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山东东营凹陷古近纪沙河街组下部普遍发育膏盐岩系和颗石藻钙质页岩.研究认为膏盐岩系形成于早期的盐湖环境,而膏盐岩系之上的颗石藻钙质页岩形成于咸度略低的咸化湖泊环境.通过古今湖泊环境和生物类群等的分析对比,认为蓝细菌是古近纪沙河街组下部膏盐层系形成过程中的主要生产力代表,生产力水平为1500~2000 g C m?2 a?1.通过对钙质页岩中钙质超微化石的研究,发现颗石藻是钙质页岩形成时的主要生产力代表.根据钙质页岩的沉积速率、沉积纹层和纹层中颗石藻化石的计数统计,定量确定了颗石藻页岩形成时的古生产力水平为2250~3810 g C m?2 a?1,平均为3120 g C m?2 a?1.通过对地层中大量草莓状黄铁矿粒径的统计,发现膏盐岩系形成时的底层水体处于富硫化氢的缺氧状态,而钙质页岩形成时的底层水体为下贫氧状态.在此条件下,有机质均能有效保存.通过多参数的地球生物学模型的分析和计算,认为东营凹陷古近纪早期盐湖及咸化湖泊中有机碳的保存效率约为10%~15%.
In the lower part of Shahejie Formation of Paleogene in Dongying Sag, Shandong Province, gypsum and calcareous shale of coccolithophytes are generally developed.The gypsum-salt rock system was formed in the early salt lake environment and calcareous calcium The shale is formed in a slightly salty lagoon environment.According to the analysis and comparison of paleoenvironmental and taxonomic groups, cyanobacteria are considered to be the main productivity representatives during the formation of gypsum-salt system in the Lower Paleogene of Shahejie Formation, Productivity levels range from 1500 to 2000 g C m-2 a-1. The study of calcareous microfossils in calcareous shale shows that coccolith is the major productivity representative of calcareous shale formation. According to the Calcareous Page The sedimentation rate of rocks, counties of sedimentary layers and counties of coccolith fossils in the stratum quantitatively determined that the level of paleoproductivity during the formation of coccolith shale was 2250-3810 g C m? 2 a? 1, with an average of 3120 g C m 2 a 1. Through the statistics of a large number of strawberry-like pyrite in the stratum, it is found that the underlying water body in the formation of gypsum-salt rock system is in an anoxic state that is rich in hydrogen sulphide, whereas in the formation of calcareous shale Of the bottom of the water for the next state of oxygen in poor conditions under which organic matter can be effectively preserved through the Senate Analysis calculated geobiological and models, that the Dongying Salt Lake Ji early and salt lakes of organic carbon storage efficiency is about 10% to 15%.