Journal of Structural Geology最新文献

{"title":"Spatial distribution of permeability in carbonate fault damage zones","authors":"Lukas Bernier ,&nbsp;Roger Soliva ,&nbsp;Delphine Roubinet ,&nbsp;Stéphane Dominguez ,&nbsp;Sylvain Mayolle ,&nbsp;Manon Bulliard ,&nbsp;Christopher Wibberley ,&nbsp;Tvrtko Korbar","doi":"10.1016/j.jsg.2025.105371","DOIUrl":"10.1016/j.jsg.2025.105371","url":null,"abstract":"<div><div>Fault conduits often localized fluid flow at specific sites related to fault segment growth and linkage. Understanding these mechanisms is essential for assessing geofluid pathways within reservoirs or leaks to the biosphere. We study here a segmented fault zone with strike-slip kinematics and pluri-decametric displacement, affecting carbonate rocks (Pag island, Croatia). This fault zone has multiple core zones surrounded by a damage zone (DZ), composed of different structures, including wall and link damage. To build discrete fracture networks (DFNs) of these structures, we conducted high-resolution fracture mapping and measurement of aperture in five areas around the main fault system. We also analyzed rock samples from each damage structure using the same method. Fluid flow simulations were performed through the DFNs to quantify the permeability and its anisotropy. We show that link damage is about 10² more permeable than the background damage, and 2 to 5 times more permeable than the wall damage. DZ permeability can be approximated by a tensor at the decametric-scale, but not at the centimetric-scale due to the strong permeability heterogeneity inherent to this scale. In the DZ, decametric-scale fracture patterns are 10–65 times more permeable than the centimetric-scale fractures, providing conduits for fluid flow. Finally, the maximum permeability strongly correlates with the product of mean aperture and connectivity, suggesting that these parameters could be used as proxy of the permeability in fault DZ. These results allow better estimation of fault zone permeability, providing constraints for flow modelling in various applications in the energy transition.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"194 ","pages":"Article 105371"},"PeriodicalIF":2.6,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464454","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":"Investigating the Messinian salt in the Lebanese Levant basin: Insights into the geology and tectonics of the eastern Mediterranean region","authors":"Karam Sarieddine,&nbsp;Tony S. Nemer,&nbsp;Reenal Faysal","doi":"10.1016/j.jsg.2025.105368","DOIUrl":"10.1016/j.jsg.2025.105368","url":null,"abstract":"<div><div>The Messinian salt layer in the eastern Mediterranean region plays a key role in the Pliocene-Quaternary deformation and formation of the tectonic structures in the Levant Basin. The objective of this paper is to leverage 3D seismic reflection data from the northern Levant Basin offshore Lebanon in order to map the Messinian salt layer and understand its effect on the structures around it. For that, we used current 3D time seismic reflection data to investigate the seafloor and interpret the top and base of the salt layer, and we generated their corresponding bathymetric and structural maps. In addition, we generated isochron maps of the salt layer and the post-salt sedimentary section in an attempt to detect the variations in the lateral thicknesses of these layers. The presented maps helped to understand the impact of the Messinian salt deformation on the surrounding geological structures. We assess the distribution and geometries of the salt structures, and discuss the change in salt thickness across the basin. We also relate the halokinetic movement of the Messinian salt to the formation of bathymetric features along the seafloor. The results provide additional knowledge about the salt tectonics of the Messinian salt layer in the Levant Basin, and offer investigators to pursue further studies on the hydrocarbon potential in relation to the Messinian salt deformation.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"194 ","pages":"Article 105368"},"PeriodicalIF":2.6,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438001","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":"Lateral growth, linkage and driving force of anticlines in the western Qaidam Basin, Northern Tibetan Plateau","authors":"Xiangdong Yang ,&nbsp;Lei Wu ,&nbsp;Bo Wang ,&nbsp;Jianchao Tang ,&nbsp;Wei Tan ,&nbsp;Xuhang Li ,&nbsp;Huitong Yang ,&nbsp;Kai Huang ,&nbsp;Junyong Zhang ,&nbsp;Xiubin Lin ,&nbsp;Ancheng Xiao ,&nbsp;Hanlin Chen","doi":"10.1016/j.jsg.2025.105370","DOIUrl":"10.1016/j.jsg.2025.105370","url":null,"abstract":"<div><div>In fold-and-thrust belts, folds usually grow laterally, and connect with neighboring folds to form larger structures. Whilst these processes significantly impact both the surface morphology and subsurface structures, there remains a gap in understanding the deep deformation involved in lateral growth and linkage of folds. To address this issue, our study focused on the northwestern Qaidam Basin hosting a series of well-exposed NW-SE-trending Cenozoic anticlines. We conducted a comprehensive analysis of the lateral growth and linkage patterns along with their subsurface structures of the anticlines, based on high-resolution remote-sensing images and seismic reflection data. Our investigation reveals that the anticlines are primarily décollement folds, with minor influence from basement-involved reverse faults. They have grown through lateral lengthening from their nuclei, with a generally faster propagation rate toward the southeast. This growth pattern is likely driven by the southeastward decrease in strain rate, coupled with the influence from southeastward tilting of the basement and topography in the Qaidam Basin. We identify six types of lateral linkage among anticlines in the Qaidam Basin: linear linkage, linear repulsion, oblique linkage, overlapped linkage, oblique non-linkage, and triple linkage. Notably, our study reports, for the first time, instances of linear repulsion and overlapped linkage, characterized by abnormally large distance to wavelength ratios. The development of linear repulsion is associated with the buried basement-involved fault between linked anticlines, whereas that of overlapped linkage likely results from rapid lateral growth of anticlines due to intense wind erosion. Moreover, our findings indicate that the en echelon-like distribution and arcuate shapes of the anticlines in the Qaidam Basin primarily stem from the lateral growth and linkage of the short-axis anticlines, rather than inferred basement strike-slip shears. The underlying driving force is the compression from the Qiman Tagh-East Kunlun Shan and the South Qilian Shan to the south and north, respectively. Our study underscores the interplay of décollements, basement-involved faults and erosional processes in shaping the diverse growth and linkage patterns of anticlines in fold-and-thrust belts.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"193 ","pages":"Article 105370"},"PeriodicalIF":2.6,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420854","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":"Hydrogeological implications of fault-related folding in a Triassic braided sandstone","authors":"Timothy C. McMillan ,&nbsp;Titus Murray ,&nbsp;Martin S. Andersen ,&nbsp;Wendy A. Timms ,&nbsp;Gabriel C. Rau","doi":"10.1016/j.jsg.2025.105351","DOIUrl":"10.1016/j.jsg.2025.105351","url":null,"abstract":"<div><div>Although our understanding of how fault-related folds influence groundwater flow has advanced, the understanding of the exact geometries and architecture of displacement propagation is often uncertain. This paper focuses on fault-related folds (i.e., fault bend, fault propagation, and detachment folding) within a braided sandstone and their implications for groundwater flow due to the internal fracture architecture. To achieve this, we combine lineament mapping, field observations, 3D regional kinematic geological restoration modelling, and juxtaposition analysis of a major aquifer system in the Permo-Triassic Sydney Basin. Our lineament mapping allowed for targeted fieldwork where outcrop observations unveiled a mechanical stratigraphy (i.e. variations in mechanical properties, layer thickness, and frictional properties of mechanical boundaries) controlled by the braided river depositional architecture. This results in systematically spaced fracture sets and rotational shearing following the sedimentary fine-grained depositional variations causing brittle folding of the sandstone mass. Our 3D geological modelling quantitated the existence of regional fault-related fold geometries. We re-interpret these folded zones as broad fault damage zones, which are likely to promote vertical fracture flow through a rock matrix otherwise dominated by horizontal porous flow controlled by the depositional braided river environment. The conceptual model for potential for flow within the folded sandstone is then placed into the regional study context by fault juxtaposition analysis of displacements across the major regional aquifers separated by a regional aquitard assuming the geometry of a fault propagation fold. Such insights were notably absent from previous conceptual groundwater models for fault-related folds in braided river deposited sandstone successions. Our findings enhance the understanding of how mechanical stratigraphy can strongly influence the internal structures of fault-related folds and, in turn, affect the groundwater system connectivity.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"193 ","pages":"Article 105351"},"PeriodicalIF":2.6,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420855","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":"Structural heterogeneities in fault-controlled cavity carbonate reservoirs: Insights into fracture and fault patterns","authors":"Duoming Zheng ,&nbsp;Lijuan Zhang ,&nbsp;Feng Shen","doi":"10.1016/j.jsg.2025.105358","DOIUrl":"10.1016/j.jsg.2025.105358","url":null,"abstract":"<div><div>This study investigates the role of fault zones and fracture networks in controlling cavity distribution and fluid flow within carbonate rocks of the Tarim Basin using static and dynamic data. By integrating multi-attribute unsupervised seismic facies analysis, fracture network modeling based on ant tracking, and slip and dilation tendency analyses, we construct 3D models to characterize fault zone patterns, cavity distribution, fracture geometry, connectivity, and deformation behavior. The results demonstrate that fault zone patterns are the primary controls on cavity distribution, with cavity arrangements closely reflecting the orientations and densities of fracture networks in the DFN model. Extensive cavity geobodies are concentrated at fault zone intersections, where fractures exhibit increased density and connectivity. The large geobody, defined by considerable connected volumes, high permeability, and high production performance, is situated in these intersections with dense, highly connected fracture networks. These networks enhance fluid flow and shape fluid pathways, highlighting their role in cavity reservoir dynamics. These findings provide insights for improving reservoir modeling and optimizing injection-related geoengineering activities, such as acid stimulation and hydraulic fracturing.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"193 ","pages":"Article 105358"},"PeriodicalIF":2.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403133","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":"Late Quaternary left-slip rate of the Dangjiang segment along the Ganzi-Yushu-Xianshuihe Fault Zone in the central Tibetan Plateau and the tectonic implications","authors":"Zhongyuan Yu ,&nbsp;Baixu Chen ,&nbsp;Ping Song ,&nbsp;Qi Zhao ,&nbsp;Yicheng Wang ,&nbsp;Wenxuan Wang","doi":"10.1016/j.jsg.2025.105359","DOIUrl":"10.1016/j.jsg.2025.105359","url":null,"abstract":"<div><div>The Dangjiang segment, as the northwestern extremity of the NW-NNW-trending sinistral-slip Ganzi-Yushu-Xianshuihe Fault Zone (GYXFZ) in the central Tibetan Plateau, plays an important role in absorbing strain and regulating the relative movement between active blocks of the Tibetan Plateau interior. However, the late Quaternary strike-slip rate of the Dangjiang segment has rarely been studied because of extreme weather and hypoxia in high-altitude areas (H &gt; 5000 m) and inconvenient transportation, which directly affects the scientific understanding of the tectonic deformation style and reasonable assessment of the strong earthquake hazard along the GYXFZ and the analysis of the present deformation characteristics and geodynamic process of the plateau. Therefore, this study investigated the active tectonics of the Dangjiang segment based on integrated data from high-resolution satellite interpretation, large-scale geomorphic and geological mapping, trench excavations, and Quaternary chronological dating. The results reveal that the Dangjiang segment branches into the main Dangjiang Fault and secondary Zhiduo Fault, both of which have experienced intensive left-strike slip with minor dip movement since the late Quaternary. By measuring offset tributary terraces of the Tongtian River using a UAV survey, and dating their abandonment age using OSL and 14C with the upper terrace model, the late Quaternary strike-slip rate of the Dangjiang Fault and the Zhiduo Fault were estimated at ∼6.9 ± 0.1 mm/a and ∼2.1 ± 0.2 mm/a, respectively. Both the linear fitting value and the slip decomposition model indicate that the strike-slip rate of ∼8–10 mm/a in the late Quaternary is more consistent with geological and geomorphic estimations as well as geodetic constraints along the GYXFZ, and that the late Quaternary slip rate (∼8–10 mm/a) is consistent with the long-term and average slip rates along the structure. This spatiotemporal variation suggests that the current tectonic deformation of the Tibetan Plateau interior may have been continuous and distributed.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"192 ","pages":"Article 105359"},"PeriodicalIF":2.6,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378442","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 activity of the Songgang Fault on the eastern Tibetan Plateau from geological and geomorphological evidence","authors":"Jiao Liu ,&nbsp;Mingjian Liang ,&nbsp;Guohong Zhang ,&nbsp;Renmao Yuan ,&nbsp;A.L. Strom ,&nbsp;Zhikun Ren ,&nbsp;Xinjian Shan","doi":"10.1016/j.jsg.2025.105348","DOIUrl":"10.1016/j.jsg.2025.105348","url":null,"abstract":"<div><div>The Late Quaternary activity characteristics of faults are essential for understanding regional strain distribution and estimating seismic hazards. The Bayan Har block, located in the northern Tibetan Plateau, is a region with a high level of seismic hazard. Remarkably, over the past three decades, many strong earthquakes have occurred on the block boundary fault zones of the Bayan Har block. However, the 2021 Ms 7.4 Maduo earthquake and the 2022 Maerkang Ms 6.0 earthquake swarm were exceptions as they took place within the Bayan Har block, not on the boundary fault zones. The reason for the occurrence of these intraplate earthquakes presents an interesting research query. The Songgang Fault (SGF) is a NW-trending strike-slip fault within the Bayan Har block. The 2022 Maerkang Ms 6.0 earthquake swarm occurred 6 km northeast of the SGF. What role did the SGF play in the process of the earthquake swarm? Through utilizing high-resolution remote sensing image interpretation, detailed field geological and geomorphologic surveys, trench analysis, and dating technologies, we found that the SGF is a sinistral strike-slip active fault since the Late Pleistocene, exhibiting tectonic behavior conducive to the preparation and occurrence of moderately large earthquakes. OSL dating of dislocated stream channels reveals a left-lateral slip rate of the SGF yields 1.6–2.1 mm/yr since the Late Pleistocene. The SGF distributes and transmits the tectonic deformation within the Bayan Har block, accommodating southeastward lateral extrusion of the Bayan Har block materials and contributing to the kinematic mechanisms of the entire eastern margin of the Tibetan Plateau. Furthermore, the 2022 Ms 6.0 Maerkang earthquake swarm exhibits a conjugate rupture phenomenon in a complex tectonic zone where several secondary fault planes of the SGF converge. This main fault zone deserves attention as a potential source zone of future earthquakes.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"194 ","pages":"Article 105348"},"PeriodicalIF":2.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428124","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":"Quartz veins in the greenstone belts of Dharwar Craton (India) and their mineralization potential – A hypothesis","authors":"Santu Biswas,&nbsp;Arindam Sarkar,&nbsp;Abhijeet Suryawanshi,&nbsp;Manish A. Mamtani","doi":"10.1016/j.jsg.2025.105355","DOIUrl":"10.1016/j.jsg.2025.105355","url":null,"abstract":"<div><div>Structural geological investigations involving statistical analysis of mineralized vs. non-mineralized (barren) veins are important in mineral exploration. In this study, we statistically analyze orientation, thickness, and spacing data of veins intruding metavolcanic rocks of three regions of Eastern Dharwar Craton (EDC, southern India) - Hutti surface (6 transects), Raichur (5 transects), and Gadwal (6 transects). While gold mineralization is known to occur in parts of Archaean greenstone belts of the Dharwar Craton, vein data collected here are from areas with no reported gold deposit. Results from this study are compared with similar published data from gold-bearing and barren domains of the Gadag region in Western Dharwar Craton (WDC). Vein data are used to prepare a “mineralization potential plot” and calculate the mineralization potential parameter (M_d) for each transect. Whilst most transects in EDC have high M_d, implying low mineralization potential, a few transects have a low M_d and fall close to the cluster of points demarcating the mineralized domain of the Gadag region. This brings to light the limitations of the mineralization potential plot developed by earlier workers, which is discussed in this study. We discuss the importance of dispersion of M_d for multiple transects of a particular region in order to evaluate its true mineralization potential. It is noted that all data for EDC (this study), as well as the non-mineralized domain of Gadag (WDC) show high dispersion on the mineralization potential plot, while data from the mineralized domain of the Gadag are clustered (low dispersion) close to the origin. We have developed a “<em>mineralization potential standard deviation (MPSD) plot</em>”, where the mean M_d and its standard deviation (S_d) from multiple transects of the individual regions of EDC and WDC are plotted. This yields a <em>MPSD curve</em> following power law equation, which is unique to the data of quartz veins intruding metavolcanic rocks of the Dharwar Craton. We hypothesize that if data of quartz veins intruding metavolcanic rocks from any part of the Dharwar region are analyzed, a high mineralization potential will be indicated if data fall on this MPSD curve and close to the origin. We envisage that every region will have its unique MPSD curve, which can be prepared from vein data of a particular mineralogical phase intruding a specific lithology. It is concluded that the MPSD curve can be used to identify potential regions of mineralization.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"192 ","pages":"Article 105355"},"PeriodicalIF":2.6,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388065","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":"Estimating complete dyke dimensions from partial exposures","authors":"Sirshendu Kumar Biswas ,&nbsp;Tridib Kumar Mondal ,&nbsp;Avijit Saha ,&nbsp;Alaap Kumar Mukhopadhyay ,&nbsp;Archishman Mukherjee","doi":"10.1016/j.jsg.2025.105350","DOIUrl":"10.1016/j.jsg.2025.105350","url":null,"abstract":"<div><div>Knowledge of complete dyke dimensions is crucial to determine the actual aspect ratio which is indispensable in estimating their magma overpressure, depth of origin and even explosivity potential of fissure eruptions. A dearth of completely exposed dykes imposes considerable uncertainty on estimates of their aspect ratios. Therefore, we have pioneered a method of estimating complete dyke dimensions from their partial exposures lacking any tip. Considering dykes as dominantly opening mode fractures, the method is built upon the idealized canonical model of opening mode fractures and utilizes differential equation of ellipse, which is the predicted shape of fracture opening in the model, to estimate their full length, maximum width and aspect ratio from limited outcrop measurements. The validity of the method has been tested against ground data and published data. From its application to two partially exposed mafic dykes devoid of tips, one each from the Western and Eastern Dharwar Cratons of India we generated results from which we further calculate their magma overpressures and depths of origin. Although developed for dykes, the method has potential for wider application, since it can be used fundamentally to predict complete dimensions of any elliptical shaped natural features from their partial exposures.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"192 ","pages":"Article 105350"},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378440","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 influence of columnar joints and joint pattern on near-surface normal faulting: An analog modeling approach","authors":"Lisa Winhausen ,&nbsp;Antonia Czepl ,&nbsp;Michael Kettermann ,&nbsp;Christoph von Hagke ,&nbsp;Janos L. Urai","doi":"10.1016/j.jsg.2025.105354","DOIUrl":"10.1016/j.jsg.2025.105354","url":null,"abstract":"<div><div>Normal faults at mid-ocean ridges develop massively dilatant structures close to the surface. Situated close to plate boundaries, these faults form in volcanic rocks such as basalt, which are characterized by columnar joints. These joints cause an orthotropic mechanical behavior of the rock mass, characterized by contrasting strong intact rock and weak, low-cohesion joint networks. To date, the influence of these columnar joints on the geometry and evolution of near-surface normal faults remains poorly understood. We present an analog modeling approach utilizing new analog modeling materials: i) layers of desiccated cornstarch forming drying cracks and resembling layered columnar joints in basaltic lava flows, and ii) systematically stacked blocks representing different joint patterns with varying block overlaps above vertical cooling joints. The geometric scaling of these models allows to assess the near-surface structures in the upper 50–150 m. The models reveal that fault formation is dominated by opening mode displacement reactivating the pre-existing joints and the style of deformation changes with progressive localization of the main fault. Observed structural features such as a tilted block bound between a main and antithetic fault, relay ramps, vertical mass transfer, and open cavities transfer well to the natural prototypes. Our newly developed experiments form a basis for future studies exploring fault processes in jointed rock masses.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"192 ","pages":"Article 105354"},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349331","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}