摘要
Based on the theory and methodology of molecular organic geochemistry, molecular paleontology and its depositional environment in the Eocene Shahejie Formation of Jiyang Depression, Bohai Bay Basin, East China, were studied. The results show that the types of molecular fossils vary significantly on level whereas cycle on vertical. Molecular heterogeneousness of member 1 and 3 of Shahejie Formation(Es1,Es3) is weaker than that of the upper part of member 4 (Es4u)on level. The scale of lake basin of Es1 and Es3 is the largest, and the basin segmentation of Es4u is strong. Photic euxinic conditions prevailed in the paleowater column during the Eocene lacustrine. Both dinoflagellates and bacteria were significant phytoplanktons in addition to coccolithophoride limited to brackish water lakes of Es1 and Es4u.