Journal of Structural Geology最新文献

{"title":"Mineral heterogeneity dominates the tensile failure mode of Eastern Himalayan Gneiss","authors":"Shijie Liu ,&nbsp;Hengxing Lan ,&nbsp;C. Derek Martin ,&nbsp;Langping Li ,&nbsp;Han Bao","doi":"10.1016/j.jsg.2025.105515","DOIUrl":"10.1016/j.jsg.2025.105515","url":null,"abstract":"<div><div>As two fundamental fracture types in rock engineering, tension and shear fractures are commonly considered to operate under different stress conditions. However, abundant recent research shows that the microscale heterogeneity of rocks leads to the possibility of microscale tensile and shear fracturing under any stress state. In particular, localised stress concentrations and tensile fractures caused by mineral heterogeneity under compressive stress have been widely studied. However, the heterogeneity-induced processes involved in the shear fracture under direct tension conditions remain ambiguous. In this study, a micro-direct tensile test was used to comprehensively reveal the process and mechanism by which mineral heterogeneity leads to shear fracture in the gneiss of the eastern Himalayas under direct tension. Microscopic observation of the failure process under direct tension, normalised crack initiation and propagation stress, and transverse strain dilation caused by shear behaviour indicate that gneiss with an exceptional anisotropy angle may exhibit more pronounced shear sliding during progressive tensile failure processes. Micro shear sliding significantly increased the strength of the gneiss and changed its tensile strain, elastic modulus, and progressive failure process, which were determined using a direct tension test. Depending on the degree of frictional sliding, the tensile failure mode of gneiss can be divided into three modes: tensile, hybrid, and shear. Mineral heterogeneity influences the pattern of crack propagation through potential fracture planes, altering the crack propagation stress, significantly affecting the mobilisation of frictional strength, and resulting in a progressive transition between the three modes. The observation of shear sliding under direct tension caused by heterogeneity emphasises the importance of mineral-scale heterogeneity in evaluating the tensile strength of anisotropic rocks.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105515"},"PeriodicalIF":2.6,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismogenesis in the brittle–plastic transition zone of the Yecheon shear zone, South Korea","authors":"Jae Hoon Kim ,&nbsp;Jin-Han Ree","doi":"10.1016/j.jsg.2025.105511","DOIUrl":"10.1016/j.jsg.2025.105511","url":null,"abstract":"<div><div>This study investigates seismogenesis in the brittle–plastic transition zone of the Yecheon Shear Zone, South Korea. The NE-to NNE-striking right-lateral shear zone cuts a Mesozoic granitoid pluton in an outcrop that was investigated in this study. We focus on light green layers within granite mylonitic rocks that preserve evidence of seismic slip events and subsequent plastic deformation. Field observations and microstructural analysis reveal a complex history of brittle and plastic deformations. The light green layers, formed by frictional melting during seismic events, contain injection structures, flow textures, and euhedral to subhedral microlites with inclusions. Elevated pore-fluid pressure might have played a crucial role in initiating seismic ruptures in the brittle–plastic transition zone, forming shear band ruptures or R shear planes and implosion breccia in the releasing stepovers in shear band ruptures. We propose a seismogenic model involving fluid pressure buildup, formation of shear band ruptures, rupture propagation into the <em>C</em> foliation, and the formation and subsequent alteration of pseudotachylytes. The fine-grained nature of the altered pseudotachylytes would have promoted strain localization during interseismic periods, leading to their transformation into ultramylonite. These findings improve our understanding of earthquake nucleation processes in the brittle–plastic transition zone and highlight the importance of fluids in inducing seismic events.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105511"},"PeriodicalIF":2.6,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of middle to deep-depth strike-slip faults in the southern Ordos Basin, China: A case study of the Xunyi area","authors":"Yunwen Guan ,&nbsp;Qichao Wang ,&nbsp;Renhai Pu ,&nbsp;Sujie Yan ,&nbsp;Shuo Chen ,&nbsp;Siyu Su","doi":"10.1016/j.jsg.2025.105509","DOIUrl":"10.1016/j.jsg.2025.105509","url":null,"abstract":"<div><div>High-resolution 3D seismic reflection data and coherence attribute analysis reveal a complex network of small-scale strike-slip faults (0.2–20 km in length) within the Xunyi area of the southern Ordos Basin at burial depths of 0.4–3.5 km. These structures exhibit a multi-phase evolution history characterized by distinct deformation patterns across different stratigraphic intervals.</div><div>Structural analysis identifies four distinct tectonic episodes: (1) initial development of NE and NW-trending fault systems during the Caledonian movement (Cambrian-Ordovician), (2) limited reactivation during the Hercynian event (Carboniferous-Permian), (3) formation of NWW to E-W-trending sinistral strike-slip faults during the Indosinian event (Early-Middle Triassic), and (4) right-lateral transpressional reactivation during the Yanshanian event (Late Jurassic-Early Cretaceous).</div><div>Mohr space analysis reveals that the angular relationship between fault orientation and regional stress fields fundamentally controls three distinct patterns of structural inheritance: (1) The XY1 fault maintains continuous activity through all tectonic phases due to its optimal N72-86°E orientation relative to successive stress fields; (2) The XY2-4 faults exhibit early termination after the Caledonian period despite their basement-cutting nature, attributed to their unfavorable orientation under subsequent stress regimes; (3) The Mesozoic faults (W1-4) initiated independently during the Indosinian period with N64-86°E strikes, displaying 33–44° counterclockwise rotation from pre-existing Paleozoic structures.</div><div>Detailed fault growth analysis reveals an early stress interaction mechanism where approaching fault segments develop secondary faults and displacement patterns before geometric overlap occurs. This observation challenges the traditional four-stage fault linkage model that assumes significant interaction only after substantial fault overlap, suggesting more complex stress field interactions during early fault development.</div><div>This integrated study provides critical insights into intraplate deformation processes within cratonic basins, demonstrating how the orientation of pre-existing structures relative to evolving regional stress fields fundamentally controls fault reactivation patterns in multi-phase tectonic settings.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"199 ","pages":"Article 105509"},"PeriodicalIF":2.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling progressive stages of formation and examining relative roles of proximity to fault, mechanical stratigraphy on fracturing in the leading-edge of thrust sheets: Insights from Ramgarh thrust, Darjeeling Himalaya","authors":"J.K. Ammu,&nbsp;Kathakali Bhattacharyya","doi":"10.1016/j.jsg.2025.105507","DOIUrl":"10.1016/j.jsg.2025.105507","url":null,"abstract":"<div><div>We decipher the progressive stages of fracture formation and examine the competing effects of proximity to a thrust, lithology, and bed thickness on fracture abundance, orientation, mode, and length. We address this study in the interfoliated quartzite-phyllite sequence of the leading-edge (∼3.4 km) of the Ramgarh thrust (RT) sheet, the roof thrust of the lower Lesser Himalayan duplex in the Darjeeling Himalaya. Only ∼30 % of the total studied fractures (n = 884) preserve slickenlines and plumose structures. Due to favorable orientations relative to the vertical outcrop bearing, small displacement faults (shear fractures) (n = 236; ∼27 % of total fractures) with slickenlines are better exposed than opening-mode (n = 32; ∼4 %) with plumose structures. Further structural analyses reveal coexisting shear (∼59 %) and opening-mode (∼41 %) fractures. Through crosscutting, fold test, and intensity distribution, we establish fracturing initiated with low-angle, shear fractures during early layer parallel shortening. High-angle, shear, and opening-mode fractures formed post-folding. Fracture density fluctuates with perpendicular distance from the footwall contact due to variation in lithology and bed thickness. Fracture density most strongly depends on lithology (quartzite_fractures &gt; phyllite_fractures), followed by bed thickness (thin beds_fractures &gt; thick beds_fractures) and distance from the RT. Fracture mode and orientation, with respect to bedding, are similar across lithologies, only intensity differs. High-angle and Riedel shear fractures are localized proximal to the RT. Shear vs opening-mode proportions remain unchanged with increasing distance from the RT. Litho-boundaries and early-formed fractures constrain fracture lengths (n_traces = 10,758), irrespective of their mode and orientation. Fracture networks show more evolved length distributions close to the RT.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105507"},"PeriodicalIF":2.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstructing the framework of the Paleo-Pacific Plate: A synthetic review","authors":"Sanzhong Li ,&nbsp;Yong-Fei Zheng ,&nbsp;Yanhui Suo","doi":"10.1016/j.jsg.2025.105505","DOIUrl":"10.1016/j.jsg.2025.105505","url":null,"abstract":"<div><div>The Paleo-Pacific Ocean Basin would evolve from the Panthalassa and develop ancient plates such as Paleo-Pacific, Farallon and Phoenix. Multilines of geological and geophysical evidence indicate that a new-born plate, named the Pacific Plate, would initially develop at 190 Ma among these three plates in the Paleo-Pacific Ocean Basin, but it did not take shape until 55 Ma when the Paleo-Pacific Plate would finally disappear on the East Asian continental margin. Therefore, the Paleo-Pacific Plate and the Pacific Plate would co-evolve or co-exist from 190 Ma to 55 Ma in the Paleo-Pacific Ocean Basin. The ocean basin after the complete disappearance of the Paleo-Pacific Plate at 55 Ma is the Pacific Ocean Basin as presently seen. Geologically, the Pacific Ocean Basin is marked by the initial formation of the plate configuration on the current Pacific seafloor in the Mesozoic. Therefore, when did the Paleo-Pacific Plate begin in the Paleo-Pacific Ocean Basin? When was the Paleo-Pacific Plate subducted beneath the East Asian continental margin? How would its appearance and disappearance are spatiotemporally recorded in geology? What are its geological effects during its subduction beneath the East Asian continental margin? Although there are numerous studies dealing with the formation and evolution of the Paleo-Pacific Plate, the results have brought many big debates on its composition and structure. Some scholars refer to the Paleo-Pacific Plate differently, leading to some great difficulties in academic exchanges. There are three mainstream viewpoints: the Paleo-Pacific Plate is either the Kula Plate, or the Izanagi Plate, or a collage of many plates. Although the Paleo-Pacific Plate existed as a mysterious on Earth in the Mesozoic, a large number of geological observations indicate that its evolution is closely related to the tectonic evolution of the East Asian continental margin in this period. Therefore, it is necessary to recognize and reconstruct the configuration of the Paleo-Pacific Plate and its tectonic effects on the East Asian continental margin. This paper attempts to systematically summarize the previous observations and interpretations of the Paleo-Pacific Plate, to distinguish between the concepts of the Kula Plate, the Izanagi Plate and the Paleo-Pacific Plate in different study stages, and to systematically explore various differences in plate reconstruction since the proposal of the Paleo-Pacific Plate. Based on the current progresses on plate tectonics, this paper also summarizes the relevant geological records of the Paleo-Pacific Plate, including the continental margin accretion of oceanic plateaus, island arc basalt-like magmatic rocks and terrane-collage accretion. The time of its subduction initiation, geometric evolution and spatial range changes are explored, and its tectonic evolutionary history is reconstructed. Finally, remaining problems are presented for the future research.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"199 ","pages":"Article 105505"},"PeriodicalIF":2.6,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinematic interpretation of the Cañamares shear zone (central Iberian zone, Iberian Massif): from late Variscan strike-slip tectonics to Alpine deformation","authors":"Diana Moreno-Martín ,&nbsp;Carlos Fernández ,&nbsp;Rubén Díez Fernández ,&nbsp;Gerardo de Vicente","doi":"10.1016/j.jsg.2025.105504","DOIUrl":"10.1016/j.jsg.2025.105504","url":null,"abstract":"<div><div>The Cañamares shear zone is located at the eastern end of the Spanish-Portuguese Central System, in the Central Iberian Zone of the Iberian Massif. It is a dextral transpressive structure, generated during the third Variscan deformation stage (D₃: 318-300 Ma), which was later reworked during the Permian and by Alpine tectonics. Once the local effects of later phases have been eliminated, the kinematic analysis of the Cañamares shear zone shows that it is a structure due to a monoclinic to slightly triclinic flow, with a vorticity dominated by the simple-shearing component (<em>W</em>_k &gt; 0.81). The convergence direction of the blocks separated by the shear zone would have been N160°E to N-S. The convergence direction calculated for the Cañamares shear zone differs from that of other D₃ shear zones of the Iberian Massif. A comparison between these vectors would help to better understand the complexities of the final phases of the Variscan Orogeny in Iberia. However, the Cañamares shear zone lies at the core of an Alpine mega-fold and its current orientation does not probably reflect its primary geometry.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"199 ","pages":"Article 105504"},"PeriodicalIF":2.6,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deformation mechanisms of compressional overlapping area in strike-slip fault zone: Insights from experimental simulation","authors":"Jingjing Zhang ,&nbsp;Lingli Guo ,&nbsp;Sanzhong Li ,&nbsp;Wei Tao ,&nbsp;Yuntao Ji ,&nbsp;Yanshuang Guo ,&nbsp;Shujuan Zhao ,&nbsp;Jiaxuan Zhang ,&nbsp;Guangzeng Wang","doi":"10.1016/j.jsg.2025.105503","DOIUrl":"10.1016/j.jsg.2025.105503","url":null,"abstract":"<div><div>As an intense deformation region, the compressional overlapping areas of strike-slip faults play a crucial and significant role in influencing fault propagation, seismic activity, and the formation and distribution of hydrocarbon reservoirs. Hence, enhancing the comprehension of detailed microscopic deformation mechanisms lays the foundation for a better understanding of the macroscopic deformation, constituting the core issue of this study. Compressional en échelon fault model experiments were conducted, combining with acoustical and optical measurements to simulate fault interactions and mechanical coupling within fault systems. The experimental results manifest that three distinct episodes of derived faults were observed during the interaction of pre-existing faults. Firstly, a group of derived faults extends from the ends of the overlapping area, conjugating with the pre-existing en échelon faults. Secondly, the fault consisting of a series of secondary fractures propagates from the ends of the overlapping area towards the interior, leading to a complete destruction of the overlapping area. Thirdly, another group of faults extends from the ends of the overlapping area, forming a rhombic region in conjunction with the two pre-existing faults. Furthermore, the analysis of the strike-slip rate distribution along two en échelon faults showed significant heterogeneity. Specifically, the segments with relatively low strike-slip rate were inferred to be locked zones, which are likely to act as nucleation points for future emergent deformation events. These simulation results contributed to understanding the issues such as the mechanical coupling between Garlock and San Andreas fault systems, the linkage fault development in the branching zones of the North Anatolian Fault Zone, and the kinematic intersection geometry between the Danghenan Shan and Altyn Tagh faults.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"199 ","pages":"Article 105503"},"PeriodicalIF":2.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural and stratigraphic control on fluid flow in the Mt. Conero anticline, Italy: An analog for offshore resource reservoirs in fold-and-thrust belts","authors":"Luca Smeraglia ,&nbsp;Luca Aldega ,&nbsp;Stefano M. Bernasconi ,&nbsp;Andrea Billi ,&nbsp;Sabina Bigi ,&nbsp;Eduardo di Marcantonio ,&nbsp;Andrea Fiorini ,&nbsp;Andrew Kylander-Clark ,&nbsp;Eugenio Carminati","doi":"10.1016/j.jsg.2025.105502","DOIUrl":"10.1016/j.jsg.2025.105502","url":null,"abstract":"<div><div>We investigate the structural control on paleofluid flow in the Mt. Conero anticline, Italy, located in the frontal part of the Apennines fold-and-thrust belt. This anticline can be considered as an exhumed analog for buried anticlines in the Adriatic offshore, currently exploited for hydrocarbons and potential geothermal reservoirs or CO₂ storage sites in the future. By integrating field structural analyses, stable and clumped isotope geochemistry of carbonates, and U-Pb geochronology, we demonstrate that the structural evolution of the Mt. Conero anticline in a carbonate-siliciclastic succession is marked by: (1) pre-orogenic normal faulting and veining during foreland flexure, (2) layer-parallel shortening during early contraction, with the development of <em>en-echelon</em> bed-perpendicular conjugate veins and stylolites, (3) syn-folding thrusting and strike-slip faulting, and (4) transtensional faulting during fold exhumation and extensional collapse. Fluid circulation took place in a closed system, predominantly involving formation water, such as marine pore water trapped during diagenesis. Effective sealing by clay-rich formations overlying the fractured, permeable carbonates, coupled with low displacement strike-slip faults and thrusts, prevented the ingress of meteoric fluids and/or the upward migration of deep (hydrothermal) fluids. Limited mixing between formation and meteoric waters in a semi-closed system was observed during fold exhumation and extensional collapse. Our results show that folds in the frontal part of offshore fold-and-thrust belts are likely to retain fluids trapped during diagenesis due to the preservation of sealing layers. This suggests that such anticlines can preserve hydrocarbon reservoirs and are excellent candidates for CO₂ storage due to their low leakage potential, offering also good storage capacity for geothermal fluids. These results may represent a benchmark for offshore anticlines in the frontal part of other offshore fold-and-thrust belts, particularly those with carbonate anticlines overlain by clay-rich sealing layers.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105502"},"PeriodicalIF":2.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure and CPO evolution of dynamically recrystallized olivine during complex deformation conditions: a full-field numerical modeling approach","authors":"Yuanchao Yu ,&nbsp;Albert Griera ,&nbsp;Enrique Gomez-Rivas ,&nbsp;Paul D. Bons ,&nbsp;Daniel Garcia-Castellanos ,&nbsp;Baoqin Hao ,&nbsp;Ricardo A. Lebensohn ,&nbsp;Cassandra Seltzer ,&nbsp;Maria-Gema Llorens","doi":"10.1016/j.jsg.2025.105500","DOIUrl":"10.1016/j.jsg.2025.105500","url":null,"abstract":"<div><div>The rheological properties of mantle rocks are strongly dependent on their crystallographic preferred orientation (CPO). Olivine CPO, defined by the orientation of seismically fast [100] axes parallel to flow direction, is also thought to be a dominant contributor to seismic anisotropy in the Earth's upper mantle. However, the amount of deformation needed to overprint a new CPO on a pre-existing fabric and the impact of the inherited CPOs on the transient microstructure evolution, remain unknown. This study employs a full-field numerical approach (VPFFT-ELLE) to explore the dynamic recrystallization and microstructural evolution of olivine polycrystalline aggregates under complex deformation conditions. We test four combinations of successive pure shear and simple shear boundary conditions. Findings indicate that inherited CPOs influence subsequent deformation in a manner dependent on the kinematic relationship between successive stages. In all cases, a minor strain increment (ε ∼0.3–0.6) is sufficient to erase the previous microstructure and CPO. However, when deformation conditions change dramatically (<em>e.g.</em>, stretching direction changes orthogonally), the intensity of the new CPO developed is significantly lower and strain distribution are specially altered. During a transient strain stage, pre-existing microstructures undergo extensive reworking, especially when deformation conditions are changed dramatically, such as switching from simple shear to a pure shear condition with a parallel shortening direction relative to the stretching direction. We estimate the significance of these results in interpreting observations of seismic velocity anisotropy, concluding that P-wave seismic anisotropy is significantly and positively correlated with the evolution of olivine CPO with deformation history. This research underscores the transient nature of microstructural rearrangement in olivine aggregates and the necessity for caution in interpreting seismic anisotropy in regions with complex deformation histories, as inherited CPOs can influence current fabric development and induce deviation to the present deformation conditions.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"199 ","pages":"Article 105500"},"PeriodicalIF":2.6,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fine geometric structures and characteristics of present-day activity of the Tianshui–Baoji segment of the West Qinling Fault, northeastern margin of the Tibetan Plateau","authors":"Ruihuan Su ,&nbsp;Daoyang Yuan ,&nbsp;Zhao Wu ,&nbsp;Jinchao Yu ,&nbsp;Yunsheng Yao ,&nbsp;Hong Xie ,&nbsp;Lijun Zhang ,&nbsp;Yameng Wen ,&nbsp;Hao Sun ,&nbsp;Yanwen Chen ,&nbsp;Hongqiang Li","doi":"10.1016/j.jsg.2025.105499","DOIUrl":"10.1016/j.jsg.2025.105499","url":null,"abstract":"<div><div>Accurately delineating the fine geometric structures of active faults and assessing their present-day activity are of paramount importance for studying regional fault tectonics and evaluating seismic risk. The West Qinling Fault (WQLF) is situated in a critical zone where material from the Tibetan Plateau is extruded towards the northeast, and the fine geometric structures, kinematic characteristics, and present-day activity of its eastern segment (Tianshui–Baoji segment) can provide important insights into the mechanisms of structural transition at the termination of strike-slip faults and the mode of material expansion in the plateau. In this study, the spatial distribution of the Tianshui–Baoji segment and the characteristics of present-day activity are systematically investigated through detailed interpretations of high-resolution satellite images, digital elevation models (DEMs), unmanned aerial vehicle (UAV) images, geological and geomorphological field surveys, and isotopic dating techniques. The results indicate that the Tianshui–Baoji segment, which begins as a single fault, gradually splays into multiple branching faults towards the east. Both the main fault and these branches have remained active since the Late Pleistocene and even during the Holocene, thus warranting attention to the seismic risk potential in the eastern segment of the WQLF, particularly at its termination. Moreover, the splay of the Tianshui–Baoji segment has led to the gradual divergence of the fault activity of the component to the east, reducing the maximum magnitude of seismic events at the fault terminus and resulting in significant differences in the seismic recurrence intervals between the eastern segment and the central segments of the WQLF (Zhangxian segment, Gangu–Wushan segment).</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"199 ","pages":"Article 105499"},"PeriodicalIF":2.6,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144596818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}