In order to study the geochemical characteristics of mudstone and aluminous mudstone in Huainan coalfield, the mudstone and aluminous mudstone samples of Lower Shihezi Formation in Xinji No.2 Mine were collected. The main and trace elements were tested by XRF and ICP-MS methods, and the geochemical differences were analyzed. The results showed that the contents of Al2O3 and rare earth elements in aluminous mudstone were significantly higher than those in mudstone, while the contents of Na2O, K2O, MgO and SiO2 / Al2O3 ratio were lower than those in mudstone. Both types of rocks showed strong enrichment of Ag and moderate enrichment of Cd. Li, V, Ge and Sr were more enriched in aluminum mudstone, and Cr, B and Zn were more enriched in mudstone. The source rocks of the lithology were felsic rocks ; the chemical weathering intensity of aluminum mudstone was higher, which was formed in brackish water and anoxic-reducing sedimentary environment. Floor mudstones were formed in freshwater-brackish water and oxygen-poor-weakly oxidized sedimentary environments. The differences in geochemical characteristics were mainly controlled by chemical weathering intensity and sedimentary environment.
