{"title":"Corrigendum to “Delineation of crustal structure and composition in the Northwest Himalaya and adjoining Indo-Gangetic Plain” [Tectonophysics 904 (2025) 230717]","authors":"Amlanjyoti Das, Devajit Hazarika, Pritom Neog, Naresh Kumar, Dilip Kumar Yadav","doi":"10.1016/j.tecto.2026.231098","DOIUrl":"https://doi.org/10.1016/j.tecto.2026.231098","url":null,"abstract":"","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"41 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072705","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 : 2026-01-25DOI: 10.1016/j.tecto.2026.231096
Lulu Jia, Shi Chen, Linhai Wang, Hongyan Lu, Mian Liu, Weimin Xu, Zhitang He, Zhaohui Chen, Jiancheng Han
The 2015 Mw 7.8 Nepal earthquake occurred in the Himalayan tectonic belt, where the Indian Plate collides with the Tibetan Plateau. High-precision ground gravimetry can be used to detect transient deep mass changes before the earthquake but limited by sparse absolute gravity stations and the effects of complex surficial factors. In this study, we present new evidence from hybrid terrestrial gravity measurements, carried out in southern Tibet near the epicenter of the 2015 Nepal earthquake. Measurements from 9 relative and 3 absolute gravity stations are integrated using a novel adjustment method. The results confirm the significant regional gravity increase before the 2015 Nepal earthquake, with a rate of about or larger than 15 μGal/yr (1 μGal = 10−8 m/s2) at four stations during 2010–2013. We show that this gravity increase cannot be explained by vertical ground motion and/or local hydrological processes. Furthermore, due to inadequate spatial resolution, the observed gravity change could not be detected by the Gravity Recovery and Climate Experiment (GRACE) measurements. We suggest that the gravity increase could be caused by preseismic strain and mass (fluid) transfer in a broad seismogenic source region north of the Main Frontal Thrust. Absolute gravity observations show that the gravity increase stopped after the 2015 Nepal earthquake. Our results contribute to the exploration of possible precursors of large continental earthquakes and shed light on the potential mechanisms of large earthquakes in the Indo-Asian collision zone.
{"title":"New evidence from hybrid ground-based gravity observations of a regional gravity increase in southern Tibet before 2015","authors":"Lulu Jia, Shi Chen, Linhai Wang, Hongyan Lu, Mian Liu, Weimin Xu, Zhitang He, Zhaohui Chen, Jiancheng Han","doi":"10.1016/j.tecto.2026.231096","DOIUrl":"https://doi.org/10.1016/j.tecto.2026.231096","url":null,"abstract":"The 2015 Mw 7.8 Nepal earthquake occurred in the Himalayan tectonic belt, where the Indian Plate collides with the Tibetan Plateau. High-precision ground gravimetry can be used to detect transient deep mass changes before the earthquake but limited by sparse absolute gravity stations and the effects of complex surficial factors. In this study, we present new evidence from hybrid terrestrial gravity measurements, carried out in southern Tibet near the epicenter of the 2015 Nepal earthquake. Measurements from 9 relative and 3 absolute gravity stations are integrated using a novel adjustment method. The results confirm the significant regional gravity increase before the 2015 Nepal earthquake, with a rate of about or larger than 15 μGal/yr (1 μGal = 10<ce:sup loc=\"post\">−8</ce:sup> m/s<ce:sup loc=\"post\">2</ce:sup>) at four stations during 2010–2013. We show that this gravity increase cannot be explained by vertical ground motion and/or local hydrological processes. Furthermore, due to inadequate spatial resolution, the observed gravity change could not be detected by the Gravity Recovery and Climate Experiment (GRACE) measurements. We suggest that the gravity increase could be caused by preseismic strain and mass (fluid) transfer in a broad seismogenic source region north of the Main Frontal Thrust. Absolute gravity observations show that the gravity increase stopped after the 2015 Nepal earthquake. Our results contribute to the exploration of possible precursors of large continental earthquakes and shed light on the potential mechanisms of large earthquakes in the Indo-Asian collision zone.","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"30 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048133","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 : 2026-01-23DOI: 10.1016/j.tecto.2026.231100
Mauricio B. Haag , Scott Jess , Lindsay M. Schoenbohm , Eva Enkelmann , Taís F. Pinto
The Brazilian margin is one of the longest elevated passive margins (EPMs) in the world. However, both the timing of uplift and the long-term evolution of this EPM remain highly debated. In this study, we present a new suite of apatite (U-Th-Sm)/He (AHe) and fission track (AFT) ages for the southern end of the Brazilian EPM, in the Aparados da Serra plateau. Combined with literature data, our results reveal that mean AHe ages range from 43 to 112 Ma, while AFT ages range from 46 to 222 Ma. Thermal history models suggest monotonic exhumation rates in the Aparados da Serra, with post-rifting rates <50 m Myr−1 in the coastal plain and < 25 m Myr−1 in the volcanic plateau. Collectively, our results imply a total erosion of 2–4 km of material from the coast and < 2 km from the plateau since rifting ca. 120–100 Ma. AHe and AFT data indicate no detectable accelerated phase of exhumation during the Cenozoic, implying that recent uplift along the margin was either absent or minimal, and that the relief observed in the Aparados da Serra is likely a consequence of sustained rift topography. Based on the absence of major recent tectonic events, we argue that Cenozoic exhumation patterns in the Aparados da Serra were largely controlled by geomorphologic processes (e.g., differential erosion). Lastly, the equivalence between long (AFT and AHe) and short-term (catchment-averaged) erosion rates argues for sustained stability of the margin over geological timescales.
巴西的边际是世界上最长的被动边际（epm）之一。然而，无论是隆升的时间和这一EPM的长期演变仍然存在高度争议。在这项研究中，我们提出了一套新的磷灰石(U-Th-Sm)/He （AHe）和裂变径迹（AFT）年龄的巴西EPM南端，在Aparados da Serra高原。结合文献资料，我们的研究结果显示，AHe的平均年龄在43 ~ 112 Ma之间，AFT的平均年龄在46 ~ 222 Ma之间。热历史模型表明，Aparados da Serra的挖掘速率单调，裂陷后的速率在沿海平原为50 m Myr−1，在火山高原为25 m Myr−1。总的来说，我们的结果表明，自大约120-100 Ma的裂谷以来，来自海岸的物质被侵蚀了2 - 4公里，来自高原的物质被侵蚀了2公里。AHe和AFT数据表明，在新生代期间没有可检测到的加速挖掘阶段，这意味着最近沿边缘的隆起要么不存在，要么很小，并且在Aparados da Serra观察到的起伏可能是持续裂谷地形的结果。基于近期主要构造事件的缺失，我们认为，阿巴拉多斯达塞拉地区的新生代发掘模式在很大程度上受地貌过程（如差异侵蚀）的控制。最后，长期（AFT和AHe）和短期（流域平均）侵蚀速率之间的等价性证明了在地质时间尺度上边缘的持续稳定性。
{"title":"Long-lived topography along rifted margins: Insights from Aparados da Serra escarpment, Southeast Brazil","authors":"Mauricio B. Haag , Scott Jess , Lindsay M. Schoenbohm , Eva Enkelmann , Taís F. Pinto","doi":"10.1016/j.tecto.2026.231100","DOIUrl":"10.1016/j.tecto.2026.231100","url":null,"abstract":"<div><div>The Brazilian margin is one of the longest elevated passive margins (EPMs) in the world. However, both the timing of uplift and the long-term evolution of this EPM remain highly debated. In this study, we present a new suite of apatite (U-Th-Sm)/He (AHe) and fission track (AFT) ages for the southern end of the Brazilian EPM, in the Aparados da Serra plateau. Combined with literature data, our results reveal that mean AHe ages range from 43 to 112 Ma, while AFT ages range from 46 to 222 Ma. Thermal history models suggest monotonic exhumation rates in the Aparados da Serra, with post-rifting rates <50 m Myr<sup>−1</sup> in the coastal plain and < 25 m Myr<sup>−1</sup> in the volcanic plateau. Collectively, our results imply a total erosion of 2–4 km of material from the coast and < 2 km from the plateau since rifting ca. 120–100 Ma. AHe and AFT data indicate no detectable accelerated phase of exhumation during the Cenozoic, implying that recent uplift along the margin was either absent or minimal, and that the relief observed in the Aparados da Serra is likely a consequence of sustained rift topography. Based on the absence of major recent tectonic events, we argue that Cenozoic exhumation patterns in the Aparados da Serra were largely controlled by geomorphologic processes (e.g., differential erosion). Lastly, the equivalence between long (AFT and AHe) and short-term (catchment-averaged) erosion rates argues for sustained stability of the margin over geological timescales.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"925 ","pages":"Article 231100"},"PeriodicalIF":2.6,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033931","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 : 2026-01-22DOI: 10.1016/j.tecto.2026.231099
A. Replumaz, J.-P. Avouac, M.-L. Chevalier, Y. Klinger, C. Lasserre, P.H. Leloup, J. Liu-Zeng, G. Peltzer, J. van der Woerd, X. Xiwei
{"title":"Paul Tapponnier, deciphering the Earth's crust deformation history in the rocks and landscapes","authors":"A. Replumaz, J.-P. Avouac, M.-L. Chevalier, Y. Klinger, C. Lasserre, P.H. Leloup, J. Liu-Zeng, G. Peltzer, J. van der Woerd, X. Xiwei","doi":"10.1016/j.tecto.2026.231099","DOIUrl":"https://doi.org/10.1016/j.tecto.2026.231099","url":null,"abstract":"","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"66 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033598","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.tecto.2026.231094
Fernando Linsalata , Daniele Melini , Giorgio Spada
Current vertical movements in the Alpine region are the result of several interacting processes operating simultaneously. Among these, Glacial Isostatic Adjustment (GIA) plays a key role as a long-term global process driven by interactions between the cryosphere, solid Earth, and oceans in response to the melting of continental ice sheets. Although the effects of GIA in the Alpine region have been the subject of numerous studies, considerable uncertainties remain, in particular regarding the extent and chronology of the Würm Alpine Ice Sheet and the rheological properties of the mantle. In this study, we take advantage of recently updated deglaciation chronologies for Late-Pleistocene ice sheets to refine estimates of GIA-induced crustal deformation. We model postglacial rebound using the open-source TABOO code in combination with a high-resolution Alpine ice model, incorporating a mini-ensemble approach to account for uncertainties in the rheological model. We also calculate the deformation components in the study area using the VISR code, allowing a detailed assessment of the evolution of the deformation rate. Our modeling shows that GIA-related strain rates reached a maximum of 7.8 nstrain yr−1 at 25 kyr BP and progressively decreased throughout the Holocene, approaching present-day values of only 0.25 nstrain yr−1. This long-term decay indicates that the Alpine GIA signal is now largely exhausted, leaving only a weak residual contribution to the modern deformation field. The combined use of the TABOO code, the Alpine ice model, and the VISR code allows us to robustly quantify the evolution of the GIA-driven deformation rates and improve our understanding of post-glacial crustal dynamics and provide new constraints for future geodynamic models in the Alpine region.
目前高寒地区的垂直运动是几个相互作用过程同时作用的结果。其中，冰川均衡调整（GIA）作为一个长期的全球过程，在冰冻圈、固体地球和海洋之间的相互作用下起着关键作用，以响应大陆冰盖的融化。虽然GIA在高山地区的影响已经成为许多研究的主题，但仍然存在相当大的不确定性，特别是关于w rm高山冰盖的范围和年代学以及地幔的流变特性。在这项研究中，我们利用最近更新的晚更新世冰盖的消冰年表来改进gia引起的地壳变形的估计。我们使用开放源代码的TABOO代码结合高分辨率高山冰模型来模拟冰后反弹，并结合一个小集合方法来考虑流变模型中的不确定性。我们还使用VISR代码计算了研究区域的变形分量，从而可以详细评估变形率的演变。我们的模型显示，在25 kyr BP时，与gia相关的应变率达到了7.8 nstrain yr - 1的最大值，并在整个全新世中逐渐降低，接近于今天的0.25 nstrain yr - 1。这种长期的衰减表明阿尔卑斯GIA信号现在基本上已经耗尽，只留下微弱的残余贡献给现代变形场。结合使用TABOO代码、高山冰模型和VISR代码，使我们能够稳健地量化gia驱动的变形率的演变，提高我们对冰川后地壳动力学的理解，并为未来高山地区的地球动力学模型提供新的约束。
{"title":"Strain-rate evolution in the European Alps due to Glacial Isostatic Adjustment since the Last Glacial Maximum","authors":"Fernando Linsalata , Daniele Melini , Giorgio Spada","doi":"10.1016/j.tecto.2026.231094","DOIUrl":"10.1016/j.tecto.2026.231094","url":null,"abstract":"<div><div>Current vertical movements in the Alpine region are the result of several interacting processes operating simultaneously. Among these, Glacial Isostatic Adjustment (GIA) plays a key role as a long-term global process driven by interactions between the cryosphere, solid Earth, and oceans in response to the melting of continental ice sheets. Although the effects of GIA in the Alpine region have been the subject of numerous studies, considerable uncertainties remain, in particular regarding the extent and chronology of the Würm Alpine Ice Sheet and the rheological properties of the mantle. In this study, we take advantage of recently updated deglaciation chronologies for Late-Pleistocene ice sheets to refine estimates of GIA-induced crustal deformation. We model postglacial rebound using the open-source TABOO code in combination with a high-resolution Alpine ice model, incorporating a mini-ensemble approach to account for uncertainties in the rheological model. We also calculate the deformation components in the study area using the VISR code, allowing a detailed assessment of the evolution of the deformation rate. Our modeling shows that GIA-related strain rates reached a maximum of 7.8 nstrain yr<sup>−1</sup> at 25 kyr BP and progressively decreased throughout the Holocene, approaching present-day values of only 0.25 nstrain yr<sup>−1</sup>. This long-term decay indicates that the Alpine GIA signal is now largely exhausted, leaving only a weak residual contribution to the modern deformation field. The combined use of the TABOO code, the Alpine ice model, and the VISR code allows us to robustly quantify the evolution of the GIA-driven deformation rates and improve our understanding of post-glacial crustal dynamics and provide new constraints for future geodynamic models in the Alpine region.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"924 ","pages":"Article 231094"},"PeriodicalIF":2.6,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146015032","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 : 2026-01-17DOI: 10.1016/j.tecto.2026.231095
Valentina Espinoza , Juan Martin de Blas , Ingo L. Stotz , Andrés Tassara Oddo , Giampiero Iaffaldano
Recent high-resolution reconstructions of plate motions reveal a complex history of alternating slowdowns and speedups, often over short timescales (5 Myr). These rapid changes offer an opportunity to reassess the geodynamic processes driving tectonic plates, which we explore using an analytical inverse framework. This approach, however, inevitably yields non-unique solutions when inferring the forces behind a motion change. We partly address this issue by focusing on forces capable of varying at rates consistent with rapid kinematic shifts, though the specific driver behind any change may remain ambiguous. We adopt a two-step methodology, using torque changes as intermediaries linking force variations to reconstructed absolute plate-motion changes. First, we employ an established method that combines rheological constraints with torque-balance principles to estimate the torque variation required for a given kinematic change. Second, we estimate torque-change vectors arising from a broad range of geodynamic scenarios — acting at plate boundaries (e.g., slab pull, interplate friction) and at the base of plates (e.g., asthenospheric flow). We then apply directional statistics to quantify the similarity between the motion-based torque-change distribution and each simulated vector. This comparison allows us to identify the location and direction of the force-change vectors most likely to produce the motion change of study. We apply this method to the Neogene Nazca–South America convergence. Our kinematic analysis reveals rapid slowdowns in the absolute motion of both plates and a pronounced Nazca speedup at 10–12 Myr. Our geodynamic analysis indicates that the force variations driving the slowdowns are likely concentrated along the central segments of the shared convergent boundary. This result aligns with established hypotheses linking reduced convergence to Central Andes orogeny, thereby supporting our approach. Key advantages of this novel method include fast computation, explicit treatment of kinematic uncertainties, and broad applicability across tectonic settings.
{"title":"Plate motion drivers: Geodynamical framework and statistical appraisal for the case of the Neogene Nazca–South America convergence","authors":"Valentina Espinoza , Juan Martin de Blas , Ingo L. Stotz , Andrés Tassara Oddo , Giampiero Iaffaldano","doi":"10.1016/j.tecto.2026.231095","DOIUrl":"10.1016/j.tecto.2026.231095","url":null,"abstract":"<div><div>Recent high-resolution reconstructions of plate motions reveal a complex history of alternating slowdowns and speedups, often over short timescales (<span><math><mo><</mo></math></span>5 Myr). These rapid changes offer an opportunity to reassess the geodynamic processes driving tectonic plates, which we explore using an analytical inverse framework. This approach, however, inevitably yields non-unique solutions when inferring the forces behind a motion change. We partly address this issue by focusing on forces capable of varying at rates consistent with rapid kinematic shifts, though the specific driver behind any change may remain ambiguous. We adopt a two-step methodology, using torque changes as intermediaries linking force variations to reconstructed absolute plate-motion changes. First, we employ an established method that combines rheological constraints with torque-balance principles to estimate the torque variation required for a given kinematic change. Second, we estimate torque-change vectors arising from a broad range of geodynamic scenarios — acting at plate boundaries (e.g., slab pull, interplate friction) and at the base of plates (e.g., asthenospheric flow). We then apply directional statistics to quantify the similarity between the motion-based torque-change distribution and each simulated vector. This comparison allows us to identify the location and direction of the force-change vectors most likely to produce the motion change of study. We apply this method to the Neogene Nazca–South America convergence. Our kinematic analysis reveals rapid slowdowns in the absolute motion of both plates and a pronounced Nazca speedup at <span><math><mo>∼</mo></math></span>10–12 Myr. Our geodynamic analysis indicates that the force variations driving the slowdowns are likely concentrated along the central segments of the shared convergent boundary. This result aligns with established hypotheses linking reduced convergence to Central Andes orogeny, thereby supporting our approach. Key advantages of this novel method include fast computation, explicit treatment of kinematic uncertainties, and broad applicability across tectonic settings.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"924 ","pages":"Article 231095"},"PeriodicalIF":2.6,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995715","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 : 2026-01-16DOI: 10.1016/j.tecto.2026.231081
James W. Handschy , H. Tim Breitfeld , Bui Huy Hoang , Sarah W.M. George , William J. Schmidt , Juliane Hennig-Breitfeld , Michael B.W. Fyhn , Mette Olivarius , Nguyen Quang Tuan , Nguyen Thanh Tung , Do Van Linh , Dinh Quang Sang
Reconstructions of the Mesozoic Palaeo-Pacific are contentious due to significant overprinting during Cenozoic tectonic reorganization in the South China Sea. Here we document rapid (c. 35 myr) basin development, infilling, and pervasive folding of the ∼4 km thick Ban Don Group, an Early to Middle Jurassic basin succession in south-central Vietnam. We address the tectonic significance of the Ban Don Group using sedimentary petrography, detrital zircon geochronology, and structural constraints. Petrography of sedimentary rocks of the Ban Don Group shows mixed recycled orogen character and volcanic arc provenance. Detrital zircon U-Pb geochronology supports sourcing from the Indochina cover units and basement blocks, such as the Kontum Massif, and importantly identifies Jurassic contemporaneous volcanic arc sources. Structural constraints require a phase of pervasive shortening shortly after deposition of the Ban Don Group. Together, these datasets, along with regional tectonic constraints suggest that the Ban Don Group was deposited along a convergent margin, interpreted here as back-arc basin during Early-Middle Jurassic subduction of the Palaeo-Pacific Plate under Indochina. Extension in the Indochina Block was likely a result of a change in the Palaeo-Pacific subduction angle. The NW basin axis of the Ban Don Group is compatible with Early to Middle Jurassic NW-directed back-arc extension and associated NW-dipping subduction. The symmetric shape and orientation of the Ban Don Group salient strongly supports NW Palaeo-Pacific Plate motion in the Late Jurassic. Therefore, NW-dipping subduction of the Palaeo-Pacific Plate during the Jurassic was the driving force for Ban Don Basin subsidence and subsequent shortening.
{"title":"Basin development and provenance of the Lower to Middle Jurassic Ban Don Group in Indochina: Implications for the Jurassic Palaeo-Pacific subduction and drainage patterns","authors":"James W. Handschy , H. Tim Breitfeld , Bui Huy Hoang , Sarah W.M. George , William J. Schmidt , Juliane Hennig-Breitfeld , Michael B.W. Fyhn , Mette Olivarius , Nguyen Quang Tuan , Nguyen Thanh Tung , Do Van Linh , Dinh Quang Sang","doi":"10.1016/j.tecto.2026.231081","DOIUrl":"10.1016/j.tecto.2026.231081","url":null,"abstract":"<div><div>Reconstructions of the Mesozoic Palaeo-Pacific are contentious due to significant overprinting during Cenozoic tectonic reorganization in the South China Sea. Here we document rapid (c. 35 myr) basin development, infilling, and pervasive folding of the ∼4 km thick Ban Don Group, an Early to Middle Jurassic basin succession in south-central Vietnam. We address the tectonic significance of the Ban Don Group using sedimentary petrography, detrital zircon geochronology, and structural constraints. Petrography of sedimentary rocks of the Ban Don Group shows mixed recycled orogen character and volcanic arc provenance. Detrital zircon U-Pb geochronology supports sourcing from the Indochina cover units and basement blocks, such as the Kontum Massif, and importantly identifies Jurassic contemporaneous volcanic arc sources. Structural constraints require a phase of pervasive shortening shortly after deposition of the Ban Don Group. Together, these datasets, along with regional tectonic constraints suggest that the Ban Don Group was deposited along a convergent margin, interpreted here as back-arc basin during Early-Middle Jurassic subduction of the Palaeo-Pacific Plate under Indochina. Extension in the Indochina Block was likely a result of a change in the Palaeo-Pacific subduction angle. The NW basin axis of the Ban Don Group is compatible with Early to Middle Jurassic NW-directed back-arc extension and associated NW-dipping subduction. The symmetric shape and orientation of the Ban Don Group salient strongly supports NW Palaeo-Pacific Plate motion in the Late Jurassic. Therefore, NW-dipping subduction of the Palaeo-Pacific Plate during the Jurassic was the driving force for Ban Don Basin subsidence and subsequent shortening.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"925 ","pages":"Article 231081"},"PeriodicalIF":2.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995714","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 : 2026-01-16DOI: 10.1016/j.tecto.2026.231087
Rupak Banerjee , Chujie Liu , Stephen P. Grand , Eric Sandvol , Supriyo Mitra , Xiaofeng Liang , Shengji Wei
Southeast Asia hosts widespread Cenozoic intraplate volcanism that is not related to arc volcanism or to the opening of the South China Sea. In this study, we analyze the Southeast Asia portion of the recently developed full waveform seismic model, FWEA23, presenting its first comprehensive interpretation for this region. We observe slow shear velocity (Vs) anomalies (∼4–5%) extending to ∼660 km depth beneath Hainan island, resembling one or more plume-like upwellings. At depths <220 km, the slow anomaly extends westward to the Sagaing fault, eastward to the subduction zones, and northward to ∼26°N latitude. This lateral spreading explains the similarities in timing and geochemical signature between the Cenozoic intraplate volcanism and the Hainan volcano. We observe that the asthenospheric mantle (100–220 km) beneath Southeast Asia is ∼1.4% slower than the global average shear velocity of oceanic asthenosphere, implying that the mantle beneath Southeast Asia is warmer than the global adiabat. We also detect high Vs anomalies (up to ∼3%) in the mantle transition zone, resembling lithospheric slab fragments which trap heat and may have facilitated plume initiation through the slab gaps. Additionally, we present evidence from radial anisotropy (> + 3%), which reveals strong horizontal mantle flow (<200 km) away from the Hainan plume. This is consistent with lateral plume-head spreading, and associated lithospheric thinning across Southeast Asia. Our results provide new constraints on mantle dynamics of Southeast Asia by (i) highlighting the super-adiabatic character of the asthenosphere, (ii) a slab-induced mechanism for Hainan plume generation and (iii) the genesis of the intraplate volcanism.
{"title":"The Hainan plume and the origin of tectonic and magmatic activity in Southeast Asia","authors":"Rupak Banerjee , Chujie Liu , Stephen P. Grand , Eric Sandvol , Supriyo Mitra , Xiaofeng Liang , Shengji Wei","doi":"10.1016/j.tecto.2026.231087","DOIUrl":"10.1016/j.tecto.2026.231087","url":null,"abstract":"<div><div>Southeast Asia hosts widespread Cenozoic intraplate volcanism that is not related to arc volcanism or to the opening of the South China Sea. In this study, we analyze the Southeast Asia portion of the recently developed full waveform seismic model, FWEA23, presenting its first comprehensive interpretation for this region. We observe slow shear velocity (Vs) anomalies (∼4–5%) extending to ∼660 km depth beneath Hainan island, resembling one or more plume-like upwellings. At depths <220 km, the slow anomaly extends westward to the Sagaing fault, eastward to the subduction zones, and northward to ∼26°N latitude. This lateral spreading explains the similarities in timing and geochemical signature between the Cenozoic intraplate volcanism and the Hainan volcano. We observe that the asthenospheric mantle (100–220 km) beneath Southeast Asia is ∼1.4% slower than the global average shear velocity of oceanic asthenosphere, implying that the mantle beneath Southeast Asia is warmer than the global adiabat. We also detect high Vs anomalies (up to ∼3%) in the mantle transition zone, resembling lithospheric slab fragments which trap heat and may have facilitated plume initiation through the slab gaps. Additionally, we present evidence from radial anisotropy (> + 3%), which reveals strong horizontal mantle flow (<200 km) away from the Hainan plume. This is consistent with lateral plume-head spreading, and associated lithospheric thinning across Southeast Asia. Our results provide new constraints on mantle dynamics of Southeast Asia by (i) highlighting the super-adiabatic character of the asthenosphere, (ii) a slab-induced mechanism for Hainan plume generation and (iii) the genesis of the intraplate volcanism.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"924 ","pages":"Article 231087"},"PeriodicalIF":2.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995810","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 : 2026-01-16DOI: 10.1016/j.tecto.2026.231086
Leidy Carolina Sandoval-Espinel , Massimiliano Zattin , Mauricio A. Bermúdez , Cesar Witt , Jorge Iglesias , Maria Jose Hernández
The cooling and exhumation history of orogens along subduction systems provides unique constraints on regional tectonic evolution, reflecting the interplay between crustal deformation and plate convergence dynamics. Southern Ecuador lies within a transitional zone between the northern and central Andes, where contrasting tectonic histories have generated variations in inherited crustal architecture that influence how regional plate-boundary forcing is expressed in the upper plate. We present new apatite fission-track thermochronology data from seventeen plutonic rock samples across five crustal blocks in southern Ecuador: Western Cordillera, Eastern Cordillera, Intermontane basins, Celica-Lancones, and Amotape-Tahuin. Our results show that cooling ages are internally consistent within each block but differ across them, revealing a pattern of diachronous exhumation in most blocks. Some blocks instead record pronounced post-magmatic cooling, suggesting shallow pluton emplacement. Thermal history modeling, based on good-fit time–temperature paths indicates that regional exhumation initiated in the middle Eocene and persisted thereafter. The cooling trajectories group into three distinct, albeit partially overlapping, intervals: ∼45–38 Ma (middle - late Eocene), ∼40–30 Ma (late Eocene – early Oligocene), and ∼ 33–25 Ma (Oligocene). We interpret this protracted and spatially variable exhumation as reflecting changes in the boundary conditions of the subduction system, including a transition from oblique to more orthogonal convergence and increases in convergence rates during the Cenozoic. However, the observed spatial variability is more directly linked to the progressive re-activation of major fault systems and, locally, to magmatic activity.
{"title":"Cenozoic cooling and exhumation history of Southern Ecuador: The role of plate-boundary reorganizations and inboard tectonic conditions","authors":"Leidy Carolina Sandoval-Espinel , Massimiliano Zattin , Mauricio A. Bermúdez , Cesar Witt , Jorge Iglesias , Maria Jose Hernández","doi":"10.1016/j.tecto.2026.231086","DOIUrl":"10.1016/j.tecto.2026.231086","url":null,"abstract":"<div><div>The cooling and exhumation history of orogens along subduction systems provides unique constraints on regional tectonic evolution, reflecting the interplay between crustal deformation and plate convergence dynamics. Southern Ecuador lies within a transitional zone between the northern and central Andes, where contrasting tectonic histories have generated variations in inherited crustal architecture that influence how regional plate-boundary forcing is expressed in the upper plate. We present new apatite fission-track thermochronology data from seventeen plutonic rock samples across five crustal blocks in southern Ecuador: Western Cordillera, Eastern Cordillera, Intermontane basins, Celica-Lancones, and Amotape-Tahuin. Our results show that cooling ages are internally consistent within each block but differ across them, revealing a pattern of diachronous exhumation in most blocks. Some blocks instead record pronounced post-magmatic cooling, suggesting shallow pluton emplacement. Thermal history modeling, based on good-fit time–temperature paths indicates that regional exhumation initiated in the middle Eocene and persisted thereafter. The cooling trajectories group into three distinct, albeit partially overlapping, intervals: ∼45–38 Ma (middle - late Eocene), ∼40–30 Ma (late Eocene – early Oligocene), and ∼ 33–25 Ma (Oligocene). We interpret this protracted and spatially variable exhumation as reflecting changes in the boundary conditions of the subduction system, including a transition from oblique to more orthogonal convergence and increases in convergence rates during the Cenozoic. However, the observed spatial variability is more directly linked to the progressive re-activation of major fault systems and, locally, to magmatic activity.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"924 ","pages":"Article 231086"},"PeriodicalIF":2.6,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995716","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 : 2026-01-14DOI: 10.1016/j.tecto.2026.231080
Jin-Zhi Ma , Lingsen Meng , Hao Yin , Yiming Bai , Zekun Li , Yinshuang Ai
Situated in the southeastern Tibetan Plateau, the Tengchong volcanic region is characterized by elevated surface heat flow and serves as a natural laboratory for investigating fluid-induced seismicity within structurally complex fault systems. Using a dense 12-month broadband seismic dataset, we construct a high-resolution earthquake catalog and identify three distinct seismic swarms. These swarms extend beyond classical stepovers, involving diverse fault structures such as conjugate systems and sharply curved fault bends. All occur along pre-existing faults, with two located to the east and southeast of the main Tengchong volcanic zone, in previously unstudied areas. This indicates that both the spatial distribution and evolution of swarm activity are strongly influenced by fault geometry. The swarms' spatiotemporal behavior is well described by a pore-pressure diffusion process, as evidenced by distinct migration fronts and back fronts, and correlated fluctuations in background seismicity rates. Notably, the swarms exhibit localized stress heterogeneity, likely driven by variations in excess pore-fluid pressure. In Swarm 3, a three-phase migration pattern and rupture orientations nearly perpendicular to the main fault trace further suggest that fault geometry and local stress heterogeneity play a dominant role in rupture behavior. Additionally, the lower b-values observed in Swarm 3 imply higher differential stress and a greater potential for moderate-to-large earthquakes. These observations indicate that swarm evolution in the Tengchong region is governed by a combination of pore-pressure diffusion, inherited fault structures, and stress field heterogeneity. Both the diffusion and the heterogeneous stress conditions are likely linked to elevated excess pore-fluid pressure.
{"title":"Multiscale fault complexity and hydrothermal processes drive earthquake swarms in the Tengchong Volcanic Field, Southeastern Tibetan Plateau","authors":"Jin-Zhi Ma , Lingsen Meng , Hao Yin , Yiming Bai , Zekun Li , Yinshuang Ai","doi":"10.1016/j.tecto.2026.231080","DOIUrl":"10.1016/j.tecto.2026.231080","url":null,"abstract":"<div><div>Situated in the southeastern Tibetan Plateau, the Tengchong volcanic region is characterized by elevated surface heat flow and serves as a natural laboratory for investigating fluid-induced seismicity within structurally complex fault systems. Using a dense 12-month broadband seismic dataset, we construct a high-resolution earthquake catalog and identify three distinct seismic swarms. These swarms extend beyond classical stepovers, involving diverse fault structures such as conjugate systems and sharply curved fault bends. All occur along pre-existing faults, with two located to the east and southeast of the main Tengchong volcanic zone, in previously unstudied areas. This indicates that both the spatial distribution and evolution of swarm activity are strongly influenced by fault geometry. The swarms' spatiotemporal behavior is well described by a pore-pressure diffusion process, as evidenced by distinct migration fronts and back fronts, and correlated fluctuations in background seismicity rates. Notably, the swarms exhibit localized stress heterogeneity, likely driven by variations in excess pore-fluid pressure. In Swarm 3, a three-phase migration pattern and rupture orientations nearly perpendicular to the main fault trace further suggest that fault geometry and local stress heterogeneity play a dominant role in rupture behavior. Additionally, the lower b-values observed in Swarm 3 imply higher differential stress and a greater potential for moderate-to-large earthquakes. These observations indicate that swarm evolution in the Tengchong region is governed by a combination of pore-pressure diffusion, inherited fault structures, and stress field heterogeneity. Both the diffusion and the heterogeneous stress conditions are likely linked to elevated excess pore-fluid pressure.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"924 ","pages":"Article 231080"},"PeriodicalIF":2.6,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995718","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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