Origin and Evolution of West Slope Breaks of Qingshankou-Yaojia Formation in Northern Songliao Basin

The slope-break zone in sedimentary basin is a favorable area for the formation of stratigraphic traps. Based on integrated analysis of geological and geophysical data, origin and evolution of the west slope break of Qingshankou-Yaojia Formation in the northern Songliao basin are discussed. During depositional period of Qingshankou-Yaojia Formation, the western Fuyu first-order slope break and Taikang-Da'an second-order slope break are clearly developed in the west part of northern Songliao basin, the evolution of these slope breaks are controlled by deep buried faults, differential deposition and compaction. The Zhalaiteqi, Nenjiang, and Halahai great buried faults penetrating into lithosphere in west Songliao basin constrain the distribution of the slope break, which also control the distribution of lowstand sandbodies with the combination of multiple deposit sources from the northern Songliao basin, Qiqihar and Yingtai areas during depositional period of Qingshankou-Yaojia Formation. For example, the evolution of the Fuyu first-order slope break is controlled by the Zhalaiteqi, Nenjiang buried faults and Qiqihar and Yingtai sources, and the Taikang-Da'an second-order slope break is controlled by the Halahai buried faults and the northern Songliao basin, Yingtai sources.