Long-term seismic activity along the Main Himalayan Thrust (MHT) raises significant concern for the Kumaun Himalaya. Using the most updated high-resolution integrated velocity field based on InSAR and GPS observations, the present study aims to provide spatial distribution of interseismic slip rates and fault geometry of MHT in the Kumaun region. Results through the Bayesian inversion framework reveal several key features of fault behavior: dip angles range between 28.2 and 34.2, with locking depths of approximately 6.70.7 km to 9.90.2 km, and fault depths around 12.90.4 km. The transition zone from locked to creeping portion displays slip rates of 1.70.6 mm/yr to 1.90.9 mm/yr. Estimated long-term slip rate of the MHT is 19.70.2 mm/yr, with a slip deficit rate of 18.0 mm/yr. The estimated moment deficit rate is approximately Nm/yr, which suggests the potential for a great earthquake of magnitude 8.3, assuming a seismic cycle of 500 years. Thus, the estimated slip deficit from the integrated velocity field highlights significant seismic hazards in the locked segments of the MHT. Overall, the findings provide crucial inputs for seismic risk assessment and mitigation efforts in the Kumaun Himalaya.
{"title":"Interseismic fault kinematics along the Kumaun Himalaya: Insights from InSAR and GPS based observations","authors":"Himanshu Verma , Sumanta Pasari , Sharmila Devi , Yogendra Sharma , Kuo-En Ching","doi":"10.1016/j.jog.2025.102133","DOIUrl":"10.1016/j.jog.2025.102133","url":null,"abstract":"<div><div>Long-term seismic activity along the Main Himalayan Thrust (MHT) raises significant concern for the Kumaun Himalaya. Using the most updated high-resolution integrated velocity field based on InSAR and GPS observations, the present study aims to provide spatial distribution of interseismic slip rates and fault geometry of MHT in the Kumaun region. Results through the Bayesian inversion framework reveal several key features of fault behavior: dip angles range between 28.2<span><math><mo>°</mo></math></span> and 34.2<span><math><mo>°</mo></math></span>, with locking depths of approximately 6.7<span><math><mo>±</mo></math></span>0.7 km to 9.9<span><math><mo>±</mo></math></span>0.2 km, and fault depths around 12.9<span><math><mo>±</mo></math></span>0.4 km. The transition zone from locked to creeping portion displays slip rates of 1.7<span><math><mo>±</mo></math></span>0.6 mm/yr to 1.9<span><math><mo>±</mo></math></span>0.9 mm/yr. Estimated long-term slip rate of the MHT is 19.7<span><math><mo>±</mo></math></span>0.2 mm/yr, with a slip deficit rate of 18.0 mm/yr. The estimated moment deficit rate is approximately <span><math><mrow><mn>5</mn><mo>.</mo><mn>40</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>18</mn></mrow></msup></mrow></math></span> Nm/yr, which suggests the potential for a great earthquake of magnitude <span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>w</mi></mrow></msub></math></span> 8.3, assuming a seismic cycle of <span><math><mo>∼</mo></math></span>500 years. Thus, the estimated slip deficit from the integrated velocity field highlights significant seismic hazards in the locked segments of the MHT. Overall, the findings provide crucial inputs for seismic risk assessment and mitigation efforts in the Kumaun Himalaya.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"167 ","pages":"Article 102133"},"PeriodicalIF":2.1,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.jog.2025.102134
Marjan Tourani, Veysel Isik
This study focuses on the eastern part of the Khazar Fault Zone, situated in N-NE Iran between the South Caspian Basin, Kopeh Dagh, and the Alborz Mountains, with the Gorgan Plain within it, as part of the seismically and tectonically active Alpine-Himalayan Mountain Belt. Additionally, widespread land subsidence is occurring in the Gorgan Plain, making the investigation of this region crucial. The aim of this research is to monitor surface deformation in the study area, assess its relationship with tectonic activity to minimize and mitigate potential hazards, and provide insights into the tectonic model of the region. We processed LiCSAR interferograms with LiCSBAS using Sentinel-1A images from January 2015 to March 2023 (descending track) and December 2023 (ascending track), calculating mean line-of-sight (LOS), vertical, and lateral velocities for the study area. Aqqala town and the eastern Gorgan region, situated on the footwall of the Khazar Fault Zone, experience the highest vertical deformation rates, reaching approximately −118.81 mm/yr and −146.20 mm/yr, respectively, over an 8-year period. Moreover, the left-lateral movement rates along the eastern section of the Khazar Fault Zone range from a mean of 3.79 mm/yr to a maximum of 8.46 mm/yr, with displacement decreasing from east to west. The results show that the eastern part of the Khazar Fault Zone is active with a left lateral component and indicate the presence of a likely NE-SW trending, north-dipping reverse/thrust fault beneath the Gorgan Plain, which is identified as the Aqqala Fault. It seems that the Aqqala Fault identified beneath the Gorgan Plain may be the source of significant seismic activity, as indicated by the earthquakes with magnitudes ≥ 5 Mw that occurred on October 7, 2004, and January 10, 2005. Our findings clearly show that the deformation in the region is controlled not only by anthropogenic factors, as mentioned in previous studies but also by tectonic activity. These findings demonstrate that the study area is highly active and poses a significant earthquake hazard, highlighting the urgent need for appropriate measures to be taken to address this concern.
{"title":"Ground deformation pattern controlled by tectonic activity in the eastern part of the Khazar Fault Zone, Northern Iran: Results from InSAR","authors":"Marjan Tourani, Veysel Isik","doi":"10.1016/j.jog.2025.102134","DOIUrl":"10.1016/j.jog.2025.102134","url":null,"abstract":"<div><div>This study focuses on the eastern part of the Khazar Fault Zone, situated in N-NE Iran between the South Caspian Basin, Kopeh Dagh, and the Alborz Mountains, with the Gorgan Plain within it, as part of the seismically and tectonically active Alpine-Himalayan Mountain Belt. Additionally, widespread land subsidence is occurring in the Gorgan Plain, making the investigation of this region crucial. The aim of this research is to monitor surface deformation in the study area, assess its relationship with tectonic activity to minimize and mitigate potential hazards, and provide insights into the tectonic model of the region. We processed LiCSAR interferograms with LiCSBAS using Sentinel-1A images from January 2015 to March 2023 (descending track) and December 2023 (ascending track), calculating mean line-of-sight (LOS), vertical, and lateral velocities for the study area. Aqqala town and the eastern Gorgan region, situated on the footwall of the Khazar Fault Zone, experience the highest vertical deformation rates, reaching approximately −118.81 mm/yr and −146.20 mm/yr, respectively, over an 8-year period. Moreover, the left-lateral movement rates along the eastern section of the Khazar Fault Zone range from a mean of 3.79 mm/yr to a maximum of 8.46 mm/yr, with displacement decreasing from east to west. The results show that the eastern part of the Khazar Fault Zone is active with a left lateral component and indicate the presence of a likely NE-SW trending, north-dipping reverse/thrust fault beneath the Gorgan Plain, which is identified as the Aqqala Fault. It seems that the Aqqala Fault identified beneath the Gorgan Plain may be the source of significant seismic activity, as indicated by the earthquakes with magnitudes ≥ 5 Mw that occurred on October 7, 2004, and January 10, 2005. Our findings clearly show that the deformation in the region is controlled not only by anthropogenic factors, as mentioned in previous studies but also by tectonic activity. These findings demonstrate that the study area is highly active and poses a significant earthquake hazard, highlighting the urgent need for appropriate measures to be taken to address this concern.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"167 ","pages":"Article 102134"},"PeriodicalIF":2.1,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-05DOI: 10.1016/j.jog.2025.102123
Gabriel de Almeida Moura Loureiro , Luana Moreira Florisbal , Vinicius Louro , Gabriel Martins Fontoura
Large Igneous Provinces (LIPs) are characterized by vast volumes of mafic lava flows and a complex network of intrusive rocks, including dike swarms, sill complexes, and layered intrusions that, together, compose the magmatic plumbing system. These magmatic events typically occur over short durations (1–5 Myr) and provide critical insights into magmatic processes and their interactions with surrounding rocks. Recent geological mapping in the Southern Brazilian Coastal region reveals a connected network of sills and dikes that represent the exposed plumbing system of high-Ti Urubici (Khumib) magma type of the Paraná Etendeka Magmatic Province (PEMP). To better constrain the extent of the intrusive bodies and investigate their link to the lava flows, we integrated field, petrographic, airborne magnetic, and whole-rock geochemical data. Magnetic field products corroborated with the field-observed interconnected intrusive bodies and highlighted the concentration of deep and shallow, large magma chambers within the area, as well as the connectivity between these reservoirs and vertical conduits. Geochemical analysis indicated that sills, dikes, and lava flows share a common origin linked to the high-Ti Urubici (Khumib) magma type that evolved through fractionation in shallow level magma chambers and partially assimilate melts from country rocks in the conduits. The results of our holistic geophysical and geological approach demonstrated that contamination and melting processes are intricately linked to the dynamics of the transcrustal high-Ti Urubici plumbing system and highlights the shallow emplacement of large volumes of mafic sills and the melting of the country rocks as a cause-effect relation.
{"title":"The Paraná Etendeka Magmatic Province high-Ti Urubici-Khumib plumbing system: Integrated hints from geophysical and geochemical data","authors":"Gabriel de Almeida Moura Loureiro , Luana Moreira Florisbal , Vinicius Louro , Gabriel Martins Fontoura","doi":"10.1016/j.jog.2025.102123","DOIUrl":"10.1016/j.jog.2025.102123","url":null,"abstract":"<div><div>Large Igneous Provinces (LIPs) are characterized by vast volumes of mafic lava flows and a complex network of intrusive rocks, including dike swarms, sill complexes, and layered intrusions that, together, compose the magmatic plumbing system. These magmatic events typically occur over short durations (1–5 Myr) and provide critical insights into magmatic processes and their interactions with surrounding rocks. Recent geological mapping in the Southern Brazilian Coastal region reveals a connected network of sills and dikes that represent the exposed plumbing system of high-Ti Urubici (Khumib) magma type of the Paraná Etendeka Magmatic Province (PEMP). To better constrain the extent of the intrusive bodies and investigate their link to the lava flows, we integrated field, petrographic, airborne magnetic, and whole-rock geochemical data. Magnetic field products corroborated with the field-observed interconnected intrusive bodies and highlighted the concentration of deep and shallow, large magma chambers within the area, as well as the connectivity between these reservoirs and vertical conduits. Geochemical analysis indicated that sills, dikes, and lava flows share a common origin linked to the high-Ti Urubici (Khumib) magma type that evolved through fractionation in shallow level magma chambers and partially assimilate melts from country rocks in the conduits. The results of our holistic geophysical and geological approach demonstrated that contamination and melting processes are intricately linked to the dynamics of the transcrustal high-Ti Urubici plumbing system and highlights the shallow emplacement of large volumes of mafic sills and the melting of the country rocks as a cause-effect relation.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"166 ","pages":"Article 102123"},"PeriodicalIF":2.1,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145529241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-30DOI: 10.1016/j.jog.2025.102122
Mohammad Bagherbandi , Hadi Amin , Robert Tenzer
Studying the Glacial Isostatic Adjustment (GIA) and land uplift modeling can be carried out utilizing geodetic observations (GNSS and precise leveling measurements), and geophysical methods. The Gravity Recovery and Climate Experiment (GRACE) satellite missions’ data has not been formally used in this context in Fennoscandia. If there is insufficient coverage of offshore or onshore data, existing estimates of GIA might be partially biased (by means of spatial pattern and magnitude), particularly over the Gulf of Bothnia where the land uplift rate reaches its maximum. To inspect this issue, we incorporated the GRACE data in estimates of the land uplift rate due to GIA. Despite satellite gravitational information having a low resolution (∼300 km) it can be used for this purpose because the GIA in Fennoscandia has a large-scale regional pattern. Our findings confirmed a bias in existing estimates. According to our results, the maximum land uplift rates reach 9.1 mm/year in the northern part of the Gulf of Bothnia, while previous estimates indicate that the maximum value is shifted westward towards land. Since GRACE data also comprises hydrological signals, we assessed its effect on the satellite gravitational information by applying different hydrological models. Our results ascertained that land uplift estimates in Fennoscandia were not significantly affected by long-term hydrological mass variations. According to our estimates over the period between 2003 and 2017, the hydrological loading effect was approximately 0.1 mm/year or less (in terms of the RMS differences when compared to the reference land uplift model). Hydrological signal variations (over the investigated period of two decades) were, therefore, dominated mainly by seasonal variations without the presence of secular trends. The results show that the land uplift model from GRACE has some discrepancies compared to existing models, so the main idea of this article is to combine land and satellite data. Therefore, we studied a combined land uplift model using GRACE and the latest land uplift model in Fennoscandia.
{"title":"GRACE-derived land uplift model in Fennoscandia: Assessing the impact of hydrological loading on land uplift rates and uncertainty","authors":"Mohammad Bagherbandi , Hadi Amin , Robert Tenzer","doi":"10.1016/j.jog.2025.102122","DOIUrl":"10.1016/j.jog.2025.102122","url":null,"abstract":"<div><div>Studying the Glacial Isostatic Adjustment (GIA) and land uplift modeling can be carried out utilizing geodetic observations (GNSS and precise leveling measurements), and geophysical methods. The Gravity Recovery and Climate Experiment (GRACE) satellite missions’ data has not been formally used in this context in Fennoscandia. If there is insufficient coverage of offshore or onshore data, existing estimates of GIA might be partially biased (by means of spatial pattern and magnitude), particularly over the Gulf of Bothnia where the land uplift rate reaches its maximum. To inspect this issue, we incorporated the GRACE data in estimates of the land uplift rate due to GIA. Despite satellite gravitational information having a low resolution (∼300 km) it can be used for this purpose because the GIA in Fennoscandia has a large-scale regional pattern. Our findings confirmed a bias in existing estimates. According to our results, the maximum land uplift rates reach 9.1 mm/year in the northern part of the Gulf of Bothnia, while previous estimates indicate that the maximum value is shifted westward towards land. Since GRACE data also comprises hydrological signals, we assessed its effect on the satellite gravitational information by applying different hydrological models. Our results ascertained that land uplift estimates in Fennoscandia were not significantly affected by long-term hydrological mass variations. According to our estimates over the period between 2003 and 2017, the hydrological loading effect was approximately 0.1 mm/year or less (in terms of the RMS differences when compared to the reference land uplift model). Hydrological signal variations (over the investigated period of two decades) were, therefore, dominated mainly by seasonal variations without the presence of secular trends. The results show that the land uplift model from GRACE has some discrepancies compared to existing models, so the main idea of this article is to combine land and satellite data. Therefore, we studied a combined land uplift model using GRACE and the latest land uplift model in Fennoscandia.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"166 ","pages":"Article 102122"},"PeriodicalIF":2.1,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1016/j.jog.2025.102112
Mohammed.S. Gumati , J. Redfern
The Kotla Graben remains a poorly investigated region. Understanding the architecture of the graben and adjacent basement highs through time is critical for resolving due to the impacts of transitional accelerated subsidence to thermal sagging and basin-bounding fault reactivation mechanisms that create such a graben. This study attempts to restore the Late Cretaceous-Middle Eocene geometry of the Central Kotla Graben, using a combination of well data from 47 boreholes and twenty-six 2D seismic reflection profiles, nine of which are selected to show examples of the new information on the present-day architecture of the deeply buried graben. This geological and geophysical integration has enabled many variables to be involved in backstripping and lithospheric stretching calculations. The shape of backstripped subsidence curves reveals four discrete tectonic (I–IV) phases of subsidence-uplift that are recognised with variable rates and separated by three different types of unconformities. The rifting initiated during the Cenomanian, and both highs were uplifted during the Santonian. The rifting peaked during the Palaeocene and was terminated by a thermal sagging phase during the Eocene. Seismic interpretation indicates that the acoustic basement is generally characterised by three main intra-basement reflection (IRP) packages, located within the Dahra Platform basement and referred to as the Dahra Shear Zone in this study. However, seismic analysis has also enabled the recognition of four different seismic facies units. These facies units are integrated with three recognised gamma-ray log trends to correlate lithological variations within the distinctive boundaries of the tectonic subsidence phases. The tectonic subsidence maps of the graben geometry indicate that during the syn- and post-rift phases, the depocentre of the Central Kotla Graben is located in the south. Two different techniques used to estimate the stretching factor (β): The subsidence-derived stretching revealed lithospheric stretching ranged from 1.0 to 1.5. Moreover, the fault-derived stretching across the Central Kotla Graben ranged from 1.5 to 2, suggesting that the maximum crustal stretching in the graben axis ranges from 50 % to 100 %. This discrepancy is described as “extension discrepancy”.
{"title":"Quantitative modelling of multiphase tectonic subsidence mechanism and lithospheric stretching controls on the evolution of the Central Kotla Graben, Sirt Basin, Libya","authors":"Mohammed.S. Gumati , J. Redfern","doi":"10.1016/j.jog.2025.102112","DOIUrl":"10.1016/j.jog.2025.102112","url":null,"abstract":"<div><div>The Kotla Graben remains a poorly investigated region. Understanding the architecture of the graben and adjacent basement highs through time is critical for resolving due to the impacts of transitional accelerated subsidence to thermal sagging and basin-bounding fault reactivation mechanisms that create such a graben. This study attempts to restore the Late Cretaceous-Middle Eocene geometry of the Central Kotla Graben, using a combination of well data from 47 boreholes and twenty-six 2D seismic reflection profiles, nine of which are selected to show examples of the new information on the present-day architecture of the deeply buried graben. This geological and geophysical integration has enabled many variables to be involved in backstripping and lithospheric stretching calculations. The shape of backstripped subsidence curves reveals four discrete tectonic (I–IV) phases of subsidence-uplift that are recognised with variable rates and separated by three different types of unconformities. The rifting initiated during the Cenomanian, and both highs were uplifted during the Santonian. The rifting peaked during the Palaeocene and was terminated by a thermal sagging phase during the Eocene. Seismic interpretation indicates that the acoustic basement is generally characterised by three main intra-basement reflection (IRP) packages, located within the Dahra Platform basement and referred to as the Dahra Shear Zone in this study. However, seismic analysis has also enabled the recognition of four different seismic facies units. These facies units are integrated with three recognised gamma-ray log trends to correlate lithological variations within the distinctive boundaries of the tectonic subsidence phases. The tectonic subsidence maps of the graben geometry indicate that during the syn- and post-rift phases, the depocentre of the Central Kotla Graben is located in the south. Two different techniques used to estimate the stretching factor (β): The subsidence-derived stretching revealed lithospheric stretching ranged from 1.0 to 1.5. Moreover, the fault-derived stretching across the Central Kotla Graben ranged from 1.5 to 2, suggesting that the maximum crustal stretching in the graben axis ranges from 50 % to 100 %. This discrepancy is described as “extension discrepancy”.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"165 ","pages":"Article 102112"},"PeriodicalIF":2.1,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144904410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magmatic activity during the Triassic-Jurassic transition coincided with the breakup of Pangea, marking a pivotal period in Western European tectonic evolution. However, this activity remains poorly documented in the External Western Alps. Dating the emplacement and alteration of Triassic magmatic rocks such as the spilites in the Alps has long been challenging due to the complex alteration history and the scarcity of suitable mineral phases. This study employs in situ U-Pb dating of carbonate to constrain the timing of hydrothermal alteration of spilites from the Pelvoux massif (France), offering a new temporal framework for these processes. Dolomite and calcite filling vesicles and veins in the spilites yield ages of 201 ± 15 Ma and 202 ± 47 Ma, respectively, consistent with the stratigraphic emplacement interval of these lavas during the Upper Triassic. Notably, the U-Pb system in dolomite has preserved hydrothermal conditions related to magmatic emplacement, without resetting during two subsequent geological events at temperatures approaching 300°C, emphasizing its reliability as a chronometer in this context. The obtained ages overlap with the temporal framework of the Central Atlantic Magmatic Province (CAMP) and geochemical signatures of the spilites correspond to medium/high-Ti transitional to alkaline basalts, comparable to continental basalts such as those of the CAMP. This suggests a shared tectono-magmatic context with mantle-derived magmatism. Furthermore, the spatial proximity of the studied spilites to lower crustal CAMP-related magmatism in the Internal Alps supports a potential genetic relationship, with magma ascent likely facilitated by inherited tectonic structures during the Upper Triassic extension and the opening of the Alpine Tethys. Hydrothermal alteration, marked by spilitization and carbonate precipitation, occurred under low- to moderate-temperature conditions (70–360°C), possibly driven by marine or continental-derived fluids. By providing the first absolute geochronological constraints on spilites in the External Western Alps, this study expands the recognized extent of CAMP. It underscores the utility of carbonates as reliable archives for unraveling hydrothermal and magmatic histories.
{"title":"In situ U–Pb dating of upper triassic magmatic flows (Spilite) in the External Western Alps (Pelvoux massif): A peripheral CAMP activity?","authors":"Dorian Bienveignant , Stéphane Schwartz , Yann Rolland , Matthias Bernet , Adrien Vezinet , Julien Léger , Maxime Bertauts , Martin Huraut , Carole Cordier , Thierry Dumont , Valérie Magnin , Mélanie Balvay , Antonin Bilau , Louise Boschetti , Jerome Nomade","doi":"10.1016/j.jog.2025.102113","DOIUrl":"10.1016/j.jog.2025.102113","url":null,"abstract":"<div><div>Magmatic activity during the Triassic-Jurassic transition coincided with the breakup of Pangea, marking a pivotal period in Western European tectonic evolution. However, this activity remains poorly documented in the External Western Alps. Dating the emplacement and alteration of Triassic magmatic rocks such as the spilites in the Alps has long been challenging due to the complex alteration history and the scarcity of suitable mineral phases. This study employs <em>in situ</em> U-Pb dating of carbonate to constrain the timing of hydrothermal alteration of spilites from the Pelvoux massif (France), offering a new temporal framework for these processes. Dolomite and calcite filling vesicles and veins in the spilites yield ages of 201 ± 15 Ma and 202 ± 47 Ma, respectively, consistent with the stratigraphic emplacement interval of these lavas during the Upper Triassic. Notably, the U-Pb system in dolomite has preserved hydrothermal conditions related to magmatic emplacement, without resetting during two subsequent geological events at temperatures approaching 300°C, emphasizing its reliability as a chronometer in this context. The obtained ages overlap with the temporal framework of the Central Atlantic Magmatic Province (CAMP) and geochemical signatures of the spilites correspond to medium/high-Ti transitional to alkaline basalts, comparable to continental basalts such as those of the CAMP. This suggests a shared tectono-magmatic context with mantle-derived magmatism. Furthermore, the spatial proximity of the studied spilites to lower crustal CAMP-related magmatism in the Internal Alps supports a potential genetic relationship, with magma ascent likely facilitated by inherited tectonic structures during the Upper Triassic extension and the opening of the Alpine Tethys. Hydrothermal alteration, marked by spilitization and carbonate precipitation, occurred under low- to moderate-temperature conditions (70–360°C), possibly driven by marine or continental-derived fluids. By providing the first absolute geochronological constraints on spilites in the External Western Alps, this study expands the recognized extent of CAMP. It underscores the utility of carbonates as reliable archives for unraveling hydrothermal and magmatic histories.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"165 ","pages":"Article 102113"},"PeriodicalIF":2.1,"publicationDate":"2025-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-05DOI: 10.1016/j.jog.2025.102111
Weicheng Gong , Yunqiang Sun
Post-seismic deformation following big earthquakes can help to better analyze the rheological structure of the lithosphere and geodynamic processes. The extensive and long-lasting post-seismic deformation following the 2008 Mw7.9 Wenchuan earthquake offers a unique opportunity. This study constructed a three-dimensional (3D) viscoelastic finite element model of the eastern Tibetan Plateau and calculate the post-seismic deformations of the 2008 Mw7.9 Wenchuan earthquake using four rheological models (Maxwell, Kelvin, Poynting-Thomson, and Burgers). The results show that among these four viscoelastic models, the Burgers model provides the best fit to the post-seismic deformation of the Wenchuan earthquake, but there is still a lack of early deformation near the co-seismic rupture zone. We then also analyze the impact of the afterslip on post-seismic deformation using three different afterslip models. The results show that afterslip plays a dominant role in the early post-seismic deformation, especially in the near field of the rupture zone. The optimal Burgers model combined with afterslip can better explain the post-seismic deformation of the Wenchuan earthquake. The optimal steady-state viscosities for the middle-lower crust and upper mantle of the Songpan-Ganzi block are 7 × 1018 Pa·s and 6 × 1019 Pa·s, respectively.
{"title":"Viscoelastic relaxation and afterslip following the 2008 Mw 7.9 Wenchuan earthquake","authors":"Weicheng Gong , Yunqiang Sun","doi":"10.1016/j.jog.2025.102111","DOIUrl":"10.1016/j.jog.2025.102111","url":null,"abstract":"<div><div>Post-seismic deformation following big earthquakes can help to better analyze the rheological structure of the lithosphere and geodynamic processes. The extensive and long-lasting post-seismic deformation following the 2008 <em>M</em><sub><em>w</em></sub>7.9 Wenchuan earthquake offers a unique opportunity. This study constructed a three-dimensional (3D) viscoelastic finite element model of the eastern Tibetan Plateau and calculate the post-seismic deformations of the 2008 <em>M</em><sub><em>w</em></sub>7.9 Wenchuan earthquake using four rheological models (Maxwell, Kelvin, Poynting-Thomson, and Burgers). The results show that among these four viscoelastic models, the Burgers model provides the best fit to the post-seismic deformation of the Wenchuan earthquake, but there is still a lack of early deformation near the co-seismic rupture zone. We then also analyze the impact of the afterslip on post-seismic deformation using three different afterslip models. The results show that afterslip plays a dominant role in the early post-seismic deformation, especially in the near field of the rupture zone. The optimal Burgers model combined with afterslip can better explain the post-seismic deformation of the Wenchuan earthquake. The optimal steady-state viscosities for the middle-lower crust and upper mantle of the Songpan-Ganzi block are 7 × 10<sup>18</sup> Pa·s and 6 × 10<sup>19</sup> Pa·s, respectively.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"165 ","pages":"Article 102111"},"PeriodicalIF":2.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-25DOI: 10.1016/j.jog.2025.102109
Shangxin Wu, Guiting Hou, Ruizhe Wang, Lunyan Wei
The East Asian marginal sea basins (EAMSB) are located at the junction between East Asia and the western Pacific plates, displaying a typical NE-trending en echelon pattern. Their formation is closely related to intense marginal extensional deformation since the Cenozoic. Owing to their intricate geological architecture and varied mechanisms of formation, these basins have emerged as a research hotspot in Earth science. However, due to limitations in geological observations and uncertainties in traditional tectonic models, the formation mechanisms of marginal sea basins remain highly controversial. This study integrates multi-source observational data and 3D spherical shell finite element method to systematically investigate the formation and evolution of the EAMSB, particularly focusing on their NE-trending en echelon pattern. The results indicate that the basin development in this region is primarily controlled by the far-field compressional stress generated by the India–Eurasia plate collision zone, as well as the extensional and radially downward shear stress imposed by the subduction of the Pacific and Philippine Sea plates. In addition, the episodic changes in regional tectonic stress play a key role in the formation of the EAMSB. The model delineates three principal evolutionary stages of the EAMSB: 1. In the early Eocene, the subduction of the Izanagi-Pacific ridge induced surface extension rather than compression along the eastern Asian margin due to shell bending. Meanwhile, under the combined influence of the India-Eurasia collision, rifting occurred along the East Asian margin. 2. In the late Eocene, the transition to subduction toward the Pacific Plate and the arrival of the Philippine Sea plate intensified boundary loads, triggering tectonic reversal and localised stress concentration. Simultaneously, as the India-Eurasia convergence zone entered the “hard collision” period, rifting was further facilitated. 3. From the Oligocene to early Miocene, the subducting plate became older and colder, with a steepening subduction angle, while the India–Eurasia collision continued. The rollback of the subducting plate induced eastward extension, which favored the development of eastward extensional deformation and led to the formation of a NE-trending en echelon pattern of the EAMSB.
{"title":"Geodynamics of East Asia marginal sea basins: Stress field modelling","authors":"Shangxin Wu, Guiting Hou, Ruizhe Wang, Lunyan Wei","doi":"10.1016/j.jog.2025.102109","DOIUrl":"10.1016/j.jog.2025.102109","url":null,"abstract":"<div><div>The East Asian marginal sea basins (EAMSB) are located at the junction between East Asia and the western Pacific plates, displaying a typical NE-trending en echelon pattern. Their formation is closely related to intense marginal extensional deformation since the Cenozoic. Owing to their intricate geological architecture and varied mechanisms of formation, these basins have emerged as a research hotspot in Earth science. However, due to limitations in geological observations and uncertainties in traditional tectonic models, the formation mechanisms of marginal sea basins remain highly controversial. This study integrates multi-source observational data and 3D spherical shell finite element method to systematically investigate the formation and evolution of the EAMSB, particularly focusing on their NE-trending en echelon pattern. The results indicate that the basin development in this region is primarily controlled by the far-field compressional stress generated by the India–Eurasia plate collision zone, as well as the extensional and radially downward shear stress imposed by the subduction of the Pacific and Philippine Sea plates. In addition, the episodic changes in regional tectonic stress play a key role in the formation of the EAMSB. The model delineates three principal evolutionary stages of the EAMSB: 1. In the early Eocene, the subduction of the Izanagi-Pacific ridge induced surface extension rather than compression along the eastern Asian margin due to shell bending. Meanwhile, under the combined influence of the India-Eurasia collision, rifting occurred along the East Asian margin. 2. In the late Eocene, the transition to subduction toward the Pacific Plate and the arrival of the Philippine Sea plate intensified boundary loads, triggering tectonic reversal and localised stress concentration. Simultaneously, as the India-Eurasia convergence zone entered the “hard collision” period, rifting was further facilitated. 3. From the Oligocene to early Miocene, the subducting plate became older and colder, with a steepening subduction angle, while the India–Eurasia collision continued. The rollback of the subducting plate induced eastward extension, which favored the development of eastward extensional deformation and led to the formation of a NE-trending en echelon pattern of the EAMSB.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"165 ","pages":"Article 102109"},"PeriodicalIF":2.1,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144703235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-22DOI: 10.1016/j.jog.2025.102110
Maria Di Rosa , Danis I. Filimon , John A. Groff , Michele Marroni
This paper presents results of the first attempt to date a normal fault system that affected the eastern side of the Alpine Corsica (France). The U–Pb method was employed to date carbonate material with associated As–Sb mineralization in the Matra Fault, a N–S striking normal fault located southward of the Castagniccia dome. This fault cuts the Alpine nappe stack, here consisting of two oceanic-derived tectonic units, including Middle–Late Jurassic metaophiolites and/or related Early Cretaceous metasediments. From the Late Cretaceous onward, these units were involved in subduction processes and record peak eclogite facies metamorphism. After a complex exhumation path to the surface, these units then experienced long-lasting extensional tectonics linked to the collapse of the Alpine wedge, followed by two rifting stages. The first rifting stage occurred in the Oligocene-Early Miocene and the second in the Middle Miocene to Quaternary that caused the opening of the Liguro–Provencal and the Tyrrhenian back-arc basins, respectively. The U–Pb dating of the Matra Fault yields a weighted age of 9.80 ± 0.37 Ma. Therefore, the Matra Fault developed, in association with syndeformational As–Sb–Fe sulfide mineralization, during the opening of the Tyrrhenian back-arc basin. This finding represents a significant advance in understanding the extensional tectonics in Corsica during the opening of the Tyrrhenian back-arc basin.
{"title":"U–Pb dating of carbonate gangue with associated As–Sb mineralization in the Matra Fault (Alpine Corsica, France): Constraints for the rifting stage in the Tyrrhenian Sea","authors":"Maria Di Rosa , Danis I. Filimon , John A. Groff , Michele Marroni","doi":"10.1016/j.jog.2025.102110","DOIUrl":"10.1016/j.jog.2025.102110","url":null,"abstract":"<div><div>This paper presents results of the first attempt to date a normal fault system that affected the eastern side of the Alpine Corsica (France). The U–Pb method was employed to date carbonate material with associated As–Sb mineralization in the Matra Fault, a N–S striking normal fault located southward of the Castagniccia dome. This fault cuts the Alpine nappe stack, here consisting of two oceanic-derived tectonic units, including Middle–Late Jurassic metaophiolites and/or related Early Cretaceous metasediments. From the Late Cretaceous onward, these units were involved in subduction processes and record peak eclogite facies metamorphism. After a complex exhumation path to the surface, these units then experienced long-lasting extensional tectonics linked to the collapse of the Alpine wedge, followed by two rifting stages. The first rifting stage occurred in the Oligocene-Early Miocene and the second in the Middle Miocene to Quaternary that caused the opening of the Liguro–Provencal and the Tyrrhenian back-arc basins, respectively. The U–Pb dating of the Matra Fault yields a weighted age of 9.80 ± 0.37 Ma. Therefore, the Matra Fault developed, in association with syndeformational As–Sb–Fe sulfide mineralization, during the opening of the Tyrrhenian back-arc basin. This finding represents a significant advance in understanding the extensional tectonics in Corsica during the opening of the Tyrrhenian back-arc basin.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"165 ","pages":"Article 102110"},"PeriodicalIF":2.1,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144703236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-10DOI: 10.1016/j.jog.2025.102101
William Cavazza , Thomas Gusmeo , Antoneta Seghedi , Ioan Munteanu , Silvia Cattò , Massimiliano Zattin , Lorenzo Gemignani , Irene Albino
The Northern Dobrogea Orogen is the onshore segment of the southeastern termination of the Trans-European Suture Zone, the most prominent tectonic boundary of Europe, and was affected by multiple superposed deformation episodes in the Paleozoic and Mesozoic. Contrary to the widely held notion that the North Dobrogea Orogen has experienced only very mild and local deformation since the mid-Cretaceous, our (U-Th)/He analyses on apatites from Precambrian, Paleozoic, and Triassic basement and cover rocks indicate a well-defined and widespread episode of cooling/exhumation starting in the late Miocene. The high level of data coherence and the fact that all tectonic units of North Dobrogea have been affected by such episode warrants a geological explanation of supra-regional extent. Miocene cooling/exhumation in Dobrogea can be placed in a larger framework of coeval intraplate compressional deformation affecting a wide area ranging from the Greater Caucasus to the Romanian sector of the Black Sea continental shelf. We propose that the structural inversion of inherited structures in the study area is a distant echo of the Arabia-Eurasia hard collision, which started in the mid-Miocene some 1200 km away to the southeast. Low-temperature thermochronologic data for the area north of the Bitlis-Pütürge suture zone of SE Anatolia indicate that the tectonic stresses related to the Arabian collision were transmitted efficiently in the Eurasian hinterland over large distances, focusing preferentially at rheological discontinuities located as far as the northern shores of the Black Sea. Late Miocene far-field deformation in the hinterland of the Arabia-Eurasia collision zone decreases gradually westward from the rapidly exhuming Greater Caucasus, located in front of the area of maximum indentation, through Crimea, to the Odessa shelf and Dobrogea, where deformation has been significantly less and therefore remained underestimated until now.
北多布罗格造山带是泛欧缝合带东南端的陆上段，是欧洲最突出的构造边界，在古生代和中生代受到多次叠加变形的影响。我们对前寒武纪、古生代和三叠纪基底和盖层磷灰石的(U-Th)/He分析表明，从中新世晚期开始，有一个明确而广泛的冷却/挖掘过程，与人们普遍认为的中白垩纪以来北多布罗格造山带只经历了非常轻微的局部变形的观点相反。高水平的数据一致性和北多布罗格亚所有构造单元都受到这种事件影响的事实，保证了超区域范围的地质解释。Dobrogea中新世冷却/挖掘可以放在一个更大的同时期板内挤压变形的框架中，影响从大高加索到黑海大陆架罗马尼亚部分的广泛地区。我们认为，研究区继承构造的构造反转是阿拉伯-欧亚大陆硬碰撞的一个遥远的回声，该碰撞始于中新世中期，东南约1200 km。安纳托利亚东南部bitlis - p ttrge缝合带以北地区的低温热年代学资料表明，与阿拉伯碰撞有关的构造应力在欧亚腹地长距离有效传递，优先集中在远至黑海北岸的流变不连续面。晚中新世阿拉伯-欧亚碰撞带腹地的远场变形逐渐向西减少，从位于最大压痕区前面的快速发掘的大高加索，穿过克里米亚，到敖德萨陆架和多布罗格亚，那里的变形明显较小，因此直到现在仍被低估。
{"title":"The North Dobrogea Orogen revisited: Late Miocene structural reactivation along the Trans-European Suture Zone","authors":"William Cavazza , Thomas Gusmeo , Antoneta Seghedi , Ioan Munteanu , Silvia Cattò , Massimiliano Zattin , Lorenzo Gemignani , Irene Albino","doi":"10.1016/j.jog.2025.102101","DOIUrl":"10.1016/j.jog.2025.102101","url":null,"abstract":"<div><div>The Northern Dobrogea Orogen is the onshore segment of the southeastern termination of the Trans-European Suture Zone, the most prominent tectonic boundary of Europe, and was affected by multiple superposed deformation episodes in the Paleozoic and Mesozoic. Contrary to the widely held notion that the North Dobrogea Orogen has experienced only very mild and local deformation since the mid-Cretaceous, our (U-Th)/He analyses on apatites from Precambrian, Paleozoic, and Triassic basement and cover rocks indicate a well-defined and widespread episode of cooling/exhumation starting in the late Miocene. The high level of data coherence and the fact that all tectonic units of North Dobrogea have been affected by such episode warrants a geological explanation of supra-regional extent. Miocene cooling/exhumation in Dobrogea can be placed in a larger framework of coeval intraplate compressional deformation affecting a wide area ranging from the Greater Caucasus to the Romanian sector of the Black Sea continental shelf. We propose that the structural inversion of inherited structures in the study area is a distant echo of the Arabia-Eurasia hard collision, which started in the mid-Miocene some 1200 km away to the southeast. Low-temperature thermochronologic data for the area north of the Bitlis-Pütürge suture zone of SE Anatolia indicate that the tectonic stresses related to the Arabian collision were transmitted efficiently in the Eurasian hinterland over large distances, focusing preferentially at rheological discontinuities located as far as the northern shores of the Black Sea. Late Miocene far-field deformation in the hinterland of the Arabia-Eurasia collision zone decreases gradually westward from the rapidly exhuming Greater Caucasus, located in front of the area of maximum indentation, through Crimea, to the Odessa shelf and Dobrogea, where deformation has been significantly less and therefore remained underestimated until now.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"164 ","pages":"Article 102101"},"PeriodicalIF":2.1,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143941515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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