Origin and growth mechanisms of strike-slip faults in the central Tarim cratonic basin, NW China

Abstract

Through fault structure analysis and chronology study, we discuss the origin and growth mechanisms of strike-slip faults in the Tarim Basin. (1) Multiple stages strike-slip faults with inherited growth were developed in the central Tarim cratonic basin. The faults initiation time is constrained at the end of Middle Ordovician of about 460 Ma according to U-Pb dating of the fault cements and seismic interpretation. (2) The formation of the strike-slip faults was controlled by the near N-S direction stress field caused by far-field compression of the closing of the Proto-Tethys Ocean. (3) The faults localization and characteristics were influenced by the pre-existing structures of the NE trending weakening zones in the basement and lithofacies change from south to north. (4) Following the fault initiation under the Andersonian mechanism, the strike-slip fault growth was dominantly fault linkage, associated with fault tip propagation and interaction of non-Andersonian mechanisms. (5) Sequential slip accommodated deformation in the conjugate strike-slip fault interaction zones, strong localization of the main displacement and deformation occurred in the overlap zones in the northern Tarim, while the fault tips, particularly of narrow-deep grabens, and strike-slip segments in thrust zones accumulated more deformation and strain in the Central uplift. In conclusion, non-Andersonian mechanisms, dominantly fault linkage and interaction, resulted in the small displacement but long intraplate strike-slip fault development in the central Tarim Basin. The regional and localized field stress, and pre-existing structures and lithofacies difference had strong impacts on the diversity of the strike-slip faults in the Tarim cratonic basin.

Keywords

• strike-slip fault
• fault dating
• fault growth mechanism
• non-Andersonian faulting
• stress field
• pre-existing structure