Influence of pre-Paleogene tectonics on Upper Paleozoic-Mesozoic source rocks in Bohai Sea area

The Bohai Sea area can be divided into 5 structural layers. The distribution of Carboniferous, Permian and Mesozoic strata was studied, indicating for close relationship between stratigraphic distribution and basin evolution. Due to the subduction of the continental margin orogeny of the northern Xingmeng ocean activities in the Late Paleozoic (the Hercynian Movement), and influenced by a number of transgression, source rocks became better from north to south gradually. From the Late Paleozoic to Triassic, source rocks became worse because of the Indosinian Movement. The Yanshan Movement during Mesozoic resulted in a large number of inland warped lake deposition in the area and excellent source rocks of large quantity generated in the center of lake basin.