The application of element geochemical characteristics to the recognition of carbonate sedimentary sequence boundary：A case study of the Mesoproterozoic Gaoyuzhuang Formation in northern Hebei depression

Abstract：Elements constitute the basic units of mineral rocks. They are sensitive to environmental changes. The characteristics of elements such as distribution，ratio and combination have recorded the information of environmental change during the evolution of sedimentary strata. These data are of important indicating significance in reconstructing sedimentary environment and studying the paleosalinity of marine carbonate rocks and the relative sea level change. The authors studied the sequence stratigraphic units of the Gaoyuzhuang Formation based on the element geochemical characteristics. The results show that, under the palaeoclimate influence， the paleosalinity， the relative sea level change and the element content in the carbonate as well as the related element ratios show obvious cyclic change characteristics. The methods of Sr/Ba and B have relatively high precision，which can serve as effective means for identifying and dividing the carbonate sequence boundary.