Weitao Wang

Structural wedges, defined as contractional structures comprising kinematically linked forethrust and backthrust, represent a fundamental structural element in fold‐and‐thrust belts. Synchronous displacement on both thrust faults drives the wedge into the surrounding rocks, creating distinctive uplift and folding patterns. While previous 2D analyses have established their kinematic configurations, resolving their 3D growth patterns remains challenging. In this study, we identify a WNW‐trending structural wedge beneath the Yingjisha (YJS) anticline in the West Kunlun piedmont, and characterize its 3D growth pattern through high‐resolution 2D seismic reflection profiles, geometric and kinematic analyses, and 3D structural model. Structural forward modeling and quantitative analysis of fault slip reveal the synchronous slip on the forethrust and backthrust, demonstrating that the YJS anticline is controlled by a structural wedge. The ages of growth strata document a progression from 1.26 ± 0.11 Ma in the core to 0.85 ± 0.11 Ma in the eastern plunging termination, indicating lateral growth of the YJS anticline, with an eastward lateral growth rate of 35–84 km/Ma. Furthermore, through 3D structural model, we discover the consistency of the fault geometry along the strike. Two other natural structural wedges (Kashi and Dafengshan anticlines) validate this discovery, suggesting that undeformed segments inherit fault geometry from adjacent deformed segments along the strike, which may represent a common characteristic of structural wedges dominated by lateral growth. Our results not only establish a framework for understanding the 3D lateral growth of structural wedges, but also provide new insights into the formation and evolution of fold‐and‐thrust belts worldwide.

The intense seismicity observed across East Asia, particularly in the southeastern Tibetan Plateau, cannot be adequately explained by classical plate tectonics. Instead, the concept of active block tectonics—viewing the continental lithosphere as a mosaic of deformable yet kinematically independent blocks bounded by active faults—provided new insights into the intracontinental deformation. In this study, we integrate active tectonic, seismological, and geophysical data sets to delineate a hierarchical system of first‐ to fourth‐order active block tectonics models in the southeastern Tibetan Plateau. Block rotations and internal strain rates are quantified using the TDEFNODE modeling framework applied to GNSS velocity data. The results reveal that present‐day deformation is partitioned among multiple blocks and accommodated through both rigid block rotation and distributed internal strain, reflecting strong lithospheric heterogeneity and mechanical segmentation. Based on these observations, we propose updated criteria for delineating active blocks in continental interiors. Our findings provide new insights into the late‐stage evolution of orogenic systems and establish a seismologically validated, geophysically constrained framework for interpreting intracontinental deformation and assessing seismic hazards in the southeastern Tibetan Plateau.

Understanding the cause and location of the end‐points of thrust earthquake ruptures is critical yet unresolved question in seismic hazard assessment for convergent margins, where numerous destructive earthquakes have occurred. Here, we offer a novel perspective on rupture termination by examining the arrest of the 1906 M 8.0 Manas earthquake in northwestern China. Integrated field surveys, seismic profiles, and microseismicity data reveal that rupture terminated at the actively growing Xiaodushan anticline. This anticline lies parallel to and in the hanging wall of the seismogenic fault. We propose active folding acts as an efficient rupture‐arrest barrier, partitioning seismic energy into strata uplift and microseismicity. Furthermore, comparative analysis of global thrust earthquakes identifies two termination mechanisms: fault geometric complexities and external structural barriers. These findings contribute to deeper understanding of rupture lengths and earthquake magnitudes for seismic hazard assessment in convergent margins globally.

The orogenic processes along the northeastern margin of the Tibetan Plateau are often regarded as critical evidence of the ongoing Cenozoic collision between the Indian and Asian plates, driving the plateau's progressive northward expansion. However, the mechanisms driving uplift in the Qilian Shan since the mid‐Miocene remain poorly constrained due to limited record directly linking mountain building. Here, we present new stratigraphic and fault activity observations from the fold‐and‐thrust belt along the northern margin of the Qaidam Basin, providing insights into the tectonic context of basin‐mountain development. By integrating high‐resolution magnetostratigraphic data, deep seismic imaging, and field observations from the fold‐and‐thrust belt, we reconstruct a comprehensive history of sedimentation and tectonic activity from 13.5 Ma to 0.5 Ma. Our findings indicate that shifts in paleocurrents/provenance are concurrent with variations in sedimentation rates and stratigraphic tilting (growth strata) due to fault‐propagation‐folding. These observations suggest that the southern Qilian Shan underwent three distinct phases of accelerated uplift and southward expansion during ∼13.5–10 Ma, ∼6–5 Ma, and ∼3.5–2 Ma. Synthesizing these results with prior studies on the timing of deformation, we propose that since the mid‐Miocene, the Qilian Shan have expanded simultaneously in opposite directions along both their northern and southern margins, with eastward growth. This expansion pattern coupled with crustal‐scale pure shear deformation, suggests that gravitational collapse triggered by ongoing internal uplift of the Tibetan Plateau, diffusing outward toward the plateau's margins, may be a key driver of the horizontal compressive stresses along the northeastern Tibetan Plateau.

The ongoing India‐Asia convergence during the Cenozoic drove intensively compressional deformation in the northern margins of the Tibetan Plateau, such as Tianshan, which formed the highest mountain peaks and lowest intermontane basins in the Central Asia. Understanding the spatial‐temporal evolution of the Tianshan and its marginal fold‐thrust belts (FTB) are crucial for interpreting intracontinental deformation processes related to the India‐Asia collision. In this work, low‐temperature thermochronology data and growth strata analysis are integrated to constrain chronologically the onset of deformation of the structures in FTB (Belt I, II, and the Huoyanshan Anticline) along the southern front of the Chinese East Tianshan (CETS), and then to underpin the Cenozoic deformational model of the CETS. We propose a three‐stage expansion model to reveal the processes by which the southern thrust belts in the CETS have extended into the Turpan Basin since the Oligocene. Stage 1: thrusting of the South Bogda Fault since ∼30 Ma, which caused the initial uplift of the CETS; Stage 2: deformation expanded southward to the Tarlang River region at ∼20 Ma; Stage 3: the thrust belts propagated southward in a thin‐skinned structural style to the Huoyanshan Anticline in the central part of the Turpan Basin since ∼10 Ma. The progressive propagation of FTB in the southern piedmont of the CETS could have responded to multi‐stage uplift of the Tibetan Plateau during the Cenozoic.

Faulting and folding of basement rocks together accommodate convergence within continental orogens, forming complex zones of intraplate deformation shaped by the fault interaction. Here we use the river terraces along the Dongda river to examine the tectonic deformation patterns of the hinterland and the foreland of the eastern North Qilian Shan, a zone of crustal shortening located at the northeast margin of the Tibetan Plateau. Five Late Pleistocene–Holocene terraces of Dongda river are displaced by three major reverse faults: Minle‐Damaying fault, Huangcheng‐Ta'erzhuang fault, and Fengle fault, from south to north. Based on displaced terrace treads, we estimated vertical slip rates along the Minle‐Damaying fault as 0.7–0.8 mm/a, and along the Fengle fault as 0.5–0.7 mm/a. Deformed terraces suggest an additional uplift of ∼0.2 mm/a through the folding of the Dahuang Shan anticline. Inhomogeneous uplift of the intermontane basins between the Minle‐Damaying fault and the Dahuang Shan anticline indicates a 0.9 ± 0.2 mm/a uplift rate along the Huangcheng‐Ta'erzhuang fault. Kinematic modeling of this thrust system shows that deformation propagated northward toward the foreland along a south‐dipping 10° décollement rooted into the Haiyuan fault at the depth of ∼20 km. This system accommodates 2.7–3.4 mm/a total crustal shortening rate. We suggest this broad thrust belt and the relatively high rate of shortening within this part of the eastern Qilian Shan is a result of the oblique convergence along a restraining bend of Haiyuan fault system. The elevated shortening rate within this area indicates high potential seismic hazard.

The formation age of the middle Yellow River and the existence of a northward‐flowing river have been fiercely debated. The age distribution of detrital zircon varied spatiotemporally and produced contradictory provenance interpretations. The Jinshaan Gorge, the main part of the middle Yellow River and key to studying fluvial evolution and clarifying disputes, developed its topography during the late Cenozoic. In this study, we systematically review the Cenozoic tectonic evolution of the North China Craton, perform detrital zircon U–Pb dating in the Neogene−Quaternary sediments and investigate the topography along the Jinshaan Gorge, and the sedimentology and chronological framework of these sediments. We propose that the Gorge of the middle Yellow River could have developed since the Neogene, controlled by the tectono‐geomorphologic evolution of the North China Craton in a dominantly extensional environment. No evidence supports a northward‐flowing river during the Early Pleistocene or even earlier in the Jinshaan Gorge. We attribute the provenance variations of the Cenozoic sediments to detrital mixing of diverse geological units, local and distant, and especially highlight the systematic provenance shift between the Neogene and Quaternary sediments caused by bedrock downcutting and recycling aeolian sediments. The increased 1.5−0.33 Ga component of the lower Yellow River during the Early Pleistocene was likely caused by enhanced loess accumulation and should not be individually used as a proxy for the Yellow River formation. We emphasize the significance of a comprehensive study of river evolution.

Faulting and folding of basement rocks together accommodate convergence within continental orogens, forming complex zones of intraplate deformation shaped by the fault interaction. Here we use the river terraces along the Dongda river to examine the tectonic deformation patterns of the hinterland and the foreland of the eastern North Qilian Shan, a zone of crustal shortening located at the northeast margin of the Tibetan Plateau. Five Late Pleistocene-Holocene terraces of Dongda river are displaced by three major reverse faults: Minle-Damaying fault, Huangcheng-Ta’erzhuang fault, and Fengle fault, from south to north. Based on displaced terrace treads, we estimated vertical slip rates along the Minle-Damaying fault as 0.7–1.2 mm/a, and along Fengle fault as 0.5–0.7 mm/a. Deformed terraces suggest additional uplift of ~ 0.2 mm/a through folding of the Dahuang Shan anticline. Inhomogeneous uplift of the intermontane basins between the Minle-Damaying fault and the Dahuang Shan anticline indicates a 0.9 ± 0.2 mm/a uplift rate along the Huangcheng-Ta’erzhuang fault. Kinematic modeling of this thrust system shows that deformation propagated northward toward the foreland along a south-dipping 10° décollement rooted into Haiyuan fault at the depth of 20–25 km. This system accommodates 2.7–3.8 mm/a total crustal shortening rate. We suggest this broad thrust belt and the relatively high rate of shortening within this part of the eastern Qilian Shan is as a result of the oblique convergence along a restraining bend of Haiyuan fault system. The elevated shortening rate within this area indicates high potential seismic hazard.

Continental rejuvenation results from the tectonic reactivation of crustal structures and lithospheric reworking by mantle flow. Geochemical observations and field mapping have traditionally provided the primary evidence for the secular evolution of crustal composition and tectonic processes during continental rejuvenation. Nonetheless, the impact of continental rejuvenation on the observed present-day strain rate and orogenic-scale lithospheric structure has not been well constrained. The pre-existing E-W–trending Central China Orogenic Belt has been overprinted by the N-S–trending Central Longitudinal Seismic Belt and constitutes the intracontinental West Qinling Syntaxis in central China, where the tectonic setting changes eastward from contraction to extension. Combining updated global positioning system data and high-resolution crustal seismic tomography, we reveal a modern continental rejuvenation process within the West Qinling Syntaxis in central China. The northward extrusion of the Tibetan Plateau's weak lithospheric layer (middle-lower crust and lithospheric mantle) of southwestern China relative to the rigid Sichuan Basin/Ordos Block of the eastern West Qinling Syntaxis results in regional dextral shearing that shapes the Central Longitudinal Seismic Belt and defines the eastern Tibetan Plateau margin. The pre-existing E-W–trending Central China Orogenic Belt has been preserved above the brittle-ductile transition zone, and the northward movement of the deep lithospheric layer drives the deformation of the upper crust in the West Qinling Syntaxis. Our results, along with previous studies, suggest the presence of an intracontinental lithospheric interchange structure in central China. The continental rejuvenation of the West Qinling Syntaxis results from a combination of fault reactivation in the upper crust (Stage I, Eocene–Oligocene) and reworking of the deep lithosphere (Stage II, middle–late Miocene) related to the plateau-wide shift in stress accommodation ultimately driven by the redistribution of mass outward from the central Tibetan Plateau. At present, the transition zone between the high- and low-velocity anomalies along the Central Longitudinal Seismic Belt not only shapes the landscape boundary but controls the size and recurrence interval of earthquakes within the West Qinling Syntaxis in central China.