Structural geometry and evolution of the eastern Yuqi strike-slip faults in the Tabei Uplift, Tarim Basin (NW China)

The strike-slip fault system in the eastern Yuqi area of the Caohu Sag, distinct from the conjugate strike-slip fault systems in the Halahatang Sag, provides a valuable case study for understanding the genetic variations among strike-slip faults across different locations within the Tabei Uplift. This system in the eastern Yuqi area comprises ENE-, NE-, N-S-, and E-W-oriented strike-slip faults. The development of the ENE- and NE-oriented faults was primarily influenced by the paleostructure, specifically the structural slope-break zone. The evolution of these fault sets can be divided into three main stages: (1) In the Late Ordovician, initial uplift occurred in the Akekule Uplift and the northern Caohu Sag, leading to the development of the western Akekule Uplift as a paleostructural high. Conjugate faults formed in the western Akekule Uplift, constrained by the rigid Yakela Fault-convex. (2) During the Silurian to Early Devonian, northward compression and subsequent extrusion along the Akekumu Fault resulted in the formation of a series of ENE- and NE-oriented sinistral strike-slip faults in the western Yuqi area, at the leading edge of the Akekumu Fault. Simultaneously, the structural slope-break zone began to develop in the eastern Yuqi area, controlling the formation and orientation of the NE- and ENE-oriented faults. (3) In the Permian, increased N-S-trending regional compression, driven by the closure of the South Tianshan Ocean, led to the formation of the reverse fault RF-ENE1 and an upward-steepening interlayer reverse fault (RF-CAO2). NEoriented strike-slip faults, such as Fault YQ13, were reactivated, and NS-oriented strike-slip faults, including Fault YQD and Fault Lungudong, potentially experienced sinistral strike-slip movement.