Carboniferous-Early Permian carbonate microfacies and sedimentary environments in the Chaohu region, Anhui

In the light of field investigation in recent years, the present paper gives a detailed description of the carbonate strata in the Fenghuanshan section in Chaohu, Anhui, including the Carboniferous Jinling Formation (C₁j), Hezhou Formation (C₁h), Huanglong Formation (C₂h), Chuanshan (C₂c) and stinkstone member in the lowermost part of the Lower Permian Qixia Formation (P₁q). Fourteen sedimentary microfacies have been distinguished for the carbonate rocks on the basis of thin-section examination of the carbonate rocks, and are involved into the following sedimentary environments:arid coastal evaporate platform (tidal flat), restricted carbonate platform, intraplatformal shoal and open carbonate platform. The results of research in this study show that the Chaohu region in Anhui was once occupied by the shallow marine carbonate platform during the Carboniferous-Early Permian, and went through three large-scale transgression-regression cycles with a number of small-scale sea-level fluctuations.