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

Located in the Naiman Banner and southern Hure Banner,Inner Mongoli a,the study area tec-tonically belongs to the Tianshan-Chifeng mobile belt on the northern margin of the North China plate.The Late Carboniferous strata i n the area consist dominantly of terrestrial clastic rocks and carbonate rocks ,which have a facies change relation in space.According to the microfacies ass emblage or essential sequence,sedimentary structures,biological features and their spatial distribution characteristics,four facies,namely lit-toral faci es,tidal-flat facies,back-platform basin facies and platform facies,and eig ht microfacies may be distinguished;they form a relatively complete transgress ive sequence,belonging to deposits of the transgres-sive systems tract.This suggests that the Late Carbonate sea trough on the northern margin of the Nort h China plate is a passive terrestrial basin,i.e.the epicontinental environme nt.