Pub Date : 2026-09-01DOI: 10.1016/j.gr.2026.09.001
Stephen F. Poropat,Christina A. Nielsen-Smith
{"title":"Comment on “Beneath the waves: extraordinary dietary insights from a dismembered ichthyosaur from the Lower Cretaceous” by","authors":"Stephen F. Poropat,Christina A. Nielsen-Smith","doi":"10.1016/j.gr.2026.09.001","DOIUrl":"https://doi.org/10.1016/j.gr.2026.09.001","url":null,"abstract":"","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"16 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-09-01DOI: 10.1016/j.gr.2026.09.002
Matt Andrew White,Joseph John Bevitt,Peter William Trusler
{"title":"Reply to Comment of Poropat & Nielsen-Smith 2026 “Beneath the waves: extraordinary dietary insights from a dismembered ichthyosaur from the Lower Cretaceous” by","authors":"Matt Andrew White,Joseph John Bevitt,Peter William Trusler","doi":"10.1016/j.gr.2026.09.002","DOIUrl":"https://doi.org/10.1016/j.gr.2026.09.002","url":null,"abstract":"","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"8 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-08-31DOI: 10.1016/j.gr.2026.08.008
Minling Wang, Xin Chen, Keith Priestley, Xiaofeng Liang
The South China continent records a complex history of lithospheric modification related to supercontinent cycles, Paleo-Pacific plate subduction, and intracontinental deformation linked to the growth of the Tibetan Plateau. However, the spatial pattern of lithospheric structure and the mechanisms responsible for Mesozoic–Cenozoic lithospheric reworking remain debated. Here we present a high-resolution shear-wave velocity model of the crust and upper mantle beneath South China derived from teleseismic two-plane-wave surface-wave tomography. By jointly inverting phase and amplitude measurements using finite-frequency sensitivity kernels, we resolve detailed lateral variations in lithospheric structure across the Yangtze and Cathaysia blocks. The results reveal pronounced east–west lithospheric heterogeneity. The western Yangtze Block, particularly beneath the Sichuan Basin, preserves a thick high-velocity lithospheric root (>200 km), consistent with the survival of an ancient cratonic keel. In contrast, the lithosphere beneath the Cathaysia Block and southeastern Yangtze is strongly thinned (∼60–100 km) and characterized by extensive low-velocity anomalies within the crust and uppermost mantle, indicating substantial lithospheric modification and magmatic reworking. Along the eastern margin of the Tibetan Plateau, prominent velocity gradients and mid–lower crustal low-velocity zones suggest distributed ductile deformation and possible channel flow within the crust. These results indicate that the present lithospheric architecture of South China reflects a two-stage geodynamic evolution involving Mesozoic lithospheric thinning driven by rollback of the Paleo-Pacific plate, followed by Cenozoic intracontinental deformation associated with outward growth of the Tibetan Plateau. Our findings provide new constraints on the mechanisms of lithospheric destruction, continental reworking, and tectonic coupling between eastern Asia and the Tibetan Plateau.
{"title":"Subduction-driven destruction and reconfiguration of the South China lithosphere: evidence from shear-wave velocity structure","authors":"Minling Wang, Xin Chen, Keith Priestley, Xiaofeng Liang","doi":"10.1016/j.gr.2026.08.008","DOIUrl":"https://doi.org/10.1016/j.gr.2026.08.008","url":null,"abstract":"The South China continent records a complex history of lithospheric modification related to supercontinent cycles, Paleo-Pacific plate subduction, and intracontinental deformation linked to the growth of the Tibetan Plateau. However, the spatial pattern of lithospheric structure and the mechanisms responsible for Mesozoic–Cenozoic lithospheric reworking remain debated. Here we present a high-resolution shear-wave velocity model of the crust and upper mantle beneath South China derived from teleseismic two-plane-wave surface-wave tomography. By jointly inverting phase and amplitude measurements using finite-frequency sensitivity kernels, we resolve detailed lateral variations in lithospheric structure across the Yangtze and Cathaysia blocks. The results reveal pronounced east–west lithospheric heterogeneity. The western Yangtze Block, particularly beneath the Sichuan Basin, preserves a thick high-velocity lithospheric root (>200 km), consistent with the survival of an ancient cratonic keel. In contrast, the lithosphere beneath the Cathaysia Block and southeastern Yangtze is strongly thinned (∼60–100 km) and characterized by extensive low-velocity anomalies within the crust and uppermost mantle, indicating substantial lithospheric modification and magmatic reworking. Along the eastern margin of the Tibetan Plateau, prominent velocity gradients and mid–lower crustal low-velocity zones suggest distributed ductile deformation and possible channel flow within the crust. These results indicate that the present lithospheric architecture of South China reflects a two-stage geodynamic evolution involving Mesozoic lithospheric thinning driven by rollback of the Paleo-Pacific plate, followed by Cenozoic intracontinental deformation associated with outward growth of the Tibetan Plateau. Our findings provide new constraints on the mechanisms of lithospheric destruction, continental reworking, and tectonic coupling between eastern Asia and the Tibetan Plateau.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"5 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148884618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-08-30DOI: 10.1016/j.gr.2026.08.002
Ben R. Mather, Maria Seton, Simon Williams, Joanne M. Whittaker, Rebecca Carey, Maëlis Arnould, Nicolas Coltice, Angus Rogers, Saskia Ruttor, Oliver Nebel, Christopher Gonzalez
Deep mantle plumes are upwellings from the Earth’s core-mantle boundary to its surface, generating most hotspot chains. The Lord Howe and Tasmantid seamount chains in the SW Pacific have remained 650–900 km apart for more than 40 million years — closer than mantle plumes typically coexist without coalescing, yet too geochemically akin to be readily explained by two unrelated sources. Using a 3D numerical model of mantle convection, we show that a single deep plume can be split into two long-lived branches by a stagnating slab in the upper mantle, producing parallel volcanic chains that track plate motion for tens of millions of years before reconverging into a single conduit. Plate reconstructions of the SW Pacific reveal a geometry consistent with this mechanism: a ribbon of relatively young slab material subducted at the d’Entrecasteaux subduction zone sits between two windows of low slab density, through which the Tasmantid and Lord Howe branches rise around the obstructing slab. A shared EM1 isotopic signature in both chains confirms the plume is sourced from the lower mantle, ruling out alternative mechanisms which invoke upper mantle plume sources to explain dual hotspot chains and fail to reproduce the observed combination of spacing, persistence, and geochemical affinity. The model further predicts that the Lord Howe branch is presently waning while the Tasmantid branch strengthens, foreshadowing the eventual return to a single conduit. Plume branching driven by slab geometry may explain other closely spaced plume tracks, including two that have been linked to the Yellowstone hotspot.
{"title":"Parallel volcanic chains generated by plume-slab interaction","authors":"Ben R. Mather, Maria Seton, Simon Williams, Joanne M. Whittaker, Rebecca Carey, Maëlis Arnould, Nicolas Coltice, Angus Rogers, Saskia Ruttor, Oliver Nebel, Christopher Gonzalez","doi":"10.1016/j.gr.2026.08.002","DOIUrl":"https://doi.org/10.1016/j.gr.2026.08.002","url":null,"abstract":"Deep mantle plumes are upwellings from the Earth’s core-mantle boundary to its surface, generating most hotspot chains. The Lord Howe and Tasmantid seamount chains in the SW Pacific have remained 650–900 km apart for more than 40 million years — closer than mantle plumes typically coexist without coalescing, yet too geochemically akin to be readily explained by two unrelated sources. Using a 3D numerical model of mantle convection, we show that a single deep plume can be split into two long-lived branches by a stagnating slab in the upper mantle, producing parallel volcanic chains that track plate motion for tens of millions of years before reconverging into a single conduit. Plate reconstructions of the SW Pacific reveal a geometry consistent with this mechanism: a ribbon of relatively young slab material subducted at the d’Entrecasteaux subduction zone sits between two windows of low slab density, through which the Tasmantid and Lord Howe branches rise around the obstructing slab. A shared EM1 isotopic signature in both chains confirms the plume is sourced from the lower mantle, ruling out alternative mechanisms which invoke upper mantle plume sources to explain dual hotspot chains and fail to reproduce the observed combination of spacing, persistence, and geochemical affinity. The model further predicts that the Lord Howe branch is presently waning while the Tasmantid branch strengthens, foreshadowing the eventual return to a single conduit. Plume branching driven by slab geometry may explain other closely spaced plume tracks, including two that have been linked to the Yellowstone hotspot.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"26 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148884594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Late Ordovician–Early Silurian global volcanism triggered a series of interrelated changes in the lithosphere, atmosphere, hydrosphere, and biosphere. The process by which environmental effects such as silicate weathering, biological pumping, and atmospheric temperature changes caused by volcanic material input into the surface system cause fluctuations in the global carbon cycle is unclear. Analysis of global changes in Hg content, Hg/TOC ratios, and δ13Ccarb values during the Ordovician-Silurian transition, combined with volcanism indicators such as the development frequency of bentonite layers, Hg content, Zr content, Hf content, and other indicators, as well as Cu content, Mo content, TOC content, δ13Ccarb values, Sr/Cu, Sr/Ba, U/Th, V/Cr, V/Ni, and other sedimentary environment indicators in the Yangtze region, revealed that severe environmental damage caused by large-scale volcanism prevents biological populations from immediately beginning to recover after volcanism ceases, resulting in a certain environmental recovery period. This delay can occasionally result in a lag in biological flourishing caused by volcanism. Volcanism releases large amounts of light carbon, increasing the amount of 12C input received by the marine environment and sequestered in organic matter, resulting in a negative shift in the δ13Ccarb value of shale. Volcanism increased the amount of CO2 in the atmospheric carbon pool, intensified continental weathering, triggered the biological pump effect in the marine environment, and led to a significant increase in CO2 sequestration and initial organic carbon production. Carbon sequestration removes excess CO2 from the atmosphere, leading to a balanced state in the surface environment between the increase in CO2 caused by degassing and the consumption of CO2 caused by carbon sequestration. The high input rate of volcanic material into the environment accelerated the sedimentation rate and circulation rate of material in the sedimentary environment, which in turn accelerated the circulation rates of elements such as C, N, O, and P. Simultaneously, it caused carbon isotope fractionation, accelerating the sequestration of more 12C in the organic-rich shales of the Wufeng–Longmaxi Formation.
{"title":"Carbon isotope and mercury anomalies evidence across the Ordovician-Silurian boundary of volcanism accelerating the global carbon cycle","authors":"Haoran Xie, Chao Liang, Jing Wu, Yingchang Cao, Yu Han, Jiahong Wang, Keyu Liu, Fang Hao","doi":"10.1016/j.gr.2026.08.005","DOIUrl":"https://doi.org/10.1016/j.gr.2026.08.005","url":null,"abstract":"Late Ordovician–Early Silurian global volcanism triggered a series of interrelated changes in the lithosphere, atmosphere, hydrosphere, and biosphere. The process by which environmental effects such as silicate weathering, biological pumping, and atmospheric temperature changes caused by volcanic material input into the surface system cause fluctuations in the global carbon cycle is unclear. Analysis of global changes in Hg content, Hg/TOC ratios, and δ<ce:sup loc=\"post\">13</ce:sup>C<ce:inf loc=\"post\">carb</ce:inf> values during the Ordovician-Silurian transition, combined with volcanism indicators such as the development frequency of bentonite layers, Hg content, Zr content, Hf content, and other indicators, as well as Cu content, Mo content, TOC content, δ<ce:sup loc=\"post\">13</ce:sup>C<ce:inf loc=\"post\">carb</ce:inf> values, Sr/Cu, Sr/Ba, U/Th, V/Cr, V/Ni, and other sedimentary environment indicators in the Yangtze region, revealed that severe environmental damage caused by large-scale volcanism prevents biological populations from immediately beginning to recover after volcanism ceases, resulting in a certain environmental recovery period. This delay can occasionally result in a lag in biological flourishing caused by volcanism. Volcanism releases large amounts of light carbon, increasing the amount of <ce:sup loc=\"post\">12</ce:sup>C input received by the marine environment and sequestered in organic matter, resulting in a negative shift in the δ<ce:sup loc=\"post\">13</ce:sup>C<ce:inf loc=\"post\">carb</ce:inf> value of shale. Volcanism increased the amount of CO<ce:inf loc=\"post\">2</ce:inf> in the atmospheric carbon pool, intensified continental weathering, triggered the biological pump effect in the marine environment, and led to a significant increase in CO<ce:inf loc=\"post\">2</ce:inf> sequestration and initial organic carbon production. Carbon sequestration removes excess CO<ce:inf loc=\"post\">2</ce:inf> from the atmosphere, leading to a balanced state in the surface environment between the increase in CO<ce:inf loc=\"post\">2</ce:inf> caused by degassing and the consumption of CO<ce:inf loc=\"post\">2</ce:inf> caused by carbon sequestration. The high input rate of volcanic material into the environment accelerated the sedimentation rate and circulation rate of material in the sedimentary environment, which in turn accelerated the circulation rates of elements such as C, N, O, and P. Simultaneously, it caused carbon isotope fractionation, accelerating the sequestration of more <ce:sup loc=\"post\">12</ce:sup>C in the organic-rich shales of the Wufeng–Longmaxi Formation.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"35 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148884591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-08-30DOI: 10.1016/j.gr.2026.08.006
Li Zhang, Jinsong Deng
China’s rapid economic expansion has intensified the carbon-emission burden of its energy system, with the East China Region’s thermal power sector emerging as a major contributor, and as the country advances toward carbon peaking and carbon neutrality targets, improving the accuracy and interpretability of carbon-emission forecasting has become increasingly important; in this context, machine learning and spatial analysis methods provide powerful tools for understanding emission dynamics and supporting evidence-based policy design. This study develops a three-stage analytical framework comprising indicator screening, scenario prediction, and policy interpretation to examine carbon-emission pathways in China’s thermal power sector, with the East China Region serving as the empirical case. The Optimal Parameter-based Geographical Detector (OPGD) is employed to identify key emission drivers and quantify their spatial explanatory power, followed by scenario-based forecasting using a machine learning model under multiple policy pathways. The results indicate significant divergence across scenarios, where the Environmental Protection and Energy Transition scenarios advance the carbon peak by approximately five and three years and reduce peak emissions by 106.48 and 73.86 Mt CO2, respectively, while the Economic Development Scenario delays the carbon peak by about three years and increases peak emissions by 92.74 Mt CO2 compared with the Baseline Scenario. These findings highlight the critical roles of renewable-energy substitution, industrial restructuring, and energy-efficiency improvement in shaping carbon-emission trajectories. The results provide indirect and policy-relevant insights related to SDG 7, SDG 12, and SDG 13 by illustrating how energy-transition pathways influence clean-energy adoption, resource efficiency, and climate-change mitigation in the East China Region’s thermal power sector, and the proposed framework offers a reproducible approach for carbon-emission assessment and scenario-based policy design, although its application to other regions and sectors requires further empirical validation.
{"title":"Integrating geographical detector and machine learning models for carbon emission scenarios in China’s thermal power sector","authors":"Li Zhang, Jinsong Deng","doi":"10.1016/j.gr.2026.08.006","DOIUrl":"https://doi.org/10.1016/j.gr.2026.08.006","url":null,"abstract":"China’s rapid economic expansion has intensified the carbon-emission burden of its energy system, with the East China Region’s thermal power sector emerging as a major contributor, and as the country advances toward carbon peaking and carbon neutrality targets, improving the accuracy and interpretability of carbon-emission forecasting has become increasingly important; in this context, machine learning and spatial analysis methods provide powerful tools for understanding emission dynamics and supporting evidence-based policy design. This study develops a three-stage analytical framework comprising indicator screening, scenario prediction, and policy interpretation to examine carbon-emission pathways in China’s thermal power sector, with the East China Region serving as the empirical case. The Optimal Parameter-based Geographical Detector (OPGD) is employed to identify key emission drivers and quantify their spatial explanatory power, followed by scenario-based forecasting using a machine learning model under multiple policy pathways. The results indicate significant divergence across scenarios, where the Environmental Protection and Energy Transition scenarios advance the carbon peak by approximately five and three years and reduce peak emissions by 106.48 and 73.86 Mt CO<ce:inf loc=\"post\">2</ce:inf>, respectively, while the Economic Development Scenario delays the carbon peak by about three years and increases peak emissions by 92.74 Mt CO<ce:inf loc=\"post\">2</ce:inf> compared with the Baseline Scenario. These findings highlight the critical roles of renewable-energy substitution, industrial restructuring, and energy-efficiency improvement in shaping carbon-emission trajectories. The results provide indirect and policy-relevant insights related to SDG 7, SDG 12, and SDG 13 by illustrating how energy-transition pathways influence clean-energy adoption, resource efficiency, and climate-change mitigation in the East China Region’s thermal power sector, and the proposed framework offers a reproducible approach for carbon-emission assessment and scenario-based policy design, although its application to other regions and sectors requires further empirical validation.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"16 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148884593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-08-29DOI: 10.1016/j.gr.2026.08.004
David A. Wood
Intraplate basaltic lavas at recently active volcanic centers (∼16 to 0 Ma) and erupted across 4000 km of Western Antarctica are divided into six regions with distinctive trace-element and radiogenic Nd-, Sr- and Pb-isotope ratios. Their compositions appear to be variably influenced in space by metasomatized mantle sources related to subduction events occurring prior to the breakup of Gondwanaland. Comparisons are made between 174 published analysis of regional and global average compositions for intraplate basalts. The West Antarctica Rift System (WARS) is divided based on Pb-isotopes and certain trace element distributions into two regions, east and west of longitude 168°, coinciding with a major tectonic boundary. Trace element and isotope cross plots and ternary diagrams, and profiles normalized to the world average intraplate basalt composition (WLD) distinguish compositional characteristics, and some anomalies in the six studied regions. The Marie Byrd Land (MBL) and WARS basalts display the widest compositional ranges that overlap to some extent. On average the WARS basalts show stronger compositional affinities with those of Australasian provenance. The MBL basalts show certain affinities with Australasian and Pacific provinces depending on the samples, elements and isotopes considered. The Peter Island (Pisl) basalts display distinctive ratios of trace elements (e.g., high Hf/Th, Zr/Nb, and Ce/Yb) and isotopes (e.g., high 207Pb/204Pb) ratios, that on average, show strong compositional affinities with those found in the Pacific region. The post-subduction basalts of the Antarctic Peninsula (Alexander Island (ALX) and Graham Land (GRH)) display distinctive compositions with several trace element and isotope characteristics close to those of Atlantic and Pacific intraplate basalts. ALX/GRH regions also display anomalies that are indicative of crustal petrogenetic influences, particularly associated with more recently subducted materials.
{"title":"Regional geochemical variations in recent intraplate basalts of Western Antarctica characterized by comparisons with global, Australasian, Atlantic and Pacific benchmarks","authors":"David A. Wood","doi":"10.1016/j.gr.2026.08.004","DOIUrl":"https://doi.org/10.1016/j.gr.2026.08.004","url":null,"abstract":"Intraplate basaltic lavas at recently active volcanic centers (∼16 to 0 Ma) and erupted across 4000 km of Western Antarctica are divided into six regions with distinctive trace-element and radiogenic Nd-, Sr- and Pb-isotope ratios. Their compositions appear to be variably influenced in space by metasomatized mantle sources related to subduction events occurring prior to the breakup of Gondwanaland. Comparisons are made between 174 published analysis of regional and global average compositions for intraplate basalts. The West Antarctica Rift System (WARS) is divided based on Pb-isotopes and certain trace element distributions into two regions, east and west of longitude 168°, coinciding with a major tectonic boundary. Trace element and isotope cross plots and ternary diagrams, and profiles normalized to the world average intraplate basalt composition (WLD) distinguish compositional characteristics, and some anomalies in the six studied regions. The Marie Byrd Land (MBL) and WARS basalts display the widest compositional ranges that overlap to some extent. On average the WARS basalts show stronger compositional affinities with those of Australasian provenance. The MBL basalts show certain affinities with Australasian and Pacific provinces depending on the samples, elements and isotopes considered. The Peter Island (Pisl) basalts display distinctive ratios of trace elements (e.g., high Hf/Th, Zr/Nb, and Ce/Yb) and isotopes (e.g., high <ce:sup loc=\"post\">207</ce:sup>Pb/<ce:sup loc=\"post\">204</ce:sup>Pb) ratios, that on average, show strong compositional affinities with those found in the Pacific region. The post-subduction basalts of the Antarctic Peninsula (Alexander Island (ALX) and Graham Land (GRH)) display distinctive compositions with several trace element and isotope characteristics close to those of Atlantic and Pacific intraplate basalts. ALX/GRH regions also display anomalies that are indicative of crustal petrogenetic influences, particularly associated with more recently subducted materials.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"46 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148884621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-08-23DOI: 10.1016/j.gr.2026.07.013
Zhenwu Liu, Huaichun Wu, Runjian Chu, Maoyang Zhou, Meinan Shi, Congcong Gai, Tianshui Yang, Yi Liu
Extrapolating the modern lunar recession rate into deep time is incompatible with the Moon’s ∼ 4.5-billion-year age, implying time-variable Earth–Moon tidal evolution. Existing models invoke different mechanisms for this variability, but remain insufficiently tested by continuous geological constraints. Here we compile 60 cyclostratigraphic records spanning 2,465–68 Ma, uniformly reprocess them with TimeOptB, synthesize Earth’s axial precession frequency estimates using Locally Adaptive Gaussian Process Regression, and convert them into probabilistic length-of-day and a corresponding tidal-dissipation trajectory. We find that relative tidal dissipation was generally reduced during intervals of supercontinent stability, but became higher and more variable during breakup–reorganization intervals. These results support a testable link between supercontinent-paced ocean-basin reorganization and long-term variations in oceanic tidal dissipation.
{"title":"Cyclostratigraphic constraints on supercontinent-modulated tidal dissipation over the past 2.5 billion years","authors":"Zhenwu Liu, Huaichun Wu, Runjian Chu, Maoyang Zhou, Meinan Shi, Congcong Gai, Tianshui Yang, Yi Liu","doi":"10.1016/j.gr.2026.07.013","DOIUrl":"https://doi.org/10.1016/j.gr.2026.07.013","url":null,"abstract":"Extrapolating the modern lunar recession rate into deep time is incompatible with the Moon’s ∼ 4.5-billion-year age, implying time-variable Earth–Moon tidal evolution. Existing models invoke different mechanisms for this variability, but remain insufficiently tested by continuous geological constraints. Here we compile 60 cyclostratigraphic records spanning 2,465–68 Ma, uniformly reprocess them with TimeOptB, synthesize Earth’s axial precession frequency estimates using Locally Adaptive Gaussian Process Regression, and convert them into probabilistic length-of-day and a corresponding tidal-dissipation trajectory. We find that relative tidal dissipation was generally reduced during intervals of supercontinent stability, but became higher and more variable during breakup–reorganization intervals. These results support a testable link between supercontinent-paced ocean-basin reorganization and long-term variations in oceanic tidal dissipation.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"25 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2026-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148884675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-06-01Epub Date: 2026-01-07DOI: 10.1016/j.gr.2025.12.007
Tianjiao Sang , Fuping Pei , Bingqian Ding , Kai Song , Pengyi Li , Guanwen Yu
The Duobaoshan island arc contains early Paleozoic association of adakitic high-Mg andesite, Nb-enriched basalt, and porphyry Cu deposits, concurrently indicating the ridge subduction in the eastern Xing’an Massif. This study further understands the unique island arc setting through the mantle metasomatism, oxygen fugacity and crustal thickness based on the zircon U–Pb geochronologic and Hf isotopic data from the early Paleozoic igneous and sedimentary rocks, as well as the whole–rock geochemical and Sr–Nd–Hf isotopic data from the igneous rocks in the Duobaoshan region, Xing’an Massif. The early Paleozoic igneous rocks are typical arc–type with low (La/Yb)N ratios (3.37–6.60), exhibiting highly depleted zircon Hf (εHf(t) = +12.44∼+16.50) and whole–rock Sr–Nd–Hf isotopic data ((87Sr/86Sr)i = 0.7036–0.7048; εNd(t) = +4.76∼+8.17; εHf(t) = +12.44∼+16.50), which were derived from the depleted mantle metasomatized mainly by slab fluid accompanied with the altered oceanic crust melt and pelagic sediment melt, and reflected the maturing process of the island arc. In addition, the Early Ordovician igneous rocks indicated the increase of mantle temperature and oxygen fugacity (ΔFMQ > 2) leading to the solubility of metallogenetic elements, and the thickening crust was also conducive to the mineralization. Then we further revealed the existence of a Precambrian basement of the Xing’an Massif based on the sedimentary rocks, the geochronology of which revealed the youngest ages of 504–478 Ma, yielding the age peaks at 771 Ma, ∼860 Ma, ∼950 Ma, and ∼1800 Ma ∼2500 Ma. In the meanwhile, the Hf isotopic data of 600–478 Ma detrital zircons show depleted to more enriched εHf(t) values (–10.22 to +12.70) and a proximal depositional traits, indicating that majority of the Neoproterozoic and early Paleozoic detrital zircons migrated from the Duobaoshan region, Xing’an Massif.
{"title":"Ridge subduction and island arc evolution in the Duobaoshan region during early Paleozoic: Insights from crustal thickness and lava geochemistry","authors":"Tianjiao Sang , Fuping Pei , Bingqian Ding , Kai Song , Pengyi Li , Guanwen Yu","doi":"10.1016/j.gr.2025.12.007","DOIUrl":"10.1016/j.gr.2025.12.007","url":null,"abstract":"<div><div>The Duobaoshan island arc contains early Paleozoic association of adakitic high-Mg andesite, Nb-enriched basalt, and porphyry Cu deposits, concurrently indicating the ridge subduction in the eastern Xing’an Massif. This study further understands the unique island arc setting through the mantle metasomatism, oxygen fugacity and crustal thickness based on the zircon U–Pb geochronologic and Hf isotopic data from the early Paleozoic igneous and sedimentary rocks, as well as the whole–rock geochemical and Sr–Nd–Hf isotopic data from the igneous rocks in the Duobaoshan region, Xing’an Massif. The early Paleozoic igneous rocks are typical arc–type with low (La/Yb)<sub>N</sub> ratios (3.37–6.60), exhibiting highly depleted zircon Hf (ε<sub>Hf</sub>(t) = +12.44∼+16.50) and whole–rock Sr–Nd–Hf isotopic data ((<sup>87</sup>Sr/<sup>86</sup>Sr)<sub>i</sub> = 0.7036–0.7048; ε<sub>Nd</sub>(t) = +4.76∼+8.17; ε<sub>Hf</sub>(t) = +12.44∼+16.50), which were derived from the depleted mantle metasomatized mainly by slab fluid accompanied with the altered oceanic crust melt and pelagic sediment melt, and reflected the maturing process of the island arc. In addition, the Early Ordovician igneous rocks indicated the increase of mantle temperature and oxygen fugacity (ΔFMQ > 2) leading to the solubility of metallogenetic elements, and the thickening crust was also conducive to the mineralization. Then we further revealed the existence of a Precambrian basement of the Xing’an Massif based on the sedimentary rocks, the geochronology of which revealed the youngest ages of 504–478 Ma, yielding the age peaks at 771 Ma, ∼860 Ma, ∼950 Ma, and ∼1800 Ma ∼2500 Ma. In the meanwhile, the Hf isotopic data of 600–478 Ma detrital zircons show depleted to more enriched ε<sub>Hf</sub>(t) values (–10.22 to +12.70) and a proximal depositional traits, indicating that majority of the Neoproterozoic and early Paleozoic detrital zircons migrated from the Duobaoshan region, Xing’an Massif.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"154 ","pages":"Pages 16-34"},"PeriodicalIF":7.2,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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