Journal of Structural Geology最新文献

{"title":"Paipote fold-and-thrust belt, a key element in understanding the upper crustal shortening mechanisms of the Central Andean forearc","authors":"F. Martínez ,&nbsp;J. Arancibia ,&nbsp;C. Torres ,&nbsp;M. Peña ,&nbsp;L. Díaz ,&nbsp;P. Reyes","doi":"10.1016/j.jsg.2024.105187","DOIUrl":"https://doi.org/10.1016/j.jsg.2024.105187","url":null,"abstract":"<div><p>The crustal shortening of the Andean forearc in northern Chile was accommodated by a combination of both thin- and thick-sinned structural styles. However, fold-related inversion of normal faults appears to be the most important structures in the area. To understand the upper crustal shortening mechanisms that acted during the tectonic uplift of this region, an original structural investigation was carried out, integrated with outcrop and regional-scale observations, balanced cross-sections, and pre-shortening restorations of structures exposed along the Paipote fold-and-thrust belt. On this basis, we presented the first balanced cross-section of this region extending for nearly 27 km is presented. The structural styles consisted of east-directed asymmetrical folds involving Paleozoic to Cenozoic strata. The folds were kinematically related to inverted normal faults and thrust ramps that penetrated downward into the basement. The inverted structures resulted from the reverse reactivation of preexisting Upper Paleozoic to Jurassic west-dipping, basement-rooted normal faults that accommodated the tectonic extension that preceeding the Andean orogenesis. The reverse-reactivation of these extensional structures controlled the development of east-verging anticlines, along which the Mesozoic syn-rift strata were elevated above their regional elevation. Other folds exhibit the typical geometry of fold-related thrust ramps (fault–bend folds and fault–propagation folds). These are proposed to result from the development of low-angle thrusts propagating across precursor normal faults with shortcut trajectories, that detach along Jurassic shales, thus forming complex thin-skinned structures in shallow structural levels. The latter is responsible for accommodating a major crustal shortening (nearly 5 km). The east-directed tectonic transport direction was influenced by the original attitude of precursor extensional faults.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141324261","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":"Fold-thrust belt in the southern front of the central High Atlas (Morocco): Analysis and implications for the tectonic inversion of the atlas system","authors":"Hicham Si Mhamdi ,&nbsp;Abdelhak Ijaajaane ,&nbsp;Salem El Ouariti ,&nbsp;Ali Charroud ,&nbsp;Lahssen Baidder ,&nbsp;Mohammed Raji","doi":"10.1016/j.jsg.2024.105185","DOIUrl":"10.1016/j.jsg.2024.105185","url":null,"abstract":"<div><p>Thrust folds have developed significantly in the meso-Cenozoic rock units of the Errachidia-Boudnib basin. The study areas correspond to the north part of the Pre-African Trough, which is located between the Anti-Atlas and the Atlas systems. It is characterized by faulted anticlines that are indicative of a foreland orogenic context.</p><p>The Atlas system's structural evolution underwent several stages, starting with a Triassic extensional event followed by a period of fault reactivation during the Atlas compression. This research focuses on examining the thrust and detachment folds associated with both reverse and strike-slip components. For this purpose, we performed detailed geological mapping and interpretation of folding and fault slip data.</p><p>As a result of shortening, field observations reveal that the study area exhibited well-developed thrusting geometry. Preexisting blind faults and multiple decollement levels within favorable formations such as Cenomanian evaporitic marls, Cenomanian-Turonian marls rich in organic matter, and Senonian argillites influence the folding patterns, which are not uniform. The findings demonstrate two key points. First, the most significant folds have formed along major blind thrusts. Subsequently, between these major faults, detachment folds were developed within the Jurassic-Cretaceous strata. Currently, due to erosion, certain thrusts have become visible, including the Ta'bbast thrust fault, Ait Atman (from the first stage), and the Timazguit fault zone (from the second stage). The South Atlas fault largely remains a blind fault. Additionally, the study emphasizes the presence of strike-slip components and en-echelon folding, indicating a transpressional regime during the uplift of the Atlas system.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141398507","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":"Slide Stacking: A new mechanism to repeat stratigraphic sequences during gravity-driven extension","authors":"G.I. Alsop ,&nbsp;S. Marco ,&nbsp;R. Weinberger ,&nbsp;T. Levi","doi":"10.1016/j.jsg.2024.105184","DOIUrl":"https://doi.org/10.1016/j.jsg.2024.105184","url":null,"abstract":"<div><p>Gravity-driven sliding of sediments down subaqueous slopes results in mass transport deposits (MTDs) recognised both in outcrop studies and from offshore margins where they may extend for 100's km. While seismic sections may reveal the large-scale geometry of such features, they fail to capture some of the structural and stratigraphic detail necessary for a fuller understanding of the processes involved. Using the late Pleistocene Lisan Formation sediments exposed around the Dead Sea Basin as our case study, we show that interplay between bed-parallel translational slides and associated normal faults may result in stratigraphic repetition through a process we term ‘slide stacking’. This mechanism, where retrogressive slope failure results in slides cutting across earlier normal faults, produces repeated sequences with older over younger stratigraphic relationships more usually attributed to compressional (thrust) deformation. Slide stacking results in a ∼25% attenuation of the upper sequence above the basal shear surface (BSS), which is itself associated with liquefaction and fluidised sediment. The displaced stratigraphy above the BSS is also marked by sedimentary rafts that are broken into blocks by normal faults and become increasingly separated from one another during downslope translation. The hangingwalls of synthetic listric faults form roll-overs that are progressively tightened towards the underlying BSS to create overturned anticlines that apparently verge upslope. The paradoxical situation therefore arises of contractional geometries, such as older over younger stratigraphic repetition across slides, and upslope-verging recumbent anticlines with locally overturned limbs being created during downslope-directed gravity-driven extension. The downslope margin of the slide stack displays earlier normal faults that created scarps where much of the sedimentary buttress, that would otherwise support the toe of the slide, was removed. Consequently, this leads to predominantly superficial and unrestrained downslope slipping, resulting in very localised contractional geometries that do not balance the overall extension, as in classical gravity-failure models. Localised deformation of the sedimentary sequence that unconformably overlies the slide stack indicates that downslope translation continued after the initial rapid slope failure, suggesting that the entire MTD remained inherently unstable. Slide stacking operates at km scales with stratigraphic repetition governed by the throw of earlier normal faults and the amount of downslope translation.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0191814124001366/pdfft?md5=17966db8332640c37fe58b426d8262be&pid=1-s2.0-S0191814124001366-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141324228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep-seated crustal faults and their role in the thermo-tectonic evolution of an active mountain belt: New evidence from the Northern Andes","authors":"Nicolas Villamizar-Escalante ,&nbsp;Carlos Augusto Zuluaga ,&nbsp;Matthias Bernet ,&nbsp;Sergio Amaya ,&nbsp;Julián Andrés López-Isaza ,&nbsp;Helbert García-Delgado ,&nbsp;Francisco Velandia","doi":"10.1016/j.jsg.2024.105177","DOIUrl":"10.1016/j.jsg.2024.105177","url":null,"abstract":"<div><p>Deep-seated structures can exhume deep crustal rocks (&gt;20 km), transmitting the signal of geodynamic processes from the subduction zone to the interiors of the continents. The role of deep-seated structures can be analyzed with low-temperature thermochronological dating techniques. However, studies coupling low-temperature thermochronology with structural geological analyses of the deformational style are not common in the Northern Andes. In this contribution, we present new apatite (AFT) and zircon (ZFT) fission-track data coupled with meso- and microstructural analyses to reveal the deformational and exhumation history of the Santander Massif (SM; Northern Andes) and the related cortical Bucaramanga strike-slip fault (BF). Samples for thermochronological analyses were collected along an elevation profile with a significant elevation difference of 2.4 km across the western flank of the SM, crossing the BF. The time-temperature history modeling of ZFT data reveals phases of prolonged residence in the zircon partial annealing zone from ∼125 to 94 Ma and a cooling phase related to an exhumation episode at around 25 Ma based on samples collected near the BF. Inverse modeling of AFT data reveals structurally-controlled Pliocene exhumation rates of 0.6–0.7 km/Myr mediated by the action of secondary faults. A shift in the deformation style resulting from the oblique interaction of the SM and Mérida Andes domain is interpreted as the main driver of the Pliocene exhumation. This deformation phase is observed in the fault damage zone, where evidence of brittle-ductile deformation was exhumed. Finally, we discuss the geodynamic implications of our thermochronological and structural analyses, contrasting local and more regional competing hypotheses (Pamplona Indenter vs. slab break-off of the Caribbean plate), which may explain the tectonic evolution of the northern part of the Eastern Cordillera and the SM in the Colombian Northern Andes.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0191814124001299/pdfft?md5=9a647500e710399e2c1a1caa9a95491b&pid=1-s2.0-S0191814124001299-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141276919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D model of the El Hornito pluton, Sierras Pampeanas of Argentina: Evidence of hybridization in the re-used feeder channels for emplacement in the ductile-brittle level","authors":"Brian L. Muñoz ,&nbsp;Eliel Enriquez ,&nbsp;Rodolfo Christiansen ,&nbsp;Augusto Morosini ,&nbsp;Ariel Ortiz Suárez ,&nbsp;Fernando D’Eramo ,&nbsp;Lucio Pinotti ,&nbsp;Manuel Demartis ,&nbsp;Gabriel Ramos ,&nbsp;Diego S. Pagano","doi":"10.1016/j.jsg.2024.105175","DOIUrl":"10.1016/j.jsg.2024.105175","url":null,"abstract":"<div><p>A comprehensive structural, petrological, and geophysical study of the 385 ± 2 Ma Devonian El Hornito Pluton (EHP) in the Sierra Grande de San Luis, Argentina, is presented. We establish that the EHP results from the intrusion of three main magma batches. The three-dimensional shape of the pluton was modeled using stochastic litho-constrained gravity data inversion and was complemented with a field geology survey. Results suggest a shallow-rooted, irregularly shaped pluton with a mean depth of 1.5 km, 16 km long and 4 km deep with a volume of 217 km³. Two areas of negative residual Bouguer anomaly reveal the existence of two root zones interpreted to indicate feeder channels. One of the feeders does not have a surface expression, but the other coincides with the central part of the pluton. A hot mafic magma intruded into and rejuvenated a crystallizing granite mush and the thermal perturbations triggered local convection with the development of an ascending magma plume developing mixing/mingling structures. Pluton emplacement was controlled by a shear zone at the boundary between two major metamorphic units. Emplacement is evidenced by the location of the two root zones along the interpreted contacts of the metamorphic zones, and the shear zone along this basement anisotropy provided the space into which magma batches were emplaced. Internal and external structures indicate that space for pluton emplacement was generated by a combination of tectonism with ballooning and stoping assisted by floor depression, which were the most effective processes during the final emplacement of the magma. This was possible due to the contrasting rheological responses of the host rocks.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141231789","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":"Development of major unconformities in the forearc regions: A signal of west Myanmar−Asia assemblage before the late Paleocene","authors":"Peng Zhang ,&nbsp;Shao-Yong Jiang ,&nbsp;Khin Zaw ,&nbsp;Renyuan Li ,&nbsp;Lianfu Mei ,&nbsp;Qi Li","doi":"10.1016/j.jsg.2024.105174","DOIUrl":"10.1016/j.jsg.2024.105174","url":null,"abstract":"<div><p>It has long been debated whether the India-Eurasia collision was a single-stage event that began 60-55 million years ago, or whether it was a two-stage process that involved a collision between India and the Trans-Tethyan Arc before the early Paleocene, and the collision of India with Eurasia during the middle Eocene. Here, we report a late Paleogene angular unconformity (ca. 40-28 Ma) in western Myanmar. This angular unconformity developed around the same time as the Assam unconformity (NE India) but is younger than those found in northern Myanmar. Development of these unconformities indicates that an oblique convergence margin in western Myanmar formed before the middle Eocene, with a major dextral strike-slip fault (proto-Sagaing/Shan Scarp Fault) in the backarc. We interpret this oblique convergence margin to be partial continental collision between the West Myanmar Terrane (WMT) and NE India. In backarc regions, syn-rift successions of the Shwebo sub-basin have formed as a consequence of transtensional tectonics along the proto-Sagaing/Shan Scarp Fault since at least the late Paleocene. The syn-rift successions consist of Asian-derived materials that were not identified in the forearc because of the Wuntho-Popa Arc served as a geographical barrier. The presence of the unconformities and tectonic configuration of the Myanmar backarc sub-basins are inconsistent with the scenario inferred from paleomagnetic data, in which the WMT was part of an intra-oceanic arc at near-equatorial latitudes before the late Oligocene. Instead, we propose that the WMT has been part of continental SE Asia since at least the Paleocene (ca. 60-58 Ma). We reconsider the paleomagnetic data and suggest that the Mawgyi Arc, rather than the WMT, is the oceanic fragment that rifted from the northern Gondwana margin during the Late Jurassic. The Mawgyi Arc collided with continental SE Asia (WMT) during the Late Cretaceous, and then with India during the early Eocene (ca. 51-49 Ma). Our results support the collision between India and Eurasia is a multistage event.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141278673","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":"Growth of the northeastern Tibetan plateau since the Middle Miocene as revealed by syn-tectonic growth strata","authors":"Xiancan Wu ,&nbsp;Weiwang Long ,&nbsp;Zhigang Li ,&nbsp;Weitao Wang ,&nbsp;Xue Yang ,&nbsp;Chuang Sun ,&nbsp;Lianwen Wu ,&nbsp;Xiangming Dai ,&nbsp;Yipeng Zhang ,&nbsp;Hao Liang ,&nbsp;Gege Hui ,&nbsp;Zhaode Yuan ,&nbsp;Zhiyi Su ,&nbsp;Ruizhi Jin ,&nbsp;Kang Liu ,&nbsp;Hulu Jing ,&nbsp;Wen Sun ,&nbsp;Peizhen Zhang","doi":"10.1016/j.jsg.2024.105176","DOIUrl":"https://doi.org/10.1016/j.jsg.2024.105176","url":null,"abstract":"<div><p>Syn-tectonic deposition of sediments (growth strata) preserves a direct record of mountain building-erosion and basin deformation. When and how these sediments incorporated into forward propagating fold-and-thrust (FTB) belts can shed light on the above processes. Despite many years of research, there is still ongoing debate about the timing and mechanisms of the southern Qaidam fold-and-thrust belt in the northeastern Tibetan Plateau. Here, we provide insight into the deformation of the Qaidam Basin and the broader tectonic processes of the northeastern Tibetan Plateau through detailed analysis of the Dafengshan (DFS), Jiandingshan (JDS) and Heiliangzi (HLZ) anticlines along the southern Qaidam FTB. Identification of the growth strata by Area-Depth analysis and age determination indicate that deformation of the DFS anticline initiated in the mid-Miocene (∼15 Ma), and has successively experienced lateral growth (∼15–8.0 Ma) and uplift (∼8.0 Ma-present). This timeline of deformation coincides with periods of mountain building in the northeastern Tibetan Plateau and might be related to the removal of mantle beneath northern Tibet. The synchronization of growth strata with an increase in sedimentation and exhumation rates reveals the reactivation of the tectonic belt around the basin in the mid-Miocene, creating the current basin-range landform; since ∼8 Ma, compression has expanded rapidly into the interior of the Qaidam Basin, leading to incorporation of basin deposits into the FTB. Geomorphological analyses coupled with 3-D fold modeling demonstrate that the JDS and HLZ-fold train with S-shaped configuration is a coherent fold system developed by lateral growth and linkage of two different fold segments in the context of the N–S directional compression of the plateau. Considering the prevalent S-shaped constructions within the basin and the current seismicity, we propose that the dominant structures in the southwestern Qaidam Basin are a series of thrust faults and folds controlled by the compression component of the East Kunlun Fault, with a limited influence from the Altyn Tagh Fault.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141286052","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":"The rise and fall of diapirs during thin-skinned extension revisited","authors":"","doi":"10.1016/j.jsg.2024.105165","DOIUrl":"10.1016/j.jsg.2024.105165","url":null,"abstract":"<div><p>Physical modelling and observations from seismic sections led to a conceptual model for the rise and fall of salt diapirs during thin-skinned extension, published by Vendeville and Jackson in 1992. Their conceptual model considers an initially tabular two-layer salt–overburden system that is deformed by thin-skinned extension during synkinematic sedimentation, and comprises the formation of turtle structure anticlines bound by passive diapirs and mock turtle anticlines above falling diapirs. The present paper revisits this conceptual model’s underlying mechanism by means of coupled continuum–discontinuum model studies in a ‘numerical sandbox’. The results obtained generally tend to support the conceptual model and show that, with a non-compacting overburden, only a buoyant viscous substratum and a significant amount of extension will lead to the formation of mock turtle anticlines. These numerical results are however at variance with the expectations of the conceptual model, in that salt-cored turtle structure anticlines are found frequently, a feature attributed to the tabular initial geometry of the turtle structure horsts. Analytical squeeze-flow models are used to clarify the mechanical genesis of salt-cored turtle structures and can explain why initially bowl-shaped basins are less prone to develop residual mounds of salt at their base than basins with a tabular geometry.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0191814124001172/pdfft?md5=e855aeefab33e8ed9c4d82696e0af3e6&pid=1-s2.0-S0191814124001172-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transtension, brittle-ductile shear zones and hydrothermal ore deposits: Towards quantitative structural and kinematic models","authors":"Sebastián Oriolo ,&nbsp;Anabel L.R. Gómez ,&nbsp;María Natalia Maffini ,&nbsp;Pedro Oyhantçabal ,&nbsp;Manuela Morales Demarco ,&nbsp;Mariana Sofía Vargas Perucca ,&nbsp;María Verónica Bastías Torres ,&nbsp;Nora A. Rubinstein","doi":"10.1016/j.jsg.2024.105173","DOIUrl":"10.1016/j.jsg.2024.105173","url":null,"abstract":"<div><p>Transtension is a fundamental process for the development of hydrothermal ore deposits, since it allows the required extension and dilatancy for hydrothermal fluid circulation and resulting ore mineralization. Transtension operates at multiple scales and, therefore, is not only relevant for deposits linked with extensional tectonics but also for those related to contraction/transpression. In this context, brittle-ductile shear zones represent a first-order metallotect that control the emplacement of mineralization. The distribution of ore minerals is largely influenced by bulk strain, kinematics and strain fabrics of these mineralized structures. The modified strain triangle is proposed as a simple tool to characterize strain conditions of transtension-related ore deposits associated with brittle-ductile shear zones, providing valuable information for metallogenetic models. In addition, a structural classification of ore deposits is proposed, based on the discussion of key deposit types and case studies. The main advantage of this approach is that it mainly relies on quantitative structural data and, therefore, is extremely useful for exploration. Furthermore, this classification avoids a priori assumptions on the tectonic setting, which can subsequently be inferred based on further regional evidence.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141188260","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":"The 2023 Mw7.7 Pazarcik earthquake caused a reversal in vertical motion along the SW branch of the East Anatolian fault","authors":"Zheng Gong ,&nbsp;Haibing Li ,&nbsp;Huiping Zhang ,&nbsp;Kerem Kuterdem ,&nbsp;Shiguang Wang ,&nbsp;Jialiang Si ,&nbsp;Yong Zheng ,&nbsp;Peng Liang ,&nbsp;Chenglong Li ,&nbsp;Chuanyou Li ,&nbsp;Zhikun Ren ,&nbsp;Jingxing Yu ,&nbsp;Xiaocheng Zhou ,&nbsp;Yueren Xu ,&nbsp;Zhifa Ma ,&nbsp;Junjie Li ,&nbsp;Fangtou Tang","doi":"10.1016/j.jsg.2024.105172","DOIUrl":"10.1016/j.jsg.2024.105172","url":null,"abstract":"<div><p>While the structural deformation at the Arabia-Anatolia-Africa junction is critical for understanding eastern Mediterranean tectonics, it remains debatable (extensional or compressional). Field survey of the 2023 Mw7.7 Pazarcik earthquake surface rupture along the Amanos Range, and microstructure and composition analyses of related fault rock were performed to investigate this issue. The surface rupture shows transtensional branches, with the main and secondary strands displaying sinistral (normal) offsets of 2.0–4.0 (0.4–0.9) and 1.0 (0.2) m. Slip plane of the secondary fault is marked by a ∼20 cm wide extensional fracture dividing fault breccia from gouge. Meanwhile, the gouge (26 % calcite, 38% serpentine and 36% smectite) is also dominated by tension cracks microscopically. In contrast to the widespread extensional deformation, geological evidence imply that this fault had experienced reverse slip in the Quaternary, as shown by thrusting of serpentine onto alluvium and the consistency of R foliations with reverse shear. We interpret it as the SW continuation of the East Anatolia fault (EAF) that was formerly characterized by transpressional deformation, and reactivated transtensionally due to the change of fault strike during this earthquake. In the broader Mediterranean tectonics framework, the Amanos segment might be interpreted as a recently formed component linking the Karasu fault to the EAF.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141139187","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}