Cretaeous Dinoflagellates, Chlorophytes And Acritarchs, And Its Genetic Potential From The Songliao Basin

The Songliao Basin has the most complete Cretaceous sedimentary deposit, yielding abundant sporopollen, ostracods, Esthenaus fossils. This article is mainly about the Cretaceous dinoflagellates seen in the drilling core of the CCSD-SK I, located in the Songliao Basin, and the target formation is from the third member of Quantou Formation to Mingshui Formation according to the change patterns from bottom to top. The main research work consists of collecting the core sample of CCSD-SK I, identifying dinoflagellates and researching the water salinity that the distribution of dinoflagellates reflected.The length of drilling core in CCSD-SK II in this work is 2300m, and 588 Algaes were found, including 12 genus of dinoflagellates, 6 genus of acritarcha and 3 genus of chlorophyta. It can be divided into 10 types of dinoflagellates assemblages. On the basis of the feature of the dinoflagellates assemblage and the formation time of sporopollen, from the third and the fourth member of Quantou Formation to the first member of Qingshankou Formation, the deposition time is confirmed of Cenomanian, the second and the third member of Qingshankou Formations are confirmed of Turonian, the Yaojia formation is confirmed of Santonian-Coniancian, the Nenjiang Formation is Campanian, Sifangtai Formation and Mingshui Formation are Maestrichtian.The Algae assemblages reflects the salt changes of water: the first member of Qingshankou Formation, the first and second member of Nenjiang Formation are in the brackish water lake environment, the salinity of water became very large suddenly, which indicates of seawater ingression, it can be connected to the globular ingression in the Santonian and Coniancian. The second and the third member of Qingshankou Formation ,the third to the fifth member of Nenjiang Formation are in the micro-salt lake environment. The sedimentary of Sifangtai and Mingshui Formation are totally belongs to continental fresh water environment.There has some relationship between the form of dinoflagellate and the temperature of lake water. The third and the fourth members of Quntou Formation have a high degree of Physoporella content in dinoflagellates, demonstrates the lake water is bit cool, while in the first member of qingshankou Formation and the first-third members of Nengjiang Formation, the contents of shrink and longispina cystosore or proximate cystosore are high, illustrates it was in the warm and deep water environment.Dinoflagellates can be found in all study formations of CCSD-SK I, especially in the Qingshankou Formation and Nengjiang Formation which are the main source bed of songliao basin and at the same time they are the flourish stage of algaes. The proofs of potential ability of hydrocarbon generation of Dinoflagellate are the concordance of oil generation stage and flourish stage of algaes as well as several alages can be found in kerogen slices.