Journal of Structural Geology最新文献

{"title":"Thermo-mechanical intrusion-wall rock interaction and granite emplacement mechanisms of the Peninsula granite at the Sea Point contact, Cape Town, South Africa","authors":"Musa Mhlanga, Russell Bailie, Jürgen Reinhardt","doi":"10.1016/j.jsg.2025.105513","DOIUrl":"10.1016/j.jsg.2025.105513","url":null,"abstract":"<div><div>The Sea Point contact, Cape Town, South Africa exposes the intrusive contact between the ∼540 Ma S-type Peninsula Granite and the ∼560–555 Ma metasedimentary rocks of the Malmesbury Group of the Pan-African Saldania Belt. The western Saldania Belt was subjected to low-grade greenschist facies metamorphism and deformation during the ∼560–540 Ma Saldanian orogeny. The Peninsula Granite intruded as a series of numerous granite sheets which made use of the pre-existing country rock anisotropy in order to propagate. These are the steeply dipping S<sub>0</sub> bedding due to folding during the Saldanian orogeny, and a steeply dipping axial planar S<sub>2</sub> foliation to the F<sub>2</sub> folds developed during the dominant D<sub>2</sub> deformation. Magma overpressure relative to tensile stresses in the country rock and regional NE-SW-orientated compressional stresses allowed intrusion of variably crystal-laden magma along the anisotropies. The granitic sheets are commonly concentrated in the hinge zones of F<sub>2</sub> folds, where structural traps facilitated magma “trapping.” Filter pressing at the tail of the magma-filled hydrofracture caused closing during magma through-flow resulting in the entrapping of magmatic crystals, most notably K-feldspar megacrysts, in the wall rock as well as xenoliths dislodged during magma infiltration and stoping, and possibly magma flow. Magma stresses have brought about the alignment of K-feldspar megacrysts as well as the long axes of xenoliths parallel to the orientation of granite sheets and wall rock septa in the complex lit-par-lit zone and adjacent to the contact. A degree of assimilation (and possibly partial melting) is evident in the rounded shapes of xenoliths, but, more notably in mixed zones where there are gradational contacts not only between different granite types, reflecting multiple granite pulse intrusion, but also between the granites and wall rock, giving rise to hybrid granites. Xenoliths with remnant S<sub>0</sub> and S<sub>2</sub> were picked up and rotated during magma flow, with some embedded in the wall rock during filter pressing. The timing of granite intrusion relative to deformation is evident from examining contact-metamorphic cordierite porphyroblasts and their inclusions. The variation of inclusion patterns relative to the external foliation indicate that thermal metamorphism and, by implication, magma intrusion, occurred from early D<sub>2</sub>- to late-D<sub>3</sub> deformation with continued flattening of the schist matrix leading to an enveloping of the porphyroblasts by the S<sub>2</sub> foliation. The intrusion thus was accompanied by progressive deformation and tightening of the F<sub>2</sub> folding. Some granites, notably the coarse-grained megacrystic granite, crosscut other granite types and intruded late-to post-tectonic. Magma loading led to the development of a shallowly dipping, widely spaced S<sub>3</sub> crenulation. Subsequent magma injections led t","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105513"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750592","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":"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":"2025-11-01","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":"A catalogue of calcite vein types in porous sandstone and their formation conditions (Huab Basin, Namibia)","authors":"Eric Salomon ,&nbsp;Anna Nele Meckler ,&nbsp;Axel Gerdes ,&nbsp;Richard Albert ,&nbsp;Harald Stollhofen","doi":"10.1016/j.jsg.2025.105506","DOIUrl":"10.1016/j.jsg.2025.105506","url":null,"abstract":"<div><div>We present a catalogue of calcite vein types in porous sandstone that have the potential to affect fluid flow properties in a reservoir. Host rock is the Lower Cretaceous aeolian Twyfelfontein Formation, covered by voluminous flood volcanic rock of the Paraná-Etendeka Large Igneous Province in the Huab Basin of NW Namibia. Since the host sandstone lacks carbonate components, these veins document advective fluid flow, where solutes were transported through the fractures from an external source. Crystal growth in veins vary from blocky, to radial, and micritic. Some veins exhibit an intergrowth with kaolinite, or show an initial dolomite and iron oxide precipitation. Deformation stages are evident in a number of veins from breccia to cataclasis and fault-slip slickenfibre generations. Some calcite generations underwent partial dissolution and replacement by chalcedony. U-Pb dating shows a predominant vein formation from 31 Ma to recent, with one outlier at ∼65 Ma. Pore-filling calcite cements of sandstone along veins and in contact with the covering volcanic rock show similar ages. Formation temperatures (16–47 °C) derived from clumped isotope analysis indicate precipitation at shallow burial depths (&lt;1 km). An outlier of 59 °C stems from the vein dated to ∼65 Ma. Carbonate δ¹³C_VPDB shows a trend from −8.3 ‰ to −1.3 ‰ between Oligocene to present and we argue this to be a reflection of the region's climatic shift from warm humid to (semi-)arid conditions in this time. We further discuss, that this shift is responsible for many of the observed vein characteristics.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105506"},"PeriodicalIF":2.6,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713550","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":"Naturally deformed polymineralic rocks provide quantitative rheological information","authors":"Kyrsten L. Johnston ,&nbsp;Laurel Goodwin ,&nbsp;Basil Tikoff ,&nbsp;Evan Earnest ,&nbsp;Christine Gopon ,&nbsp;Thomas G. Blenkinsop","doi":"10.1016/j.jsg.2025.105539","DOIUrl":"10.1016/j.jsg.2025.105539","url":null,"abstract":"<div><div>Polyphase rocks are more common than monomineralic rocks, but their rheologies are less well constrained. We utilize a combination of strain markers, natural variations in mineral content, and microstructural observations to quantify the rheology of deformed and metamorphosed turbidite sequences from the Eastern Fold Belt in the Mount Isa Inlier, Queensland, Australia. At the outcrop scale, continuous deflection of quartz-rich veins records changes in shear strain magnitude that correspond to variations in mineralogy. Larger deflections (higher strains) are recorded in biotite- and muscovite-rich (phyllosilicate) domains relative to stratigraphically lower quartz- and feldspar-rich (quartzofeldspathic) domains. X-ray diffraction analyses of cores from a representative turbidite sequence show an increase in mica content (12–52 %) and a decrease in quartz and feldspar content (86–38 %) with increasing stratigraphic height. Electron backscatter diffraction analyses show a measurable crystallographic preferred orientation in quartz, indicating intracrystalline deformation in a quartzofeldspathic domain, which is absent in the adjacent phyllosilicate domain. Back-scattered electron images document evidence of solution-precipitation creep and grain-boundary sliding in a phyllosilicate domain, indicating deformation was accommodated by intercrystalline processes. Despite similar differential stress recorded by both domains, relative strain rates, calculated from ratios of shear strain, increase with mica content. A conceptual model that characterizes strain partitioning in layered systems quantitatively demonstrates the dependence of bulk deformation on the relative thicknesses and viscosity ratios of mineralogical domains.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105539"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907786","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":"Late Quaternary crustal shortening rate of the Wensu fault-bend fold in the southern Tian Shan, NW China","authors":"Kezhi Zang ,&nbsp;Chuanyong Wu ,&nbsp;Zhan Gao ,&nbsp;Xuezhu Wang ,&nbsp;Haiyang Yuan ,&nbsp;Jinshuo Zhang ,&nbsp;Sihua Yuan ,&nbsp;Xiaohui Yu ,&nbsp;Yunxiao Ma","doi":"10.1016/j.jsg.2025.105536","DOIUrl":"10.1016/j.jsg.2025.105536","url":null,"abstract":"<div><div>N‒S crustal shortening in the Tian Shan shows an obvious eastward decrease, which results in an eastward decrease in the width and uplift height of the topography. However, the highest peak in the Tian Shan region appears in its middle part (the Wensu area) instead of at the expected western end. At present, the kinematic information and N‒S crustal shortening rate of the Wensu foreland thrust system remain poorly constrained, which has led to controversy regarding the deformation characteristics and mechanism of geomorphic growth in this area. In this study, we focused on the kinematics and shortening rate of the Wensu fault-bend fold (WFBF), the frontal structural belt of the Wensu foreland thrust system. On the basis of interpretations of detailed high-resolution remote sensing images, field investigations, surveying of displaced terraces with an unmanned drone, the dating of late Quaternary sediments via OSL and trench excavation, we determined a relatively low N‒S crustal shortening rate of 1.31 ± 0.23 mm/yr over the past 24,000–40,000 years for the WFBF. We suggest that a listric thick-skinned fault geometry at depth results in more vertical uplift components, which is the key factor of significant topographic uplift amplitude in this region.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105536"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144840641","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":"Mapping fault architecture from depth to surface: integrating microseismicity and structural geology in low-strain Apennine regions","authors":"Giusy Lavecchia ,&nbsp;Francesco Brozzetti ,&nbsp;Simone Bello ,&nbsp;Rita de Nardis","doi":"10.1016/j.jsg.2025.105518","DOIUrl":"10.1016/j.jsg.2025.105518","url":null,"abstract":"<div><div>High-resolution microearthquake data provide a powerful window into active fault architecture from depth to surface in slowly deforming regions with sparse instrumental seismicity. We integrate microseismic clusters from enhanced catalogs with detailed structural mapping to reconstruct the 3D geometry of seismogenic extensional faults in the Latium-Abruzzi sector of central Italy. Investigated earthquake clusters align geometrically and kinematically with known and newly mapped normal faults showing evidence of Late Quaternary activity. The 3D model depicts a set of SW-to-SSW-dipping, non-planar faults with an average dip of ∼55° (Sora, San Donato Val di Comino, Villavallelonga, and Pescasseroli). Their cut-off depths deepen NNE-ward, from ∼7 to ∼14 km, suggesting an underlying basal discontinuity dipping∼30–35°. Microseismic patches at the roots of these faults are mostly elongated along dip rather than along strike. This unusual geometry suggests a stress release pattern governed by iso-oriented anisotropic roughness and corrugations on the basal discontinuity, which may focus upward fluid migration and trigger earthquakes along hangingwall splays. Stress inversion reveals a persistent NE–SW tensional stress field consistent across geological and instrumental timescales. An empirical magnitude-area relationship, accounting for both epistemic uncertainty in scaling laws and areal variability of fault surfaces, yields maximum magnitudes between 6.0 and 6.5, consistent with the regional seismotectonic framework. These findings provide new constraints on fault connectivity, stress distribution, and fluid-fault interactions, and help identifying potentially seismogenic sources that may remain unrecognized when geological and seismic data are considered separately.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105518"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828062","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":"3D modeling and visualization of geological structures with python-implemented Bézier curves/surfaces","authors":"Manuel Bullejos ,&nbsp;Manuel Martín-Martín","doi":"10.1016/j.jsg.2025.105508","DOIUrl":"10.1016/j.jsg.2025.105508","url":null,"abstract":"<div><div>Interactive 3D HTML models and visualizations of geological structures derived from classic surface geological information have been developed, for the first time, in a Python environment, using the key case of the tectonic Mula sheets in the Betic Cordillera (southern Spain). These models were performed through several steps: a geological 2D sketch map, creating equispaced geological cross-sections, 3D topography, a complete 3D model, and detailed 3D block diagrams. The result of the extrapolation of the equispaced geological cross-sections and their integration with the geological map into a 3D geological model shows the thrust-faulted and contractionally folded structure of the entire area, which affects the Cretaceous to Lower Miocene succession. The faults (strike-slip and normal) present in the tectonic thrust sheets are also represented. Three detailed 3D HTML blocks of illustrative regions within the modeled area were also created. For the 3D modeling, Bézier curves/surfaces as well as linear interpolation were used, as geological (stratigraphic and tectonic) contacts and surfaces between different stratigraphic units can be expressed geometrically with these tools. Compared to commercial alternatives, our software offers three key advantages: free user-friendly solutions, browser-compatible 3D models, and open-source software. The 3D visualization of stratigraphic-structural architecture enables predictive interpretations with applications in environmental and economic geology (e.g., groundwater, geotechnical studies, mining research, etc.). Moreover, 3D visualization and modeling provide valuable insights into geological phenomena, benefiting both the scientific community and society at large. Furthermore, advances in interactive 3D visualization bridge the gap between cutting-edge geological research and public understanding, enhancing social awareness.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105508"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750591","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":"Multi-phase deformation in the Qixingtai region of Western Shandong Province: insights into the Neoarchean tectonic evolution of the eastern North China Craton","authors":"Shuhui Zhang ,&nbsp;Jian Zhang ,&nbsp;Guochun Zhao ,&nbsp;Qihang Wu ,&nbsp;Chen Zhao ,&nbsp;Xiaoguang Liu ,&nbsp;Changqing Yin ,&nbsp;Jiahui Qian ,&nbsp;Mingtao He","doi":"10.1016/j.jsg.2025.105516","DOIUrl":"10.1016/j.jsg.2025.105516","url":null,"abstract":"<div><div>The Neoarchean era marks a pivotal period in Earth's tectonic evolution and continental crust formation. In this context, crustal architecture and structural patterns serve as key indicators for reconstructing Neoarchean geodynamic processes. The Western Shandong Province (WSP) granite-greenstone belt, located in the North China Craton (NCC), preserves well-exposed Neoarchean rock assemblages and provides valuable insights into the Neoarchean tectonics. In this study, we conducted systematic geological mapping and detailed structural analysis, integrated with LA-ICP-MS zircon U-Pb geochronology, in the Qixingtai region of the WSP. Three stages of compressional deformation (D1 to D3) were identified. The earliest deformation D1, predating ∼2663 Ma, is characterized by NW-SE-trending, sub-vertically penetrative S1 foliation in early Neoarchean supracrustal rocks and TTG rocks, indicating an initial NE-SW compressional regime. This was followed by a regional extension during 2.60-2.55 Ga and deposition of the Shancaoyu Formation during 2.55-2.52 Ga. The subsequent deformation D2 (∼2520-2514 Ma) progressively overprinted earlier structures and generated NW-SE-trending upright isoclinal folds in late Neoarchean supracrustal and TTG rocks, indicating a consistent and prolonged compressive stress field. The last deformation D3, occurring around ∼2500 Ma, resulted in the development of ductile shear zones of variable scales along the major lithological boundaries and generated regional L-S tectonites with near-vertical foliation and horizontal lineation. Our results suggest that the WSP experienced a long-lasting NE–SW compressive stress field throughout the Neoarchean but lacks diagnostic features of typical subduction or collisional belts. Combined with previous studies, we propose a tectonic model for the tectonic evolution of the Qixingtai area. This area initially developed from an oceanic plateau in the early Neoarchean, experienced regional extension in the middle Neoarchean, and ultimately underwent extensive magmatism and horizontal shortening during the late Neoarchean.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105516"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750594","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":"Residual stress in diopside: insight into localized transient high stress in seismogenic faults in the lower crust, Lofoten, Norway","authors":"Hugo W. van Schrojenstein Lantman ,&nbsp;Patricia A. Carvalho ,&nbsp;David Wallis ,&nbsp;Luca Menegon","doi":"10.1016/j.jsg.2025.105517","DOIUrl":"10.1016/j.jsg.2025.105517","url":null,"abstract":"<div><div>Pseudotachylytes in the metamorphosed anorthosites of the Lofoten archipelago, Norway, preserve a record of seismic rupture in dry lower crust at temperatures and pressures of 650–750 °C and 0.8 GPa. Transient gigapascal-level stresses are suggested from microstructural evidence, however such high stresses have not been quantified. In this contribution, we combine microstructural analysis with the mapping of heterogeneity in residual stress in diopside from a lower-crustal pseudotachylyte from Nusfjord (Lofoten) using high-angular resolution electron backscatter diffraction (HR-EBSD). We aim to elucidate the deformation processes that led to this residual stress and to its spatial heterogeneity in the diopside grains.</div><div>The diopside contains micro-to nanoscale deformation twins within 3 mm of the fault and in clasts in the pseudotachylyte. Within clasts, the diopside lattice strongly undulates, indicating crystal plasticity at high driving stress. Residual stress heterogeneity ranges between ∼200 MPa and ∼800 MPa for in-plane normal stress, with greater values occurring closer to and in the pseudotachylyte. This trend is not apparent for the in-plane shear stress, which has residual stress heterogeneity between ∼150 and ∼250 MPa, not correlating with distance to the fault. The greatest residual stresses are present in a clast that exhibits lattice distortion resulting from dislocation glide. Mechanical twins, lattice undulations, and the distribution patterns of residual stress are truncated by coseismic fractures, suggesting that the microstructures and residual stress are the result of stress build-up prior to slip.</div><div>Given the extreme spatial localization of the residual stress heterogeneity, we conclude that it results from deformation occurring during earthquake rupture propagation. Despite high temperatures during frictional heating, thermal pressure did not contribute significantly to the residual stress. The behaviour of diopside as a stress recorder is influenced by mechanical twins: stress build-up in diopside may have partially dissipated by the formation of twins, and twins also appear to affect the residual stress, in particular shear stress.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105517"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810157","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 role of cretaceous tectonics in the present-day architecture of the nice arc (Western Subalpine foreland, France)","authors":"R. Bauer ,&nbsp;M. Corsini ,&nbsp;C. Matonti ,&nbsp;D. Bosch ,&nbsp;O. Bruguier ,&nbsp;B. Issautier","doi":"10.1016/j.jsg.2025.105538","DOIUrl":"10.1016/j.jsg.2025.105538","url":null,"abstract":"<div><div>The Nice arc architecture, located at the southern tip of the Western Alps, is very singular, with a strong and narrow curvature. This particular shape could be the result of inherited structures that guide subsequent deformations during compressional events, as has been demonstrated in other parts of the belt. To achieve this objective, we adopted a multidisciplinary approach to characterize the geometry, kinematics, and timing of deformations associated with the various tectonic episodes that structured the arc. A special focus on the Cretaceous formations has revealed that the Cenomanian deposits show significant thickness variations and strong disturbances associated with fault activity. At this time, the formation of narrow, elongated basins was controlled by a system of NNE-SSW trending left-lateral strike-slip faults associated with NW-SE trending normal strike-slip faults and normal faults, dated at 81 ± 13 Ma on calcite recrystallised on the fault planes. During the Cenozoic, two phases of shortening reactivated the faults bounding these basins. An Oligocene phase corresponds to a NE-SW compression, expressed by NW-SE trending folds and thrust and reactivation of first phase faults, dated at 28.7 ± 6.1 Ma, 28.8 ± 8.4 Ma and 27.3 ± 6.3 Ma. The Mio-Pliocene phase is characterised by N-S compression with E-W folds that interfere with the Oligocene folds and reactivate the earlier faults. A Lower Miocene age of 18.2 ± 1.1 Ma and a Pliocene age of 3.16 ± 0.47 Ma pinpoint the timing of these last deformation phases.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"200 ","pages":"Article 105538"},"PeriodicalIF":2.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144867380","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}