摘要
Based on the petrology characteristics and the data of sedimentary characteristics and sedimentary geochemistry, this paper analyzes the genesis of lacustrine dolomite in the fourth member of Shahejie Formation, Dongying sag. The study result indicates that the dolomites of different genesis have the different rock structures, development environments and geochemistry characteristics. Controlled by the sequence development, the dolomites were mainly developed in the late highstand system tract at this period. The geochemistry data indicate that the dolomite ordering degree is generally low, that the Sr content is high and that the average value is close to the Sr content of sea water, which shows that the transgression and structural hydrothermal fluid-deep fluid occurred in the fourth member of Shahejie Formation.