River system reformed by the Eastern Kunlun Fault: Implications from geomorphological features in the Eastern Kunlun Mountains, Northern Tibetan Plateau

Abstract

The Eastern Kunlun Fault is a famous sinistral strike-slip fault, and the Eastern Kunlun Mountains is one of the most outstanding landmarks on the Tibetan Plateau. Comprehensive geomorphic analyses in this study constrain the activation of the Eastern Kunlun Fault and the uplift process of the Eastern Kunlun Mountains. The three largest rivers flowing into the Qaidam basin, the Nalenggele River, the Golmud River and the Xiangride River, all run across the mechanically strong granitoid belt and Precambrian basement in the Eastern Kunlun Mountains and reach the soft Mesozoic and Cenozoic Hoh-Xil basin. Meanwhile, the drainage patterns and longitudinal profiles of these three rivers are significantly reformed by the Eastern Kunlun Fault. The horizontal throws caused by the Eastern Kunlun Fault inferred from drainage pattern (∼110 km for the Golmud River and ∼90 km for the Xiangride River) are consistent with the previous estimated strike-slip displacement of the Eastern Kunlun Fault. Horizontal segments occur on river longitudinal profiles, induced by the rapid strike-slip movement of the Eastern Kunlun Fault. All the above evidences imply that the river system of the Eastern Kunlun Mountains was built before the initiation of the Eastern Kunlun Fault. Meanwhile, the distribution of normalized steepness indices (ksn) shows that rapid rock uplift occurred between the Eastern Kunlun Fault and the northern front of the Eastern Kunlun Mountains.