Carboniferous lithofacies-paleogeography in the southern part of Tongliao, Inner Mongolia

Abstract: Located in the Naiman Banner and southern Hure Banner, Inner Mongolia, the study area tectonically belongs to the Tianshan-Chifeng mobile belt on the northern margin of the North China plate. The Late Carboniferous strata in the area consist dominantly of terrestrial clastic rocks and carbonate rocks, which have a facies change relation in space. According to the microfacies assemblage or essential sequence, sedimentary structures, biological features and their spatial distribution characteristics, four facies, namely littoral facies, tidal-flat facies, back-platform basin facies and platform facies, and eight microfacies may be distinguished; they form a relatively complete transgressive sequence, belonging to deposits of the transgressive systems tract. This suggests that the Late Carbonate sea trough on the northern margin of the North China plate is a passive terrestrial basin, i. e. the epicontinental environment.