Evidence of Existence and Research Significance of Toutunhe Formationin Middle-Che-Mo Palaeo-Uplift within the Central Part of Junggar Basin
准噶尔盆地腹部车—莫古隆起中段头屯河组

Various types of stratigraphic traps formed during the formation of Che-Mo palaeo-uplift in Middle-Late Jurassic are target areas of prolonged oil-gas migration-accumulation,and hence the existence or nonexistence of Toutunhe Formation in the target strata near the unconformity between Jurassic and Cretaceous is of great importance to the exploration work of the study area.Based on charatersitics of the litho-electrical assemblage,paleontology,clay minerals,stratigraphic contact relationships in the strata beneath J/K unconformity,some evidence can be found as follows:a typical red layer is developed commonly,the strata have typical Classopollis-Quadraeculina-Piceaepollenites spore assemblage and typical clay mineral assemblage(rich illite,insufficient kaolinite),and a thin Toutunhe Formation platform can also be seen on the seismic horizon flattening section and stratigraphic correlation section.The existence of Toutunhe Formation will be helpful to the oil-gas exploration in the study area in such aspects as trap estimation,reserve calculation,and oil-gas accumulation condition evaluation.