Delimiting the eastern extent of the Altyn Tagh Fault: Insights from structural analyses of seismic reflection profiles

Abstract

The Altyn Tagh Fault (ATF) serves as a key continental‐scale controlling structural element of the Tibetan Plateau. However, its eastward extent remains controversial. Here we use high‐resolution seismic reflection profiles to investigate the subsurface structures of the easternmost ATF and use these to delimit the easternmost extent of the fault. The structural analyses show an eastward geometric change from transpressional positive flower structures to compressional thrusts, with transpression‐induced shortening magnitudes decreasing eastwards from a maximum of ~5.3 km to being absent. Stratigraphic controls indicate that the deformation took place over the last ~<1.2 Ma. Our wider findings lead us to: (a) reject the suggestion that the ATF previously extended beyond the Kuantan Shan‐Hei Shan to link with the Alxa‐East Mongolia Fault; and (b) propose that the rigid block model used to describe the Tibetan Plateau crust is not consistent with the extent and structural details of the easternmost ATF.

An Evolving Lithospheric‐Scale Wrench Fault System Along the Eastern End of the Altyn Tagh Fault: Kinematics and Quaternary Activity of the Heishan Fault System, Western China

“…Two different models have been proposed to explain the eastward continuation of the ATF system in the western Hexi Corridor region (e.g., Y. Zhang, Zhang, et al., 2020 and their Figure 1). The ”fault termination model” suggests that the active fault trace of the ATF terminates on the west side of the Kuantanshan, or the ATF merges with the southern Kuantanshan fault (Figure 2, Gong et al., 2007; SSBC, 1992; W. J. Zheng, Zhang, Zhang, et al., 2013).…”

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

“…The model shows a first‐order pattern characterized by strain transfer from the strike‐slip to shortening from west to east. Based on the interpretations of a set of high‐resolution seismic reflection profiles, Zhang, Zhang, et al (2021) study the termination of the Altyn Tagh fault by constraining its slip history and the transition from slip motion to shortening. The numerical modelling study of Pei et al (2021) investigates the arcuate structure and relates the formation of arcuate structure to lateral heterogeneities related to pre‐existing strong blocks and varying sediment strata thickness and fault geometry.…”

“…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.…”