Structural deformation and its controlling factors in the Yining Sag of Yili Basin

Balanced section recovery techniques were used to restore tectonic evolution in the Yining Sag of Yili Basin based on drilling, logging, outcrop and seismic data. The sag is faulted in the north and onlapping in the south. The intensity of tectonic deformation is stronger in the north. The study area entered the continental stage in the Permian, and has experienced four compression periods:end Permian, the end of Triassic to the early Jurassic, end Jurassic and end Neogene. Compressive deformation was the most severe from east to west at the end Permian, and then decreased and changed to north-south compression. The zonation structure from south to north in the sag formed at the end of the Neogene. Hedge and thrust structures developed in the sag and adjacent areas due to north-south compression, resulting in the present compressive tectonic style.