Journal of Structural Geology最新文献

{"title":"The low acoustic impedance of fault zones in the Wisting field, Barents Sea: Gas saturation or damage zone?","authors":"Jake H. Butcher ,&nbsp;Nestor Cardozo ,&nbsp;Lothar Schulte ,&nbsp;Luis Rojo","doi":"10.1016/j.jsg.2025.105347","DOIUrl":"10.1016/j.jsg.2025.105347","url":null,"abstract":"<div><div>The presence of faults in reservoirs can directly affect reservoir energy and feasibility in hydrocarbon bearing formations as well as repository potential for subsurface storage. Subsurface fault characterisation is an important but challenging workflow because a geoscientist is limited to the resolution of seismic data and sparse well data. The Barents Sea is renowned for exhumation generated gas seepage allowing preferential retainment of oil. In this study, observations in the fault zones of the Wisting field show reductions of acoustic impedance (A_imp) on seismic images. We characterise five intersecting E–W and N–S normal faults in the Wisting Central blocks using a novel approach, whereby low A_imp is mapped onto modelled fault surfaces and compared to parameters such as fault throw and shale gouge ratio. Low A_imp dominates E–W faults which exhibit more brittle response when compared to two N–S faults, where low A_imp values are sparse and the faults tip-out below a monocline. Two potential mechanisms causing the reduction of A_imp are proposed: 1) gas saturation, which can be as little as 2% to significantly reduce A_imp; 2) fault damage, which can decrease wave velocities and A_imp. The E–W faults in Wisting Central show higher reductions of A_imp than their N–S counterparts, indicating that they are either saturated with gas or have undergone higher damage.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105347"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151531","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":"Strain rates recorded in the perimeter-area relationship of recrystallized quartz aggregates from the Sandhill Corner shear zone, Maine, USA","authors":"Erik K. Anderson,&nbsp;Won Joon Song,&nbsp;Scott E. Johnson,&nbsp;Christopher C. Gerbi","doi":"10.1016/j.jsg.2024.105330","DOIUrl":"10.1016/j.jsg.2024.105330","url":null,"abstract":"<div><div>Current available methods for determining strain rates during viscous deformation are limited, generally relying on the preservation of appropriate microstructures. A lesser-known method to determine strain rates of monomineralic quartz aggregates relates the perimeter-area fractal dimension (D-value) of grain boundaries to deformation conditions. We explore this method by applying it to the Sandhill Corner shear zone (SCSZ), a seismogenic shear zone exhumed from the base of the frictional-to-viscous transition. Strain-rate patterns from D-values are similar to those from flow laws combined with grain size piezometry and predict comparable magnitudes to rates from flow laws using the theoretical piezometer of Shimizu (2012). We compare quartz D-values with proxies for grain shape and grain boundary roughness and find a clear correlation between D-value and grain size, suggesting it may record flow stress. We interpret the disparity in spatial trends between D-value and recrystallized grain size within the inner shear zone as reflecting the influence of transient deformation events associated with the seismic cycle. While the D-value is commonly referred to as a measure of the degree of serration or roughness of grain boundaries, this study suggests a more complex interrelationship of the D-value, grain size, aspect ratio, and roundness. Future field work and experimental calibrations are encouraged to test our findings and refine strain-rate estimates derived from D-values.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105330"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150907","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 impact of multiscale cleat geometry on coal's petrophysical properties in the Lorraine basin, NE France: Implications for coalbed methane (CBM) production and CO2 storage","authors":"Ghislain de Joussineau","doi":"10.1016/j.jsg.2025.105346","DOIUrl":"10.1016/j.jsg.2025.105346","url":null,"abstract":"<div><div>The effectiveness of Coalbed Methane (CBM) production relies on the presence of connected, permeable cleat networks through which the desorbed gas could flow to the producing wells. The geometrical and dynamic (flow) properties of cleats and their spatial variability are essential for predictive economical scenarios, and reference databases are needed for such predictions. This paper contributes to this end by studying cleat networks in a series of coal beds and natural fracturing in the adjacent rock formations, in cores from three wells of the Lorraine basin.</div><div>Cleats occur at three scales in non-shaly coal: multi-centimeter- to decimeter-scale master cleats, multi-millimeter- to multi-centimeter-scale primary cleats and sub-millimeter- to millimeter-scale secondary cleats. The last two types are vertically controlled by the distribution of bed interfaces and local heterogeneities such as shale or ash lenses. Only master and primary cleats form connected permeable systems. The cleat geometrical parameters (intersection angle between face and butt cleats, cleat spacing, length and height) are consistent between the studied seams and all exhibit multifractal characteristics. This dataset is used to build representative Discrete Fracture Network (DFN) models of the cleat networks, calibrated to the permeability of the coal beds estimated by two pressure transient well tests. The built models show the key impact of multiscale cleat properties on coal's petrophysical properties and provide a reference source for robust flow simulations, that could be used in first approximation in any CBM context.</div><div>The good connectivity of cleat networks expected in the coal beds at a pluri-kilometer scale, the favorable gas content and saturation of the seams and the negligible fracturing detected in adjacent formations suggest a high CBM production potential in the studied area of the Lorraine basin. This area is also particularly favorable for Enhanced CBM (ECBM), where injected CO₂ replaces the desorbed methane, allowing at the same time the production of methane and lasting storage of CO₂.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105346"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151536","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":"Sustained strain localisation and coeval brittle-ductile deformation in an exhuming low-grade shear zone: Insights from the Saih Hatat Window (NE Oman)","authors":"A. Petroccia ,&nbsp;F. Giuntoli ,&nbsp;S. Pilia ,&nbsp;G. Viola ,&nbsp;P. Sternai ,&nbsp;I. Callegari","doi":"10.1016/j.jsg.2024.105328","DOIUrl":"10.1016/j.jsg.2024.105328","url":null,"abstract":"<div><div>Synkinematic phyllosilicates play a key role in controlling the rheology and the style of shear zones. At the same time, aqueous fluids released by metamorphic dehydration reactions may transiently increase pore pressure, triggering cyclic switching between brittle and ductile deformation. The Hulw Shear Zone in Oman is an exhumation-related shear zone wherein these processes can be studied. Its footwall is mostly composed of metapelites, with a modal enrichment in phyllosilicates matched by a progressive increase in their physical interconnectivity along its internal strain gradient. Similarly, marbles in the hanging wall evolve from mylonitic to ultramylonitic toward the core of the shear zone. The Hulw Shear Zone started from peak conditions of 300–350 °C and 0.9–1.2 GPa, followed by the main shearing event at 350–420 °C and 0.6–0.9 GPa and ended at 350 °C, 0.3–0.4 GPa between c. 76-75 Ma. Decompression-driven fluid-gain reactions facilitated the growth of phyllosilicates, which created a pervasive and interconnected network that promoted strain localisation, causing mechanical weakening as well as the potential compartmentalized fluid cells within the mylonitic foliation. Brittle structures formed due to aqueous fluid release by metamorphic dehydration reactions, transiently increasing pore pressure and triggering brittle failure, resulting in coeval mylonitic foliation and veins. Our findings support sustained shearing promoted by synkinematic K-rich white mica and pyrophyllite growth and cyclic switching between brittle and ductile deformation conditions. The studied structures might represent a record of deep episodic tremors and slow slip events during exhumation-related tectonics in the accretionary wedge of the Oman continental lithosphere.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105328"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150912","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":"Extensional perpendicular orthogonal quartz veins related to early Variscan Orogeny","authors":"Akbar Aydin Oglu Huseynov,&nbsp;Bernd Andeweg,&nbsp;H.J.L. van der Lubbe Jeroen","doi":"10.1016/j.jsg.2025.105344","DOIUrl":"10.1016/j.jsg.2025.105344","url":null,"abstract":"<div><div>Orthogonal sets of veins perpendicular to the bedding occur in fold-and-thrust belts; however, the timing of their formation remains unclear in relation to orogeny. This study aims to explain the development of perpendicular orthogonal vein sets from the iconic outcrops at northern Almograve in southwestern Portugal also known as “Chocolate-Tablet Structures”, which are affected the Variscan Orogeny. Determining whether these vein sets formed pre- and/or syn-folding of the main deformation (i.e., Variscan) requires multiple independent lines of evidence. Based on a limited number of outcrops, previous studies suggest that these veins are nearly vertical and horizontal to the Variscan folded strata. Here, we present a detailed structural study including drone photogrammetry (a few cm to m resolution) of stretches of the coastal section that are hard to reach. A nearly continuous and much longer stretch of the coast near Almograve and Zambujeira do Mar has been structurally analysed in this study. Field observations and stereographic projections of different sets of veins and the refolded host rock show a very consistent perpendicular relationship between two sets of veins, both perpendicular to the bedding as well. A genetic relation to the Variscan folding is tempting, but our new data question such previous interpretations. This study proposes that the perpendicular orthogonal vein sets are results of hydraulic fracturing and have formed during an early stage of the Variscan Orogeny, either through sedimentary loading (hydraulic fracturing) and simultaneous veining or through forebulge-foredeep stretching of the initial foreland basin.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105344"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151530","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":"Characteristics and origin of rift migration within the East China Sea Basin: Coupling relation with deep mantle dynamics","authors":"Yiming Liu ,&nbsp;Fang Hao ,&nbsp;Zhiping Wu ,&nbsp;Lijun Liu ,&nbsp;Qizhen Du","doi":"10.1016/j.jsg.2024.105334","DOIUrl":"10.1016/j.jsg.2024.105334","url":null,"abstract":"<div><div>Tectonic migration is a significant geological phenomenon in rift basins, offering valuable insights into regional tectonic processes. This study comprehensively investigates the Cenozoic tectonic deformation, sedimentation, and magmatism of the East China Sea Basin. Through detailed analysis, we systematically outline the tectonic migration pattern and dynamic mechanism were systematically outlined, contributing novel and insightful findings to the field. Our results reveal that the basin experienced three episodic syn-rift stages during the Cenozoic, with the rift center migrated progressively oceanward. Differential deformation within the syn-depositional fault system caused spatial and temporal variations in the internal basin architecture. Based on these observation and numerical modeling results, we propose a new model to elucidate the mechanism of tectonic migration in back-arc rift basin. The initial rifting began in the West subbasins during the late Mesozoic and Paleocene, driven by the delamination-style removal of the younger Izanagi slab. During the Eocene, the second rifting episode migrated to the East subbasins, triggered by landward mantle wind and the resulting basal traction after detachment of the subduction of the former Izanagi slab. In contrast, the back-arc extension in the Okinawa Trough primarily resulted from slab rollback of the Philippine Sea Plate since the late Miocene. We emphasize that rifting mechanism within the basin varied significantly across time and space, reflecting the intricate interplay between plate dynamics and mantle processes. This refined understanding of the Cenozoic evolution of East Asia enhances our knowledge of crust-mantle interactions and provides deeper insights into lithosphere deformation.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105334"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151528","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":"EBSD: Towards a better understanding of the role of deformation in the formation of schistose hypogene high-grade iron ore","authors":"Carlos Alberto Rosière ,&nbsp;Leonardo E. Lagoeiro ,&nbsp;Flavia Cristina Silveira Braga ,&nbsp;Ricardo Pagung","doi":"10.1016/j.jsg.2025.105337","DOIUrl":"10.1016/j.jsg.2025.105337","url":null,"abstract":"<div><div>The Cuité iron ore deposit is located in the Guanhães tectonic block at the eastern margin of the São Francisco craton, and consists of schistose to massive lenses of high-grade ore (&gt;50 wt% Fe) hosted in a tectonic sliver of iron formation and quartz mica schist of the Serra da Serpentina Group. The orebody is encased in a sheared domain of the Statherian Açucena granite of the Borrachudos Suite in association with quartz and pegmatite veins. The structure and mineralogy of the iron oxides distinguish four main textural types: a) the granular-textured hematite ore (GO), b) the schistose lamellar-granular or specularitic hematite ore (SO), c) the coarse-grained granular hematite ore (CGO) and (d) the massive magnetite ore (MO). The orebodies exhibit a ubiquitous continuous to domanial anastomosed schistosity defined by millimeter-sized elongated hematite plates (specularite), minor quartz, and shreds of kaolinite wrapping around granoblastic domains or laterally grading into coarse granular textured bodies. Magnetite occurs as single idioblastic grains or aggregates, usually oxidized to kenomagnetite/maghemite and martite, overgrowing the foliated fabric to form a massive textured ore. The sheared kaolinite is associated with the occurrence of anatectic pegmatite bodies and extensive hydrothermal alteration in the country rocks during the late collisional stages of the Brasiliano Orogeny which spanned from the Ediacaran to the early Cambrian periods. Textural EBSD (Electron Backscatter Diffraction) studies reveal a tectonic evolution during iron mineralization under ductile conditions, characterized by progressive (and overlapping) hematite crystal-plastic deformation, dynamic recrystallization, grain growth and the development of a typical CPO (crystallographic preferred orientations) pattern. The hematite [c]-axes form a maximum that coincides with the foliation pole extending along a girdle perpendicular to the stretching orientation. The textural modifications of the orebody developed during shearing and alteration by pegmatite fluids. The fingerprints of hydrothermal activity can be identified through the alteration of the country rocks, crystallization of minerals, and the mobilization of quartz by hot fluids, which is a major process of iron enrichment in shear zones.</div><div>The internal deformation of hematite contrasts with the observations of oriented strain-free fibrous specularite which is typically found precipitated in interstitial open spaces and strain shadow domains although in very small proportions in the Cuité deposit. This highlights the diversity of mechanisms involved in the formation of shear zone-hosted, schistose high-grade iron ore and brings new insights into its genetic interpretation.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105337"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151534","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":"Energy dissipation and fault dilation during intact-rock faulting","authors":"Ze'ev Reches ,&nbsp;Nadav Wetzler","doi":"10.1016/j.jsg.2024.105325","DOIUrl":"10.1016/j.jsg.2024.105325","url":null,"abstract":"<div><div>Rock-failure is usually analyzed by using the stress-based Coulomb criterion with the empirical parameters of cohesion and internal friction. We recently developed an alternative rock failure theory that is based on two conditions: rocks fail under a critical elastic energy threshold, and the applied elastic strain is accommodated by shear and dilation along the faults. We refer to this theory as Critical Energy Fault Failure (CEFF) and demonstrated its applicability to a range of rock failure experimental configurations from uniaxial to polyaxial loadings (Reches and Wetzler, 2022). In the present analysis, we utilized the energy-based CEFF theory to highlight further aspects of rock faulting: A. Evaluation of the dissipated energy associated with rock faulting which revealed that intact rock failure dissipates 35–55% of the available elastic energy. B. For a given normal stress, the CEFF calculated shear strength of a developing fault is smaller than the equivalent of the Coulomb shear strength. C. The predicted dilation associated with faulting of intact brittle rocks that is calculated by CEFF is supported by experimental observations. These three analyzed subjects provide important contributions for the understanding of rock failure processes.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105325"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151899","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":"Long-lived seismic instability of a large intraplate brittle shear zone revealed by distributed slip zones and paleoseismic frictional melt, eastern Botswana","authors":"Debbie Mfa ,&nbsp;Folarin Kolawole ,&nbsp;Boniface Kgosidintsi ,&nbsp;Rasheed Ajala ,&nbsp;Elisha Shemang","doi":"10.1016/j.jsg.2024.105324","DOIUrl":"10.1016/j.jsg.2024.105324","url":null,"abstract":"<div><div>In cratonic interiors, long-lived brittle shear zones host records of polyphase deformation, representing inherited structures that can host damaging earthquakes. Here, we explore the internal structure of the Kgomodikae Shear Zone (KSZ), signifying the western continuation of the ∼800-km long Precambrian Kgomodikae-Thabazimbi-Murchinson Fault System which extend along a region of widespread seismicity in southern Africa. At satellite-scale, the KSZ exhibits ENE-to-NE-striking subparallel zones of alternating high/low lineament clustering intensities, with peak-intensity zones that represent hydrologically-permeable principal brittle shear bands. In outcrops, we find pervasive occurrence of slip surfaces with dominant strike-slip paleo-slip vectors, and silica-cemented fault rocks hosting collocated quartz and pseudotachylyte vein clusters. Ground-based scanline fracture mapping reveals peak damage intensity in proximity of the satellite-mapped lineaments (localized high strain zones?), but with the pseudotachylytes occurring in both the peak- and flanking lower-intensity damage zones. The results suggest that the KSZ hosted paleoseismic ruptures that were not confined to its principal slip zones but may have nucleated on- or ruptured into off-fault splays; and that the NW-striking splays have greater reactivation tendency in contemporary stress field. In general, our findings highlight the nature of preexisting off-fault damage networks that accommodated earthquake rupture and propagation patterns in intraplate regions.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105324"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150878","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":"Cretaceous to Paleogene polyphase faulting and paleostress inversions in the Taoshan-Zhuguangshan uranium metallogenic belt, South China Block","authors":"Xianbing Xu ,&nbsp;Shutao Chen ,&nbsp;Meng Li ,&nbsp;Lei Liu ,&nbsp;Pulin Xu ,&nbsp;Yuan Xia ,&nbsp;Xiangsheng Tang","doi":"10.1016/j.jsg.2025.105340","DOIUrl":"10.1016/j.jsg.2025.105340","url":null,"abstract":"<div><div>Polyphase faulting and fault reactivation are liable to occur in hydrothermal ore fields. However, the relationship between fault reactivation and mineralization remains ambiguous, particularly in the NE-SW-striking Taoshan-Zhuguangshan uranium metallogenic belt, South China Block. Field investigations, core observations, and paleostress inversions were carried out for the Lujing and Gulonggang hydrothermal ore fields. Field investigations and previous exploration profiles show that the main ore-controlling structures are the NE-SW-striking high-angle faults. The maximum density of poles shows that these faults dip mainly to SE at high angles (70–88°). Kinematic indicators and plunges of slickenlines indicate that these NE-SW-striking high-angle faults have undergone polyphase faulting and fault reactivation, including left-lateral strike-slip shearing, normal dip-slip motion, and right-lateral strike-slip shearing. Dip angles of faults (n = 667) and quartz veinlets (n = 407) in sub-vertical drill cores vary mainly from 30 to 65°and 60 to 70°for the Lujing ore field and from 20 to 50°and 25 to 85°for the Gulonggang ore field, respectively. The difference suggests that hydrothermal fluids migrated preferentially along the high-angle secondary fractures of the main faults. Paleostress inversions of fault-slip data (n = 375) revealed six stages of paleostress regimes, including 1) the early to middle Early Cretaceous extensional regime (subhorizontal NW-SE-trending σ₃), 2) the late Early Cretaceous strike-slip regime (subhorizontal NNW-SSE-trending σ₁), 3) the latest Early Cretaceous to early Late Cretaceous extensional regime (subhorizontal NW-SE-trending σ₃), 4) the latest Cretaceous strike-slip regime (subhorizontal WNW-SEE-trending σ₁), 5) the early Eocene strike-slip regime (subhorizontal NE-SW-trending σ₁), and 6) the middle to late Eocene extensional regime (subhorizontal NE-SW-trending σ₃). Field investigations, core observations, and previous metallogenic ages show that uranium mineralization in the Taoshan-Zhuguangshan uranium metallogenic belt occurred mainly along NE-SW-striking high-angle normal faults under the latest Early Cretaceous to early Late Cretaceous NW-SE extension. These high-angle normal faults were not new-born but reactivated from left-lateral strike-slip faults formed in the late Early Cretaceous strike-slip regime. NE-SW-striking polyphase faulting and fault reactivation during the Cretaceous were triggered by the subduction of the Paleo-Pacific Plate underneath the South China Block.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105340"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151533","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}