 The Dongying Depression, Bohai Bay Basin, Eastern China, was filled with layers of evaporite and hydrite and halite during the Paleogene period, particularly during the middle of the fourth member of the Shahiji formation, ES4. These layers are interbedded with mudstone strata. The strata of ES4 are divided into three sections, referred to as the upper layers, evaporite layers, and lower layers, respectively. The analysis of elemental concentrations, elemental ratios, and PR slash pH suggests that the lower layers were deposited in an intermittent saline lake environment within a relatively dry climate. Evaporite layers were formed in a highly saline lake environment, whereas the upper layers were formed in a brackish saline to freshwater environment. Organic matter, OM, abundance indices, including total organic carbon, TOC, chloroform extracts, total hydrocarbon content, HC, hydrocarbon generation potential, S1 plus S2, and OM type, show that the source rock potential for petroleum generation in the upper layers is best, that in the evaporite layers is fair. This article was authored by Yongchen, Yun Han, Pengfei Zhang, and others. We are article.tv, links in the description below.