Pub Date : 2025-12-13DOI: 10.1016/j.gr.2025.11.019
Moujahed Al-Husseini , Ian C.F. Stewart
Three major NW-trending fault zones are assigned to the Ediacaran Najd fault system in the exposed Proterozoic Arabian Shield of Saudi Arabia. The total left-lateral displacement along the three zones has been previously interpreted as ca. 250 km, and to project from the southeastern edge of the Arabian Shield to beneath the Phanerozoic cover rocks in Saudi Arabia. In this article, aeromagnetic and geological maps, geochronological data, and structural evidence are integrated in a new Ediacaran tectonic framework of the Arabian Shield. It indicates only the middle branch of Najd system, the Ar Rika–Qazaz, constitutes a major strike-slip fault zone with a left-lateral displacement ranging between 55 and 80 km as estimated at several locations. The fault zone became active at ca. 620/615 Ma when it broke across the NS-oriented collisional front of the Amar orogeny and ceased to move by ca. 560 Ma, or possibly later.
{"title":"Aeromagnetic mapping and geodynamic reconstruction of the Ediacaran Najd fault system in the Arabian Shield","authors":"Moujahed Al-Husseini , Ian C.F. Stewart","doi":"10.1016/j.gr.2025.11.019","DOIUrl":"10.1016/j.gr.2025.11.019","url":null,"abstract":"<div><div>Three major NW-trending fault zones are assigned to the Ediacaran Najd fault system in the exposed Proterozoic Arabian Shield of Saudi Arabia. The total left-lateral displacement along the three zones has been previously interpreted as ca. 250 km, and to project from the southeastern edge of the Arabian Shield to beneath the Phanerozoic cover rocks in Saudi Arabia. In this article, aeromagnetic and geological maps, geochronological data, and structural evidence are integrated in a new Ediacaran tectonic framework of the Arabian Shield. It indicates only the middle branch of Najd system, the Ar Rika–Qazaz, constitutes a major strike-slip fault zone with a left-lateral displacement ranging between 55 and 80 km as estimated at several locations. The fault zone became active at ca. 620/615 Ma when it broke across the NS-oriented collisional front of the Amar orogeny and ceased to move by ca. 560 Ma, or possibly later.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"153 ","pages":"Pages 38-59"},"PeriodicalIF":7.2,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759819","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.018
Minglong Li , Liang Qiu , Can Chen , Keyuan Xu , Haiyan Tan , Deshun Zheng , Xilin Fang
Mercury (Hg) anomalies in sedimentary records have long served as proxies for historical volcanic activity. However, previous studies have focused mainly on large igneous provinces (LIPs) and mass extinctions. For identifying Hg anomalies, the residual Hg method is rigorous but requires extensive, high-quality data. The enrichment coefficient method (often normalized to total organic carbon (TOC)) is simpler but less accurate. Furthermore, due to insufficient constraints on long-term geological Hg background values, a unified threshold for defining anomalies remains lacking. The South China block (SCB), with relatively complete Cambrian to Jurassic sediments, holds records of numerous volcanic events. A total of 1010 carbonate samples, 749 clastic rock samples, and 272 black rock series samples from the Cambrian to Jurassic of the SCB were collected for Hg and TOC analyses. Using the interquartile range, we set the following background ranges for Hg concentrations: 6.0–22.4 ppb (carbonates) and 10.1–31.2 ppb (clastic rocks). When the TOC content was < 0.2 %, the Hg concentration was used to describe the anomaly threshold, with values of 33.4 ppb (carbonates) and 47.1 ppb (clastic rocks). When the TOC content was ≥ 0.2 %, the Hg/TOC ratio was used, with threshold values of 166.9 ppb/% for carbonates, 235.7 ppb/% for clastic rocks, and 258.5 ppb/% for black rock series. Six significant Hg anomaly signals were identified in the Cambrian to Jurassic strata of the study area. These signals correspond to the Late Ordovician, Late Devonian, end-Guadalupian, end-Permian, end-Triassic, and early Toarcian mass extinction events, potentially reflecting responses to large-scale volcanism associated with the Alborz, Vilyui, Emeishan, Siberian, Central Atlantic Magmatic Province (CAMP) and Karoo-Ferrar LIPs. The intensities of the Hg anomaly signals were influenced by the TOC, silicate and sulfide components and the distance between the sedimentary basin and erupting volcanoes.
{"title":"Mercury anomalies in Paleozoic–Mesozoic strata of South China: Implications for global volcanism and mass extinctions","authors":"Minglong Li , Liang Qiu , Can Chen , Keyuan Xu , Haiyan Tan , Deshun Zheng , Xilin Fang","doi":"10.1016/j.gr.2025.11.018","DOIUrl":"10.1016/j.gr.2025.11.018","url":null,"abstract":"<div><div>Mercury (Hg) anomalies in sedimentary records have long served as proxies for historical volcanic activity. However, previous studies have focused mainly on large igneous provinces (LIPs) and mass extinctions. For identifying Hg anomalies, the residual Hg method is rigorous but requires extensive, high-quality data. The enrichment coefficient method (often normalized to total organic carbon (TOC)) is simpler but less accurate. Furthermore, due to insufficient constraints on long-term geological Hg background values, a unified threshold for defining anomalies remains lacking. The South China block (SCB), with relatively complete Cambrian to Jurassic sediments, holds records of numerous volcanic events. A total of 1010 carbonate samples, 749 clastic rock samples, and 272 black rock series samples from the Cambrian to Jurassic of the SCB were collected for Hg and TOC analyses. Using the interquartile range, we set the following background ranges for Hg concentrations: 6.0–22.4 ppb (carbonates) and 10.1–31.2 ppb (clastic rocks). When the TOC content was < 0.2 %, the Hg concentration was used to describe the anomaly threshold, with values of 33.4 ppb (carbonates) and 47.1 ppb (clastic rocks). When the TOC content was ≥ 0.2 %, the Hg/TOC ratio was used, with threshold values of 166.9 ppb/% for carbonates, 235.7 ppb/% for clastic rocks, and 258.5 ppb/% for black rock series. Six significant Hg anomaly signals were identified in the Cambrian to Jurassic strata of the study area. These signals correspond to the Late Ordovician, Late Devonian, end-Guadalupian, end-Permian, end-Triassic, and early Toarcian mass extinction events, potentially reflecting responses to large-scale volcanism associated with the Alborz, Vilyui, Emeishan, Siberian, Central Atlantic Magmatic Province (CAMP) and Karoo-Ferrar LIPs. The intensities of the Hg anomaly signals were influenced by the TOC, silicate and sulfide components and the distance between the sedimentary basin and erupting volcanoes.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"153 ","pages":"Pages 1-16"},"PeriodicalIF":7.2,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759820","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.010
Mike J. Zawaski, James W. Hagadorn, Karen R. Whiteley, Mark Longman, Michael Yusas, Bonita L. Lahey, Alexandra A. Phillips, Thomas J. Algeo, Jun Shen, János Haas, Zhanhong Liu, Stephen J. Mojzsis
The Permian-Triassic Lykins Formation of Colorado contains thick redbed and carbonate successions preserving information about environmental conditions in western Pangea. We investigated outcrops and drillcores through these epicontinental sedimentary facies to assess their record of environmental change using several proxies: δ13Ccarb, δ18Ocarb, carbonate-associated-sulfate (δ34SCAS), magnetic susceptibility, and major and trace element concentrations. The B/Ga and Bxs values of the carbonate units in the Lykins Formation suggest they precipitated from a predominantly marine water source, as do most of the carbonate cements in the redbeds of the succession. A portion of the unit’s carbon and sulfur isotopic signatures parallel the global geochemical record. Stromatolites are abundant in all the laterally extensive carbonates of the unit, but body and trace fossils are very rare. This biota suggests an expanse that was challenging for plant and animal life. This hostile setting comports with the assembly of Pangea and a climatic shift to hotter and drier conditions. An ongoing question for the end-Permian mass extinction is how Siberian Traps volcanism modulated global environmental change. There is no reliable indicator of the stratigraphic location of the end-Permian mass extinction in the Lykins Formation. Biostratigraphic and geochemical proxies suggest the unit’s Poudre Member may have been deposited during the Permian-Triassic transition. To facilitate assessment of this new epicontinental Permian-Triassic record, we assembled a robust dataset of trace elements spanning Permian-Triassic boundary successions. We present a meta-analysis of these geochemical records to evaluate the sensitivity of trace elements as recorders of eruptions from this time. Few sections contain distinct elemental enrichments that could point to volcanic influences and those that do appear to have been downwind from the volcanic sources in Siberia.
{"title":"Tracing paleoenvironmental change across the Permian-Triassic transition in Colorado","authors":"Mike J. Zawaski, James W. Hagadorn, Karen R. Whiteley, Mark Longman, Michael Yusas, Bonita L. Lahey, Alexandra A. Phillips, Thomas J. Algeo, Jun Shen, János Haas, Zhanhong Liu, Stephen J. Mojzsis","doi":"10.1016/j.gr.2025.11.010","DOIUrl":"https://doi.org/10.1016/j.gr.2025.11.010","url":null,"abstract":"The Permian-Triassic Lykins Formation of Colorado contains thick redbed and carbonate successions preserving information about environmental conditions in western Pangea. We investigated outcrops and drillcores through these epicontinental sedimentary facies to assess their record of environmental change using several proxies: δ<ce:sup loc=\"post\">13</ce:sup>C<ce:inf loc=\"post\">carb</ce:inf>, δ<ce:sup loc=\"post\">18</ce:sup>O<ce:inf loc=\"post\">carb</ce:inf>, carbonate-associated-sulfate (δ<ce:sup loc=\"post\">34</ce:sup>S<ce:inf loc=\"post\">CAS</ce:inf>), magnetic susceptibility, and major and trace element concentrations. The B/Ga and B<ce:inf loc=\"post\">xs</ce:inf> values of the carbonate units in the Lykins Formation suggest they precipitated from a predominantly marine water source, as do most of the carbonate cements in the redbeds of the succession. A portion of the unit’s carbon and sulfur isotopic signatures parallel the global geochemical record. Stromatolites are abundant in all the laterally extensive carbonates of the unit, but body and trace fossils are very rare. This biota suggests an expanse that was challenging for plant and animal life. This hostile setting comports with the assembly of Pangea and a climatic shift to hotter and drier conditions. An ongoing question for the end-Permian mass extinction is how Siberian Traps volcanism modulated global environmental change. There is no reliable indicator of the stratigraphic location of the end-Permian mass extinction in the Lykins Formation. Biostratigraphic and geochemical proxies suggest the unit’s Poudre Member may have been deposited during the Permian-Triassic transition. To facilitate assessment of this new epicontinental Permian-Triassic record, we assembled a robust dataset of trace elements spanning Permian-Triassic boundary successions. We present a <ce:italic>meta</ce:italic>-analysis of these geochemical records to evaluate the sensitivity of trace elements as recorders of eruptions from this time. Few sections contain distinct elemental enrichments that could point to volcanic influences and those that do appear to have been downwind from the volcanic sources in Siberia.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"19 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759383","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.009
Zhongqi Hu, Bolin Zhang, Xianguo Lang, Jian Cao, Suping Yao
The Guadalupian (Middle Permian) marks a critical interval of climatic–oceanographic transition during the waning of the Late Palaeozoic Ice Age (LPIA), accompanied by widespread phosphorite deposits in South China and North America. However, the linkage between palaeoenvironmental change and phosphorite formation remains poorly understood. Here we investigate the Kuhfeng Formation phosphorite deposition of the Lower Yangtze region in South China through integrated petrographic, mineralogical, geochronologic, and geochemical analyses. Our results suggest that phosphorite accumulated mainly in continental margin slope settings during the early Guadalupian (∼272.95 – 270.6 Ma), with phosphorus (P) hosted primarily in apatite. Left-sloping REE patterns, high Y/Ho values, and strong Al–P2O5 anti-correlation point to a dominantly marine source of phosphorus with limited volcanic input. Palaeoenvironmental proxies reveal warm-humid climates, strong upwelling, high productivity, suboxic-anoxic conditions, and elevated salinity during deposition. Based on an integrated tectonic–climatic–oceanic analysis, we propose an upwelling-driven high productivity mechanism under deglacial warming and intensified tectonism, controlling phosphorite formation. Following the deglaciation of the LPIA, enhanced upwelling and volcanic activity supplied abundant P, stimulating high primary productivity and abundant organic matter formation. This process promoted the deposition and decomposition of P–rich organic matter near the sediment–water interface, releasing large amounts of P into pore waters and finally facilitating phosphate precipitation. Comparison with contemporaneous phosphorite deposits in North America further suggests a global upwelling-driven mechanism for Guadalupian phosphorite formation.
{"title":"Formation mechanism and global implications of the early Guadalupian phosphorite deposition along the eastern Palaeo-Tethys upwelling region (South China)","authors":"Zhongqi Hu, Bolin Zhang, Xianguo Lang, Jian Cao, Suping Yao","doi":"10.1016/j.gr.2025.11.009","DOIUrl":"https://doi.org/10.1016/j.gr.2025.11.009","url":null,"abstract":"The Guadalupian (Middle Permian) marks a critical interval of climatic–oceanographic transition during the waning of the Late Palaeozoic Ice Age (LPIA), accompanied by widespread phosphorite deposits in South China and North America. However, the linkage between palaeoenvironmental change and phosphorite formation remains poorly understood. Here we investigate the Kuhfeng Formation phosphorite deposition of the Lower Yangtze region in South China through integrated petrographic, mineralogical, geochronologic, and geochemical analyses. Our results suggest that phosphorite accumulated mainly in continental margin slope settings during the early Guadalupian (∼272.95 – 270.6 Ma), with phosphorus (P) hosted primarily in apatite. Left-sloping REE patterns, high Y/Ho values, and strong Al–P<ce:inf loc=\"post\">2</ce:inf>O<ce:inf loc=\"post\">5</ce:inf> anti-correlation point to a dominantly marine source of phosphorus with limited volcanic input. Palaeoenvironmental proxies reveal warm-humid climates, strong upwelling, high productivity, suboxic-anoxic conditions, and elevated salinity during deposition. Based on an integrated tectonic–climatic–oceanic analysis, we propose an upwelling-driven high productivity mechanism under deglacial warming and intensified tectonism, controlling phosphorite formation. Following the deglaciation of the LPIA, enhanced upwelling and volcanic activity supplied abundant P, stimulating high primary productivity and abundant organic matter formation. This process promoted the deposition and decomposition of P–rich organic matter near the sediment–water interface, releasing large amounts of P into pore waters and finally facilitating phosphate precipitation. Comparison with contemporaneous phosphorite deposits in North America further suggests a global upwelling-driven mechanism for Guadalupian phosphorite formation.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"47 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759384","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.017
Lianghui Guo , Yang Chen , Mei Han , Xueyang Bao
Sandwiched by the Siberia and North China cratons, the eastern Central Asian orogenic belt (CAOB) is one of the ideal natural laboratories for studying Phanerozoic continental crust accretion, reworking and metallogenesis in the world. The Solonker suture has been commonly considered as the final Paleo-Asian Ocean closure and is crucial for understanding the tectonic formation and evolution of the eastern CAOB, but its eastern extension remains unknown in Northeast China due to thick cover of the Songliao Basin and a general lack of key geological markers. In addition, the deep metallogenic background of the Mesozoic polymetallic ore deposits in this area is still unclear and is in urgent need of high-resolution structure of crust and upper mantle. In this paper, we assemble seismic data from both permanent and portable seismic stations around the eastern CAOB along with the complete Bouguer gravity anomalies data, and then simultaneously construct the high-resolution 3-D Vs and density models of crust and uppermost mantle around this area by the full-waveform ambient noise and gravity joint inversion. Our Vs and density models reveal approximately symmetric features of velocity and density structures across the eastern CAOB, and suggest that the northern boundary of the Solonker suture extends eastward along the Xilinhot–Tonglu–Baicheng–Daqing line and the southern one is along the Linxi–Changling–Jilin line. Moreover, our Vs model illustrates that the Mesozoic polymetallic ore deposits in the southern Great Xing’an Range are mostly located around the overlay of the upper-crustal high-Vs values and the transition zones of Moho depression and uplift on the west of the NNE-trending Moho gradient belt. The Moho transition zone likely represents the deep crustal boundaries facilitating the ascent of ore-forming magmas and fluids from mantle into upper crust, and the overlay indicates the prospect areas for the future polymetallic mineral exploration.
{"title":"Three-dimensional crustal velocity and density structures around the eastern Central Asian orogenic belt and implications for the Solonker suture and metallogenic background","authors":"Lianghui Guo , Yang Chen , Mei Han , Xueyang Bao","doi":"10.1016/j.gr.2025.11.017","DOIUrl":"10.1016/j.gr.2025.11.017","url":null,"abstract":"<div><div>Sandwiched by the Siberia and North China cratons, the eastern Central Asian orogenic belt (CAOB) is one of the ideal natural laboratories for studying Phanerozoic continental crust accretion, reworking and metallogenesis in the world. The Solonker suture has been commonly considered as the final Paleo-Asian Ocean closure and is crucial for understanding the tectonic formation and evolution of the eastern CAOB, but its eastern extension remains unknown in Northeast China due to thick cover of the Songliao Basin and a general lack of key geological markers. In addition, the deep metallogenic background of the Mesozoic polymetallic ore deposits in this area is still unclear and is in urgent need of high-resolution structure of crust and upper mantle. In this paper, we assemble seismic data from both permanent and portable seismic stations around the eastern CAOB along with the complete Bouguer gravity anomalies data, and then simultaneously construct the high-resolution 3-D <em>Vs</em> and density models of crust and uppermost mantle around this area by the full-waveform ambient noise and gravity joint inversion. Our <em>Vs</em> and density models reveal approximately symmetric features of velocity and density structures across the eastern CAOB, and suggest that the northern boundary of the Solonker suture extends eastward along the Xilinhot–Tonglu–Baicheng–Daqing line and the southern one is along the Linxi–Changling–Jilin line. Moreover, our <em>Vs</em> model illustrates that the Mesozoic polymetallic ore deposits in the southern Great Xing’an Range are mostly located around the overlay of the upper-crustal high-<em>Vs</em> values and the transition zones of Moho depression and uplift on the west of the NNE-trending Moho gradient belt. The Moho transition zone likely represents the deep crustal boundaries facilitating the ascent of ore-forming magmas and fluids from mantle into upper crust, and the overlay indicates the prospect areas for the future polymetallic mineral exploration.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"153 ","pages":"Pages 73-81"},"PeriodicalIF":7.2,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145731547","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.016
Dominik Keiner, Yousef Pourjamal, Siavash Khalili, Christian Breyer
Carbon dioxide removal is likely needed to reach the 1.5 °C and a more ambitious 1.0 °C target rebalancing the climate within planetary boundaries. Research on carbon dioxide removal is usually done either on global scale or for large regions. Dedicated energy system integration of a large-scale carbon dioxide removal industry sector into a national energy system is not yet state-of-the-art. This study closes this research gap for the case of Iceland, one of the most promising countries in the world to act as a carbon dioxide removal hub due to its geologically favourable conditions for in-situ mineralisation, and abundance of renewable energy sources including geothermal energy. Incorporating a novel method to represent the legacy transition cost in an overnight system transition model, several scenarios are applied varying the availability of geothermal energy and carbon dioxide removal service contribution to global demand for ambitious climate targets. The results indicate the requirement of alternative renewable energy sources beyond hydropower and geothermal energy, while large-scale carbon dioxide removal is possible. Renewable power generation capacities are required to significantly increase; onshore wind power, solar photovoltaics, and wave power are identified as additional pillars to supply the energy required. Instead of energy supply, the availability of workforce is identified as the main limitation, and 1 GtCO2/a seems a realistic upper bound for carbon dioxide removal in Iceland. The gross domestic product per capita could be doubled by 2070, turning Iceland into one of the richest countries in the world and the ‘El Dorado’ of carbon dioxide removal.
{"title":"Seeking El Dorado: Iceland’s carbon dioxide removal service opportunities to meet global demand and a new lens on overnight transition cost","authors":"Dominik Keiner, Yousef Pourjamal, Siavash Khalili, Christian Breyer","doi":"10.1016/j.gr.2025.11.016","DOIUrl":"https://doi.org/10.1016/j.gr.2025.11.016","url":null,"abstract":"Carbon dioxide removal is likely needed to reach the 1.5 °C and a more ambitious 1.0 °C target rebalancing the climate within planetary boundaries. Research on carbon dioxide removal is usually done either on global scale or for large regions. Dedicated energy system integration of a large-scale carbon dioxide removal industry sector into a national energy system is not yet state-of-the-art. This study closes this research gap for the case of Iceland, one of the most promising countries in the world to act as a carbon dioxide removal hub due to its geologically favourable conditions for in-situ mineralisation, and abundance of renewable energy sources including geothermal energy. Incorporating a novel method to represent the legacy transition cost in an overnight system transition model, several scenarios are applied varying the availability of geothermal energy and carbon dioxide removal service contribution to global demand for ambitious climate targets. The results indicate the requirement of alternative renewable energy sources beyond hydropower and geothermal energy, while large-scale carbon dioxide removal is possible. Renewable power generation capacities are required to significantly increase; onshore wind power, solar photovoltaics, and wave power are identified as additional pillars to supply the energy required. Instead of energy supply, the availability of workforce is identified as the main limitation, and 1 GtCO<ce:inf loc=\"post\">2</ce:inf>/a seems a realistic upper bound for carbon dioxide removal in Iceland. The gross domestic product per capita could be doubled by 2070, turning Iceland into one of the richest countries in the world and the ‘El Dorado’ of carbon dioxide removal.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"1 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759821","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.014
Xinlin Zhao, Yuan Zhong, Ping Li
Rock permeability, as a significant parameter, plays a crucial role in research related to geological exploration, reservoir resource development, and the movement and distribution of subsurface fluids. Despite significant advancements in artificial intelligence technology for rock analysis in recent years, challenges remain in terms of prediction accuracy, computational complexity, and resource dependency. To address these issues, this paper proposes a superpixel-based graph neural network (SP-GNN) method to achieve rock permeability prediction. Specifically, the flow space of the rock medium is superpixelized to construct graph data. Based on the superpixel graph data, a graph neural network designed to learn multi-level cascading features is developed, while also implementing an algorithm to extract neighborhood spatial features that contain sequential relationships. A temporal pooling strategy is proposed to perform collaborative learning of the cascading features and neighborhood spatial features of graph data from a temporal perspective, in order to obtain hierarchical global features of dynamic nodes. Finally, the global features of the graph are input into the downstream tasks to achieve accurate prediction of permeability. Experimental results show that the SP-GNN significantly outperforms various existing benchmark schemes for permeability prediction across seven comprehensive performance metrics, demonstrating the ability to accurately and efficiently predict permeability for both mixed-type and single-type rocks; ablation experiments further validate the effectiveness of the proposed temporal pooling strategy.
{"title":"Porous rock permeability quantification: A superpixel-driven graph neural network method for pore region analysis","authors":"Xinlin Zhao, Yuan Zhong, Ping Li","doi":"10.1016/j.gr.2025.11.014","DOIUrl":"https://doi.org/10.1016/j.gr.2025.11.014","url":null,"abstract":"Rock permeability, as a significant parameter, plays a crucial role in research related to geological exploration, reservoir resource development, and the movement and distribution of subsurface fluids. Despite significant advancements in artificial intelligence technology for rock analysis in recent years, challenges remain in terms of prediction accuracy, computational complexity, and resource dependency. To address these issues, this paper proposes a superpixel-based graph neural network (SP-GNN) method to achieve rock permeability prediction. Specifically, the flow space of the rock medium is superpixelized to construct graph data. Based on the superpixel graph data, a graph neural network designed to learn multi-level cascading features is developed, while also implementing an algorithm to extract neighborhood spatial features that contain sequential relationships. A temporal pooling strategy is proposed to perform collaborative learning of the cascading features and neighborhood spatial features of graph data from a temporal perspective, in order to obtain hierarchical global features of dynamic nodes. Finally, the global features of the graph are input into the downstream tasks to achieve accurate prediction of permeability. Experimental results show that the SP-GNN significantly outperforms various existing benchmark schemes for permeability prediction across seven comprehensive performance metrics, demonstrating the ability to accurately and efficiently predict permeability for both mixed-type and single-type rocks; ablation experiments further validate the effectiveness of the proposed temporal pooling strategy.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"14 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759823","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.012
Chen Ji , Kai-Jun Zhang
The Dongco ophiolite in central Tibet represents an ideal profile of a Meso-Tethyan oceanic plateau lithosphere. In this paper, we presented petrological, geochronological, geochemical, Hf–Nd–Os isotopic and Pt-group elemental data for its primary igneous units, in an attempt to constrain the architecture and building process of oceanic plateau. The oceanic plateau basalts erupted over the Middle Jurassic (∼167 Ma) normal mid-oceanic ridge basalt (N-MORB)-like oceanic lithosphere dominantly composed of ultramafic and mafic plutons (εNd(t) = 6.5–9.5; εHf(t) = 15–21), at the Early Cretaceous (∼125 Ma). The absence of MORB-type basalt in the Dongco ophiolite, as well as the presence of diabase dikes intruding the mantle peridotite and cumulate gabbro, indicates the base of the oceanic plateau formed under an ultraslow spreading setting. The plateau basalts have positive εNd(t) values (3.8–5.1), geochemically with distinct ocean-island basalt (OIB) affinity, and represent plume melts that were estimated to form at a depth over 160 km (1600 ℃ potential temperature). Wehrlites at the bottom of the OIBs, isotopically consistent with the OIBs, have highly siderophile element (HSE) compositions similar to Hawaii picrite and tholeiitic basalt with suprachondritic Os isotopic compositions (87Os/188Os = 0.1306–0.1329), signifying the plume melt cumulates based on modeling. The harzburgites are geochemically heterogeneous due to the plume melt–rock interaction. Type 1 harzburgites, mantle residues, have abyssal peridotite-like HSE compositions with subchondritic 187Os/188Os ratios (0.1182–0.1204) and ancient Re depletion model ages (1.0–1.3 Ga), indicating a complex depletion history. Type 2 harzburgites are characterized by fractionated Ir-group Pt group element compositions, higher subchondritic 187Os/188Os ratios (0.1211–0.1251) and younger Re depletion model ages (0.3–0.9 Ga), likely a percolation effect of plume melts with radiogenic Os isotopic compositions.
{"title":"Early Cretaceous Meso-Tethyan oceanic plateau built on an ultraslow-spreading oceanic lithosphere: Insights from Hf–Nd–Os isotopes and Pt-group elements of the Dongco ophiolite, central Tibet","authors":"Chen Ji , Kai-Jun Zhang","doi":"10.1016/j.gr.2025.11.012","DOIUrl":"10.1016/j.gr.2025.11.012","url":null,"abstract":"<div><div>The Dongco ophiolite in central Tibet represents an ideal profile of a Meso-Tethyan oceanic plateau lithosphere. In this paper, we presented petrological, geochronological, geochemical, Hf–Nd–Os isotopic and Pt-group elemental data for its primary igneous units, in an attempt to constrain the architecture and building process of oceanic plateau. The oceanic plateau basalts erupted over the Middle Jurassic (∼167 Ma) normal mid-oceanic ridge basalt (N-MORB)-like oceanic lithosphere dominantly composed of ultramafic and mafic plutons (ε<sub>Nd</sub>(t) = 6.5–9.5; ε<sub>Hf</sub>(t) = 15–21), at the Early Cretaceous (∼125 Ma). The absence of MORB-type basalt in the Dongco ophiolite, as well as the presence of diabase dikes intruding the mantle peridotite and cumulate gabbro, indicates the base of the oceanic plateau formed under an ultraslow spreading setting. The plateau basalts have positive ε<sub>Nd</sub>(t) values (3.8–5.1), geochemically with distinct ocean-island basalt (OIB) affinity, and represent plume melts that were estimated to form at a depth over 160 km (1600 ℃ potential temperature). Wehrlites at the bottom of the OIBs, isotopically consistent with the OIBs, have highly siderophile element (HSE) compositions similar to Hawaii picrite and tholeiitic basalt with suprachondritic Os isotopic compositions (<sup>87</sup>Os/<sup>188</sup>Os = 0.1306–0.1329), signifying the plume melt cumulates based on modeling. The harzburgites are geochemically heterogeneous due to the plume melt–rock interaction. Type 1 harzburgites, mantle residues, have abyssal peridotite-like HSE compositions with subchondritic <sup>187</sup>Os/<sup>188</sup>Os ratios (0.1182–0.1204) and ancient Re depletion model ages (1.0–1.3 Ga), indicating a complex depletion history. Type 2 harzburgites are characterized by fractionated Ir-group Pt group element compositions, higher subchondritic <sup>187</sup>Os/<sup>188</sup>Os ratios (0.1211–0.1251) and younger Re depletion model ages (0.3–0.9 Ga), likely a percolation effect of plume melts with radiogenic Os isotopic compositions.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"153 ","pages":"Pages 82-99"},"PeriodicalIF":7.2,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759498","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 : 2025-12-13DOI: 10.1016/j.gr.2025.11.015
Jing Sun , Ross N. Mitchell , Luc S. Doucet , Kouki Kitajima , Ranpeng Li , Jinglin Su , Qiqi Ou , Tanya Kalashnikova , Sergey I. Kostrovitsky
Mantle eclogite represents a rare and unique archive for understanding the dynamics and implications of subduction, but its origin is still debated especially for high-MgO eclogites. We report new chemical and Mg–O isotopic data on high-MgO mantle eclogites from the Obnazhennaya kimberlite, Siberia craton. Obnazhennaya high-MgO eclogites have lower bulk δ26Mg isotopes (-1.47– -0.36‰) and mantle-like garnet δ18O isotopes (+5.18–+6.39‰). A bulk mixing calculation among oceanic crust, carbonate sediment and kimberlite, and its effects on Mg isotopes and MgO content indicate that metasomatism can only increase the MgO content but not δ26Mg, and more than 50% dolostone by mass is needed, under conditions with no kimberlitic melt metasomatism, to account for both high-MgO contents, which is unrealistically high for natural settings. The ternary mixing model on both O–Mg isotopic compositions and MgO–Mg isotopic compositions suggest that subducted oceanic crusts modified by mantle metasomatism (e.g., kimberlite-like melt) as well as carbonate sediments involvement collectively provides the best explanation for such a high magnesian origin. This model is also compatible with global mantle eclogite observations, where there is also a clear chemical composition distinction between high- and low-MgO eclogites globally. In light of our new results and global compilation, we propose that mantle eclogites represent a spectrum of metasomatized subducted oceanic crust with variable amounts of the involvement of carbonate sediments, the latter of which represents a novel ingredient in the recipe for making previously enigmatic high-MgO eclogite xenoliths in kimberlites.
{"title":"Mantle eclogite evidence of subducted carbonate sediments in Earth’s deep carbon cycle","authors":"Jing Sun , Ross N. Mitchell , Luc S. Doucet , Kouki Kitajima , Ranpeng Li , Jinglin Su , Qiqi Ou , Tanya Kalashnikova , Sergey I. Kostrovitsky","doi":"10.1016/j.gr.2025.11.015","DOIUrl":"10.1016/j.gr.2025.11.015","url":null,"abstract":"<div><div>Mantle eclogite represents a rare and unique archive for understanding the dynamics and implications of subduction, but its origin is still debated especially for high-MgO eclogites. We report new chemical and Mg–O isotopic data on high-MgO mantle eclogites from the Obnazhennaya kimberlite, Siberia craton. Obnazhennaya high-MgO eclogites have lower bulk δ<sup>26</sup>Mg isotopes (-1.47– -0.36‰) and mantle-like garnet δ<sup>18</sup>O isotopes (+5.18–+6.39‰). A bulk mixing calculation among oceanic crust, carbonate sediment and kimberlite, and its effects on Mg isotopes and MgO content indicate that metasomatism can only increase the MgO content but not δ<sup>26</sup>Mg, and more than 50% dolostone by mass is needed, under conditions with no kimberlitic melt metasomatism, to account for both high-MgO contents, which is unrealistically high for natural settings. The ternary mixing model on both O–Mg isotopic compositions and MgO–Mg isotopic compositions suggest that subducted oceanic crusts modified by mantle metasomatism (e.g., kimberlite-like melt) as well as carbonate sediments involvement collectively provides the best explanation for such a high magnesian origin. This model is also compatible with global mantle eclogite observations, where there is also a clear chemical composition distinction between high- and low-MgO eclogites globally. In light of our new results and global compilation, we propose that mantle eclogites represent a spectrum of metasomatized subducted oceanic crust with variable amounts of the involvement of carbonate sediments, the latter of which represents a novel ingredient in the recipe for making previously enigmatic high-MgO eclogite xenoliths in kimberlites.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"153 ","pages":"Pages 60-72"},"PeriodicalIF":7.2,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759822","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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