Identification and Application of Growth Strata Associated with Strike-Slip Faults: Example from the Piqiang Fault in the Northwestern Margin of the Tarim Basin

Growth strata, which are deposited during tectonic deformation, serve as vital markers for dating the timing of such deformation events. While the utilization of growth strata analysis to constrain the timing of tectonic activities is well-established in regions characterized by compressional and extensional tectonics, its application to strike-slip faults remains largely unexplored. This study employs a comprehensive methodology integrating field geological investigations, remote sensing image analysis, and seismic profile interpretation to elucidate the geometric patterns and structural attributes of the Piqiang Fault located at the northwestern margin of the Tarim Basin. By identifying syntectonic growth strata through their map-view characteristics, we aim to determine the active period of the Piqiang Fault. The results show that the Piqiang Fault exhibits characteristics of a sinistral strike-slip fault, evidenced by left-lateral dislocation of surface marker beds, nearly horizontal scratches and vertical steps on the fault plane, the linear fault trace, and the positive flower structural style in seismic profiles. Notably, the strata of N₁ and older intervals maintain consistent thicknesses and curvatures within the same limb of the syncline to the west of the Piqiang fault. In contrast, the N₂ strata display an angular unconformity with the underlying strata. Furthermore, from N₂ to Q₁¹, strata thicknesses decrease progressively towards the Piqiang Fault, accompanied by a reduction in map-view curvatures with decreasing stratigraphic age. These observations collectively suggest that the strata from N₂ to Q₁¹ represent growth strata associated with intense strike-slip activity along the Piqiang Fault. This interpretation is corroborated by growth strata analysis from seismic profile data. Our findings not only contribute to a deeper understanding of tectonic evolution of the Piqiang Fault, but also provide novel insights into the identification and application of growth strata in the context of strike-slip faulting.