Geoscience frontiers最新文献

{"title":"Fine characterization of micro-nano fractures and analysis of network connectivity: Mechanistic controls on hydrocarbon enrichment in shale reservoirs","authors":"Boyang Wang ,&nbsp;Dengfu Yuan ,&nbsp;Jingjing Li ,&nbsp;Shichao Li ,&nbsp;Fei Xiao ,&nbsp;Shansi Tian ,&nbsp;Mengjing Yin ,&nbsp;Jianguo Yang","doi":"10.1016/j.gsf.2025.102233","DOIUrl":"10.1016/j.gsf.2025.102233","url":null,"abstract":"<div><div>Micro-nano fractures serve as the bridge connecting nanopores and macro-fractures. The unclear understanding of their developmental characteristics and controlling factors significantly hinders the large-scale, efficient development of continental shale oil. To address this, this study employs the entropy weight method to establish an evaluation model for fracture development strength that comprehensively considers fracture number, average width, areal density, and areal porosity. Additionally, topology is introduced to evaluate fracture connectivity. The research clarifies the differences in micro-nano fracture developmental characteristics and primary controlling factors among different lithofacies and elucidates the impact of micro-nano fracture development on pore structure and hydrocarbon accumulation in Gulong shale. The results indicate that the HQS (high-organic laminated felsic shale) lithofacies exhibits high micro-nano fracture development strength and connectivity, yielding the highest comprehensive evaluation index. The HCS (high-organic laminated mixed shale) shows high development strength but low connectivity, resulting in a secondary comprehensive evaluation index. Higher organic matter content correlates with greater fracture development strength; clay mineral content controls the characteristics of nano-fracture development; felsic mineral content positively influences fracture connectivity. The development of micro-nano fractures not only enhances macropore content and average pore size but also effectively connects pores of various scales, increasing the effectiveness of the pore-fracture system. Lithofacies with low fracture connectivity (primarily HCS) exhibit more complex pore structures. Shale oil in such lithofacies mainly accumulates via a self-sealing model, making it difficult to form complex fracture networks during hydraulic fracturing and hindering efficient development. Conversely, the HQS lithofacies demonstrates optimal pore-fracture connectivity, favorable oil content, and represents the most favorable lithofacies for Gulong shale oil development. These findings contribute to the optimization of sweet-spot intervals for shale oil exploration in the study area.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102233"},"PeriodicalIF":8.9,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797718","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}

{"title":"Probabilistic quantification of global drought risk amplification from temperature-enhanced evapotranspiration under climate change","authors":"Akinwale T. Ogunrinde ,&nbsp;Paul Adigun ,&nbsp;Xian Xue ,&nbsp;Koji Dairaku ,&nbsp;Sabab Ali Shah ,&nbsp;Ifeoluwa S. Adawa","doi":"10.1016/j.gsf.2025.102235","DOIUrl":"10.1016/j.gsf.2025.102235","url":null,"abstract":"<div><div>Droughts pose escalating threats to global water security, agriculture, and socioeconomic stability amid anthropogenic climate change, with projections indicating an increase in frequency, duration, and severity driven by altered precipitation patterns and amplified evaporative demand. This study introduces a probabilistic framework to quantify drought risk amplification, employing the Risk Ratio (RR) methodology integrated with extreme value theory and non-parametric inference. Utilizing multi-model ensemble (MME) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) under Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5), we evaluate changes in drought characteristics—duration, frequency, and severity — via the Standardized Precipitation Evapotranspiration Index (SPEI) at 3- and 12-month timescales for near-future (NF) and far-future (FF) periods. Our analyses reveal pervasive global intensification, with over 90% of land grids exhibiting positive severity shifts under SSP5-8.5 in the FF, attributed to atmospheric evaporative demand, which accounts for approximately 44% of the trends in SPEI. Threshold-stratified RR assessments reveal nonlinear escalations at higher percentiles (P90 vs. P75), compressing the return periods of extreme events by 20%–30% under high-emission scenarios. Regional hotspots, including the Amazon basin, sub-Saharan Africa, southwestern North America, and Central Asian drylands, exhibit frequency risks that are 4-fold or more amplified, signaling transitions to chronic water stress and potential ecosystem tipping points. These findings underscore the dominance of thermodynamic drivers in drought dynamics, advocating for emissions mitigation to curtail risks by 15%–25% under moderate pathways. By addressing uncertainties in non-stationary regimes, this framework provides adaptive strategies for resilient water management, offering policymakers critical insights to mitigate cascading impacts on global food security and biodiversity in a warming world.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102235"},"PeriodicalIF":8.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797652","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}

{"title":"First observation of coexisting crystalline and amorphous mineral phases in the Bhawad LL6 chondrite: Evidence from Micro-Raman spectroscopic studies","authors":"Bhaskar J. Saikia ,&nbsp;G. Parthasarathy ,&nbsp;Binoy K. Saikia ,&nbsp;Puja Bordoloi ,&nbsp;Rashmi R. Borah","doi":"10.1016/j.gsf.2025.102236","DOIUrl":"10.1016/j.gsf.2025.102236","url":null,"abstract":"<div><div>We report here for the first time the detailed spectroscopic investigations on Bhawad meteorite using micro-Raman spectroscopic and high-resolution transmission electron microscopy (HR-TEM) investigation of the Bhawad LL6 ordinary chondrite, focusing on its mineralogical composition and carbonaceous phases. Raman spectroscopy reveals crystalline silicates including olivine, pyroxene, and plagioclase, along with accessory chromite containing ≤20% of Al. Carbonaceous material exhibits broad <em>I</em>_D (∼1336 cm⁻¹) and <em>I</em>_G (∼1587 cm⁻¹) bands with an <em>I</em>_D/<em>I</em>_G ratio of ∼1.04, indicative of disordered graphite and nanocrystalline carbon, reflecting shock-induced metamorphism. High-pressure TiO₂ polymorphs are identified by characteristic Raman modes at 146, 394, 446, and 610 cm⁻¹. HR-TEM imaging confirms the presence of nanocrystalline TiO₂ particles embedded within amorphous carbonaceous matrices, demonstrating the coexistence of crystalline and amorphous phases. The Raman spectra of the Bhawad meteorite reveal the presence of high-temperature plagioclase phases, characterized by these distinct vibrational features. This observation indicates possible quenching of the melts having feldspar components, representing the complex thermal and shock metamorphic history of the meteorite. This coexistence of crystalline and amorphous phases highlights the complex thermal and shock history of the Bhawad meteorite, revealing insights into phase transitions and structural order–disorder phase transition induced by impact processes.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102236"},"PeriodicalIF":8.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797653","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}

{"title":"Physics-informed dictionary learning of time-varying 3D settlements from sparse monitoring data and 2D numerical models with consideration of complex stratigraphy","authors":"Dan-Ni Zhang ,&nbsp;Hua-Ming Tian ,&nbsp;Yu Wang ,&nbsp;Chao Shi ,&nbsp;Kostas Senetakis","doi":"10.1016/j.gsf.2025.102222","DOIUrl":"10.1016/j.gsf.2025.102222","url":null,"abstract":"<div><div>Digital twins of geotechnical structures replicate their physical counterparts, such as underground spaces developed from land reclamations. These spaces often exhibit intricate three-dimensional (3D) stratigraphic distributions, including irregular and interbedded soil layers. Developing a virtual 3D model, such as finite element model (FEM), with complex stratigraphy poses significant computational challenges due to the necessity for numerous stratum voxels, high-resolution meshing, and prohibitive analysis times. Incorporating field settlement data for model updating escalates the computational burden, as repeated evaluations of 3D FEM models are required for each model updating. To address this challenge, this study develops a novel approach for efficiently predicting time-varying 3D settlement from two-dimensional (2D) numerical models with sparsely measured monitoring data. Settlements from 2D FEM analyses, which account for complex stratigraphy, are compiled within a dictionary learning framework and combined with limited monitoring data to estimate time-varying settlements at multiple 2D cross-sections. The 2D settlements are then utilized to reconstruct high-resolution 3D settlements through 3D compressive sampling (3D-CS), eliminating a need for additional numerical model evaluations when integrating new monitoring data. The proposed approach is illustrated using a reclamation project in Hong Kong, China.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102222"},"PeriodicalIF":8.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797654","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}

{"title":"Fast production of large lithologic maps using lithologic sample generation strategies based on 3D spatial positioning","authors":"Tao Zhang ,&nbsp;Zhifang Zhao ,&nbsp;Min Zeng ,&nbsp;Haiying Yang","doi":"10.1016/j.gsf.2025.102217","DOIUrl":"10.1016/j.gsf.2025.102217","url":null,"abstract":"<div><div>The acquisition of spatiotemporal information for lithological mapping with timeliness, accuracy, and high precision is crucial for mineral resource exploration and geological hazard prevention. However, large-scale lithological mapping remains severely constrained by the limitations of visual interpretation in obtaining representative samples from remote sensing data and error propagation during sample collection based on existing geological maps. To address this, we propose a three-dimensional spatial dual-positioning sample generation methodology (SG-3DSD) using Sentinel-2 (S2) and Landsat 8 (L8) data on the Google Earth Engine (GEE) platform, enabling automated generation of 11 lithological class samples across the Beishan region of Gansu Province, China (covering approximately 6,000 km²). First, boundary association rules were established to reconstruct 1:200,000-scale geological maps, mitigating data acquisition biases and cartographic compilation errors. Second, principal component analysis (PCA) was performed on seven S2 spectral bands, with the first three principal components (capturing &gt; 98% information variance) constituting a 3D feature space for localized clustering. Concurrently, four L8 bands were selected through lithological spectral curve analysis to implement band ratio (BR) transformations for secondary positioning. Finally, a two-step refinement strategy was implemented to filter high-confidence samples across 11 lithological classes, balancing intraclass feature consistency and sample purity. Applying SG-3DSD-derived samples to multiple machine learning models revealed that (1) the Stacking ensemble model demonstrated superior lithological discrimination capability compared to conventional algorithms, achieving peak accuracy of 94.15% and mean F1-score of 93.87%; (2) integrating topographic data (especially Elevation) enhanced lithological positioning accuracy by 4.43% ± 1.13%; (3) PCA and BR transformations effectively enhanced lithological separability, particularly at lithological boundary zones; (4) while SG-3DSD enables efficient large-scale sample generation, it is advisable to avoid using excessively large training samples for regional-scale mapping. This methodology mitigates the weighting dependence on geological maps during sample selection and dilutes inherent cartographic error propagation, providing a novel paradigm for large-scale lithological mapping with broad application potential.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102217"},"PeriodicalIF":8.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748586","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}

{"title":"Knowledge-based data-driven prediction of shield tail clearance under karst geological condition","authors":"Wengang Zhang ,&nbsp;Han Han ,&nbsp;Weixin Sun ,&nbsp;Yunhao Wang ,&nbsp;Zhihao Wu ,&nbsp;Peng Xiao ,&nbsp;Yumiao Yan","doi":"10.1016/j.gsf.2025.102221","DOIUrl":"10.1016/j.gsf.2025.102221","url":null,"abstract":"<div><div>Precise control of shield tail clearance is a critical factor influencing the safety and quality of shield tunneling construction. Although various methods exist for accurately measuring shield tail clearance, predictive capabilities remain insufficient. This study is based on a shield tunnel project in the karst region of Longgang, Shenzhen, China. By integrating geological parameters obtained from advanced geological prediction with shield construction monitoring data, a predictive calculation method for shield tail clearance is developed, grounded in the spatial relationship between the shield machine and the pipe segments. A knowledge-based data-driven prediction approach is proposed using a Transformer-LSTM deep learning model. Case analysis demonstrates that the proposed Transformer–LSTM model consistently outperformed baseline models such as GRU, LSTM, and pure Transformer. The predicted <em>R</em>² values for the four positions of the shield tail—top, bottom, left, and right—reached 0.990, 0.901, 0.976, and 0.908, respectively, while error indicators (MAE, RMSE, and MAPE) were also minimized. These results confirm that the proposed hybrid approach effectively captures both global dependencies and temporal dynamics, enabling accurate prediction of shield tail clearance and offering practical engineering significance for guiding shield tunneling construction.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102221"},"PeriodicalIF":8.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748664","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}

{"title":"Genesis of shallow-water manganese nodules with uniquely high Mn/Fe ratios","authors":"Hyo Jin Koo ,&nbsp;Hyen Goo Cho ,&nbsp;Young Keun Jin ,&nbsp;Dong-Hun Lee ,&nbsp;Ji-Hoon Kim ,&nbsp;Tae Siek Rhee ,&nbsp;Jong Kuk Hong ,&nbsp;Sung Keun Lee","doi":"10.1016/j.gsf.2025.102219","DOIUrl":"10.1016/j.gsf.2025.102219","url":null,"abstract":"<div><div>While manganese (Mn) nodules are authigenic metal concretions that form predominantly on deep-sea seafloor, they have also been found along shallow seafloors. The formation environments of these nodules — deep sea <em>vs.</em> shallow water — often result in distinct chemical and morphological characteristics. As Mn is one of the essential components of energy-storing technologies, assessing the proper estimation of Mn and metal contents in both deep- and shallow-water Mn nodules is critical. It has been found that the Mn content of shallow-water nodules is often lower than that from deep-sea environments. Here, we report the discovery of shallow-water Mn nodules with exceptionally high Mn/Fe ratios on the continental slope of the East Siberian Sea, Arctic Ocean. Despite their shallow-water origin, Mn nodules show morphological and chemical characteristics that are typically unique to deep-sea nodules. These distinctive features, including exceptionally high Mn/Fe ratios, may reflect suboxic diagenesis and the preferential remobilization and re-precipitation of Mn from the adjacent continental shelf. The formation of high Mn/Fe nodules may reflect unique ocean circulation patterns that provided oxygenated bottom waters to the study area. Particularly, Pacific Water entering through the Bering Strait, which overlaps with the nodule formation depth (160 – 240 m) and is enriched in dissolved oxygen, could facilitate Mn-rich nodule growth under suboxic diagenetic conditions since the Holocene. Shallow-water Mn nodules with uniquely high Mn/Fe ratios may offer a novel paleo-environmental proxy for reconstructing paleohydrology and bio-geochemical evolutions in shallow marine environments.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"17 2","pages":"Article 102219"},"PeriodicalIF":8.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748581","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}

{"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 ,&nbsp;Cristiano Lana ,&nbsp;Davi Carvalho ,&nbsp;Gabriel J. Uhlein ,&nbsp;Carolina Reis ,&nbsp;Paulo Henrique A. Dias ,&nbsp;Denise Canabrava ,&nbsp;Juliana Okubo ,&nbsp;George Luiz Luvizotto ,&nbsp;Lucas Warren ,&nbsp;Shuhai Xiao ,&nbsp;Tian Gan ,&nbsp;Galen Halverson ,&nbsp;Peter Crockford ,&nbsp;Kristin Bergmann ,&nbsp;Katharine W. Huntington ,&nbsp;Andrew J. Schauer ,&nbsp;Mariana M. Leite","doi":"10.1016/j.gsf.2025.102218","DOIUrl":"10.1016/j.gsf.2025.102218","url":null,"abstract":"&lt;div&gt;&lt;div&gt;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 (&lt;em&gt;T&lt;/em&gt;&lt;sub&gt;Δ47&lt;/sub&gt;) 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 &lt;em&gt;δ&lt;/em&gt;&lt;sup&gt;13&lt;/sup&gt;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 &lt;em&gt;T&lt;/em&gt;&lt;sub&gt;Δ47&lt;/sub&gt; 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 &lt;em&gt;T&lt;/em&gt;&lt;sub&gt;Δ47&lt;/sub&gt; 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}

{"title":"Multi-modal characterization of ultramafic rock: Precursors relevant to serpentinization and hydrogen generation","authors":"Jiejie Li ,&nbsp;Emma Black ,&nbsp;Christopher Miller ,&nbsp;Kunning Tang ,&nbsp;Peyman Mostaghimi ,&nbsp;Andrew Feitz ,&nbsp;T.David Waite ,&nbsp;Ryan T. Armstrong","doi":"10.1016/j.gsf.2025.102220","DOIUrl":"10.1016/j.gsf.2025.102220","url":null,"abstract":"<div><div>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.</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}

{"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 ,&nbsp;Lijuan Cui ,&nbsp;Wei Li ,&nbsp;Xinsheng Zhao ,&nbsp;Chenxi Liu ,&nbsp;Hua Ma ,&nbsp;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⁻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.</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}