Fig. 8
Chemical weathering trends indicated by chemical weathering indices CIAcorr., WIP and MIA(O) of mudstones from the Shahai and Fuxin formations, which can be divided into four stages in vertical direction: A, B, C and D. T is land surface temperature in °C, which is calculated by the linear relationship of CIA-temperature provided by Yang et al. (2014). Humidity and temperature characteristics of palaeoclimate are inferred from palynoflora (modified after Wan et al. 2017). Green shading represents the location of OAE1b. Red circle - borehole DY-1; Blue circle - borehole FY-1. I, II, III and IV represent the first, second, third and fourth members of the Shahai Formation, respectively