Applied Geochemistry最新文献

{"title":"Indication of triple oxygen isotopes to replenishment mechanisms and evaporation processes in Yongding River Basin, North China","authors":"Yaxin Zhu ,&nbsp;Guilin Han ,&nbsp;Di Wang ,&nbsp;Shitong Zhang ,&nbsp;Xi Gao","doi":"10.1016/j.apgeochem.2025.106427","DOIUrl":"10.1016/j.apgeochem.2025.106427","url":null,"abstract":"<div><div>Urban rivers are important water sources for surrounding agglomerations. Understanding their hydrological processes is crucial for the sustainable water resource development. However, driven by societal demands, extensive human projects to rivers have introduced uncertain consequences for the water cycle in the basin. Therefore, employing the advanced triple oxygen isotopes technique and correlation analysis, the study examined the effects of human intervention on urban river hydrology in Beijing-Tianjin-Hebei region. The results illustrated that the average values of δ²H, δ¹⁸O and δ¹⁷O were at a high level, which effectively reflect the influence of human activities. In conjunction with previous studies, the supplementary effects of anthropogenic water sources and natural replenishment on river discharge were investigated. Besides, the additional evaporation caused by artificial water retention was quantified by using the isotope model. The results elucidated that Guanting Reservoir caused 8.7 % evaporation across the river, and a substantial volume of agricultural water also promoted the evaporation of local river sections. Overall, the study reveals the triple oxygen isotopes signatures in urban rivers, deeply explores and quantifies the effect of anthropic activities on the water cycle process, offering a scientific foundation for the continuable exploitation of regional water resources.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106427"},"PeriodicalIF":3.1,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin of composite fibrous carbonate veins in Middle Jurassic ultra-low-ash coal, Ordos Basin, China: Insights on the interaction between organic carbon and inorganic carbonates after peat burial","authors":"Jintian Zheng ,&nbsp;Shifeng Dai ,&nbsp;Victor P. Nechaev ,&nbsp;David French ,&nbsp;Ian T. Graham ,&nbsp;Na Wang ,&nbsp;Pan Yang ,&nbsp;Shuai Kang ,&nbsp;Mengda Yao ,&nbsp;Yang Liang","doi":"10.1016/j.apgeochem.2025.106430","DOIUrl":"10.1016/j.apgeochem.2025.106430","url":null,"abstract":"<div><div>Valuable geological information on coal is contained within both the organic and inorganic constituents. Buried organic matter and precipitated carbonate minerals, as key elements of the lithospheric carbon reservoir, raise questions about whether their co-occurrence in coal is coincidental or reflects an underlying connection. Authigenic carbonate minerals in coal exhibit diverse species (e.g., siderite, calcite, and the ankerite-dolomite series) and morphologies (e.g., coal balls; nodules; and cell-, cleat- and fracture-filling forms), reflecting various formation processes during coalification. Fibrous carbonate veins in black shales consist of elongated calcite crystals with large aspect ratios (a rare calcite habit), and are associated with hydrocarbon fluid activity. However, the identification, formation mechanism, and material sources of fibrous carbonate veins within coal remains unclear. To resolve this problem, detailed petrographic, mineralogical, and geochemical analyses were conducted on the middle Jurassic No. 2(2) coal of the Ordos Basin, China, including stable isotopic analysis of carbon and oxygen in composite carbonates excluding siderite. The No. 2(2) coal seam is classified as an ultra-low-ash, super-low-sulfur, and high volatile B bituminous coal, according to the Chinese national standards GB/T 15224.1-2018, GB/T 15224.2-2021, and ASTM Standard D388-23, respectively. It contains abundant fusinite and semifusinite fragments dispersed in collodetrinite. Compared with average world coals, only Sr in the coal is slightly enriched. The carbonates in the coal (33.5 %; low temperature ash basis) consist of calcite, ankerite, and siderite. The values of <em>δ</em>¹³C_VPDB and <em>δ</em>¹⁸O_VPDB associated with composite carbonate veins (calcite and ankerite) range from −34.87 ‰ to −11.43 ‰ and from −14.66 ‰ to −10.84 ‰, respectively. Two types of high-ash yield intervals (Si-rich and Ca-rich) were identified within the low-ash coal seam. The Si-rich benches are attributed to the influx of Si–Al-rich fluids during peat accumulation. Composite carbonate veins, which formed during coalification, represent another source for inorganic matter in high-ash intervals (Ca-rich). Optical and electron microscope observations, together with carbon-oxygen isotopic analyses, indicate that overpressurised fluids from coal maturation and methane oxidation led to <em>in situ</em> coal fracturing, followed by the formation of composite fibrous carbonate veins and crack-seal structures in low-ash coal. Based upon these results, a model for the formation of fibrous carbonate veins within low-ash coal from the Cuijiagou mine is proposed to facilitate an understanding of the carbon transformation from organic matter to minerals after peat burial.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"188 ","pages":"Article 106430"},"PeriodicalIF":3.1,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine-learning applications for magmatic–hydrothermal systems: Quartz trace-element insights into ore deposits","authors":"Denghui Zhu ,&nbsp;Jiajie Wang ,&nbsp;Tatsu Kuwatani ,&nbsp;Noriyoshi Tsuchiya","doi":"10.1016/j.apgeochem.2025.106431","DOIUrl":"10.1016/j.apgeochem.2025.106431","url":null,"abstract":"<div><div>Magmatic–hydrothermal activity is critical in ore genesis, as it forms a variety of economically significant ore deposits. Quartz chemistry is key to identifying the types and origins of such deposits; however, conventional analytical methods that use binary/ternary quartz trace-element plots are insufficient for elucidating the full complexity of quartz chemistry. To address this limitation, machine learning is applied to analyze high-dimensional quartz chemistry and improve the identification accuracy. We compiled 8710 quartz samples from a range of geological environments including various host rocks and ore deposits derived from I-, S-, and A-type magmas, and examined 18 trace elements. We developed two approaches—eXtremely Greedy tree Boosting-Recursive Feature Elimination-SHapley Additive exPlanations (XGBoost-RFE-SHAP), and Principal Component Analysis-Uniform Manifold Approximation and Projection (PCA-UMAP)—to discriminate these geological environments based on quartz trace elements. XGBoost-RFE-SHAP achieved highly accurate discrimination and identified key quartz trace elements. B, Ti, P, Li, Ge and Al are key to identifying I-, S-, and A-type parental magmas. For rocks and ore deposits related to I-type magma, key discriminators include Ti, Ge, Al, Li, Sb, and P; for S-type magma, Ge, P, Ti, Al, Li, and B; and for A-type magma, Ti, P, K, Al, Rb, and As. PCA-UMAP generated plots for classifying rocks and ore deposits, revealing quartz trace-element patterns across various geological environments. This integrated approach enhances the understanding of magmatic–hydrothermal evolution and offers a powerful tool for identifying economically viable deposits, with potential applications in diverse geological settings.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106431"},"PeriodicalIF":3.1,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional geochemical survey of Canadian Arctic sediments: insights into provenance, sediment dynamics and trace metal enrichment","authors":"Camille Brice ,&nbsp;Jean-Carlos Montero-Serrano ,&nbsp;Richard Saint-Louis","doi":"10.1016/j.apgeochem.2025.106432","DOIUrl":"10.1016/j.apgeochem.2025.106432","url":null,"abstract":"<div><div>Major and trace element contents, grain size distribution and total organic carbon contents were measured in 141 marine surface and terrestrial sediment samples to study modern sediment dynamics in the Canadian Arctic (CA) and to provide an assessment of metal enrichment for V, Zn, Mn and Fe. Samples were collected from different areas between Baffin Bay and the Beaufort Sea during the ArcticNet 2016–2022 expeditions onboard the Canadian Coast Guard icebreaker Amundsen. Geochemical data combined with multivariate statistical analyses allowed the division of the CA into three chemical clusters (CC) and four regional provinces. Central CA (CC#1) and southeastern CA (CC#2) are mainly composed of relatively coarse sediments rich in detrital carbonates (Ca, Mg) and siliciclastic elements (Si, K, Zr), respectively, reflecting coastal erosion of surrounding land (e.g., Victoria Island, Baffin Island) and transport of sediment-laden sea ice. The sediments of CC#3, comprising western and eastern CA, are characterized by organic carbon and Fe–Mn oxyhydroxides. Western CA, which is also characterized by fine-grained aluminosilicates, is influenced by the Mackenzie River discharge, while eastern CA is shaped by polynyas and glacial erosion. The highest concentrations of V and Zn are recorded in the western CA. Over the whole region, significant positive correlations of Al with Zn, V and Fe suggest that lithogenic-derived inputs influence the distribution of these metals in sediments from the CA and that Fe oxides represent the main carrier phase. In western CA, Mn displays positive but weaker relationships with Al and Fe, suggesting a mixed source of Mn oxyhydroxides linked to both detrital fractions and authigenic processes near the sediment-water interface. High terrestrial Mn oxyhydroxide inputs from the Mackenzie River are remobilized and transported to areas with lower oxygen consumption in sediment, i.e., the Amundsen Gulf and Banks Island coasts, which leads to surface sediment enrichment in Mn. The enrichment factor and the geo-accumulation index, two pollution indices commonly used for identifying anthropogenic metal inputs, were also studied to evaluate their suitability in the context of this study. Discrepancies from the normalization of metals with a geochemical background and a normalizing element revealed that pollution indices should be used with caution. Overall, according to the pollution indices and the regional survey, the surface sediments of the CA show minor enrichment in trace metals and thus present natural concentrations relative to regional background values.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106432"},"PeriodicalIF":3.1,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of molybdenum immobilization mechanisms in naturally contaminated excavated rocks and soils stabilized with zero-valent iron","authors":"Maxime Brandely ,&nbsp;Samuel Coussy ,&nbsp;Denise Blanc-Biscarat ,&nbsp;Hicham Khodja ,&nbsp;Rémy Gourdon","doi":"10.1016/j.apgeochem.2025.106433","DOIUrl":"10.1016/j.apgeochem.2025.106433","url":null,"abstract":"<div><div>Chemical stabilization of naturally contaminated excavated materials could be used to limit environmental risks. Nevertheless, due to the low levels of contamination in such materials a more precise characterization of immobilization mechanisms is required. To overcome this lack of data, zero valent iron (Fe⁰) was used as a stabilizing agent at rates of 1 or 3 wt% in four different sets of excavated rock and soil from the Paris basin that were contaminated with low levels of molybdenum (with a total content of from 2 to 11 mg Mo kg⁻¹) but that involved leachability issues. Molybdenum (Mo) release was reduced by at least one order of magnitude after adding Fe⁰ over a wide pH range (i.e. 2 &lt; pH &lt; 12). Geochemical modeling of pH-dependent leaching tests was done to identify potential immobilizing mechanisms. For Mo, experimental results were well represented at pH close to and below the natural pH of the samples by considering surface adsorption with iron (hydr-)oxides involving non-, mono- and bi-protonated Mo surface species. Zero valent iron stabilization remained relatively significant under alkaline conditions where complexation of anionic species was not favored. These results suggested that stronger binding mechanisms are likely to occur concomitantly with surface adsorption. Finally, thanks to their high sensitivity, μ-particle-induced X-ray emission (μ-PIXE) and μ-Rutherford backscattering spectroscopy (μ-RBS) were successfully used to directly observe Mo presence in iron (hydr-)oxides formed after addition of Fe⁰.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"188 ","pages":"Article 106433"},"PeriodicalIF":3.1,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of near-surface waters in identifying elemental associations with geothermal-sourced Li","authors":"Andrew David Robinson ,&nbsp;Sanem Acikalin ,&nbsp;Gavin Stewart ,&nbsp;Brendan A. Bishop ,&nbsp;Leslie J. Robbins ,&nbsp;Shannon L. Flynn","doi":"10.1016/j.apgeochem.2025.106428","DOIUrl":"10.1016/j.apgeochem.2025.106428","url":null,"abstract":"<div><div>Unprecedented demand for lithium (Li) is being driven by its use in electric vehicle batteries. Currently, the majority of Li comes from pegmatite mining and salar brines, however, new sources such as geothermal brines will be required to meet future demand. The North Pennines, Northern England has been found to host brines with lithium concentrations exceeding 90 mg/L from 411 to 995 <em>m</em>. However, deep subsurface water chemistry for the region is limited to a single abandoned borehole, necessitating the use of other techniques in assessing the resource potential of these brines. This work investigated the potential of surface and near-surface water samples from abandoned mine workings to expand the known geographic extent of the underlying Li brine resource. Li concentrations were 1.9–784 μg/L at the 44 locations sampled. Principal component, cluster, and covariate analyses identified two distinct water chemistry clusters mostly related to dimension 1 of the PCA (22.5 % of variance) and included alkalinity, Ca, Cd, Cl, F, K, Li, Mg, Na, Se, and SO₄²⁻; the “near surface” or potentially orebody related group which included Al, As, Cu, Eu, Fe, P, Pb, V, and Y. Two smaller clusters are present on the positive and negative axis of dimension two (14.1 %); on the positive is B, Ba, Br, Cr, pH, and Si, and on the negative, Co, Mn, Ni, Sc, Sr, and Zn. The Cambokeels Mine, 0.5 km from the original borehole, had the highest Li concentration of 78.4 mg/L. However, the deep brine signature and Li enrichment were also found at a cluster of mines 15 km away, significantly expanding the geographical extent of the North Pennine Li brine resource. These findings show that relatively low-cost elemental analysis and statistical analyses could be a promising exploration tool for regions where there is limited data. Developing tools using geochemical finger printing of near-surface waters to identify Li resources in deeper geothermal brines will be essential for the cost-effective development of critical minerals.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"188 ","pages":"Article 106428"},"PeriodicalIF":3.1,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Permeate fluxes from desalination of brines and produced waters: A reactive transport modeling study","authors":"Sergi Molins ,&nbsp;Nicolas Spycher ,&nbsp;Sarah M. Dischinger ,&nbsp;Mostafa Nassr ,&nbsp;Ji Yeon Lee ,&nbsp;Jacob Johnston ,&nbsp;Nils Tilton ,&nbsp;Kristofer L. Gleason ,&nbsp;Benny D. Freeman ,&nbsp;William T. Stringfellow ,&nbsp;Daniel J. Miller","doi":"10.1016/j.apgeochem.2025.106429","DOIUrl":"10.1016/j.apgeochem.2025.106429","url":null,"abstract":"<div><div>The increasing interest in the use of membrane systems to desalinate inland brackish water, agricultural drainage, and industrially produced wastewater demands improved means of predicting desalination system performance under variable feedwater compositions. The interaction among water flow, solute transport, and chemical composition in these systems impacts permeate flux evolution. Here, an established multicomponent reactive transport simulator that accounts for these coupled processes is applied to compute osmotic pressure and permeate fluxes in reverse osmosis (RO) systems. The model is first validated by predicting permeate fluxes for a set of benchtop crossflow experiments subject to a range of feed flow rates and compositions, under fouling and non-fouling conditions. Results compare favorably with measured data that show that solutions with similar total dissolved solids concentrations but different compositions result in different permeate fluxes. The model is then applied to predict permeate fluxes from the desalination of produced waters using a commercial spiral wound RO module. For NaCl-dominant brines, at total dissolved salt concentrations (TDS) below about 70 g/L, permeate fluxes are inversely proportional to water mole fraction as the latter is a reasonable approximation of water activity (i.e. ideal mixing). In the case of Ca–Cl-, Na–CO₃- and Na–SO₄-dominant brines below about 70 g/L TDS, this relationship does not hold as well and tends to overpredict osmotic pressure and thus underpredict permeate fluxes. However, the opposite becomes true at higher TDS values for typical produced waters. The scaling potential of these waters is also computed by allowing the precipitation of minerals above their saturation limit on the RO membrane. This work demonstrates how reactive transport models developed for the analysis of waters from geological systems can be extended to improve process design, optimization, and control in desalination systems from produced waters and beyond.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106429"},"PeriodicalIF":3.1,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biogeochemical cycle of radium: Insights into alkaline-earth cations budget and evidence of hidden vegetation uptake","authors":"S. Rihs ,&nbsp;E. Lascar ,&nbsp;F. Chabaux ,&nbsp;L. Pourcelot ,&nbsp;P. Calmon ,&nbsp;P.O. Redon ,&nbsp;C. Galy ,&nbsp;M.P. Turpault","doi":"10.1016/j.apgeochem.2025.106418","DOIUrl":"10.1016/j.apgeochem.2025.106418","url":null,"abstract":"<div><div>The migration of radionuclides in the environment represents a major current issue, especially radium (Ra) that hold one of the main radiation exposure hazards among Naturally Occurring Radioactive Materials. This study aims to assess the biogeochemical radium cycling within a forested ecosystem and to highlight the relevance of Ra isotopes for understanding calcium and other alkaline earth cations behavior. This study was carried out at the INRAE-Andra experimental beech-forested site of Montiers (Meuse, France). ²²⁶Ra and ²²⁸Ra concentrations were measured in various compartments of the ecosystem: soil solutions, vegetation and soil samples. In-situ experiment of litter decomposition was also performed.</div><div>Variations in the ²²⁸Ra/²²⁶Ra isotopic ratio across ecosystem compartments allowed to distinguish between ²²⁸Ra-rich weathering inputs and ²²⁸Ra-poor biological return fluxes, thereby enabling to trace the radium cycle. Radium exported by soil solutions predominantly originates from litter decomposition which begins releasing radium only 12–18 months after litterfall. Conversely, the (²²⁸Ra/²²⁶Ra) ratio in fine roots implied that trees absorbed Ra primarily from mineral soil weathering rather than from litter-derived sources. As a result, approximately 95 % of litter-derived Ra remains in the soil rather than being reabsorbed by vegetation, challenging traditional assumptions of significant reabsorption in cation budget models.</div><div>Flux calculations showed vegetation uptake and return fluxes dominate over drainage or atmospheric inputs fluxes. (²²⁸Ra/²³²Th) radioactive disequilibrium within the soil enabled estimation of Ra leaching flux and subsequent vegetation uptake. Results revealed that 7–23 % of the absorbed Ra is incorporated into annual, non-perennial biomass, while 12–43 % is allocated to new biomass increments. Consequently, 34–80 % of the Ra absorbed by vegetation appears to accumulate in unexpected, presumably long-lived, perennial tree structures such as sapwood. These results imply sustained accumulation over multiple years in perennial tissues. While this immobilization of Ra within beech trees may not be generalizable to all tree species, it highlights the need for specific species of detailed analyses across all tree compartments - including radial variations in sapwood - to avoid underestimating vegetation uptake, particularly for alkaline-earth cations such as calcium.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"187 ","pages":"Article 106418"},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selective recovery of native copper from basalt tailings using alkaline glycinate solution","authors":"Wei Xiong ,&nbsp;Jonathan Yang ,&nbsp;Sophia Bauer","doi":"10.1016/j.apgeochem.2025.106416","DOIUrl":"10.1016/j.apgeochem.2025.106416","url":null,"abstract":"<div><div>Mafic and ultramafic rocks present an intriguing pathway for CO₂ capture through strategic enhancements to the natural silicate weathering cycle. Simultaneously, these rock types are often hosts to appreciable amounts of metals critical to U.S. energy independence, particularly in the context of alkaline mine tailings from historical metal mining. The research and scientific prerogative, then, is to identify promising mafic and ultramafic feedstocks and conduct exploratory studies to effectively recover these critical minerals while preserving the potential for mineral carbonation. The Keweenaw Peninsula of Michigan hosts the largest native Cu reservoir within basalt in the world and experienced a rich history of Cu production spanning from pre-historic times to the mid-1900s. Today, much of the Cu mining legacy remains as mine waste tailings. In this study, we examined the Cu extractability from Keweenaw Basalt tailings using a sodium glycinate solution, in comparison with acid and sodium hydroxide leaching. Experimental results showed an 85 % Cu extraction rate using sodium glycinate as the extraction solution with negligible release of other cations from the basalt. The kinetic and extraction mechanisms of Cu selective recovery using glycinate solution were discussed using time-resolved experimental data and kinetic geochemical modeling. Theoretical estimation of carbon mineralization potential of all the existing basalt waste tailings (∼500 million tons) can reach 85.5 MMT CO₂. A total of 0.786 MMT Cu can be recovered with sodium glycinate, with a value of 7.7 billion USD. This novel application of alkaline glycinate for selective Cu recovery from basalt mine tailings demonstrates the viability of selective metal recovery using a non-hazardous chemical while preserving CO₂ capture potential and presents a potential pathway toward reducing energy-related emissions and providing an unconventional domestic source of critical minerals.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"187 ","pages":"Article 106416"},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A study of palsa bog organic matter stabilization in response to holocene climate change using 13C NMR and FTICR MS","authors":"Roman Vasilevich ,&nbsp;Alexander Zherebker ,&nbsp;Oleg Kuznetsov","doi":"10.1016/j.apgeochem.2025.106417","DOIUrl":"10.1016/j.apgeochem.2025.106417","url":null,"abstract":"<div><div>The ¹³C NMR and high-resolution mass spectrometry (HRMS) methods have been employed to elucidate the principal pathways of soil organic matter (SOM) stabilization in the peat deposit of palsa bogs in the European Arctic. Extremes of labile/condensed constituents and structural moieties have been found to be related to climatic and hydrological conditions during different periods of the Holocene. The initial stage of SOM stabilization includes decomposition of plant residues, formation of (pro)humic substances (HSs) molecules from high-molecular-weight precursors, and primary transformation of HS molecules with degradation of the most labile fragments.</div><div>The more favorable climatic conditions of the Early Holocene (Atlantic Optimum) and Middle Holocene (SB2) determined the botanical composition of the peat, which was dominated by sedge and tree-sedge communities with high contents of lignin components and, as a consequence, a greater proportion of aromatic fragments, characterized by thermo-biodynamic resistance in the humic acids (HAs) of horizons in the lower and central parts of the profile. Older HAs, which underwent intense degradation were enriched in the N,S-containing components as compared to HAs from surface layers. This is in turn accompanied by an overall decrease in the proportion of unoxidised aliphatic and carbohydrate fragments. A substantial proportion of highly condensed fragments were identified in HAs by HRMS. It was suggested that aromatic and condensed HA molecules contain long-chain substituents which contribute to the content of aliphatic carbon. The ratio of pentosans to hexosans in HAs is demonstrated to increase down the peat profile as a consequence of the redistribution of the dominant peat formers. The HA branching indices demonstrate a significant transformation of long-chain structures and an increase in the contribution of substituted aliphatic fragments in the HA structure.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"187 ","pages":"Article 106417"},"PeriodicalIF":3.1,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}