Structural geometry and evolution of an intracratonic strike-slip fault zone: A case study from the north SB5 fault zone in the Tarim Basin, China

Abstract

The north SB5 fault zone (NSB5FZ) in the Tarim Basin experienced a multistage tectonic evolution, thereby displaying complex structural features. Three-dimensional seismic data were utilized to document the structural geometry and evolution of the fault zone. Comprehensive analysis of the seismic data suggests that the NSB5FZ is a strike-slip fault zone, and it slipped right-laterally during the early Paleozoic with a varying slip azimuth. Three different types of responses of the late structural deformation to the pre-existing structures exist on the NSB5FZ in its evolution. During the early Paleozoic, the NSB5FZ has experienced at least three strike-slip movements. (1) Induced by the first strike-slip movement, the lower-middle Cambrian strata were folded, and positive flower structures occurred. (2) During the second strike-slip movement period, several faults were produced and arranged both left- and right-stepping. The traces of these faults were right above the faults or anticline axes at depth. Sequentially, positive and negative relief occurred right above the left and right stepovers, respectively. (3) Induced by the third strike-slip movement, a series of en echelon normal faults developed above the NSB5FZ, while the contractional deformation in the stepovers at depth has not ceased but propagated upward.