Sedimentary system distribution and evolution of Permian in South Guizhou-Middle Guangxi,China

Based on the data of outcrop measurements and drilling wells and combined with the determination of thin sections,the paper analyzes the microfacies and divides Permian into 2 super sequences and 12 third-order sequences.The coast,carbonate plateau and platformal basin sedimentary systems are recognized after studying the sequence stratigraphy,sedimentary system and evolution of palaeogeography in South Guizhou and Middle Guangxi.Carbonate plateau facies is dominant in South Guizhou and platform-basin facies in Middle Guangxi.The evolution of palaeogeography in the stratigraphic framework shows that South Guizhou was a denuded area because of the affections of sealevel changing and structure uplift and Middle Guangxi was a alternate pattern of plateau and uplift in Early Permian;Carbonate plateau dominated in South Guizhou and the alternation of plateau and uplift did in Middle Guangxi because of the rising of sealevel in Middle Permian;The study area uplifted and exposed because of the Dongwu tectonic movement in the early phase of Late Permian;Carbonate plateau dominated in South Guizhou again and the alternation of plateau and uplift occurred again in Middle Guangxi because of transgression in the middle-late phase of Late Permian.The above basin structure evolution controls the reef facies distribution.