The coupling relationship between sedimentary sequence development and basin filling evolution of Jurassic in Ordos Basin,China

By using the technique of sedimentary facies analysis and sequence stratigraphy theory,the paper systematically studies the depositional characteristics and sequence surface of Jurassic in Ordos Basin and summarizes that there have seven sequence surface types of material expression.According to the depositional characteristics,assemblage and sequence surface of Jurassic,there exist 2 super-long,9 long and 19 middle base-level cycles of Jurassic in Ordos Basin.Based on the research of the sedimentary sequence characters and depositional system,there develop alluvial fan,river,lake-delta,alluvial plain and drift bed during Jurassic stage.Finally,the paper inquires further out the coupling relationship of sequence-sedimentation-structure in Ordos Basin,and points out that the basin underwent 4 great tectonic fluctuation cycles from Yan'an stage to Fuxian stage,corresponding to 4 long base-level cycle(LSC1~LSC4),and 5 huge cycles during Zhiluo stage to Fenfanghe stage,corresponding to 5 long base-level cycle(LSC5~LSC9).