Sedimentary model of coal and shale in Paleogene Lijiaya Formation of Huangxian Basin: insight from petrological and geochemical characteristics of coal and shale.

Paleogene Huangxian Basin which lies in Eastern China contains deposits of many types of coal and shale associations. The sedimentary models of coal and shale associations are very important to explore the coal and shales. However, whether the transgression affected the lithofacies and geochemical characteristics of coal and shale in the Paleogene Huangxian Basin in eastern China has not been reported in detail, which is important to construct the sedimentary models. In this study, petrological and geochemical methods are used to comprehensively analyze the mineral composition, contents of major and trace elements, and distribution characteristics of geochemical parameters of coal and shale in Huangxian Basin. The results show that coal and shale have different macerals. The study of typical geochemical parameters (Mn/Ti, K2O/Na2O, Sr/Ba, and Th/U) shows that the no. 1 coal seam (CB1) and no. 4 coal seam (CB4) are least affected by seawater, while the no. 1-3 coal seam (CB1-3) is affected by seawater to s...