Late Quaternary thrusting in the southern margin of the Chaiwopu Basin, northern Chinese Tian Shan foreland

Abstract

Thrusting and the associated folding are crucial geological processes accommodating the crustal shortening in a foreland setting. This work focuses on the late Quaternary thrusting of the Banfanggou fault (BF) in the southern Chaiwopu Basin, northern Chinese Tian Shan foreland. The outcrops at the Urumqi River in the western part of the southern margin of the basin show that the BF, dipping south with angle of 60–80 °, has thrust the Neogene mudstone onto the Quaternary gravels and has displaced the terrace surfaces. In contrast, the eastern segment of the BF exists as a blind thrust fault. By using the geomorphic surface (river terrace and alluvial fan) as the reference, the average rate of vertical slip on the western segment of the BF over the past ~12 ka is estimated to ~1.7 mm/year, and the estimated rate at the eastern segment of the fault is ~1.0–1.3 mm/year. Despite of the uncertainties of the rates deriving from the vertical offsets and the geomorphic ages, the resultant vertical slip rates might imply relatively high seismic risk in the southern Chaiwopu Basin.

Introduction to the special issue “Tibetan tectonics and its effect on the long‐term evolution of climate, vegetation and environment”

“…This study suggests that secondary faulting within the northeastern Tibetan Plateau may play a key role in regulating Cenozoic regional crustal deformation. The Tianshan is located >2000 km away from Indus–Tsangpo suture zone where the Indian and Asian continents first collided, but it has accommodated a substantial portion of India–Asia convergence. By applying optically stimulated luminescence (OSL) dating to offset geomorphic features, Pang et al (2021) map a lateral variation in the late Quaternary folding and thrusting of the Banfanggou fault (BF) in the southern Chaiwopu Basin, northern margin of Chinese Tian Shan foreland. The study bears societal implications, by providing estimates of relatively high seismic risk in the southern Chaiwopu Basin.…”

“…To communicate the latest advances on this coupled tectonic, climatic, and biological system, we have launched a special virtual issue in Terra Nova and solicited submissions of 20 papers in total. The papers cover a wide range of topics that fall in the following, partially overlapping, categories: (a) Pre‐India–Asia collision tectonic configuration (Liu, Liu, et al, 2021; Zhang, Liu, et al, 2021); (b) post‐collision deformation that are subdivided into three sub‐categories, including (1) Himalayan geology (Fu et al, 2020; Liu, Wang, et al, 2021; Xu et al, 2021), (2) intracontinental deformation (Pan et al, 2021; Pang et al, 2021; Pei et al, 2021; Wang, Replumaz, et al, 2022; Zhang, Zhang, et al, 2021), and (3) exhumation and topographic evolution (He et al, 2020; Ma et al, 2021; Wang, Wang, et al, 2021; Zhang, Li, et al, 2021); (c) sedimentary system: source to sink studies, climatic forcing, and river incision (Feng et al, 2021; Wen et al, 2022; Yang et al, 2021; Zhang, Daly, et al, 2021); and (d) climatic and biospheric influence of the Tibetan Plateau (Averyanova et al, 2021). Research locations of this special issue are distributed across the plateau, spanning from the frontal Himalayas in the south to the Qilian Shan and Tian Shan ranges in the north, and extending into the continental interior (e.g.…”

“…(1) Himalayan geology (Fu et al, 2020;Liu, Wang, et al, 2021;Xu et al, 2021), (2) intracontinental deformation (Pan et al, 2021;Pang et al, 2021;Pei et al, 2021;Wang, Replumaz, et al, 2022;, and (3) exhumation and topographic evolution (He et al, 2020;Ma et al, 2021;Wang, Wang, et al, 2021;; (c) sedimentary system: source to sink studies, climatic forcing, and river incision (Feng et al, 2021;Wen et al, 2022;Yang et al, 2021;Zhang, Daly, et al, 2021); and (d) climatic and biospheric influence of the Tibetan Plateau (Averyanova et al, 2021). Research locations of this special issue are distributed across the plateau, spanning from the frontal Himalayas in the south to the Qilian Shan and Tian Shan ranges in the north, and extending into the continental interior (e.g.…”