1. School of Energy Resources��China University of Geosciences��Beijing 100083��China; 2. School of Earth Sciences and Resources��China University of Geosciences��Beijing 100083��China

Through the sedimentologic analysis of Niaohe and Hongshishan sections in Niaohe village of Binxian�� combined with the information of paleontology��geochemistry and paleogeography��the authors restored paleoenvironment characteristics preliminarily. In the Niaohe section��the strata mainly consist of gray-green mudstone with pyrite and dolomitic tuberculosis layers��belonging to lake bay environmental deposit. In the bottom of Hongshishan section��the strate are mainly composed gray-green mudstone��changed to red mudstone in top and middle part��belonging to shallow lake at early stage��gradually turned to mud-flat deposit. The sediments were mainly mudstone and developed horizontal bedding when the provenance was not sufficient; yielding less fossils��but the layered property was good; there were dolostone and pyrite in mudstone. The lake bay accepted deposition by water deepening from the fracture depression of lake basin��and water flow or wave erosion damaged the barrier in lake bottom and lakeshore which led to water shallowed and turned to slough finally.