The eastern and northeastern (NE) Tibet serves as a natural laboratory for unraveling the evolutionary history, uplift mechanisms, and outward growth of the Tibetan Plateau. In this study, we employed ambient noise tomography to construct a 3-D crustal SH-wave velocity (VSH) model extending to 60 km depth beneath eastern and NE Tibet, based on fundamental-mode Love-wave dispersion measurements (5–40 s) from seismic data recorded at 165 stations. We derived the radial anisotropy structure across the study region by integrating our VSH model with existing 3-D SV-wave (VSV) model. Through the combined analysis of VSH and radial anisotropy structures, we delineated the possible extent of mid-lower crustal ductile flow beneath NE Tibet. Cross-validation with previous magnetotelluric imaging results helped to exclude confounding effects from non-flow mechanisms (e.g., mineral lattice-preferred orientation) on the identification of ductile flow boundaries, thereby confirming the robustness of our delineation. Notably, our model reveals an isolated low-VSH anomaly beneath the Qilian orogen, which we interpret as resulting from the upwelling of mantle-derived material induced by the southward underthrusting of the Alxa block. To illustrate this, we propose a conceptual model to explain the genesis of this isolated low-VSH anomaly. These findings shed new light on the deep dynamic processes in eastern and NE Tibet.
{"title":"Love-wave tomography and radial anisotropy reveal crustal ductile flow extent and Alxa block underthrusting beneath eastern and northeastern Tibet","authors":"Tengfei Wu , Shuangxi Zhang , Chenyang Zou , Yujin Hua , Meng Chen","doi":"10.1016/j.jog.2026.102136","DOIUrl":"10.1016/j.jog.2026.102136","url":null,"abstract":"<div><div>The eastern and northeastern (NE) Tibet serves as a natural laboratory for unraveling the evolutionary history, uplift mechanisms, and outward growth of the Tibetan Plateau. In this study, we employed ambient noise tomography to construct a 3-D crustal SH-wave velocity (V<sub>SH</sub>) model extending to 60 km depth beneath eastern and NE Tibet, based on fundamental-mode Love-wave dispersion measurements (5–40 s) from seismic data recorded at 165 stations. We derived the radial anisotropy structure across the study region by integrating our V<sub>SH</sub> model with existing 3-D SV-wave (V<sub>SV</sub>) model. Through the combined analysis of V<sub>SH</sub> and radial anisotropy structures, we delineated the possible extent of mid-lower crustal ductile flow beneath NE Tibet. Cross-validation with previous magnetotelluric imaging results helped to exclude confounding effects from non-flow mechanisms (e.g., mineral lattice-preferred orientation) on the identification of ductile flow boundaries, thereby confirming the robustness of our delineation. Notably, our model reveals an isolated low-V<sub>SH</sub> anomaly beneath the Qilian orogen, which we interpret as resulting from the upwelling of mantle-derived material induced by the southward underthrusting of the Alxa block. To illustrate this, we propose a conceptual model to explain the genesis of this isolated low-V<sub>SH</sub> anomaly. These findings shed new light on the deep dynamic processes in eastern and NE Tibet.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"167 ","pages":"Article 102136"},"PeriodicalIF":2.1,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022758","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 : 2026-01-20DOI: 10.1016/j.jog.2026.102135
Jozef Madzin , Emő Márton , Dušan Plašienka , Gábor Imre
The studied part of the Central Western Carpathians represents a pile of thick- and thin-skinned thrust sheets of the Tatric, Fatric and the uppermost Hronic nappe systems, appearing today in the form of an arc. From the two lower units Mesozoic paleomagnetic results of limited number were published from the western and central segments of the nappe stack, while the eastern segment was well represented. Due to the distribution of the clockwise and counterclockwise rotated paleo-declinations the oroclinal bending was considered as a possible model to account for the shape of the Central Western Carpathians. The uppermost Hronic Unit, however, exhibits only clockwise rotations. The primary aim of this study was to collect new data from the western and central segments of the lower units to decide if they were bended before the emplacement of the Hronic Unit between 90 and 84 Ma. The new results come from 26 localities of Middle Triassic to Lower Cretaceous (mid-Eocene) formations. In the western sector and the outer zones of the central sector post-Middle Eocene remagnetizations related to long-lasting contractional deformation were recognized. They are interpreted as reflecting Miocene ∼50° counterclockwise rotation of the ALCAPA. Locally occurring counterclockwise rotated paleo-declinations elsewhere (earlier published data) may be related to pre-Late Cretaceous tectonic movements. With the addition of data from the present study, mainly from the central segment of the Central Western Carpathians, there are now 46 locality-mean paleomagnetic directions which must have acquired the magnetic signal during the Cretaceous Normal Polarity interval. They do not indicate significant difference in the general rotation between the central and eastern segments of the Tatric and Fatric units. These results constrain a post-84 Ma ∼70° clockwise rotation of the Central Western Carpathian nappe stack, taken into account the ∼50° counterclockwise regional Miocene rotation, which may indicate closing of the South Penninic-Vahic ocean.
喀尔巴阡山脉中西部的研究部分代表了一堆厚皮和薄皮的推覆体，这些推覆体属于塔特里克、法提里克和最上层的赫伦推覆体，今天以弧形的形式出现。在这两个较低的单元中，推覆体的西段和中段公布了有限数量的中生代古地磁结果，而东段则有较好的代表。由于沿顺时针和逆时针方向旋转的古赤纬分布，因此人们认为，斜向的弯曲可能是解释喀尔巴阡山脉中西部形状的一种模式。然而，最上面的时间单位只显示顺时针旋转。本研究的主要目的是收集下部单元的西部和中部部分的新数据，以确定它们在90至84 Ma之间的慢性单元就位之前是否弯曲。新的结果来自中三叠世至下白垩世（中始新世）地层的26个地点。在中始新世以后，在西段和中央段的外带发现了与长期收缩变形有关的再磁化现象。它们被解释为反映了中新世~ 50°的ALCAPA逆时针旋转。其他地方局部发生的逆时针旋转的古赤纬（早期发表的资料）可能与晚白垩世前的构造运动有关。加上本研究的资料（主要来自喀尔巴阡山脉中部），目前有46个地区平均古地磁方向在白垩纪正极性区间获得了磁信号。它们并没有显示出中部和东部的塔特里克和法特里克单位在一般旋转上的显著差异。这些结果约束了84 Ma ~ 70°后喀尔巴阡山脉中西部推覆体的顺时针旋转，考虑到~ 50°逆时针的中新世区域旋转，这可能表明南半岛-瓦希海的闭合。
{"title":"A large post-Santonian clockwise rotation of the Central Carpathian nappe stack constrained by new and published paleomagnetic results","authors":"Jozef Madzin , Emő Márton , Dušan Plašienka , Gábor Imre","doi":"10.1016/j.jog.2026.102135","DOIUrl":"10.1016/j.jog.2026.102135","url":null,"abstract":"<div><div>The studied part of the Central Western Carpathians represents a pile of thick- and thin-skinned thrust sheets of the Tatric, Fatric and the uppermost Hronic nappe systems, appearing today in the form of an arc. From the two lower units Mesozoic paleomagnetic results of limited number were published from the western and central segments of the nappe stack, while the eastern segment was well represented. Due to the distribution of the clockwise and counterclockwise rotated paleo-declinations the oroclinal bending was considered as a possible model to account for the shape of the Central Western Carpathians. The uppermost Hronic Unit, however, exhibits only clockwise rotations. The primary aim of this study was to collect new data from the western and central segments of the lower units to decide if they were bended before the emplacement of the Hronic Unit between 90 and 84 Ma. The new results come from 26 localities of Middle Triassic to Lower Cretaceous (mid-Eocene) formations. In the western sector and the outer zones of the central sector post-Middle Eocene remagnetizations related to long-lasting contractional deformation were recognized. They are interpreted as reflecting Miocene ∼50° counterclockwise rotation of the ALCAPA. Locally occurring counterclockwise rotated paleo-declinations elsewhere (earlier published data) may be related to pre-Late Cretaceous tectonic movements. With the addition of data from the present study, mainly from the central segment of the Central Western Carpathians, there are now 46 locality-mean paleomagnetic directions which must have acquired the magnetic signal during the Cretaceous Normal Polarity interval. They do not indicate significant difference in the general rotation between the central and eastern segments of the Tatric and Fatric units. These results constrain a post-84 Ma ∼70° clockwise rotation of the Central Western Carpathian nappe stack, taken into account the ∼50° counterclockwise regional Miocene rotation, which may indicate closing of the South Penninic-Vahic ocean.</div></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"167 ","pages":"Article 102135"},"PeriodicalIF":2.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022757","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}
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}
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