Study on marine transgression of Paleogene Shahejie Formation in Jiyang Depression

The question whether marine transgression happened in the Paleogene of Jiyang Depression was discussed according to following arguments.Firstly,evolution series of saline minerals had the maritime characteristics.Secondly,Paleodictyon of sea facies was discovered.Thirdly,dinosterane was discovered in the host lithology of Paleodictyon,and dinosterane was the sign of marine transgression.Lastly,lacustrine advance of Shahejie Formation was basically consistent with global marine transgression.Those features indicated that Jiyang Depression was once affected by seawater or connected with sea.Marine transgression has important role in generating the excellent source rocks and the paleogeographical pattern of Bohai Bay Basin as well as the stratigraphy sequence of the Cenozoic sedimentary basins of East China.