摘要
Trace element concentrations of the upper Es4 submember of the Dongying Basin were analyzed by ICP-AES in order to facilitate palaeoenvironmental reconstruction. The trace elements Fe and Mn show different geochemical behaviors. Therefore, Fe/Mn ratio of about 0.7×102 can be used a cutoff geochemical proxy to differentiate nearshore from deep lacustrine facies. The Ca/Mg ratio is also useful in paleoenvironmental reconstructions: Ca/Mg ratios of <5 are typical of fluvial or nearshore facies; Ca/Mg ratios of 5~10 (up to 20) are characteristic of deep lacustrine facies at the southern slope in the Dongying Basin. The Sr/Ba ratios respond to salinity and lake restriction. Sr/Ba ratios < 1 are indicative of nearshore environment and influence of riverine input, Sr/Ba ratios of 1~4 are typical of lacustrine facies, and Sr/Ba ratios of 4~8 represent restricted saltwater lacustrine facies.