinese Journal of Geology, 2019, 54(3): 953-972.