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Simultaneous normal and reverse faulting in reactivating caldera faults: A detailed field structural analysis from Campi Flegrei (southern Italy) J. Struct. Geol. (IF 3.1) Pub Date : 2024-03-13 Jacopo Natale, Stefano Vitale, Roberto Isaia
Models of volcanic collapses proposed in the literature rely on combining field examples with analogue and numerical modelling to connect superficial observables to sub-surface volcano-tectonic processes. However, the behaviour of such collapses in an already faulted and fractured medium needs to be better explored.
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Spatial migration of temporal earthquake clusters driven by the transfer of differential stress between neighbouring fault/shear-zone structures J. Struct. Geol. (IF 3.1) Pub Date : 2024-03-13 G.P. Roberts, C. Sgambato, Z.K. Mildon, F. Iezzi, J. Beck, J. Robertson, I. Papanikolaou, A.M. Michetti, J.P. Faure Walker, M. Meschis, R. Shanks, R. Phillips, K.J.W. McCaffrey, E. Vittori, S. Mitchell
Uncertainty concerning the processes responsible for slip-rate fluctuations associated with temporal clustering of surface faulting earthquakes is a fundamental, unresolved issue in tectonics, because strain-rates accommodated by fault/shear-zone structures are the key to understanding the viscosity structure of the crust and seismic hazard. We constrain the timing and amplitude of slip-rate fluctuations
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Finite strain, kinematic vorticity, rheological behavior and thermochronology of the diancang Shan complex: Insights into channel flow of the southeastern Tibetan plateau J. Struct. Geol. (IF 3.1) Pub Date : 2024-03-11 Xiaofan Li, Han Zheng, Huan Li, Scott A. Whattam, Wei Pi, Linlin Zeng
This study investigates the crustal flow within the southeastern orogenic belt of the Tibetan Plateau, with a focus on the Diancang Shan (DCS) complex. As an A-type gneiss dome, the DCS complex offers valuable insights into the deformation and evolution of intra-continental orogenic belts and the flow of deep crustal material. We have identified three main stages of deformation within the DCS complex
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Estimating accurate and precise strain in low-magnitude penetratively deformed rocks: Integrating forward strain modeling and natural data J. Struct. Geol. (IF 3.1) Pub Date : 2024-03-08 Chirantan Parui, Kathakali Bhattacharyya
Estimating grain-scale strain using commonly used strain methods from a low-magnitude penetratively deformed rock is typically fraught with uncertainties as the measured strain is influenced by the pre-deformed grain shapes and grain-scale strain partitioning. Therefore, developing kinematic and mechanical models of orogenic wedge evolution based on such strain data can be misleading without knowing
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Overprinting orogenic events, ductile extrusion and strain partitioning during Caledonian transpression, NW Mainland Shetland J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-21 Timothy B. Armitage, Robert E. Holdsworth, Robin A. Strachan, Edward D. Dempsey, Richard J. Walker, Diana T. Alvarez-Ruiz, Geoffrey E. Lloyd
A 3.6 km thick stack of mid-crustal deformed Precambrian rocks is associated with the North Roe Nappe (NRN) and Walls Boundary Fault in the northernmost Scottish Caledonides on NW Mainland Shetland. The greenschist- to amphibolite-facies rocks display unusually complex and heterogeneous combinations of coaxial and non-coaxial transpressional deformation. Previously published isotopic dating, together
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Late Quaternary normal faulting along the western boundary fault of Peiku Co graben in southern Nyalam-Coqen rift: Implications for extensional deformation in southern Tibet and seismic hazard J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-19 Yang Gao, Meng Li, Zhonghai Wu, Keqi Zhang, Jiameng Zuo, Tingting Tian, Shifeng Wang
The NS-trending rifts play an important role in accommodating E-W extensional deformation in the interior of the Tibetan Plateau. Although ∼380 km long Nyalam-Coqen rift (NCR) is one of the most prominent rifts in southern Tibet, the late Quaternary fault activity, strong earthquakes and extensional deformation along the NCR remain unknown. Here, we focus on the western boundary fault of Peiku Co graben
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Analysis and prediction of contact characteristics of rock fracture surfaces under normal loading J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-17 Yuzong Li, Yue Cui, Yingchun Li, Yuxiang Gan
The real contact area of rock fractures is smaller than the nominal area, and actual stresses on contacts are significantly higher. Evaluating contact characteristics and predicting potential contact areas are crucial for understanding mechanical and hydraulic properties of geological fractures under compression or shear. We measured the real contact area of mated tensile fractures using pressure-sensitive
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Structural architecture and maturity of Val d’Agri faults, Italy: Inferences from natural and induced seismicity J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-16 G. Schirripa Spagnolo, F. Agosta, L. Aldega, G. Prosser, L. Smeraglia, S. Tavani, N. Looser, M. Guillong, S.M. Bernasconi, A. Billi, E. Carminati
The Val d’Agri Basin is a Quaternary sedimentary basin topping multiple tectonic units of the southern Apennines fold-and-thrust belt and a giant oilfield within deeper Apulian Platform carbonates. This basin is bounded by the seismically active East Agri (EAFS) and Monti della Maddalena (MMFS) extensional fault systems. The reservoir rocks are sealed and separated from shallower thrust sheets by a
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Geomorphic expression of transverse drainages across the Tugerming anticline, southern Tian Shan: Implications for the river-fold interaction in the foreland J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-15 Feng Li, Xuhua Shi, Julien Charreau, Xiaogan Cheng, Rong Yang, Hanlin Chen, Jin Ge, Jinghan Wang
Transverse drainages are prominent landscape features in active foreland thrust-and-fold belts. Understanding their response to folding processes is pivotal for comprehending landscape evolution and erosion-deformation interactions within the foreland. Here, we focus on the extensively developed transverse drainages across the Tugerming anticline in the southern Tian Shan foreland. Based on fold topography
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Corrigendum to “A simple computer program for calculating stress and strain rate in 2D viscous inclusion-matrix systems” [J. Struct. Geol. 160 (2022) 104617] J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-14 William R. Halter, Emilie Macherel, Stefan M. Schmalholz
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Carbonate deformation through the brittle-ductile transition: The case of the SW Helvetic nappes, Switzerland J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-13 G.L. Cardello, S.M. Bernasconi, M.G. Fellin, M. Rahn, R. Rosskopf, C. Maden, N.S. Mancktelow
Carbonate deformation through the brittle-ductile transition (BDT) remains incompletely documented in the field. We therefore investigate the exhumation of the SW-Helvetic nappe stack using a new multi-method approach that integrates optical observations with a revised nomenclature, thermochronology, stable isotopes, and clumped isotope thermometry, aiming to constrain the time-temperature history
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Structural expression of the frontal thrust of an active fold-and-thrust belt: The Holocene 123-km-long Kur fault, Greater Caucasus, Azerbaijan J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-13 Alessandro Tibaldi, Fabio Luca Bonali, Federico Pasquaré Mariotto, Paolo Oppizzi, Nino Tsereteli, Hans Havenith, Gulam Babayev, Tomáš Pánek
Here we present the main features of the frontal structure, known as Kur Fault, of the Plio-Quaternary Kura fold-and-thrust belt in the Greater Caucasus (Azerbaijan). The Kur Fault has been analysed thanks to geological-structural and geomorphological surveys of its whole length, integrated by a relocation of instrumental seismicity, data on historical seismicity, new focal mechanism solutions, and
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The influence of the geometry of salt detachments on thrust salient development: An analogue modelling approach based on the South-Central Pyrenean thrust salient J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-11 Josep A. Muñoz, Oriol Ferrer, Oscar Gratacós, Eduard Roca
Inspired by the structural evolution of the South-Central Pyrenean Thrust Salient we have designed an experimental program to investigate the role of the geometry of viscous detachments on the formation of thrust salients. The precontractional wedge geometry of the salt overburden facilitates propagation of the deformation front to the forward edge of the viscous detachment. As deformation progresses
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Kink-bands as indicators of shock-wave propagation direction: Results from experimental impact cratering on gneiss J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-07 Gaurav Joshi, Amar Agarwal, Thomas Kenkmann, Arun Kumar Ojha
Microscopic kink-bands in platy minerals are a common occurrence at impact craters. The geometry of kink-bands formed in biotite due to an impact cratering experiment on Maggia gneiss was analyzed to see if they might be utilized to deduce the shock wave propagation direction. Here, we investigated the kink-bands in a vertical profile just below the impact point. The intensity of kinking decreases
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Mesozoic transpressional structural inversion and synkinematic crustal fluid circulation around the northeastern Chungnam basin, southwestern Korean Peninsula: Tectonic implications J. Struct. Geol. (IF 3.1) Pub Date : 2024-02-01 Yujung Kwak, Seung-Ik Park, Changyun Park, Yungoo Song, Luca Smeraglia
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Kinematic-structural modeling of hybrid fold-thrust belt systems: Insights from the Southern Patagonian Andes J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-29 Juan F. Albano, Miguel Ramos, Emilio Rocha, Matías C. Ghiglione
This paper focuses on the analysis of the Southern Patagonian fold-thrust belt at ca. 50° SL, employing a kinematic-structural approach that makes it possible to define its step-by-step structural evolution. Seismic interpretation is combined with outcrop structural data to provide the basis for an integrated evolutionary model including a Jurassic extensional stage, followed by contraction events
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Using seismic methods to detect connectivity of fracture networks controlled by strike-slip faults in ultra-deep carbonate reservoirs: A case study in northern tarim basin, China J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-28 Yingtao Yao, Lianbo Zeng, Shaoqun Dong, Cheng Huang, Dongsheng Cao, Zhe Mao, Anpeng Kuang, Wenya Lyu
Ordovician tight carbonate rocks in the Tarim Basin are typically ultra-deep, with targets deeper than 7000 m. The fracture networks associated with strike-slip faults are the primary reservoir space. Fracture intensity near faults is higher than in wall rock areas and decreases with distance from faults. Based on the relationships of fracture network with the structure of strike-slip faults imaged
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Corrigendum to “Role of confinement in coseismic pulverization: Testing the rock record of rupture directivity on the San Jacinto fault, Southern California” [J. Struct. Geol. (2023) 104999] J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-26 C.K. Weigandt, W.A. Griffith, T.K. Rockwell
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Effect of interface morphology on the heterogeneous development of bedding-perpendicular joints in soft–hard interbedded strata J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-26 Han Bao, Xiaoguang Li, Hengxing Lan, Runsheng Pei, Changgen Yan
Bedding-perpendicular joints (BPJs) in soft-hard interbedded masses exhibit heterogeneous distribution. Statistical analysis revealed the impacts of interface morphology on the heterogeneity distribution of joint spacing and strike. It was observed that there existed a negative exponential relationship between joint spacing and roughness of macroscopic interface morphology. Furthermore, the heterogeneity
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Influence of multiple detachments on structural vergence and evolution of the thin-skinned fold-and-thrust belt in the eastern Sichuan Basin: Insights from numerical modeling J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-24 Wenqiao Xu, Hongwei Yin, Shengxian Zhao, Chenglin Zhang, Bo Li, Dong Jia, Changsheng Li, Wei Wang
The thin-skinned fold-and-thrust belt with multiple detachments in the eastern Sichuan Basin is characterized by a series of fault-detachment folds with a backward preferred structural vergence, which is rare in nature and can't be explained well by the classic critically taper theory. Here, three discrete element simulations were conducted to study the influence of multiple detachments on the structural
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Tectonic signals documented in gravel and silt beds: A comprehensive review of the eastern Tibetan plateau J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-23 Wei Shi, Hanchao Jiang, G. Ian Alsop
Extracting tectonic signals from sediments in tectonically active areas is important for revealing the history of regional tectonic activity. However, in previous studies, tectonic and climatic signals have often been confused. In this study, we discuss the tectonic signals recorded in Quaternary sediments on the eastern Tibetan Plateau, combined with the geological, geomorphic, regional climate and
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Migmatite dome as a result of multi-fold interference pattern, in the Damara Belt, Namibia J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-23 Robyn J. Ormond, Jérémie Lehmann, Pavlína Hasalová, Marlina Elburg
The western part of the Pan-African Damara Orogen in Namibia is located at the intersection of two highly oblique mobile belts: the coastal NNW-trending Kaoko-Gariep belts and the inland NE-trending Damara Belt. The Namibfontein-Vergenoeg (NV) domes are two, basement-cored, migmatite domes exposed in this orogenic intersection. These domes formed through the superposition of four deformation phases
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Seismic faulting and CO2-rich fluid interactions: Evidence from carbonate spherulitic grains in ultramafic fault damage zones J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-17 Michele Locatelli, Laura Crispini, Elisabetta Mariani, Giovanni Capponi, Marco Scarsi, Laura Federico
Faults and shear zones in the metamorphic ultramafic rocks of the Voltri Massif (Ligurian Alps, NW Italy) are often accompanied by intense or complete carbonation of the host rocks. One of these fault zones, hosted in peridotite and serpentinite, is characterized by distinctive structural features that can be related to a fluid-assisted multistage brittle deformation, indicative of paleoseismic activity
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A study of fluid overpressure microstructures from the creeping segment of the San Andreas fault J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-17 Jafar Hadizadeh, Alan P. Boyle, Andrea E. Gaughan
Evidence of episodic fluid overpressure events noted in samples from the San Andreas Fault Observatory at Depth (SAFOD) have remained largely uncorrelated in terms of their collective significance for seismic history of the fault zone. The compositional and microstructural correlations sought in this study could shed light on questions about potential for major seismic events in the creeping segment
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Geomechanical modeling of fault-propagation folds: A comparative analysis of finite-element and the trishear kinematic model J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-17 Berenice Plotek, Jeremías Likerman, Ernesto Cristallini
Fault-propagation folds are common structures within fold and thrust belts. The trishear kinematic model has been widely used to understand the kinematics and geometry of these folds, effectively reproducing various characteristics. However, the resulting geometry of natural prototypes may diverge from the predictions of the trishear model depending on the rheological properties involved in the deformation
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Kinematics, intensity, and spatial arrangement of extensional fractures in the Tuxtla-Malpaso fault system: Chiapas strike-slip fault province, southern Mexico J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-17 Alberto Vásquez Serrano, María Fernanda Sampayo Rodriguez, Elisa Fitz Díaz, Gustavo Tolson
We describe the orientation, number, size, distribution, and fracture spatial arrangement in the central part of the kilometric Tuxtla-Malpaso fault system, one of the largest in the south of Mexico which cuts Cretaceous calcareous rocks. In this area, there are two sub-vertical extensional fracture sets (T1 and T2). The T1 fractures have ∼ N–S orientation and recorded 4.48 % of extension. The T2 fractures
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Investigating paleoseismicity using high-resolution airborne LiDAR data - A case study of the Huangxianggou fault in the northeastern Tibetan plateau J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-14 Liao Wang, Hong Xie, Daoyang Yuan, Yanxiu Shao, Bo Zhang, Aiguo Wang, Weitong Wang
Fault-offset landforms have long been recognized as holding important information about paleoseismic slip. Constructing an along-strike fault slip distribution could help reveal a fault's long-term rupture patterns and facilitate a more precise assessment of its future behavior. In this study, we documented the paleoseismic history of the Huangxianggou Fault, an oblique sinistral-thrust segment of
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The effect of weathering on cohesion in granitic fault rocks: A case study from the Yeongdeok Fault, South Korea J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-09 Jae Hoon Kim, Jin-Han Ree, Wataru Tanikawa, Hee-Cheol Kang
Weathering can alter fault-rock cohesion, which is an important criterion in the classification of fault rocks, and can also alter fault-rock mechanical and hydraulic properties. To investigate the effects of weathering on fault rocks, we studied relatively fresh and weathered fault rocks collected from a drill core and outcrop, respectively, of a granitic fault zone (the Yeongdeok Fault, a northern
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Late-orogenic extension ceases with waning plate convergence: The case of the Simplon normal fault (Swiss Alps) J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-09 Reinhard Wolff, Kyra Hölzer, Ralf Hetzel, István Dunkl, Aneta A. Anczkiewicz
The Simplon normal fault in the Western Alps caused tens of kilometers of orogen-parallel extension during convergence of the European and Adriatic plates, but the slip rate of the fault and the time when normal faulting ended are still debated. Here, we constrain the slip history of the Simplon fault with low-T thermochronology and thermo-kinematic modeling. Closely spaced samples from an elevation
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Seismogenic fault of the 2021 Ms 6.0 Luxian induced earthquake in the Sichuan Basin, China constrained by high-resolution seismic reflection and dense seismic array J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-06 Renqi Lu, Changsheng Jiang, Dengfa He, Weilai Wang, Zhi Guo, Weikang Zhang, Wei Tao, Xuhang Yang, Guijuan Lai, Yan Zhan, Guanshen Liu, Fang Xu, Xiao Sun
Accurate documentation of the location and geometry of seismogenic faults are critical for understanding strong seismicity and seismic hazard mitigation. A rising concern worldwide is induced seismicity caused by hydraulic fracturing, yet the geological characteristics and mechanisms of such seismogenic faults remain insufficiently understood. In particular, a first-order issue is whether the strong
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Regional-scale 3D modelling in metamorphic belts: An implicit model-driven workflow applied in the Pennine Alps J. Struct. Geol. (IF 3.1) Pub Date : 2024-01-01 Gloria Arienti, Andrea Bistacchi, Guillaume Caumon, Giovanni Dal Piaz, Bruno Monopoli, Davide Bertolo
Leveraging a high resolution geological and structural dataset acquired over decades of fieldwork, we build the 3D structural model of a portion of the highly deformed core of the Alpine orogen, in the Northern Aosta Valley. The model represents tectonic contacts separating the tectono-metamorphic units outcropping along the section between Mont Blanc and Monte Rosa, and it covers an area of ca. 1500
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Along-strike variations of structural style in the external Western Alps (France): Review, insights from analogue models and the role of salt J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-30 Naïm Célini, Alexandre Pichat, Frédéric Mouthereau, Jean-Claude Ringenbach, Jean-Paul Callot
The European Alps result from the closure of a former Triassic to Cretaceous rifting system in which significative accumulation of Upper Triassic salt deposited. The thickness and spatial distribution of these salts had a major impact on the morphology and dynamic of the Alpine orogen all over the Western Alps. Following a bibliographical review, four regional cross-sections are revisited over the
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Exhumation mechanisms of the Himalayan metamorphic core in the Bhagirathi Valley, NW India: Insights from an integrated structural and metamorphic analysis J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-26 Aranya Sen, Purbajyoti Phukon, Koushik Sen, Subham Bose, Hari B. Srivastava
The Himalayan metamorphic core in the Bhagirathi valley (NW India) consists of low-grade rocks belonging to the Lesser Himalayan Sequence to the south, and of high-grade rocks of the Greater Himalayan Sequence (GHS), to the north. The contact between these two units is a 2–3 km thick high-strain zone known as the Main Central Thrust zone (MCTz). Structural studies in the GHS identify the superposition
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Evaluating controls on deformation patterns and styles in the salt-detached Sureste Basin, southern gulf of Mexico: Insights from physical models J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-29 Tim P. Dooley, Michael R. Hudec
The Sureste Basin forms the southern portion of the Isthmian Salt Province in the southern Gulf of Mexico. This basin is unique in this region as it is both part of a passive/divergent margin and also part of an active/convergent margin due to its proximity to Pacific margin plate tectonics. As a result it has experienced both orogenic and gravity-driven deformation resulting in a complex array of
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Inherited extensional faults and bed-parallel slip in Mae Moh Basin, Thailand with implication for basement fabrics J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-29 Sukonmeth Jitmahantakul, Pichet Kaewsomwang, Jirapan Sumpaothong, Randall Simpson
The 3D seismic analysis with structural reconstruction and outcrop study in Mae Moh mine, located in the Central Sub-basin of the Mae Moh Basin, unveil multiple extensional phases and the controls of pre-existing basement fabrics on extensional faults, bed-parallel slip (BPS) and post-rift folding. The coexistence of orthogonal and oblique extensional fault systems characterizes the mine area as a
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Origin of oblique structures controlled by pre-tectonic thickness variations in frictional and salt-bearing fold-and-thrust belts: Insights from analogue modelling J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-24 Pablo Santolaria, Esther Izquierdo-Llavall, Ruth Soto, Teresa Román-Berdiel, Antonio Casas-Sainz
This work includes, first, a synthesis of experimental analogue modelling programs assessing the influence of along-strike thickness variations in the development of oblique structures in fold-and-thrust belts. As a second part, we present a new experimental program testing, systematically, the influence of tapered décollement-cover thrust wedges. Previous experiments show that frictional, brittle
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Deformation microstructures of low- and high-strain epidote-blueschist (Ryukyu arc, Japan): Implications for subduction interface rheology J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-23 Sara De Caroli, Åke Fagereng, Kohtaro Ujiie, Thomas Blenkinsop, Francesca Meneghini, Duncan Muir
We present field and microstructural data from an exhumed subduction complex in the Ryukyu arc, Japan, where epidote-blueschist, Triassic, Tomuru metamorphic rocks with block-in-matrix structure crop out. With the aim to constrain epidote-blueschist rheology, we investigate fabric development and infer deformation mechanisms of blocks and matrix through microstructural analyses on the main fabric-forming
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Using crystal-lattice distortion data for geological investigations: the weighted Burgers vector method J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-23 J. Wheeler, S. Piazolo, D.J. Prior, P.W. Trimby, J.A. Tielke
Distorted crystals carry useful information on processes involved in their formation, deformation and growth. The distortions are accommodated by geometrically necessary dislocations, and therefore characterising those dislocations is an informative task, to assist in, for example, deducing the slip systems that produced the dislocations. Electron backscatter diffraction (EBSD) allows detailed quantification
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Stepwise decrease in strike-slip rate along the eastern Altyn Tagh Fault and its relation to the Qilian Shan thrust system, northeastern Tibetan Plateau J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-12 Bing Yan, Peng Chen, Yang Gao
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Restoring a syntectonic transtensional pluton by integrating structural geology, anisotropy of magnetic susceptibility, and gravimetric modelling J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-12 João A.S. Fontoura, Maria de Fátima Bitencourt, Jairo F. Savian, Dionatan F. Padilha, Victor Soares Cardoso, Camila Rocha Tomé, Christian Meneghini, Robson dos Santos Aquino, Ricardo I.F. Trindade
The kinematic analysis of magmatic structures is key evidence for the tectonic settings and deformation mechanisms related to the emplacement of intrusive bodies. The Dom Feliciano Belt (DFB), southernmost Brazil, registers voluminous post-collisional magmatism during the Neoproterozoic and the Arroio do Silva Pluton (ASP) is a diorite-monzonite-syenite body emplaced in this tectonic setting. The ASP
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Fracturing and widening of grain boundary networks in quartz, plagioclase and olivine crystal aggregates during exhumation at low P-T conditions J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-12 Jörn H. Kruhl, Erika Griesshaber, Wolfgang W. Schmahl, Richard Wirth
Grain boundary networks of quartz, plagioclase and olivine crystal aggregates in metamorphic rocks have been investigated from the nanometer to the millimeter scale by polarized-light microscopy, SEM, and TEM. The studied materials show different grain sizes and experienced different retrograde P-T histories. The aggregates of quartz and plagioclase are traversed by networks of ∼90% continuously open
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Unravelling multiple thermotectonic events accommodated by the Highland Boundary Fault: Insights from K–Ar dating J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-17 Lucy McKay, Simon J. Kemp, Graham A. Leslie, Andrew Todd, Zoe K. Shipton, Rebecca J. Lunn, John Booth
Multiple reactivation episodes and long slip histories lead to complex fault structures, whose unravelling remains challenging in the absence of absolute time constraints. We apply K–Ar isotopic dating of illitic fault rocks, coupled with X-ray diffraction and microstructural analyses to constrain, for the first time, timing of illite-producing brittle fault movements accommodated by the Highland Boundary
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Three-dimensional velocity structure beneath the Song Ma area, Vietnam J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-13 Wei-Jhe Wu, Chein-Min Su, Strong Wen, Chau-Huei Chen, Hop Phong Lai, Van Toan Dinh, Wen-Yen Chang
The Song Ma fault zone, located in northern Vietnam, plays a crucial role in understanding the mechanism and evolution of the collision zone between the Indian Plate and the Eurasian Plate. To investigate these mechanism and their evolution, we deployed a temporary broadband seismograph network surrounding the Song Ma fault to examine the body wave tomography and ultimately obtained the velocity structure
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Evolution of tensile fractures in feldspar porphyroclast and its implication in paleostress estimation J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-16 Gourav Das, Sirshendu Kumar Biswas, Tridib Kumar Mondal, Sourav Mondal
Fractures are ubiquitous brittle features of the upper crust. Syntectonic granites are often replete with fractures of various attitudes, cross-cutting each other, which develop under the prevalent states of stress. In this article, we study the origin and mechanism of formation of tensile fractures restricted within rectangular alkali feldspar porphyroclasts found in Closepet granite (Dharwar Craton
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The well log and seismic expression of faults in the Wisting field, Barents Sea J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-12 Lothar Schulte, Nestor Cardozo, Ana Batista
Seismic facies in large fault zones (dam to km throw) can rarely be constrained with well log data. High-resolution seismic data (ca. 3.1 × 3.1 m bins) from the highly faulted Wisting field in the Barents Sea, is compared with log data along a horizontal and a vertical well. The target of both wells is the Lower Jurassic, oil-bearing Stø Fm., which due to Cenozoic uplift and erosion is just ca. 250 m
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Structural control on the alteration and fluid flow in the lithocap of the Allumiere-Tolfa epithermal system J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-15 Barbara Marchesini, Stefano Tavani, Marco Mercuri, Nicola Mondillo, Mattia Pizzati, Fabrizio Balsamo, Luca Aldega, Eugenio Carminati
Zones of advanced argillic alteration with general low permeability (i.e., lithocaps) are common place in the shallow parts of porphyry and epithermal ore deposits and active geothermal systems. The study of structural control on alteration distributions is of paramount importance for exploitation purposes as it really influences the caprock efficiency. We present the results of a structural-mineralogical
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Evolution of H2O content in deforming quartz aggregates: An experimental study J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-10 H. Stünitz, H. Raimbourg, L. Nègre, J. Précigout, M. Jollands, P. Pongrac, P. Jeřabek, N. Gies, M. Lüder
Deformation experiments were carried out on pure quartzite samples (>99% quartz) with a grain size of ∼200 μm from Tana, Northern Norway. Deformation conditions were 900 °C, 0.1 wt% H2O added, strain rate ∼1 × 10−6 s−1 at variable confining pressures from 600 to 2000 MPa. Detailed FTIR measurements of H2O indicate that the H2O content in the grain boundary region is higher than that inside quartz grains
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Analysis of aperture values of stratabound fractures in bedded rock: Use of the maximum likelihood method in studying a truncated data set J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-12 Vincenzo Guerriero
In this study, a truncated data set of aperture values of stratabound joints in carbonate rocks, already studied in a previous work and in which sampling of smallest fractures was problematic, has been reanalysed through regression analysis by means of Maximum Likelihood Estimation (MLE). This analysis criterion has been tested through Monte Carlo simulations, which demonstrated that MLE is able to
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Strain in sulphide filled foliation boudinage structures at the Mount Isa Cu deposit, Australia J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-10 B.J. Williams, T.G. Blenkinsop
Foliation boudinage structures are vein-like boudins forming in homogeneous, anisotropic rocks that can be filled with significant volumes of mineral infilling. At Mount Isa, foliation boudinage structures are associated with and filled by ore-related sulphides, predominantly pyrrhotite. Deformation of syn-tectonic, ore-related sulphides at Mount Isa has generally not been documented, fuelling controversy
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A key role for diffusion creep in eclogites: Omphacite deformation in the Zermatt-Saas unit, Italian Alps J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-10 David D. McNamara, John Wheeler, Mark Pearce, David J. Prior
Eclogites commonly form from subducted oceanic crust and as such carry key information on subduction zone rheology. Using a combination of microanalytical techniques on deformed eclogites from the Zermatt-Saas unit of the Italian Alps, we explore the mechanisms which resulted in both an omphacite shape and lattice preferred orientation. Omphacite defines both foliation and lineation in these rocks
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Study on the late quaternary activity of the Jinyang-Ningnan segment of the Lianfeng fault zone J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-04 Liangliang Wu, Zhongtai He, Dongsheng Xu, Linlin Li, Long Guo, Xingao Li
The Lianfeng fault zone is located at the junction of the Daliangshan subblock and the South China block and is the southern boundary of the Daliangshan subblock. It is a very active tectonic area, which is of great significance to understanding its seismogenic environment. However, there are relatively little existing data on its activity and the timing of its latest activity. In the Jinyang-Ningnan
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Deformation conditions and kinematic vorticity within the footwall shear zone of the Wildhorse detachment system, Pioneer metamorphic core complex, Idaho J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-09 R.R. McFadden, J.M. Taylor, D.L. Whitney, C. Teyssier, N.C.A. Seaton, H. Schroeder, A. Senjem, I. Johnson
Detailed analysis of numerous sequential fabrics and microstructures preserved in the footwall shear zones of detachment fault systems can be used to clarify the spatial relationships and timing of deformation related to emplacement and exhumation of metamorphic core complexes. To quantify the kinematics during deformation, we conducted microstructural analyses along two ∼300 m transects across mylonitic
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Newly discovered, the Kayapa-Yenişehir cross-basin fault: As revealed by geological and geophysical studies along the southern branch of the North Anatolian Fault Zone, a possible source of the destructive 1855 Bursa earthquakes J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-05 Gürol Seyitoğlu, Korhan Esat, Muammer Tün, Bülent Oruç, Ertan Pekşen, Bahadır Aktuğ, Bülent Kaypak, Begüm Koca, Emir Balkan, Sunay Mutlu, Emrah Pekkan, Delal Çetinkaya
This study presents our geological and geophysical findings about a right-lateral cross-basin fault (Kayapa-Yenişehir Fault-KYF) formed in the composite Bursa-west, Bursa-east, and Yenişehir pull-apart basins on the southern branch of the North Anatolian Fault Zone around Bursa in southern Marmara. We examined the compatibility of our observations with various models proposed in the literature. The
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Seismic damage in Quaternary fluvial gravels in low-seismicity thrust-and-fold-belts: Case study of the Outer Western Carpathians (Poland and Slovakia) J. Struct. Geol. (IF 3.1) Pub Date : 2023-12-04 Antek K. Tokarski, Anna Świerczewska, Piotr J. Strzelecki, Staszek Lasocki, Janusz Olszak, Helena Alexanderson, Edit Thamó-Bozsó, Józek Kukulak, Mateusz Mikołajczak, Marek Krąpiec, Judit Izabella Füri
In this contribution, we propose a model of Quaternary seismicity in the Outer Western Carpathians. The model presents results of analysis of fractured clasts performed in 268 exposures of Quaternary fluvial gravels within the ca. 5,000 km2 large segment of the Outer Western Carpathians comprising: Outer Carpathian nappes, the innermost part of the Carpathian Foredeep, and two intramontane basins –
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An integrated 3D digital model of stratigraphy, petrophysics and karstified fracture network for the Cristal Cave, NE-Brazil J. Struct. Geol. (IF 3.1) Pub Date : 2023-11-27 João Victor F. Pereira, Walter E. Medeiros, Renato R.S. Dantas, Francisco H.R. Bezerra, Vincenzo La Bruna, Milton M. Xavier Jr., Rubson P. Maia, Daniel D.M. Gomes, Danielle C.C. Silva, Ingrid B. Maciel
Digital Outcrop Models (DOMs) are virtual representations of geological features. Although DOMs are widely used tools in geosciences, their integration with other datasets remains relatively underexplored. We combined a DOM, derived from a photogrammetric survey of a carbonate sequence, with lithostratigraphic, petrophysical (porosity, permeability and uniaxial compressive strength), fracture distribution
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Mineralogical and frictional properties of fault rocks from the Laohushan creep segment of the Haiyuan fault, Northeastern Tibet J. Struct. Geol. (IF 3.1) Pub Date : 2023-11-30 Xi Ma, Yongsheng Zhou, Jiaxiang Dang, Lei Zhang, Changrong He
Shallow creep has been observed in the Laohushan segment which lies within a seismic gap between the co-seismic ruptures of the 1920 Haiyuan M8.5 earthquake and the 1927 Gulang M8.0 earthquake. However, there has been a lack of geological and mechanical evidence to explain the mechanism behind this shallow creep. In this study, we carried out detailed fieldwork along the Laohushan fault, analyzed the
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Focal mechanism of a Late Triassic large magnitude earthquake along the Longmen Shan fault belt, eastern Tibetan Plateau J. Struct. Geol. (IF 3.1) Pub Date : 2023-11-30 Lei Zhang, Haibing Li, Eric C. Ferré, Zhiming Sun, You-Min Chou, Yong Cao, Huan Wang, Yong Zheng, Chenglong Li, Elham Hosseinzadehsabeti
Stress states near active fault zones are key to understand their seismogenic setting, geodynamic evolution and future seismic activity. The Longmen Shan Fault Belt (LSFB) is a prominent fault zone that has had a long history of activity and major recent earthquakes in the eastern Tibetan Plateau. However, we have no records of major events prior to the 2008 Wenchuan earthquake, and this hinders progress
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Magnetic multi-fabrics as tools for understanding ignimbrite emplacement processes: An example from late-Variscan Tharandter Wald Caldera, Bohemian Massif J. Struct. Geol. (IF 3.1) Pub Date : 2023-11-28 Irena Olšanská, Filip Tomek, Martin Chadima, Marine S. Foucher, Michael S. Petronis
Felsic collapse calderas pose a hazard to our society, thus detailed knowledge of collapse mechanisms and behavior of eruptive products could help us to better understand the active calderas. We present a model of the eruption and collapse of Late Carboniferous Tharandter Wald Caldera (Variscan Bohemian Massif) based on field mapping and a magnetic multi-fabric approach. We investigate intra-caldera