Applied Geochemistry最新文献

{"title":"Influence of weathering-driven mineralogical evolution on phosphorite dissolution behavior","authors":"Bing Liu ,&nbsp;Caixiang Zhang ,&nbsp;Jidao Xie ,&nbsp;Mingjian Gao ,&nbsp;Shuxin Huang ,&nbsp;Ruihan Xiong ,&nbsp;Hao Luo","doi":"10.1016/j.apgeochem.2025.106502","DOIUrl":"10.1016/j.apgeochem.2025.106502","url":null,"abstract":"<div><div>The phosphorite dissolution and aqueous species release play a pivotal role in the global phosphorus (P) cycle. To elucidate differences in dissolution mechanisms between phosphorite of different weathering degrees, three phosphorite samples (with high, moderate, and low weathering degrees) were collected from field environments; then, a series of mineralogical characterizations coupled with dissolution experiments were conducted. Compared to primary phosphorite, weathered phosphorite exhibited substantial depletion of carbonate minerals, while silicate minerals and phosphate minerals were relatively enriched, and secondary minerals (e.g., FePO₄ and CaF₂) were formed. Furthermore, the dissolution rates of phosphorite samples within a pH range of 3–7 were determined using a mixed-flow reactor. The results demonstrated a negative linear relationship between the logarithm of dissolution rate and pH (R² = 0.54–0.94). The P release rate constant (from 0.7 to 1.52 mol g⁻¹ s⁻¹) and kinetic reaction order (from 0.58 to 0.74) of weathered phosphorite were significantly higher than those of primary phosphorite. We modeled the co-dissolution behavior of associated minerals with fluorapatite using transition state theory. Calcite exhibited the strongest inhibitory effect on fluorapatite dissolution, whereas the effects of other minerals were relatively weak. In the column leaching experiment, compared to the primary phosphorite, the elements released from weathered phosphorite were predominantly present in ionic forms with a higher migration capability. During the leaching process, phosphate minerals in phosphorite were mainly converted to Exchangeable/loosely bound P (Ex-P), Iron-bound P (Fe–P), and Calcium-bound P (Ca–P); Ca²⁺ and CO₃²⁻ were mainly converted to dolomite, and F⁻ was mainly converted to fluorite and fluorapatite. This systematic investigation provides critical insights into weathering-driven mineralogical evolution and its mechanistic control on phosphorite dissolution.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106502"},"PeriodicalIF":3.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655432","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":"Mechanisms controlling the release of inorganic contaminants, organic matter fractions, and ammonium from solid landfill waste: pH dependent leaching experiments and geochemical modelling","authors":"Frank van Raffe ,&nbsp;Joris J. Dijkstra ,&nbsp;Rob N.J. Comans","doi":"10.1016/j.apgeochem.2025.106503","DOIUrl":"10.1016/j.apgeochem.2025.106503","url":null,"abstract":"<div><div>With the intention of making landfilling more sustainable, three full-scale projects have been set up to investigate the effects of leachate recirculation and aeration on the stabilization of contaminants. Prior to this (an)aerobic stabilization, solid waste was sampled from all three landfills to identify the mechanisms behind contaminant leaching and stabilization, as a reference point for evaluation of the treatment effects at a later stage of the project. Processes underlying the leaching of a wide range of inorganic contaminants were identified using a combined approach of pH dependent leaching experiments, organic matter fractionation, and geochemical modelling. We additionally focused on organic matter, being an important surface controlling the leaching of inorganic elements, and ammonium, for which compliance with intended environmental limit values for sustainable landfill management is challenging for many landfills. Three types of pH dependent leaching behaviour could be identified for the investigated elements: non-reactive behaviour, anionic behaviour, and cationic behaviour. Reactive elements, including ammonium, showed maximum dissolved concentrations around the upper and lower ends of the pH range, while leaching of non-reactive elements was pH-independent. Organic matter became increasingly soluble with increasing pH, while its relative composition became increasingly enriched in fractions reactive for metal binding, most notably humic acid, only for the most organic landfill. The organic signature of the waste samples, together with their varying organic matter content, resulted in distinct differences in leaching behaviour between landfills. These differences result from the seemingly strong influence of organic matter on the pH at which minimum solubility of elements occurs, being lower for elements with higher organic matter binding affinity, an effect being more pronounced for more organic-rich samples. The model, based on independently determined generic sorption parameters, provided adequate descriptions of most elements, yet arsenic and ammonium were poorly described due to mechanisms not captured by the model while chromium was inadequately described due to limitations of the current binding parameters. As the three landfills have been shown to differ strongly with respect to waste properties (e.g. organic versus. inorganic) an important outcome of this study is that landfill-specific combinations of proposed treatment strategies (aeration, leachate recirculation) are necessary to reduce the leaching of specific contaminant groups to below limit values and are anticipated to be most effective for less mature landfills characterized by a lower ratio of solid to dissolved OM.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106503"},"PeriodicalIF":3.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665804","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":"Mechanisms of arsenic and iodine co-enrichment in shallow groundwater from typical fluvial plain and littoral plain of the Lubei plain in the lower Yellow River, China","authors":"Chongsheng Lu ,&nbsp;Wengeng Cao ,&nbsp;Xiangzhi Li ,&nbsp;Yu Ren ,&nbsp;Yanyan Wang","doi":"10.1016/j.apgeochem.2025.106504","DOIUrl":"10.1016/j.apgeochem.2025.106504","url":null,"abstract":"<div><div>High arsenic (As) and iodine (I) groundwater in shallow aquifers have been extensively investigated, but the co-enrichment under different environments is not well-understood. To address these issues, we explored the hydrochemistry of groundwater in typical fluvial plain (FP) and littoral plain (LP) of the Lubei Plain, and elucidated the source apportionment, further revealed its control mechanism on As and I enrichment. Results showed that the groundwaters in FP were mainly HCO₃–Mg·Ca and in LP were mainly Cl–Na. Silicate weathering (35.6 %), evaporite dissolution (26.9 %), and reductive dissolution (20.1 %) dominated hydrochemistry in FP, but in LP were evaporation-seawater intrusion (32.8 %) and silicate weathering (29.3 %), followed by reductive dissolution of Mn (22.5 %) and the Fe minerals (15.4 %). Furthermore, the reductive dissolution of Fe(III) and silicate weathering were the dominat processes for As and I co-enrichment. Specifically, groundwater As release were controlled by the reductive dissolution of Fe(III) and the competitive adsorption of HCO₃⁻ in LP, while promoted by the reductive dissolution of Fe(III) and silicate weathering in FP. Groundwater I enrichment were driven by silicate weathering and seawater intrusion in LP, but facilitated by reductive dissolution of Fe–Mn minerals and silicate weathering in FP. Risk assessment results showed a higher risk of groundwater As than I, especially for children both in LP (23.3 %) and FP (35.5 %). This work has enriched the co-enrichment mechanism of As and I, providing a basis for the safe utilization of groundwater in the Lubei Plain.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106504"},"PeriodicalIF":3.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655450","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":"The gangue sponge: implications for in-situ/heap leaching of chalcopyrite","authors":"Mareike Rosemann ,&nbsp;Barbara Etschmann ,&nbsp;Luis Verdugo ,&nbsp;Kalotina Geraki ,&nbsp;Nick D. Owen ,&nbsp;John O'Callaghan ,&nbsp;Nicolas Meisser ,&nbsp;Bin Hu ,&nbsp;Luke Vollert ,&nbsp;Joël Brugger","doi":"10.1016/j.apgeochem.2025.106500","DOIUrl":"10.1016/j.apgeochem.2025.106500","url":null,"abstract":"<div><div>As the demand for copper increases, processing increasingly low-grade ore has become a critical challenge. Most of these ores are dominated by aluminosilicate gangue minerals, among which Fe-bearing phyllosilicates are the most reactive. The effect of Fe-bearing minerals on the acid leaching of chalcopyrite, the most common primary Cu ore mineral was investigated by comparing mixtures of chalcopyrite with (i) chamosite, (ii) berthierine-chamosite, and (iii) pyrite. The lixiviant consisted of solutions with 0.1 <em>m</em> Fe₂(SO₄)₃ + 0.3 <em>m</em> H₂SO₄, and the experiments were conducted in an orbital shaking water bath at 50 °C for 43 days. The solution pH increased and Eh decreased for all systems, resulting in conditions that became less optimal for Cu recovery. Scanning electron microscope imaging highlighted the porous nature and variable elemental composition of the (partially) dissolved phyllosilicate minerals/amorphous-silica-residue after leaching. Micro X-ray Absorption Near Edge Structure (μXANES) measurements revealed that sulfur exists in multiple oxidation states both <em>within</em> the silicate gangue and <em>around</em> chalcopyrite, emphasising how the formation of an amorphous-silica-residue increased the complexity of the system. This complexity is related to the fact that (partial) dissolution of phyllosilicate gangue minerals during acid leaching results in the release of ions that change the solution chemistry; and form an amorphous-silica-residue, that contains numerous pores. These pores can act as local micro-reactors with non-equilibrium conditions and promote a heterogenous chemical composition. Subsequent mineral surface-fluid interactions in (partially) dissolved phyllosilicate/amorphous-silica-residue pores can vary, depending on the local chemical composition, making the leaching behaviour of chalcopyrite highly dependent on local conditions and on the mineralogical composition of the ores.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106500"},"PeriodicalIF":3.1,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670582","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":"Intermediate oxidation products from pyrrhotite grains in natural waste rock: A synchrotron study using Fe K-edge XANES","authors":"Lianna J.D. Smith ,&nbsp;Dogan Paktunc ,&nbsp;David W. Blowes","doi":"10.1016/j.apgeochem.2025.106501","DOIUrl":"10.1016/j.apgeochem.2025.106501","url":null,"abstract":"<div><div>Sulfide mineral oxidation releases acidity, sulfate, iron and trace element impurities to the environment. Iron K-edge X-ray absorption near edge spectra (XANES) were collected across transects of partially oxidized pyrrhotite grains in natural samples of waste rock and compared to measurements conducted on standards of ferric iron, ferrous iron, and compounds of mixed oxidation states. The XANES spectra were analyzed by pre-edge centroid deconvolution and linear combination fitting. Linear combination fitting of the pre-edge region and energy range of the XANES spectra (7070–7220 eV) produced best fits with differing species and higher ferric iron contributions (difference of typically f &lt; 0.1) than linear combination fitting of the XANES energy range. Deconvolution of the pre-edge centroids produced centroid energies that were correlated to the ferric iron contribution of the linear combination best fits of both the pre-edge and full spectrum, but a ferric iron content below a threshold value may affect the centroid energy. Ferrous iron standards that exhibited oxidation characteristics maintained a pre-edge centroid energy characteristic of ferrous iron species, and several transect spots at a calculated ferric iron contribution of f ≈ 0.2 exhibited a 0.6 eV range in pre-edge centroid energies. This study provides insight into sulfide oxidation mechanisms, including the formation and transformation of minerals, and implications for the retention and release of sulfide oxidation products and trace elements to the environment.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106501"},"PeriodicalIF":3.1,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670580","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":"Widespread occurrence of amphibole minerals in Paris urban dust samples: a mineralogical tracer of urban wear?","authors":"Pierre Le Pape ,&nbsp;Guillaume Morin ,&nbsp;Benoît Baptiste ,&nbsp;Thierry Allard ,&nbsp;Etienne Balan ,&nbsp;Ludovic Delbes ,&nbsp;Claire Carvallo ,&nbsp;Clara Vaccaro ,&nbsp;Maëva Philippe ,&nbsp;Sophie Ayrault ,&nbsp;Cécile Quantin ,&nbsp;Gaël Monvoisin ,&nbsp;François Guyot","doi":"10.1016/j.apgeochem.2025.106497","DOIUrl":"10.1016/j.apgeochem.2025.106497","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Manufactured infrastructures of urban areas, including buildings and roads, are contributors of solid particles to the environment due to wear processes and further weathering. Mineral dusts produced by such mechanisms are transported by air or water across urban compartments until they accumulate in surrounding natural and artificial sediment reservoirs, mixing with other minerals of geogenic sedimentary origin. With the expansion of artificialized urban surfaces over time, the contribution of urban-sourced minerals is expected to increase in sediment fluxes, thus taking an increasing importance in biogeochemical cycles. In this study, we postulate that mineral particles emitted from specific man-made materials could be traced in different compartments of urban environments on the basis of their mineralogical signature. Such identified urban mineralogical components could then serve as useful markers to monitor urbanization wear processes and subsequent emprise of urbanization at the regional scale. Here, we have analyzed a collection of urban samples, which comprises urban dusts, road sediment deposits, suspended particulate matter from the Seine and Orge rivers near Paris, and sediments accumulating in stormwater basins along high traffic roads in the Paris region (N118, N104). In almost all of the solid samples studied (n = 34), whose sampling span over a ten-year period, we show by powder X-ray diffraction (XRD) the presence of minerals belonging to the amphibole group, which are necessarily derived from human activities since these minerals do not belong to the Parisian sedimentary basin. Detailed analysis of a mineral pellet embedded in bitumen of road treads sampled in a Paris street by analytical electron microscopies and Rietveld refinement analysis of powder XRD pattern show that a ferro-magnesio-actinolite is a major constituent (17 wt%) of this road material. Further analysis of an amphibole grain in a road dust sample by single crystal X-ray diffraction also points to such FeMg-actinolite of Ca&lt;sub&gt;2.15&lt;/sub&gt;Mg&lt;sub&gt;2.44&lt;/sub&gt;Fe&lt;sub&gt;2.56&lt;/sub&gt;Si&lt;sub&gt;8&lt;/sub&gt;O&lt;sub&gt;22&lt;/sub&gt;(OH)&lt;sub&gt;2&lt;/sub&gt; composition. Other samples collected in the vicinity of areas subjected to road water runoff also contain amphibole minerals of close crystal-chemical composition to this FeMg-actinolite, likely designating road aggregates as sources of amphiboles in our broad set of samples. A large distribution of sizes was observed for amphibole particles using electron microscopy, from massive (100-10 μm) to micrometric packages of elongated mineral particles, likely produced by cleavage of massive particles. The presence of micrometric minerals with elongated fiber habit raises questions about public exposure to such urban dusts. This amphibole signature is also detected in samples of river suspended particulate matter from strongly artificialized urban areas, including in a punctual sample collected in the Seine River, which emphasizes the pervasive oc","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106497"},"PeriodicalIF":3.1,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679811","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":"Reactive transport modeling of CO2 and CH4 plumes during a gas-rich water leakage in a shallow carbonate freshwater aquifer","authors":"David Segura ,&nbsp;Nathalie Collard ,&nbsp;Adrian Cerepi ,&nbsp;Corinne Loisy","doi":"10.1016/j.apgeochem.2025.106495","DOIUrl":"10.1016/j.apgeochem.2025.106495","url":null,"abstract":"<div><div>The recent advances in geological carbon capture and storage and the worldwide proliferation of such projects to reach net-zero emissions by 2050 highlight the importance of investigating the risks associated with CO₂ leakage from carbon storage reservoirs into shallow aquifers. A recent experiment indicates that residual CH₄ from legacy hydrocarbon fields could be a potential early indicator of CO₂ leakage. In this study, numerical reactive transport simulations are performed to examine the reasons behind the different behavior of CH₄ in regard to CO₂ as well as its potential and limitations as a monitoring parameter. The base case model was calibrated using a large data set, including a tracer test, major element concentrations, dissolved CO₂ and CH₄ concentrations, and pH monitoring.</div><div>The results show that the delay of CO₂ with respect to CH₄ is likely related to sorption, which plays a significant role in CO₂ retardation but has a minimal effect on CH₄ transport. The presence of clay minerals (montmorillonite and illite) did not significantly change the delay between the two gases. Furthermore, CO₂ retardation was found to increase in a scenario with a lower natural groundwater CO₂ concentration. The CH₄ oxidation simulation revealed that oxidation decreased the CH₄ concentration below the CH₄ concentrations from baseline water reported in the literature, suggesting that CH₄ oxidation is a critical process able to reduce the efficiency of CH₄ monitoring and should be considered if CH₄ monitoring is implemented.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106495"},"PeriodicalIF":3.1,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144634192","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":"Organic P poses high releasing risk from sediments in lake with long history of eutrophication and algal blooms","authors":"Yong Liu ,&nbsp;Yanlin Yang ,&nbsp;Dengjun Wang ,&nbsp;Xue Feng ,&nbsp;Guocheng Wang ,&nbsp;Zhihui Dai ,&nbsp;Zuxue Jin ,&nbsp;Jingfu Wang","doi":"10.1016/j.apgeochem.2025.106499","DOIUrl":"10.1016/j.apgeochem.2025.106499","url":null,"abstract":"<div><div>Organic phosphorus (P_o) is an important component of sediment P in eutrophic lakes and may play a crucial role in maintaining eutrophication, but this is often overlooked. This study analyzed the contents, various chemical forms of P_o in surface sediments collected from the Dianchi Lake in China, with long history of eutrophication and algal blooms. The simultaneous release of P_o and inorganic P (P_i) from the collected sediments under varied pH, temperatures, and oscillation simulation conditions was also investigated. The results showed that: (1) P_o accounts for 42.3 %–49.3 % of the total P (P_t), and contributs almost equally to P_i toward sediment P load. Organic residues such as endophytic algae are likely the main source of P_o in sediments; (2) P_o in sediments was primarily in the forms of NaHCO₃-P_o, HCl-P_o, and residual-P_o (Res-P_o) (over 90 % of P_o). The labile P_o (LP_o) and moderately labile P_o (MLP_o) components accounted for about 60 % of total P_o, indicating its significant potential for participation in the P biogeochemical cycles; (3) The simultaneous release of P_o and P_i from the sediments was significantly affected by pH, temperature, and oscillation simulation conditions. Especially the simultaneous release of P_o relative to P_i becomes consistently higher and shows a significant positive correlation with the release of P_t (<em>P</em> &lt; 0.01), indicating P_o poses high releasing risk from sediments in the Dianchi Lake. Our findings suggest that against the backdrop of increasing eutrophication worldwide, the control of internal P_o pollution in closed water systems (e.g., lake) is urgently needed.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106499"},"PeriodicalIF":3.1,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611655","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":"Occurrence and provenance of ion-adsorbed rare earth elements mineralization in alumina-rich rocks of the Permian Heshan formation, Western Guangxi, China","authors":"Chunfang Dong ,&nbsp;Zhixuan Han ,&nbsp;Xiaocheng Wei ,&nbsp;Junhong Liu ,&nbsp;Haonan Zhao ,&nbsp;Zhiyan Gu ,&nbsp;Bimin Zhang ,&nbsp;Cheng Xu","doi":"10.1016/j.apgeochem.2025.106498","DOIUrl":"10.1016/j.apgeochem.2025.106498","url":null,"abstract":"<div><div>The enrichment of rare earth elements (REEs) in alumina-rich rocks (ARR) is widely observed. However, REEs in ARR are primarily present in mineral forms, which poses significant challenges to their practical utilization. Recently, the Permian Heshan Formation in Shangsi County, western Guangxi, China, has attracted attention due to the discovery of an unusual occurrence of ion-adsorbed REEs mineralization within ARR. In this study, four ARR samples and an underlying limestone were collected from a single geological profile to investigate the occurrence of REEs through chemical sequential extraction, scanning electron microscopy (SEM), X-ray diffraction (XRD). Furthermore, the provenance of REEs was analyzed based on U–Pb geochronology and chemical compositions in detrital zircons. The results show that REEs content in four ARR ranges from 897 to 2753 ppm, with an average of 1507 ppm, exceeding the industrial grade (1000 ppm) for ion-adsorbed REEs deposits. Notably, the ion-exchangeable phase (F2, average 58.97 %) constitutes the dominant REEs fraction, followed by the residual phase (F7, average 17.98 %), Fe–Mn oxide phase (F5, average 7.01 %), humic acid phase (F4, average 5.58 %), organic-matter phase (F6, average 5.50 %), water soluble phase (F1, average 3.19 %), and carbonate-bound phase (F3, average 0.52 %). Moreover, distinct REEs fractionation patterns are evident across different phases. Light REEs (LREEs) are predominantly adsorbed by clay minerals, whereas heavy REEs (HREEs) primarily retained in the residual phase. The morphology and U–Pb geochronology of detrital zircons provide evidence that the provenance of REEs underwent a significant change from the bottom to the top of the stratigraphic profile. Additionally, mineralogical compositions, chondrite-normalized REE patterns, and zircon geochemical characteristics further support that the variation in REE sources within the profile. Geochemical plots and tectonic discrimination diagrams suggest that REEs in the upper section of the profile primarily originated from the Permian Paleo-Tethys magmatic arc, whereas the lower section predominantly inherited its REEs from the underlying limestone. The introduction of foreign acidic magmatic materials is presumed to have contributed to the formation of the ion-adsorbed REEs enrichment zone within the ARR of the Heshan Formation. The present study contributes to an enhanced and more comprehensive understanding of the mechanism governing REEs enrichment in paleo-weathered horizons.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106498"},"PeriodicalIF":3.1,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144634527","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":"Weathering promotes the sorption of radiocesium in mafic minerals of river sediments in the Fukushima Prefecture, Japan","authors":"Hiroki Hagiwara ,&nbsp;Yusuke Watanabe ,&nbsp;Hiromi Konishi ,&nbsp;Hironori Funaki ,&nbsp;Kenso Fujiwara ,&nbsp;Kazuki Iijima","doi":"10.1016/j.apgeochem.2025.106490","DOIUrl":"10.1016/j.apgeochem.2025.106490","url":null,"abstract":"<div><div>Radiocesium (¹³⁴Cs and ¹³⁷Cs) was sorbed on minerals and transported to river systems due to the Fukushima Daiichi Nuclear Power Plant accident. Recently, the authors have reported that mafic minerals sorb ¹³⁷Cs equally or more strongly than micaceous minerals in fine sands. We characterized mafic minerals and elucidated their weathering using electron microscopy to determine whether they can sorb ¹³⁷Cs. The surface of hornblende particles is weathered and altered to vermiculite. The surface of micas is less weathered than that of hornblende, indicating the ¹³⁷Cs activity concentrations of highly weathered mafic minerals are higher than those of micas in part of sampling site. The results indicate that the effects of ¹³⁷Cs sorption for hornblende depend on the weathering product at the surface.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106490"},"PeriodicalIF":3.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614689","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}