Pub Date : 2025-11-30DOI: 10.1016/j.gsf.2025.102218
Fabrício A. Caxito , Cristiano Lana , Davi Carvalho , Gabriel J. Uhlein , Carolina Reis , Paulo Henrique A. Dias , Denise Canabrava , Juliana Okubo , George Luiz Luvizotto , Lucas Warren , Shuhai Xiao , Tian Gan , Galen Halverson , Peter Crockford , Kristin Bergmann , Katharine W. Huntington , Andrew J. Schauer , Mariana M. Leite
<div><div>Direct dating of sedimentary successions is a main challenge in geochronology, key for the establishment of chronostratigraphic frameworks for both regional and global events. U-Pb in-situ LA-ICPMS direct dating of carbonate samples is emerging as a promising tool, but complications such as mobility and low U contents hinder most of the attempts on common carbonate rocks. We present new U-Pb in-situ LA-ICPMS data for Ediacaran cap carbonate and related successions from Brazil, China and Canada, along with stable carbon, oxygen, and clumped isotope data for the same samples. The novel dataset reveals that in some instances, especially within calcite-after-aragonite crystal fans and microbialite facies, U is retained from early diagenesis through intermediate to deep burial, resulting in tightly constrained and well-spread linear fits in the Concordia space. Calcite-after-aragonite crystal fan samples from the Guia Fm. (Brazil) and Hayhook Fm. (Canada) caps, sitting immediately above glacial diamictite, yielded 632 ± 14 Ma and 631 ± 6 Ma, respectively, supporting quick deposition and diagenesis following Marinoan deglaciation. Clumped isotope apparent equilibrium temperatures (<em>T</em><sub>Δ47</sub>) of 79 (+12/−11) °C and 181 (+14/−13) °C (95% confidence level), respectively, indicate that the U-Pb system remained unreset within the crystal fans even through the deep burial realm. In the Sete Lagoas Formation of the Bambuí Group (Brazil), crystal fans are not restricted to the immediate cap carbonate sitting above glacial deposits, but instead occur throughout ca. 400 m of carbonate-dominated facies, in distinct stratigraphic intervals corresponding to the Pedro Leopoldo and Lagoa Santa members. Samples from the basal Pedro Leopoldo member yielded U-Pb ages between 625 Ma and 605 Ma. A crystal-fan bearing sample of the Acauã Formation in the Sergipano Belt (Brazil) yielded similar results, suggesting protracted deposition/diagenesis of the negative <em>δ</em><sup>13</sup>C-bearing limestone above the basal cap dolostone. Crystal fans in the topmost Lagoa Santa member, just below the contact with the mudstone-rich Serra de Santa Helena Formation and 330 m above the contact with the glacials, yielded late Ediacaran ages at ca. 570–550 Ma. All of these yielded <em>T</em><sub>Δ47</sub> of around 110–149 °C. These ages are identical within uncertainty to U-Pb ages obtained in stromatolites at the same stratigraphic level, and from the phosphorite-bearing stromatolites of the Salitre Formation, Una Group, further north in the São Francisco craton, which yielded a lower <em>T</em><sub>Δ47</sub> of 91 ± 7 °C. Finally, both the cap dolostone matrix and isopachous cement filling sheet-cavities from a sample of the basal Doushantuo Formation of South China align in a regression with a lower intercept at ca. 619 Ma. The new U-Pb carbonate data are highly coherent with available U-Pb zircon and Re-Os whole-rock data worldwide, and also with previou
{"title":"Coda of the snowball: combined U-Pb LA-ICPMS dating of calcite-after-aragonite crystal fans and clumped isotope thermometry of Ediacaran cap carbonates","authors":"Fabrício A. Caxito , Cristiano Lana , Davi Carvalho , Gabriel J. Uhlein , Carolina Reis , Paulo Henrique A. Dias , Denise Canabrava , Juliana Okubo , George Luiz Luvizotto , Lucas Warren , Shuhai Xiao , Tian Gan , Galen Halverson , Peter Crockford , Kristin Bergmann , Katharine W. Huntington , Andrew J. Schauer , Mariana M. Leite","doi":"10.1016/j.gsf.2025.102218","DOIUrl":"10.1016/j.gsf.2025.102218","url":null,"abstract":"<div><div>Direct dating of sedimentary successions is a main challenge in geochronology, key for the establishment of chronostratigraphic frameworks for both regional and global events. U-Pb in-situ LA-ICPMS direct dating of carbonate samples is emerging as a promising tool, but complications such as mobility and low U contents hinder most of the attempts on common carbonate rocks. We present new U-Pb in-situ LA-ICPMS data for Ediacaran cap carbonate and related successions from Brazil, China and Canada, along with stable carbon, oxygen, and clumped isotope data for the same samples. The novel dataset reveals that in some instances, especially within calcite-after-aragonite crystal fans and microbialite facies, U is retained from early diagenesis through intermediate to deep burial, resulting in tightly constrained and well-spread linear fits in the Concordia space. Calcite-after-aragonite crystal fan samples from the Guia Fm. (Brazil) and Hayhook Fm. (Canada) caps, sitting immediately above glacial diamictite, yielded 632 ± 14 Ma and 631 ± 6 Ma, respectively, supporting quick deposition and diagenesis following Marinoan deglaciation. Clumped isotope apparent equilibrium temperatures (<em>T</em><sub>Δ47</sub>) of 79 (+12/−11) °C and 181 (+14/−13) °C (95% confidence level), respectively, indicate that the U-Pb system remained unreset within the crystal fans even through the deep burial realm. In the Sete Lagoas Formation of the Bambuí Group (Brazil), crystal fans are not restricted to the immediate cap carbonate sitting above glacial deposits, but instead occur throughout ca. 400 m of carbonate-dominated facies, in distinct stratigraphic intervals corresponding to the Pedro Leopoldo and Lagoa Santa members. Samples from the basal Pedro Leopoldo member yielded U-Pb ages between 625 Ma and 605 Ma. A crystal-fan bearing sample of the Acauã Formation in the Sergipano Belt (Brazil) yielded similar results, suggesting protracted deposition/diagenesis of the negative <em>δ</em><sup>13</sup>C-bearing limestone above the basal cap dolostone. Crystal fans in the topmost Lagoa Santa member, just below the contact with the mudstone-rich Serra de Santa Helena Formation and 330 m above the contact with the glacials, yielded late Ediacaran ages at ca. 570–550 Ma. All of these yielded <em>T</em><sub>Δ47</sub> of around 110–149 °C. These ages are identical within uncertainty to U-Pb ages obtained in stromatolites at the same stratigraphic level, and from the phosphorite-bearing stromatolites of the Salitre Formation, Una Group, further north in the São Francisco craton, which yielded a lower <em>T</em><sub>Δ47</sub> of 91 ± 7 °C. Finally, both the cap dolostone matrix and isopachous cement filling sheet-cavities from a sample of the basal Doushantuo Formation of South China align in a regression with a lower intercept at ca. 619 Ma. The new U-Pb carbonate data are highly coherent with available U-Pb zircon and Re-Os whole-rock data worldwide, and also with previou","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102218"},"PeriodicalIF":8.9,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748582","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 : 2025-11-30DOI: 10.1016/j.gsf.2025.102220
Jiejie Li , Emma Black , Christopher Miller , Kunning Tang , Peyman Mostaghimi , Andrew Feitz , T.David Waite , Ryan T. Armstrong
Natural hydrogen (H2) generated by the reaction of ultramafic rocks with water is increasingly recognized as a promising low-carbon energy resource with the analysis of rock mineralogy and structural characteristics recognized to play a crucial role in assessing its subsurface generation potential. In this study, micro-computed tomography (micro-CT), micro-X-ray fluorescence spectroscopy (micro-XRF), X-ray diffraction (XRD), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) are employed to analyze the density, elemental distribution, mineral composition, and surface spatial relationships of an ultramafic rock sample. In addition, deep learning-based image analysis is employed to achieve high-resolution mineral phase characterization, enabling quantitative analysis of the spatial distribution, co-location, and contact surfaces of the mineral phases. Focusing on a particular sample that was considered a likely initiator of hydrogen generation due to its mineral contents, our results indicate that the sample is primarily composed of Fe-Mg-rich olivine and silicate minerals, with most olivine phases being Mg-rich forsterite or mixtures of forsterite and Fe-rich fayalite. The sample also contains Fe-S sulfides and high-density metal-enriched phases, including Ni-rich phases that may enhance the H2-generating potential of serpentinization reactions. These findings highlight the mineralogical complexity of the studied ultramafic rock and the value of integrating compositional and spatial data when considering the potential of particular materials for hydrogen generation. The integrated analytical approach proposed in this study provides new insights and practical tools for evaluating the hydrogen generation potential associated with subsurface serpentinization in ultramafic rock.
{"title":"Multi-modal characterization of ultramafic rock: Precursors relevant to serpentinization and hydrogen generation","authors":"Jiejie Li , Emma Black , Christopher Miller , Kunning Tang , Peyman Mostaghimi , Andrew Feitz , T.David Waite , Ryan T. Armstrong","doi":"10.1016/j.gsf.2025.102220","DOIUrl":"10.1016/j.gsf.2025.102220","url":null,"abstract":"<div><div>Natural hydrogen (H<sub>2</sub>) generated by the reaction of ultramafic rocks with water is increasingly recognized as a promising low-carbon energy resource with the analysis of rock mineralogy and structural characteristics recognized to play a crucial role in assessing its subsurface generation potential. In this study, micro-computed tomography (micro-CT), micro-X-ray fluorescence spectroscopy (micro-XRF), X-ray diffraction (XRD), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) are employed to analyze the density, elemental distribution, mineral composition, and surface spatial relationships of an ultramafic rock sample. In addition, deep learning-based image analysis is employed to achieve high-resolution mineral phase characterization, enabling quantitative analysis of the spatial distribution, co-location, and contact surfaces of the mineral phases. Focusing on a particular sample that was considered a likely initiator of hydrogen generation due to its mineral contents, our results indicate that the sample is primarily composed of Fe-Mg-rich olivine and silicate minerals, with most olivine phases being Mg-rich forsterite or mixtures of forsterite and Fe-rich fayalite. The sample also contains Fe-S sulfides and high-density metal-enriched phases, including Ni-rich phases that may enhance the H<sub>2</sub>-generating potential of serpentinization reactions. These findings highlight the mineralogical complexity of the studied ultramafic rock and the value of integrating compositional and spatial data when considering the potential of particular materials for hydrogen generation. The integrated analytical approach proposed in this study provides new insights and practical tools for evaluating the hydrogen generation potential associated with subsurface serpentinization in ultramafic rock.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102220"},"PeriodicalIF":8.9,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748580","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 : 2025-11-25DOI: 10.1016/j.gsf.2025.102214
Xiajie Zhai , Lijuan Cui , Wei Li , Xinsheng Zhao , Chenxi Liu , Hua Ma , Mingshuo Xiong
The Yellow River provides an important foundation for the sustainable development of Chinese civilization. Compared with the upper part (dominated by the Tibetan Plateau) and the lower part (represented by the Yellow River Delta), the central part of the Yellow River Basin (encompassing most of the Loess Plateau) is the most arid and exhibits the most complex relationship between humans and nature. The Chinese government is continuously promoting the protection and management of the ecological environment in the central part of the Yellow River Basin, as it is related to the country’s food security and people’s health, biodiversity conservation and sustainable socio-economic development. However, the distribution patterns and evolution of key ecological elements in the region, which are important determinants of ecosystem productivity and health, have yet to be revealed. This study focused on three key ecological elements, namely, macronutrients (sediment organic carbon, SOC, total nitrogen, TN and total phosphorous, TP), heavy metals (Cu, Ni, Pb, Zn, Cr, Cd, Hg, and As) and microplastics, and aimed to systematically elucidate the change patterns of their concentrations and compositions in sediments from the mainstem of the Yellow River and neighboring typical lakes. The results revealed that the TN content was mostly greater than the SOC content in the sediments from the mainstem of the Yellow River. Moreover, the TN, SOC and heavy metal concentrations increased significantly as a result of agricultural cultivation. Among the six typical lakes, the highest concentrations of both macronutrients and heavy metals were observed in sediment samples from Mingcui Lake (MC; an urban wetland), followed by those in sediment samples from Wuliangsuhai Lake (WLS; surrounded by agricultural fields). Among the heavy metals, the concentrations of Zn and Cr were highest. The abundance of microplastics in the sediments from the mainstream of the Yellow River ranged from 233 to 3333 items kg−1, while the abundance of microplastics in lake sediments ranged from 967 to 1556 items kg−1. The other characteristics of microplastics were consistent, including the concentration of microplastic particles within the 0.2–2 mm range. The main colors of the sampled microplastics were blue, transparent, and gray-black. In addition, rayon accounted for the highest proportion among all polymer types, followed by PET and PE + PP. In general, the amount of the above three environmental elements is closely correlated with the intensity of human activities such as agriculture and urbanization. Stronger correlations were obtained between the concentrations of macronutrients and heavy metals. This study systematically reveals the change patterns of key ecological elements in the study area and advances the understanding of environmental changes, ecosystem evolution and sustainable development in the Yellow River Basin.
{"title":"Spatial distributions of macronutrients, heavy metals and microplastics in surface sediments of the mainstem and lakes in the middle part of the Yellow River Basin","authors":"Xiajie Zhai , Lijuan Cui , Wei Li , Xinsheng Zhao , Chenxi Liu , Hua Ma , Mingshuo Xiong","doi":"10.1016/j.gsf.2025.102214","DOIUrl":"10.1016/j.gsf.2025.102214","url":null,"abstract":"<div><div>The Yellow River provides an important foundation for the sustainable development of Chinese civilization. Compared with the upper part (dominated by the Tibetan Plateau) and the lower part (represented by the Yellow River Delta), the central part of the Yellow River Basin (encompassing most of the Loess Plateau) is the most arid and exhibits the most complex relationship between humans and nature. The Chinese government is continuously promoting the protection and management of the ecological environment in the central part of the Yellow River Basin, as it is related to the country’s food security and people’s health, biodiversity conservation and sustainable socio-economic development. However, the distribution patterns and evolution of key ecological elements in the region, which are important determinants of ecosystem productivity and health, have yet to be revealed. This study focused on three key ecological elements, namely, macronutrients (sediment organic carbon, SOC, total nitrogen, TN and total phosphorous, TP), heavy metals (Cu, Ni, Pb, Zn, Cr, Cd, Hg, and As) and microplastics, and aimed to systematically elucidate the change patterns of their concentrations and compositions in sediments from the mainstem of the Yellow River and neighboring typical lakes. The results revealed that the TN content was mostly greater than the SOC content in the sediments from the mainstem of the Yellow River. Moreover, the TN, SOC and heavy metal concentrations increased significantly as a result of agricultural cultivation. Among the six typical lakes, the highest concentrations of both macronutrients and heavy metals were observed in sediment samples from Mingcui Lake (MC; an urban wetland), followed by those in sediment samples from Wuliangsuhai Lake (WLS; surrounded by agricultural fields). Among the heavy metals, the concentrations of Zn and Cr were highest. The abundance of microplastics in the sediments from the mainstream of the Yellow River ranged from 233 to 3333 items kg<sup>−1</sup>, while the abundance of microplastics in lake sediments ranged from 967 to 1556 items kg<sup>−1</sup>. The other characteristics of microplastics were consistent, including the concentration of microplastic particles within the 0.2–2 mm range. The main colors of the sampled microplastics were blue, transparent, and gray-black. In addition, rayon accounted for the highest proportion among all polymer types, followed by PET and PE + PP. In general, the amount of the above three environmental elements is closely correlated with the intensity of human activities such as agriculture and urbanization. Stronger correlations were obtained between the concentrations of macronutrients and heavy metals. This study systematically reveals the change patterns of key ecological elements in the study area and advances the understanding of environmental changes, ecosystem evolution and sustainable development in the Yellow River Basin.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 1","pages":"Article 102214"},"PeriodicalIF":8.9,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145690947","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 : 2025-11-25DOI: 10.1016/j.gsf.2025.102216
Hao Chen , Xin Chen , Youye Zheng , Xian Che , Yuanping Lai , Xingkai Huang , Shunbao Gao , Bei Pang
<div><div>The Gangdese metallogenic belt in Xizang, a world-class copper polymetallic province, has a poorly understood western segment due to extensive volcanic cover and limited historical exploration. The recent discovery of the Sangmoladong (SMLD) deposit, the first undocumented volcanic- to subvolcanic-hosted, tin-dominant polymetallic system in western Gangdese, provides a unique opportunity to investigate collisional metallogeny. Through integrated LA-ICP-MS U-Pb geochronology of zircon and cassiterite, comprehensive whole-rock geochemistry, and Nd-Hf isotopes, this research establishes a genetic link between Paleocene magmatism and Sn-polymetallic mineralization. The mineralization is hosted within granite porphyry stocks and associated rhyolitic tuff breccias of a volcanic dome complex. It comprises two main stages: an early, disseminated cassiterite-sulfide stage with chloritic alteration, followed by later fluorite-cassiterite-tourmaline veins and veinlets. New LA-ICP-MS U-Pb dating constrains the timing of granite porphyry emplacement to 61.3 ± 0.2 Ma and rhyolitic tuff deposition to 61.8 ± 0.5 Ma. Cassiterite mineralization occurred between 61.0 ± 2.2 Ma and 59.3 ± 3.5 Ma, confirming that Sn metallogenesis was coeval with this Paleocene magmatic pulse during the Indo-Asian collision. The ore-forming granitic porphyries are highly evolved, A-type granites, characterized by high SiO<sub>2</sub> (77.50 – 80.40 wt.%), elevated zircon saturation temperatures (831 – 870 °C), and high Ga/Al ratios (10,000 × Ga/Al = 5.75 – 6.51). Their Nd-Hf isotopic signatures (<em>ε</em><sub>Nd</sub>(<em>t</em>) = −6.5 to −6.3; zircon <em>ε</em><sub>Hf</sub>(<em>t</em>) = −5.2 to +2.1) indicate an origin from anatexis of ancient Lhasa terrane metapelites, likely triggered by lithospheric extension during Neo-Tethyan slab rollback. This generated a reduced, fluorine- and boron-rich magmatic-hydrothermal system highly efficient at mobilizing and concentrating tin. On a regional scale, a metallogenic framework is proposed where Fe-Cu mineralization is sourced from hybridized mantle-crust magmas, whereas Pb-Zn and Sn systems derive from similar crustal-dominated sources. This metallogenic divergence of Pb-Zn and Sn reflects contrasting thermal regimes and magma crystallization pathways during a transtensional setting with local extension in pull-apart and uplift structures. The formation of the SMLD tin deposit is attributed to prolonged fractional crystallization of a high-temperature, low <em>f</em>O<sub>2</sub> magma within a subvolcanic dome complex. These conditions suppressed early cassiterite saturation and promoted extreme tin enrichment in the residual melt. This study makes two key contributions: (1) it identifies the first volcanic-hosted tin system in the western Gangdese, challenging traditional exploration models focused on porphyry skarn Cu-Pb-Zn deposits; and (2) it establishes a new tectono-metallogenic model that elucidates the spatiotempor
{"title":"Collision-related tin metallogeny: Insight from a new discovery of the volcanic-subvolcanic-hosted Sn deposit in the western Gangdese, Xizang","authors":"Hao Chen , Xin Chen , Youye Zheng , Xian Che , Yuanping Lai , Xingkai Huang , Shunbao Gao , Bei Pang","doi":"10.1016/j.gsf.2025.102216","DOIUrl":"10.1016/j.gsf.2025.102216","url":null,"abstract":"<div><div>The Gangdese metallogenic belt in Xizang, a world-class copper polymetallic province, has a poorly understood western segment due to extensive volcanic cover and limited historical exploration. The recent discovery of the Sangmoladong (SMLD) deposit, the first undocumented volcanic- to subvolcanic-hosted, tin-dominant polymetallic system in western Gangdese, provides a unique opportunity to investigate collisional metallogeny. Through integrated LA-ICP-MS U-Pb geochronology of zircon and cassiterite, comprehensive whole-rock geochemistry, and Nd-Hf isotopes, this research establishes a genetic link between Paleocene magmatism and Sn-polymetallic mineralization. The mineralization is hosted within granite porphyry stocks and associated rhyolitic tuff breccias of a volcanic dome complex. It comprises two main stages: an early, disseminated cassiterite-sulfide stage with chloritic alteration, followed by later fluorite-cassiterite-tourmaline veins and veinlets. New LA-ICP-MS U-Pb dating constrains the timing of granite porphyry emplacement to 61.3 ± 0.2 Ma and rhyolitic tuff deposition to 61.8 ± 0.5 Ma. Cassiterite mineralization occurred between 61.0 ± 2.2 Ma and 59.3 ± 3.5 Ma, confirming that Sn metallogenesis was coeval with this Paleocene magmatic pulse during the Indo-Asian collision. The ore-forming granitic porphyries are highly evolved, A-type granites, characterized by high SiO<sub>2</sub> (77.50 – 80.40 wt.%), elevated zircon saturation temperatures (831 – 870 °C), and high Ga/Al ratios (10,000 × Ga/Al = 5.75 – 6.51). Their Nd-Hf isotopic signatures (<em>ε</em><sub>Nd</sub>(<em>t</em>) = −6.5 to −6.3; zircon <em>ε</em><sub>Hf</sub>(<em>t</em>) = −5.2 to +2.1) indicate an origin from anatexis of ancient Lhasa terrane metapelites, likely triggered by lithospheric extension during Neo-Tethyan slab rollback. This generated a reduced, fluorine- and boron-rich magmatic-hydrothermal system highly efficient at mobilizing and concentrating tin. On a regional scale, a metallogenic framework is proposed where Fe-Cu mineralization is sourced from hybridized mantle-crust magmas, whereas Pb-Zn and Sn systems derive from similar crustal-dominated sources. This metallogenic divergence of Pb-Zn and Sn reflects contrasting thermal regimes and magma crystallization pathways during a transtensional setting with local extension in pull-apart and uplift structures. The formation of the SMLD tin deposit is attributed to prolonged fractional crystallization of a high-temperature, low <em>f</em>O<sub>2</sub> magma within a subvolcanic dome complex. These conditions suppressed early cassiterite saturation and promoted extreme tin enrichment in the residual melt. This study makes two key contributions: (1) it identifies the first volcanic-hosted tin system in the western Gangdese, challenging traditional exploration models focused on porphyry skarn Cu-Pb-Zn deposits; and (2) it establishes a new tectono-metallogenic model that elucidates the spatiotempor","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102216"},"PeriodicalIF":8.9,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748583","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 : 2025-11-24DOI: 10.1016/j.gsf.2025.102215
Wenchao Huangfu , Haijun Qiu , Jiading Wang , Ninglian Wang , Yang Zhang , Ya Liu , Ali Darvishi Boloorani , Mohib Ullah
Landslides have different topographic and morphological characteristics due to their different triggering mechanisms. However, the differences in the characteristics of earthquake- and rainstorm-induced landslides remain unclear. In this paper, we collect 12 cases of earthquake- and rainstorm-induced landslides around the world and reveal the differences in characteristics of the two types of landslides. By examining the geometric characteristics and location distribution of the landslides, the results show that earthquake-induced landslides tend to have larger areas, perimeter, lengths, widths, area to perimeter ratios (area/perimeter), major axis (SM), and minor axis (sm) than rainstorm-induced landslides. In addition, earthquake-induced landslides have more complex, rounded, and compact shapes than rainstorm-induced landslides. Earthquake-induced landslides are predominantly clustered near ridges, whereas rainstorm-induced landslides are predominantly clustered near valleys. The results also indicate that earthquake- and rainstorm-induced landslides mostly occur on 30°–50° and 10°–30° slopes, respectively, and both types are more likely to occur on sunny slopes. Moreover, the compactness and major axis are negatively logarithmically correlated for earthquake-induced landslides, while they are negatively exponentially correlated for rainstorm-induced landslides. Additional earthquake- and rainstorm-induced landslide events have verified the reliability and extensibility of the research conclusions. This work is beneficial for the management of landslide hazards and the effective implementation of landslide prediction and risk assessment.
{"title":"Topographic and morphological effects of global earthquake- and rainstorm-induced landslides","authors":"Wenchao Huangfu , Haijun Qiu , Jiading Wang , Ninglian Wang , Yang Zhang , Ya Liu , Ali Darvishi Boloorani , Mohib Ullah","doi":"10.1016/j.gsf.2025.102215","DOIUrl":"10.1016/j.gsf.2025.102215","url":null,"abstract":"<div><div>Landslides have different topographic and morphological characteristics due to their different triggering mechanisms. However, the differences in the characteristics of earthquake- and rainstorm-induced landslides remain unclear. In this paper, we collect 12 cases of earthquake- and rainstorm-induced landslides around the world and reveal the differences in characteristics of the two types of landslides. By examining the geometric characteristics and location distribution of the landslides, the results show that earthquake-induced landslides tend to have larger areas, perimeter, lengths, widths, area to perimeter ratios (area/perimeter), major axis (<em>S</em><sub>M</sub>), and minor axis (<em>s</em><sub>m</sub>) than rainstorm-induced landslides. In addition, earthquake-induced landslides have more complex, rounded, and compact shapes than rainstorm-induced landslides. Earthquake-induced landslides are predominantly clustered near ridges, whereas rainstorm-induced landslides are predominantly clustered near valleys. The results also indicate that earthquake- and rainstorm-induced landslides mostly occur on 30°–50° and 10°–30° slopes, respectively, and both types are more likely to occur on sunny slopes. Moreover, the compactness and major axis are negatively logarithmically correlated for earthquake-induced landslides, while they are negatively exponentially correlated for rainstorm-induced landslides. Additional earthquake- and rainstorm-induced landslide events have verified the reliability and extensibility of the research conclusions. This work is beneficial for the management of landslide hazards and the effective implementation of landslide prediction and risk assessment.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102215"},"PeriodicalIF":8.9,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145645721","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 : 2025-11-19DOI: 10.1016/j.gsf.2025.102213
Xinyue Ke , Ni Wang , Tianhao Li , Zheng Liu , Zhiwei Li , Ganggang Zuo , Yiting Chen
Flash floods cause substantial economic losses and casualties worldwide. Susceptibility-based flash flood mapping supports the development of effective flood mitigation strategies. While machine learning (ML) models offer superior accuracy, converting their outputs into spatially coherent and actionable maps remains challenging. Existing susceptibility maps often rely on subjective discretization and exhibit fragmented spatial patterns, limiting their utility in practice. In this context, this study proposes a novel framework that achieves the effective transformation of susceptibility prediction results into a management-oriented regionalization map. The framework integrates supervised learning, unsupervised clustering, and spatial explanatory feedback to enable information fusion and spatial restructuring of multi-model outputs. Flash flood susceptibility was first modelled using two supervised algorithms: Random Forest and CatBoost. Their outputs, along with exposed elements, were integrated and discretized using a two-stage clustering approach based on Self-Organizing Maps (SOM) and Ward’s method. Finally, a GeoDetector-based iterative optimization process was implemented to refine the regionalization by maximizing alignment with historical flash flood distributions. Results show that all susceptibility models achieved excellent predictive performance (AUC > 0.95), with the CatBoost model trained on grid-based samples performing best (AUC = 0.997). The final regionalization map exhibits regional contiguity and effectively captures historical flood patterns, explaining 73% of their spatial variability. The integration of hybrid ML with explanatory feedback provides a novel perspective for generating susceptibility regionalization maps that are both expressive of flash flood risk and spatially coherent, in addition to providing support for exploring region-specific defense measures.
{"title":"From prediction to regionalization: Enhancing flash flood susceptibility mapping using machine learning and GeoDetector","authors":"Xinyue Ke , Ni Wang , Tianhao Li , Zheng Liu , Zhiwei Li , Ganggang Zuo , Yiting Chen","doi":"10.1016/j.gsf.2025.102213","DOIUrl":"10.1016/j.gsf.2025.102213","url":null,"abstract":"<div><div>Flash floods cause substantial economic losses and casualties worldwide. Susceptibility-based flash flood mapping supports the development of effective flood mitigation strategies. While machine learning (ML) models offer superior accuracy, converting their outputs into spatially coherent and actionable maps remains challenging. Existing susceptibility maps often rely on subjective discretization and exhibit fragmented spatial patterns, limiting their utility in practice. In this context, this study proposes a novel framework that achieves the effective transformation of susceptibility prediction results into a management-oriented regionalization map. The framework integrates supervised learning, unsupervised clustering, and spatial explanatory feedback to enable information fusion and spatial restructuring of multi-model outputs. Flash flood susceptibility was first modelled using two supervised algorithms: Random Forest and CatBoost. Their outputs, along with exposed elements, were integrated and discretized using a two-stage clustering approach based on Self-Organizing Maps (SOM) and Ward’s method. Finally, a GeoDetector-based iterative optimization process was implemented to refine the regionalization by maximizing alignment with historical flash flood distributions. Results show that all susceptibility models achieved excellent predictive performance (AUC > 0.95), with the CatBoost model trained on grid-based samples performing best (AUC = 0.997). The final regionalization map exhibits regional contiguity and effectively captures historical flood patterns, explaining 73% of their spatial variability. The integration of hybrid ML with explanatory feedback provides a novel perspective for generating susceptibility regionalization maps that are both expressive of flash flood risk and spatially coherent, in addition to providing support for exploring region-specific defense measures.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 1","pages":"Article 102213"},"PeriodicalIF":8.9,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620319","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 : 2025-11-18DOI: 10.1016/j.gsf.2025.102211
Yaoling Niu
I have recently published “Do we really need to drill through the intact ocean crust?” in this journal (Geoscience Frontiors, 2025, Volume 16, 101954), which is a theme talk at the “International Workshop on Fulfilling the Quest of Drilling Through the Ocean Crust Using D/V Meng Xiang (‘梦想号’)” held in Guangzhou (November 24 ‒ 27, 2024), and is an objective account of petrological properties of the oceanic Moho. The global geoscience community universally acknowledges that Moho is a seismic discontinuity representing the boundary between the crust (VP ≤ 7 km/s) and mantle (VP ≥ 8.0 km/s). However, the longstanding assumption of purely magmatic origin for the ocean crust has misled the subject field. Evidence shows that the ocean crust formed at many slow-spreading ridge localities maintains a globally constant seismic thickness of ∼ 6 ± 1 km yet paradoxically comprises predominantly serpentinited mantle peridotite. This observation rationalizes the 60-year-old Hess-type Ocean crust hypothesis, while also underscoring the imperative for direct verification through intact ocean crust drilling − the core objective of the abandoned Project Mohole (1957‒1966). The workshop participants unanimously concurred that D/V Meng Xiang is currently the only operational platform capable of achieving intact ocean crust penetration. However, selection of optimal drilling sites needs further multidisciplinary discussion for successful Moho penetration, allowing addressing the core question on the petrological nature of the oceanic Moho. Here, I suggest the following with justifications for consideration: (1) It is not possible and thus has no significance to drill into the Moho on seafloors formed at slow- and ultraslow-spreading ridges; (2) it is feasible to succeed with well-prepared efforts in drilling through intact magmatic crust at ideal sites of seafloors produced at the fast-spreading East Pacific Rise; (3) if the Pacific Moho is discovered to be serpentinization front, this will bring about a paradigm shift.
{"title":"Using D/V Meng Xiang to drill intact magmatic crust in the Pacific to reveal the petrological nature of the oceanic Moho","authors":"Yaoling Niu","doi":"10.1016/j.gsf.2025.102211","DOIUrl":"10.1016/j.gsf.2025.102211","url":null,"abstract":"<div><div>I have recently published “Do we really need to drill through the intact ocean crust?” in this journal (Geoscience Frontiors, 2025, Volume 16, 101954), which is a theme talk at the “<em>International Workshop on Fulfilling the Quest of Drilling Through the Ocean Crust Using D/V Meng Xiang</em> (‘梦想号’)” held in Guangzhou (November 24 ‒ 27, 2024), and is an objective account of petrological properties of the oceanic Moho. The global geoscience community universally acknowledges that Moho is a seismic discontinuity representing the boundary between the crust (<em>V</em><sub>P</sub> ≤ 7 km/s) and mantle (<em>V</em><sub>P</sub> ≥ 8.0 km/s). However, the longstanding assumption of purely magmatic origin for the ocean crust has misled the subject field. Evidence shows that the ocean crust formed at many slow-spreading ridge localities maintains a globally constant seismic thickness of ∼ 6 ± 1 km yet paradoxically comprises predominantly serpentinited mantle peridotite. This observation rationalizes the 60-year-old Hess-type Ocean crust hypothesis, while also underscoring the imperative for direct verification through intact ocean crust drilling − the core objective of the abandoned <em>Project Mohole</em> (1957‒1966). The workshop participants unanimously concurred that <em>D/V Meng Xiang</em> is currently the only operational platform capable of achieving intact ocean crust penetration. However, selection of optimal drilling sites needs further multidisciplinary discussion for successful Moho penetration, allowing addressing the core question on the <em>petrological nature of the oceanic Moho</em>. Here, I suggest the following with justifications for consideration: (1) It is not possible and thus has no significance to drill into the Moho on seafloors formed at slow- and ultraslow-spreading ridges; (2) it is feasible to succeed with well-prepared efforts in drilling through intact magmatic crust at ideal sites of seafloors produced at the fast-spreading East Pacific Rise; (3) if the Pacific Moho is discovered to be serpentinization front, this will bring about a paradigm shift.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 1","pages":"Article 102211"},"PeriodicalIF":8.9,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620322","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 : 2025-11-14DOI: 10.1016/j.gsf.2025.102210
J.A. Parera-Portell , F.d.L. Mancilla , J. Morales , X. Yuan , B. Heit , J. Diaz
We present a new lithosphere-asthenosphere boundary (LAB) depth map of Iberia and adjacent areas built using 34500 Sp receiver functions from 998 broadband seismic stations, alongside an updated Ps-derived crustal thickness map of Iberia. We found an overall shallow LAB, with a minimum depth of 70–80 km in areas of Cenozoic extension such as the eastern coast of Iberia and the Gibraltar-Alboran subduction back-arc, as well as in the Massif Central and the tectonically stable northwest of Iberia. LAB depths from 90 km to 110 km were only found within the areas of thickened crust in north-central Iberia and bordering the Gulf of Cádiz. The much deeper (150–180 km) oceanic LAB of the Gibraltar-Alboran slab was also imaged in the western Gibraltar Arc. Sublithospheric negative-velocity gradients (NVG) in the 110–140 km depth range are widespread in the back-arc of the Gibraltar-Alboran subduction system and in north-central Iberia, picturing a layered asthenospheric structure. In the Gibraltar Arc, the detachment of the slab through the subduction-transform edge propagator fault in the eastern Betics seems linked to the formation of the NVG, which are limited to the north by this structure.
{"title":"Imaging the seismic LAB and deeper asthenospheric low-velocity layers in the Ibero-Maghrebian region","authors":"J.A. Parera-Portell , F.d.L. Mancilla , J. Morales , X. Yuan , B. Heit , J. Diaz","doi":"10.1016/j.gsf.2025.102210","DOIUrl":"10.1016/j.gsf.2025.102210","url":null,"abstract":"<div><div>We present a new lithosphere-asthenosphere boundary (LAB) depth map of Iberia and adjacent areas built using <span><math><mrow><mo>∼</mo></mrow></math></span>34500 Sp receiver functions from 998 broadband seismic stations, alongside an updated Ps-derived crustal thickness map of Iberia. We found an overall shallow LAB, with a minimum depth of 70–80 km in areas of Cenozoic extension such as the eastern coast of Iberia and the Gibraltar-Alboran subduction back-arc, as well as in the Massif Central and the tectonically stable northwest of Iberia. LAB depths from 90 km to 110 km were only found within the areas of thickened crust in north-central Iberia and bordering the Gulf of Cádiz. The much deeper (150–180 km) oceanic LAB of the Gibraltar-Alboran slab was also imaged in the western Gibraltar Arc. Sublithospheric negative-velocity gradients (NVG) in the 110–140 km depth range are widespread in the back-arc of the Gibraltar-Alboran subduction system and in north-central Iberia, picturing a layered asthenospheric structure. In the Gibraltar Arc, the detachment of the slab through the subduction-transform edge propagator fault in the eastern Betics seems linked to the formation of the NVG, which are limited to the north by this structure.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 1","pages":"Article 102210"},"PeriodicalIF":8.9,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620320","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 : 2025-11-05DOI: 10.1016/j.gsf.2025.102206
Yutong Su , Renbiao Tao , Zhijun Jin , Runchao Liu , Yunhua Fu , Lu Wang , Haozhe Zhang
Metal hydrides are essential materials with broad scientific and technological significance, showing unique properties in the fields of energy storage, catalysis, and superconductivity. Inspired by material science, we propose that natural hydrides can form in the Earth’s sedimentary basins due to existing favorable basis of matter and energy, which may provide a new perspective on understanding the geological origin and storage of natural hydrogen. In this study, we use a high-pressure gas reaction analyzer system to explore the hydrogenation reaction of typical transition metal powders (i.e., titanium (Ti), vanadium (V), chromium (Cr), and manganese (Mn)) under 50–200 °C and 3–5 MPa conditions relevant to sedimentary basins, and find that the hydrogenation reaction processes show apparent temperature dependence and can be efficiently promoted by pressure. Titanium exhibits a strong affinity for hydrogen, and its reaction with hydrogen is the largest among the four metals. The affinity of vanadium is second only to titanium. The affinity of chromium and manganese is at a similarly low level. As the temperature rises, the reaction quantity of titanium with hydrogen continues to increase; in contrast, the reaction quantity of vanadium and manganese with hydrogen shows a trend of first decreasing and then increasing; at 3 MPa, the reaction quantity of chromium with hydrogen shows a trend of first decreasing and then increasing, and at 5 MPa, the reaction quantity of chromium with hydrogen shows a trend of first increasing and then decreasing. After the in-situ hydrogenation experiments, combined XRD, ToF-SIMS, and NMR analysis on the quenched samples confirm the formation and stability of metal hydrides. Our study not only reveals the possibility of forming metal hydrides in sedimentary basins but also deepens our understanding of the metal-hydrogen interaction mechanism, providing a specific research basis for the formation of hydrides in shallow basins, which sheds light on the search for natural hydrides in sedimentary basins as a new energy source in the future.
{"title":"Experimental simulation of the formation processes of natural metal hydrides in sedimentary basins","authors":"Yutong Su , Renbiao Tao , Zhijun Jin , Runchao Liu , Yunhua Fu , Lu Wang , Haozhe Zhang","doi":"10.1016/j.gsf.2025.102206","DOIUrl":"10.1016/j.gsf.2025.102206","url":null,"abstract":"<div><div>Metal hydrides are essential materials with broad scientific and technological significance, showing unique properties in the fields of energy storage, catalysis, and superconductivity. Inspired by material science, we propose that natural hydrides can form in the Earth’s sedimentary basins due to existing favorable basis of matter and energy, which may provide a new perspective on understanding the geological origin and storage of natural hydrogen. In this study, we use a high-pressure gas reaction analyzer system to explore the hydrogenation reaction of typical transition metal powders (i.e., titanium (Ti), vanadium (V), chromium (Cr), and manganese (Mn)) under 50–200 °C and 3–5 MPa conditions relevant to sedimentary basins, and find that the hydrogenation reaction processes show apparent temperature dependence and can be efficiently promoted by pressure. Titanium exhibits a strong affinity for hydrogen, and its reaction with hydrogen is the largest among the four metals. The affinity of vanadium is second only to titanium. The affinity of chromium and manganese is at a similarly low level. As the temperature rises, the reaction quantity of titanium with hydrogen continues to increase; in contrast, the reaction quantity of vanadium and manganese with hydrogen shows a trend of first decreasing and then increasing; at 3 MPa, the reaction quantity of chromium with hydrogen shows a trend of first decreasing and then increasing, and at 5 MPa, the reaction quantity of chromium with hydrogen shows a trend of first increasing and then decreasing. After the in-situ hydrogenation experiments, combined XRD, ToF-SIMS, and NMR analysis on the quenched samples confirm the formation and stability of metal hydrides. Our study not only reveals the possibility of forming metal hydrides in sedimentary basins but also deepens our understanding of the metal-hydrogen interaction mechanism, providing a specific research basis for the formation of hydrides in shallow basins, which sheds light on the search for natural hydrides in sedimentary basins as a new energy source in the future.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 1","pages":"Article 102206"},"PeriodicalIF":8.9,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526144","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 : 2025-11-04DOI: 10.1016/j.gsf.2025.102208
Shiqi Liu , Ping Wang , Jingjie Yu , Renjie Zhou , Bing Bai , Olga I. Gabysheva , Natalia L. Frolova , Sergey P. Pozdniakov
Warming-driven acceleration of hydrological processes is altering the carbon cycle in permafrost-dominated Arctic regions, yet the underlying drivers remain unclear. This study analyzes ArcticGRO data (2003–2021) from six major Arctic rivers (Ob, Yenisei, Lena, Kolyma, Yukon, and Mackenzie) to investigate trends and spatial–temporal variations in riverine particulate organic carbon (POC). The annual POC flux from these six rivers, estimated using the Load Estimator (LOADEST), averaged 2.78 Tg. Only the Lena River showed a notable annual decrease in POC flux (−3.9%/yr, p < 0.001) and concentration (−12%/yr, p < 0.001), while the Yukon River exhibited increasing streamflow (+0.98%/yr, p < 0.001) and POC flux (+3.2%/yr, p < 0.001). POC flux variations were primarily governed by streamflow and POC concentration, with higher concentrations in spring floods period and lower during winter. Spatial differences were linked to drainage density (Dd) and forest coverage (Fc). The Yukon River basin, with a higher Dd of 0.2 km/km2 and lower Fc approximately 24%, exhibits the highest POC concentrations (2.3 mg/L). In contrast, the Yenisei River basin has the lowest POC concentration (∼0.4 mg/L), along with a relatively low drainage density (Dd = 0.18 km/km2) and a high forest cover (Fc = 67%). Permafrost conditions constrained riverine POC export, with isotopic evidence indicating a shift from a carbon sink to a source, as POC carbon age increased by ∼ 200 to 1700 years (4%–68%) annually, peaking in winter (700–2500 years) after 2012. Rivers with lower permafrost coverage (e.g., Ob, Yenisei), exhibit higher winter POC fluxes contributions (10%–20%), while others contributed < 5%, suggesting the role of permafrost degradation in winter carbon export. This study emphasizes the need to assess climate-driven hydrological shifts and permafrost thaw in shaping Arctic land-to-ocean carbon fluxes.
{"title":"Changes in hydrological regime regulate POC export across permafrost-dominated Arctic River basins","authors":"Shiqi Liu , Ping Wang , Jingjie Yu , Renjie Zhou , Bing Bai , Olga I. Gabysheva , Natalia L. Frolova , Sergey P. Pozdniakov","doi":"10.1016/j.gsf.2025.102208","DOIUrl":"10.1016/j.gsf.2025.102208","url":null,"abstract":"<div><div>Warming-driven acceleration of hydrological processes is altering the carbon cycle in permafrost-dominated Arctic regions, yet the underlying drivers remain unclear. This study analyzes ArcticGRO data (2003–2021) from six major Arctic rivers (Ob, Yenisei, Lena, Kolyma, Yukon, and Mackenzie) to investigate trends and spatial–temporal variations in riverine particulate organic carbon (POC). The annual POC flux from these six rivers, estimated using the Load Estimator (LOADEST), averaged 2.78 Tg. Only the Lena River showed a notable annual decrease in POC flux (−3.9%/yr, <em>p</em> < 0.001) and concentration (−12%/yr, <em>p</em> < 0.001), while the Yukon River exhibited increasing streamflow (+0.98%/yr, <em>p</em> < 0.001) and POC flux (+3.2%/yr, <em>p</em> < 0.001). POC flux variations were primarily governed by streamflow and POC concentration, with higher concentrations in spring floods period and lower during winter. Spatial differences were linked to drainage density (<em>Dd</em>) and forest coverage (<em>Fc</em>). The Yukon River basin, with a higher <em>Dd</em> of 0.2 km/km<sup>2</sup> and lower <em>Fc</em> approximately 24%, exhibits the highest POC concentrations (2.3 mg/L). In contrast, the Yenisei River basin has the lowest POC concentration (∼0.4 mg/L), along with a relatively low drainage density (<em>Dd</em> = 0.18 km/km<sup>2</sup>) and a high forest cover (<em>Fc</em> = 67%). Permafrost conditions constrained riverine POC export, with isotopic evidence indicating a shift from a carbon sink to a source, as POC carbon age increased by ∼ 200 to 1700 years (4%–68%) annually, peaking in winter (700–2500 years) after 2012. Rivers with lower permafrost coverage (e.g., Ob, Yenisei), exhibit higher winter POC fluxes contributions (10%–20%), while others contributed < 5%, suggesting the role of permafrost degradation in winter carbon export. This study emphasizes the need to assess climate-driven hydrological shifts and permafrost thaw in shaping Arctic land-to-ocean carbon fluxes.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 1","pages":"Article 102208"},"PeriodicalIF":8.9,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526176","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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