Late Quaternary slip rate of the strike-slip faults on the eastern margin of the Qaidam Basin on the Tibetan Plateau and its implication on regional strain partitioning

Abstract

The spatial variation in slip rates of large-scale strike-slip faults provides crucial support for the conceptual models of continental collision. However, the reasons for the decrease in slip rate of the East Kunlun Fault at the eastern margin of the Qaidam Basin on the Tibetan Plateau are still unclear. At the eastern margin of the Qaidam Basin, we identified four active strike-slip faults—two NW-SE−orientated dextral (the Xiariha Fault and Yingdeerkang Fault) and two E-W−orientated sinistral (the Reshui-Taosituohe Fault and Taosituohenan Fault)—and determined their slip rates using uncrewed aerial vehicle-based topography and optically stimulated luminescence dating. For the Xiariha Fault, from north to south slip rates are 1.39 +0.51/−0.34 mm/yr, 1.19 +0.15/−0.14 mm/yr, and 0.9 +0.19/−0.16 mm/yr. The Yingdeerkang Fault slips at 0.66 +0.08/−0.07 mm/yr. The Reshui-Taosituohe Fault, from west to east, slips at 0.95 +0.22/−0.19 mm/yr and 1.20 +0.11/−0.09 mm/yr. The Taosituohenan Fault, west to east, slips at 0.62 +0.12/−0.12 mm/yr to 1.01 +0.21/−0.19 mm/yr and 1.21 +0.43/−0.25 mm/yr. We believe that the gradual decrease in slip rate of the East Kunlun Fault at the Tuosuo Lake segment toward the east is influenced by the activity of the four active strike-slip faults with a slip rate of ∼1 mm/yr along the eastern margin of the Qaidam Basin and the Elashan Fault. The decrease in fault slip rate is not solely attributed to the diverse structural styles of the fault itself but also to the strain absorption by the development of differently oriented faults around its periphery.