Journal of Structural Geology最新文献

{"title":"The impact of hydrothermal silicification on fault zone porosity and permeability: insights from the Kornos-Aghios Ioannis normal fault, Lemnos Island, Greece","authors":"L.R. Berio ,&nbsp;F.H.R. Bezerra ,&nbsp;M.F.P. Brito ,&nbsp;M.A.F. Rodrigues ,&nbsp;F. Storti ,&nbsp;F. Balsamo","doi":"10.1016/j.jsg.2025.105444","DOIUrl":"10.1016/j.jsg.2025.105444","url":null,"abstract":"<div><div>In fault zones, silica-bearing hydrothermal fluids may strongly affect petrophysical and mechanical properties of rocks with significant implications on fluid storage and flow potential. However, it is extremely difficult to predict the geometry and petrophysical properties of silicified rocks around km-long fault zones affecting reservoirs. The Kornos-Aghios Ioannis Fault (KAIF) is a 10-km long silicified extensional fault system juxtaposing volcanic rocks against turbidite sandstones. In this study, we investigate the distribution, petrophysics and mineralogy of silicified rocks through a multi-analytical approach that combines X-ray diffraction analysis, Hg-intrusion porosimetry, digital image analysis, X-ray micro-computed tomography and unsteady-state gas permeametry. Silicification is mostly localized in the footwall sandstones and extends 50–300 m from the master fault. The porosity of silicified fault cores and silicified sandstones varies over a wide range (1–13 %) depending on the degree of post-silicification dissolution that is strongly controlled by the mineralogy. However, the permeability of silicified rocks always decayed by 2–3 orders of magnitude with respect to pristine host rocks. In silicified volumes, permeability drops imparted by cementation are partially counterbalanced by higher fracture density and connectivity because of increased rock brittleness. Our results show that hydrothermal silicification along fault zones may severely degrade reservoir quality in the surrounding areas, where its effect can be locally counterbalanced by an excess permeability produced by silica dissolution, fractures, and subsidiary faults. However, the intensity and extension of silicification and dissolution are spatially variable, controlling the along-strike distribution of potentially sealing and non-sealing areas.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"197 ","pages":"Article 105444"},"PeriodicalIF":2.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural geology in active tectonic regions: An introduction","authors":"Soumyajit Mukherjee ,&nbsp;Swagato Dasgupta ,&nbsp;G. Ian Alsop","doi":"10.1016/j.jsg.2025.105443","DOIUrl":"10.1016/j.jsg.2025.105443","url":null,"abstract":"","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"198 ","pages":"Article 105443"},"PeriodicalIF":2.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904105","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":"Discrete-element numerical simulations of thrust-related folding: Insights into back-limb deformation","authors":"Wenxiong Yang ,&nbsp;Gang Rao ,&nbsp;Pengcheng Tang ,&nbsp;Chao Zhu ,&nbsp;Renfu Wang","doi":"10.1016/j.jsg.2025.105442","DOIUrl":"10.1016/j.jsg.2025.105442","url":null,"abstract":"<div><div>The theory of thrust-related folding has significantly enhanced our comprehension of the kinematic evolution of folds, especially those associated with fault ramps. Despite extensive research into the deformation mechanisms of the fore-limb in the hanging wall folds, the factors influencing back-limb deformation remain relatively underexplored. This study employs a series of discrete-element simulations to investigate the evolution of ramp-related folding, particularly focusing on the factors governing the development of back-thrusts. Comparative analyses reveal diverse deformation styles within the hanging wall of a ramp fold. Notably, when the upper layer exhibits significantly greater strength relative to the lower layer, and an intermediate décollement exists between them, decoupled deformation occurs, characterized by back-thrusting predominantly in the lower layer. This phenomenon is analogous to the deep thrust belts beneath the Shizigou anticline in the western Qaidam Basin, northern Tibetan Plateau, where multiple hydrocarbon-bearing layers have been identified. The findings offer significant insights into the mechanisms of thrust-related folding, thereby improving efficient hydrocarbon exploration in relevant regions. Furthermore, unlike the commonly reported nucleation of a fault ramp from the basal décollement or at an intermediate level, our observations indicate initiation from the shallow section. The detailed mechanism underlying such differential deformation warrant further investigation.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"197 ","pages":"Article 105442"},"PeriodicalIF":2.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143877275","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":"External and internal salt geometries – a mining and geoscience review","authors":"P.A. Kukla ,&nbsp;J.L. Urai ,&nbsp;S. Back ,&nbsp;F. Sachse","doi":"10.1016/j.jsg.2025.105438","DOIUrl":"10.1016/j.jsg.2025.105438","url":null,"abstract":"<div><div>The Central European Basin System contains the Permian Zechstein salt giant, which includes a large number and variety of subsurface salt structures formed by salt tectonics in Mesozoic and Cenozoic times. Early descriptions of salt-body geometries originate mostly from salt-mining activities of the early 20th century in Germany and Poland. Inventories found in the mines are primarily documented as line drawings and from descriptions of miners and mine geologists. With the advancement of geophysical acquisition of the past decades, in particular active multidimensional seismic-reflection surveying combined with borehole geophysics and numerical and analogue modelling techniques, the description and interpretation of the external form of salt bodies and internal salt stratigraphy and geometry has made a major step forward. This study highlights the value of integrating detailed high-resolution salt-system knowledge from legacy field and mining data with modern 2D and 3D seismic-reflection data and observations from modelling for improved geological subsurface interpretations in salt terrains. Such integration will play an important role in the increased utilization of subsurface salt structures in the context of energy-transition strategies and the sustainable storage of renewable energy materials and waste.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"197 ","pages":"Article 105438"},"PeriodicalIF":2.6,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873569","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":"Fluid infiltration in the southern segment of the Red River Fault, China: Insights from rock magnetic, mineralogical, and geochemical analyses of fault rocks","authors":"Erhui Ren ,&nbsp;Xiuli Yan ,&nbsp;Tao Yang ,&nbsp;Tsafrir Levi ,&nbsp;Ram Weinberger ,&nbsp;Shmuel Marco ,&nbsp;Lishun Luo ,&nbsp;Guodong Wang","doi":"10.1016/j.jsg.2025.105437","DOIUrl":"10.1016/j.jsg.2025.105437","url":null,"abstract":"<div><div>Fluid infiltration within fault zones is intimately linked to the physical and chemical attributes of fault rocks, thereby playing a critical role in deformation and evolution of faults. Magnetic properties of fault rocks have proven to be an emerging source of information on faulting processes. To document evidence of fluid infiltration within the Red River Fault (RRF), detailed rock magnetic measurements in combination with mineralogical, and geochemical analyses are conducted on fault rocks collected from the Matouzhai outcrop along the range-front fault of the southern segment of the RRF. The results reveal that the ferrimagnetic fraction in the fault rocks is dominated by magnetite, with a small amount of hematite present in (proto-)cataclasites and fault gouges. Magnetic grain size and concentration decrease significantly from host rocks (mylonitized gneiss), via (proto-)cataclasites to fault gouges. Fault gouges are enriched in volatiles (CO₂, LOI, H₂O⁺), rare earth elements (REEs), and calcite, but are depleted in high-field strength (HFS) elements and exhibit negative δEu and δCe anomalies. These results indicate pervasive infiltration of the fault zone by CO₂-rich oxidizing hydrothermal fluids, leading to the depletion of magnetite and oxidation of magnetite to hematite, with dissolution of silicates and precipitation of abundant calcite (high pH). Magnetic parameters, particularly the high-field magnetic susceptibility, show significant correlations with HFS elements and REEs. These observations suggest that the rock magnetic properties of fault rocks are highly sensitive to fluid infiltration, and could serve as indicators of fluid conditions and fluid-rock interactions within fault zones.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"197 ","pages":"Article 105437"},"PeriodicalIF":2.6,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873570","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":"Magnetic and microstructural perspectives on faulting in carbonate rocks, northern Israel","authors":"Sreyashi Bhowmick ,&nbsp;Tsafrir Levi ,&nbsp;Yuval Boneh ,&nbsp;Shmuel Marco ,&nbsp;Tao Yang ,&nbsp;Bhupesh Meher ,&nbsp;Ram Weinberger","doi":"10.1016/j.jsg.2025.105436","DOIUrl":"10.1016/j.jsg.2025.105436","url":null,"abstract":"<div><div>Shallow crustal faulting involves complex processes, including brittle and ductile deformation, frictional heating, and fluid interaction, which may all leave distinct geological signatures. However, deciphering these mechanisms is challenging. This study investigates the deformation near two faults in northern Israel: the active Nahef East fault and the Qiryat Shemona fault, a major strand of the Dead Sea Fault (DSF) system, both cutting through diamagnetic carbonate rocks. We employ a range of methods, including anisotropy of magnetic susceptibility (AMS), magnetic properties, electron backscatter diffraction (EBSD), and geochemical analyses to target specific faulting processes. Both faults exhibit magnetic fabrics with foliations formed by AMS maximum (K₁) and intermediate (K₂) axes which are scattered on a plane sub-parallel to fault surfaces, extending ∼0.5 m from these fault surfaces. In the Nahef East fault, slight changes in magnetic properties, overall mineralogy and microstructures such as lobate calcite grains, indicate moderate temperatures (&lt;200-250 °C), and fluid interaction, which constrains grain reorientation and the development of crystallographic preferred orientation (CPO). Conversely, in the Qiryat Shemona fault, the small (∼5 μm) twinned calcite grains indicate moderate to high temperatures (&gt;250–300 °C), high stress (≥100 MPa) and dry conditions, potentially reflecting the fault's maturity. Distinct deformation fabrics and microstructural features around these faults reveal localized plastic deformation. The results underscore a potential gap between the extent of deformation observed in natural faults and those replicated in laboratory experiments, likely due to limited sample size and timescale considerations in laboratory settings.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"198 ","pages":"Article 105436"},"PeriodicalIF":2.6,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936237","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":"Microstructural evolution of compacted granular salt: insights from 40-year-old backfill at a former potash mine (Sigmundshall, northern Germany)","authors":"Kristoff Svensson ,&nbsp;Bart van Oosterhout ,&nbsp;Jürgen Hesser ,&nbsp;Christopher J. Spiers ,&nbsp;Ben Laurich","doi":"10.1016/j.jsg.2025.105429","DOIUrl":"10.1016/j.jsg.2025.105429","url":null,"abstract":"<div><div>Compacted granular salt backfill is widely regarded as the most favorable geotechnical barrier for sealing a radioactive waste repository within a rock salt formation. However, the reduction of salt backfill porosity and permeability during compaction by slowly converging cavity walls is still a matter of on-going research, both in laboratory and underground experiments, as well as in computational forecasting. Here, we present an in-depth microstructural analysis of a dense, formerly deployed salt backfill material, recovered from the decommissioned salt mine Sigmundshall, Bokeloh, Germany. The backfill compacted over 40 years, resulting in as little as 1 % porosity (+4/-1 %). Some differences are inevitable compared to a potential future backfill emplaced in a radioactive repository, notably in grain size, moisture content and backfill height (178 m vs. ∼ 5 m). However, this valuable “natural laboratory” sampling opportunity has allowed microstructural evidence to be sought for the deformation mechanisms that control salt backfill compaction under in-situ deployment conditions and on timescales that cannot be achieved in laboratory tests. For the present example of grain sizes in the range of 50 μm to 3 mm, our results show that more or less complete densification of granular salt is feasible in a timeframe of decades (&lt;40 y). Pressure solution is likely the main deformation mechanism along with limited cataclasis, which presumably occurred only in the early stages during/after emplacement. This conclusion is evident from tight, indenting, truncating and interpenetrating grain boundaries, as well as from the fact that almost all grains appear to be substructure-free, despite limited signs of recrystallization. The absence of intra-crystalline deformation indicators excludes dislocation creep as a compaction-contributing mechanism, which, on the other hand, is known to occur in many laboratory-based compaction tests. We outline the impact of this difference on the long-term in-situ compaction under repository conditions.</div><div>Note: The Sigmundshall mine is not considered as a future repository for radioactive waste.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"197 ","pages":"Article 105429"},"PeriodicalIF":2.6,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143877277","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":"Cooling induced fracturing in impact melt dikes derived from drone photogrammetry and Python simulation: Example from the Lesutoskraal Granophyre Dike in South Africa","authors":"Martin D. Clark ,&nbsp;Elizaveta Kovaleva ,&nbsp;Matthew S. Huber ,&nbsp;Stephanus Riekert ,&nbsp;Francois D. Fourie","doi":"10.1016/j.jsg.2025.105428","DOIUrl":"10.1016/j.jsg.2025.105428","url":null,"abstract":"<div><div>Large meteorite impact events produce significant amounts of crustal melt, which can be emplaced as dikes below the crater floor over protracted time periods following the cratering process. Their emplacement is theorized to be controlled by stresses associated with the presence and opening of crustal-scale fractures, hydrostatic pressures associated with the overlying melt sheet, and lithostatic stresses of the impacted crust. At least two compositionally distinct phases of impact melt are present within the impact melt dikes at the Sudbury and Vredefort Impact Structures, underpinning the debated concept of a prolonged and multi-phase emplacement process.</div><div>In this study, cooling fractures within the Lesutoskraal impact melt dike at Vredefort are investigated as a possible pathway to facilitate multi-phase emplacement. Through a combination of high-resolution (0.612 mm/pixel) drone orthophotography and numerical simulation of stress induced during cooling of impact melt shows that (1) the dominant fracture orientation within the impact melt dike is parallel to dike margins, related to a perpendicular and tensional cooling stress, and (2) the magnitude of the tensional cooling stress could reach up to −75 MPa, sufficient to overcome the lithostatic stresses at the observed depth of dike emplacement. Depending on simulation parameters such as the initial temperature of the impact melt, cooling fractures in the impact melt are shown to form within 150 days after their emplacement representing a possible mechanism for emplacement of later phases of impact melt into the centre of earlier impact melt phase.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"197 ","pages":"Article 105428"},"PeriodicalIF":2.6,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826309","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":"Corrigendum to “Structural evolution of the southern Swayze greenstone belt, Superior Craton: Implications for the Neoarchean crustal dynamics” [J. Struct. Geol. (2025) 105373]","authors":"Qǐháng Wú ,&nbsp;Shoufa Lin ,&nbsp;Thomas Gemmell ,&nbsp;Sandra L. Kamo ,&nbsp;Jian Zhang ,&nbsp;Lijun Wang","doi":"10.1016/j.jsg.2025.105419","DOIUrl":"10.1016/j.jsg.2025.105419","url":null,"abstract":"","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"196 ","pages":"Article 105419"},"PeriodicalIF":2.6,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838103","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":"Record of seismic slip in carbonates: Insights from the Venere Fault during the 1915 Avezzano earthquake (Mw 7.0), Central Italy","authors":"Nina Zamani ,&nbsp;Sara Satolli ,&nbsp;Michael Murphy ,&nbsp;Francois Demory ,&nbsp;Bruno Pace ,&nbsp;Jérôme Gattacceca ,&nbsp;Ján Kaňuk ,&nbsp;Michaela Nováková ,&nbsp;Raphael Gottardi ,&nbsp;Eric C. Ferré","doi":"10.1016/j.jsg.2025.105421","DOIUrl":"10.1016/j.jsg.2025.105421","url":null,"abstract":"<div><div>The Mw 7.0 Avezzano earthquake in the Abbruzzo region of Italy claimed ∼33,000 lives on January 13, 1915 making it one of the worst disasters in modern Italian history. The main rupture occurred along the Venere Fault, characterized by a polished, locally shiny, or powdery fault mirror showing extensive downdip striations, slickensides, and local reddish iron-oxide/hydroxide stains. The layer immediately below the mirror is a carbonate ultracataclasite that locally grades into an unconsolidated carbonate gouge.</div><div>This type of carbonate fault mirror typically forms through two distinct synkinematic processes: i) intense frictional heating causing decarbonation, or ii) progressive grain-size reduction during slip at seismic velocities. In either case, friction drops substantially after initial displacement. The first process also results in intense fault pressurization followed by subsequent drastic drop in normal stress. Despite recent advances, the switch from high-friction/low slip velocity to low-friction/high slip velocity conditions in carbonate is still not fully understood.</div><div>The Venere Fault, characterized by proven friction at seismic slip velocity, provides an ideal setting to investigate the nature and extent of dynamic weakening processes in carbonate faults. We use the high temperature sensitivity of iron oxide/hydroxide assemblages, and their magnetic remanence, to estimate frictional heat. Evidence for seismic slip in iron oxides and temperature uniformity along the fault surface have been tested through demagnetization experiments and 1D heat conduction modeling. Our data shows that the fault mirror underwent frictional heating during the 0.8 m slip event, but that this displacement was insufficient to reach pervasive decarbonation. We constrain the peak coseismic temperature along the fault plane to &lt;400 °C through demagnetization experiments and 1D heat conduction modeling. Our results emphasize that coseismic deformation along natural faults is complex and therefore requires complementary field observations at multiple scales in order to encompass a broad range of faulting processes.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"197 ","pages":"Article 105421"},"PeriodicalIF":2.6,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143843330","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}