A number of oil and gas-bearing closed rift basins were formed at Early Tertiary along the great faults, stretching in a NE or NNE direction in East China.These basins were often evolved into closed or semi-closed saline lakes as a result of arid climate.The chemical content of mudstones in some of there basins indicates that mudstones are composed of clay minerals and a small amount of carbonates. The relationship between the sedimentary environments, especially salinity and some geochemical indexes, is studied and it is believed that Sr/Ba, total Ca/Mg, Ca/Mg, V/Ni and Mn/Fe can reveal the temporal and spatial changes in salinity of the lakes at the stage of low salinity.However, there exists no positive correlation among Sr/Ba, CaCO₃, B and salinity at supersaturated stage.