Applied Geochemistry最新文献

{"title":"Petrogenesis and prospecting implications of early Permian Daqishan plutons in the Beishan region, southern Central Asian Orogenic Belt, NW China: constraints from zircon U–Pb geochronology and petrogeochemistry","authors":"Yu Liu , Biao Jiang , Jichang Zhao , Peibin Xu , zongfu Fan , Yinding Zhang , Xudong Zhu","doi":"10.1016/j.apgeochem.2025.106461","DOIUrl":"10.1016/j.apgeochem.2025.106461","url":null,"abstract":"<div><div>The Beishan Orogenic Belt, as a critical component of the Central Asian Orogenic Belt (CAOB), holds pivotal significance for understanding the tectonic evolution of the CAOB. The Beishan region records multiphase tectono-magmatic events spanning from the Proterozoic to the Mesozoic. Magmatic flux peaked during the Early Paleozoic and Early Mesozoic, accompanied by the formation of numerous Cu–Ni and Cu–Au deposits. Early Permian magmatic rocks in the Beishan region exhibit restricted spatial distribution and have a relatively lower degree of research. This study integrates geochronological, petrochemical, and zircon geochemical analyses of Permian plutons exposed in the Daqishan area, Beishan, Gansu Province. Research on the monzogranite (274.1–279.6 Ma), quartz diorite (271.8 Ma), and dacite porphyry (273.2–274.1 Ma) from the Yin'aoxia and Luotofang areas in the Daqishan region has revealed that the zircon U–Pb ages of these rocks are relatively concentrated. This indicates that there was a relatively intense magmatic activity in the Daqishan area during the Early Permian (between 270 and 280 Ma), with an emplacement sequence of monzogranite → dacite porphyry → quartz diorite. The monzogranite exhibits high SiO<sub>2</sub> (69.5–78.1 wt%), Al<sub>2</sub>O<sub>3</sub> enrichment (11.9–14.3 %), and low CaO (0.6–3.7 %) and TiO<sub>2</sub> (0.1–0.4 %), classifying as calc-alkaline to high-K calc-alkaline series. The dacite porphyry shows moderate SiO<sub>2</sub> (69.0–71.0 wt%), low K<sub>2</sub>O (0.7–2.8 wt%), elevated Na<sub>2</sub>O (4.9–5.3 wt%) and Al<sub>2</sub>O<sub>3</sub> (14.4–15.0 wt%), belonging to tholeiitic to calc-alkaline series. The quartz diorite displays lower SiO<sub>2</sub> (63.9–69.0 wt%) but higher Al<sub>2</sub>O<sub>3</sub> (14.5–17.3 wt%), TFe<sub>2</sub>O<sub>3</sub> (3.5–4.1 wt%), MgO (1.1–1.6 wt%), and CaO (2.7–2.9 wt%), characterized by Na-enrichment and classified as tholeiitic-calc-alkaline series. Together with the monzogranite, both are classified as I-type granites. All three rock types have A/CNK >1.1 and A/NK > 1.1, indicating their peraluminous nature. These rocks exhibit volcanic arc signatures and are interpreted as post-collisional products derived from deep crustal melting maybe with mantle contribution and subduction-related fluid metasomatism. Zircon crystallization temperatures decrease sequentially from quartz diorite to dacite porphyry to monzogranite. The Ce<sup>4+</sup>/Ce<sup>3+</sup> ratios (monzogranite: 57.17; quartz diorite: 47.42; dacite porphyry: 75.25) suggest low oxygen fugacity (<em>f</em>O<sub>2</sub>) conditions for all three rock types. The Early Permian magmas in Daqishan are highly differentiated (whole-rock SiO<sub>2</sub> >70 wt%) with low <em>f</em>O<sub>2</sub>, water-poor signatures (V/Sc < 9). Minor sphalerite grains observed in thin sections suggest that the intrusions underwent post-magmatic processes. These characteristics indicate that the Early Permian ","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106461"},"PeriodicalIF":3.1,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144262397","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":"Isotopic signaling and environmental significance of cave waters in a heavily rocky desertification area","authors":"Ju Ni ,&nbsp;Yurong Mu ,&nbsp;Dayun Zhu ,&nbsp;Jialu Wang ,&nbsp;Yurong Han ,&nbsp;Yingshan Zhao ,&nbsp;Ning Yang ,&nbsp;Juanfang Du","doi":"10.1016/j.apgeochem.2025.106468","DOIUrl":"10.1016/j.apgeochem.2025.106468","url":null,"abstract":"<div><div>Cave systems are important tools for inversion of rock desertification. However, the complexity of the climate system, the long-term nature of cave sediment accumulation and the spatial and temporal heterogeneity of karst geologic processes allow the original signals to be altered during transmission. In this work, the isotopic values and environmental parameters of atmospheric precipitation, plant water, soil water, cave drip water and underground river outflow water in the Guizhou karst cave system are monitored in situ on a monthly scale, and the processes of water migration and change are explored in detail. The results showed that precipitation has a significant regulatory effect on the physicochemical properties of the cave microenvironment, and cave drip water exhibits a Ca²⁺•Mg²⁺-HCO₃^- hydrochemical type. Atmospheric precipitation is the main water source in the study area, except for plant water isotopes, the remaining water bodies are characterized by seasonal changes. The lag times of the water bodies in the cave system significantly differ during the transmission process, ranging from 2 d to 1 year, which is closely related to the mechanism of water accumulation and release in typical karst landscape areas. The spatial and temporal distributions of water vapor sources, as well as seasonal variations in temperature and precipitation, significantly influence the isotopic changes in water bodies in the study area. Overall, this study provides a systematic study on the migration and transformation process of water bodies in Guizhou karst caves, which provides a new approach and perspective for an improved understanding of hydrological processes and climate change in karst areas.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106468"},"PeriodicalIF":3.1,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270223","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":"Tracing organic matter sources in upland lakes of southeastern Amazonia: Insights from a Bayesian mixing model","authors":"Luiza Santos Reis ,&nbsp;José Tasso Felix Guimarães ,&nbsp;Prafulla Kumar Sahoo ,&nbsp;Alessandro Sabá Leite ,&nbsp;Lourival Tyski ,&nbsp;Markus Gastauer","doi":"10.1016/j.apgeochem.2025.106464","DOIUrl":"10.1016/j.apgeochem.2025.106464","url":null,"abstract":"<div><div>This study investigates organic matter (OM) sources in upland lakes within the Carajás and Araguaia regions, in the southeastern Amazonia. Focusing on lakes developed on lateritic crusts, the research encompasses different types of lake basins to better understand variations in OM sources, using a Bayesian mixing model (MixSIAR), based on a dataset of carbon isotopes (δ¹³C) and C:N ratio from sediment cores. Our results underscore the influence of local vegetation and lake basin evolution on OM composition, revealing some similarities between the two regions. For instance, in the Carajás region, active lakes (AM, LV2, LTI, and LSL) exhibit higher proportions of OM sourced from C3 plants, macrophytes, and soils compared to filled lakes (R5, ST02, LB3, LB4, and LTM). While, filled lakes in the Araguaia region demonstrate greater contributions of OM from C3 plants, phytoplankton, and soils. The Bayesian mixing model effectively estimates OM contributions and tracks historical changes in sediment profiles, offering a robust framework for similar studies in tropical lake ecosystems. Overall, this research enhances our understanding of OM dynamics in tropical upland lakes and lays the groundwork for future investigations into environmental change and management strategies in these distinct regions of the Amazon ecosystem.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106464"},"PeriodicalIF":3.1,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254173","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":"Deposition and early diagenesis of terrestrial plant-derived terpenoids in deep-sea sediments in the northwestern Pacific ocean off Japan","authors":"Ken Sawada ,&nbsp;Madoka Kobayashi","doi":"10.1016/j.apgeochem.2025.106462","DOIUrl":"10.1016/j.apgeochem.2025.106462","url":null,"abstract":"<div><div>Terrestrial plant-derived terpenoids (TPTs) in deep-sea surface to subsurface sediments of the northwestern Pacific were investigated at two sites along the Kuroshio Current and in the gyre over the Nishishichitou Ridge following a latitudinal transect at 138°36′E (Sites LM3 and LM5P), as well as the Japan Trench off the Sanriku coast of northeastern Japan (Site LM8). Cadalene, oleanene, and retene were detected as geoterpenoids in all cores. Possible sources of these geoterpenoids are soil materials, which were attached to clay minerals with or without early diagenetic alteration of precursor bioterpenoids. Friedelin and dehydroabietic acid (DAA) were identified as major functionalized TPTs, or bioterpenoids, in all core samples. Concentrations of TPTs in the core-top samples from all study sites varied with distance from land, sediment lithology, and upland vegetation. Bioterpenoids in the TPTs are relatively abundant at all sites. These results suggest that TPT biomarkers are mainly transported to the open ocean as bioterpenoids. The ratio of friedelin to DAA in core-top samples clearly varied (2.53 in LM3, 1.12 in LM5P, and 0.95 in LM8) depending on upland vegetation, and therefore the bioterpenoid ratio is proposed to be a (paleo)vegetation indicator. Vertical profiles of TPT concentrations showed pronounced variability. The concentrations of oleanene and retene generally decreased with depth in all cores, indicating that these compounds are labile in surface to subsurface sediments. However, the cadalene concentration increased or decreased slightly with depth in cores from the Nishishichitou Ridge, indicating that cadalene is a refractory compound. The DAA concentration decreased markedly with depth, and the gradients were similar in all cores. Thus, DAA was effectively decomposed and behaved as a typical labile compound. On the other hand, the friedelin concentration increased slightly with depth in the core collected off the Sanriku coast. Thus, friedelin appeared to behave as a refractory compound in surface to subsurface sediments despite being a bioterpenoid.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106462"},"PeriodicalIF":3.1,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144240745","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":"Complexation of Cm(III) with monosilicic acid in chloride media","authors":"Sema Özyagan ,&nbsp;Kim J. Warth ,&nbsp;Thomas Sittel ,&nbsp;Petra J. Panak","doi":"10.1016/j.apgeochem.2025.106465","DOIUrl":"10.1016/j.apgeochem.2025.106465","url":null,"abstract":"<div><div>In this work, we present a detailed complexation study of Cm(III) with monosilicic acid in a NaCl medium at low to medium ionic strengths (I_m = 0.01–3.00 m). The complexation has been monitored using time-resolved laser fluorescence spectroscopy (TRLFS) in the pH_m range of 4–6. The results show that the formation of the monosilicate complex, [Cm(H₃SiO₄)]²⁺, is decreased with increasing ionic strength, leading to vast changes in the complex stability constant. Using the Specific Ion Interaction Theory (SIT), we were able to determine the complex stability constant at ionic strength I_m = 0 with <span><math><mrow><mi>log</mi><mspace></mspace><msubsup><mi>K</mi><mi>m</mi><mn>0</mn></msubsup></mrow></math></span> = 8.1 ± 0.8 and the binary ion-ion interaction coefficient ε ([Cm(H₃SiO₄)]²⁺,Cl⁻) = 0.40 ± 0.04. Additionally, we studied the complexation at elevated temperatures at low to medium ionic strength. Using the van't Hoff equation, <span><math><mrow><msub><mo>Δ</mo><mi>r</mi></msub><msubsup><mi>H</mi><mi>m</mi><mn>0</mn></msubsup></mrow></math></span> = 16.4 ± 0.5 kJ mol⁻¹, <span><math><mrow><msub><mo>Δ</mo><mi>r</mi></msub><msubsup><mi>S</mi><mi>m</mi><mn>0</mn></msubsup></mrow></math></span> = 210 ± 21 J K⁻¹ mol⁻¹ and the free Gibbs Energy <span><math><mrow><msub><mo>Δ</mo><mi>r</mi></msub><msubsup><mi>G</mi><mi>m</mi><mn>0</mn></msubsup></mrow></math></span> = − 46.2 ± 5 kJ mol⁻¹ have been determined. These results show that the complexation reaction is endothermic and driven by an increase of entropy. These novel results obtained in a wide range of various ionic strengths are very important for the modeling of actinide behavior under near-field conditions of a nuclear waste repository in clay formations containing pore and formation waters with increased ionic strength.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"190 ","pages":"Article 106465"},"PeriodicalIF":3.1,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144240744","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":"CAFM: a freeware for geochemical data processing and concentration–area fractal modeling and its application for identifying uranium anomalies of different genesis","authors":"Jun-Ting Qiu ,&nbsp;Jiang-Kun Li ,&nbsp;Hong-Xu Mu ,&nbsp;Xin-Min Rui ,&nbsp;Yun-Han Yang ,&nbsp;Liang Qiu","doi":"10.1016/j.apgeochem.2025.106445","DOIUrl":"10.1016/j.apgeochem.2025.106445","url":null,"abstract":"<div><div>We present a freeware named CAFM, which is specifically designed for geochemical data interpolation, computation, and concentration-area (C-A) fractal modeling. Additionally, we propose a Fixed Scale Moving Average Error (FSMAE) method to achieve rapid and automatic classification of C-A fractal populations. This freeware has been successfully applied to identify U anomalies and distinguish their genesis based on surface concentrations of U, Th, and K derived from airborne gamma data. The Yingen area in the southeastern part of the Bayingobi Basin serves as the research focus of our study. In this area, we utilized the breakpoints between adjacent straight-line segments on Log-Log plots of C-A relationships for U, Th, and K to differentiate elemental populations. These separated datasets were subsequently analyzed using the C-A fractal method, and the results were compared with geological observations. The comparison reveals that U populations are highly effective in identifying U enrichment anomalies, particularly surface mineralization anomalies. In contrast, Th populations can indicate the presence of intrusive rocks and hydrothermal activities. However, K populations provide limited geological information due to their susceptibility to surface sediment influences. Furthermore, with the aid of CAFM, we proposed a U/Th bimetal index, which has been demonstrated to effectively distinguish between magmatic, hydrothermal, and sedimentary –hosted U enrichment anomalies. Utilizing this index, we discovered a new area with sedimentary-related U anomalies in the southeastern part of the Yingen area, highlighting its potential value for future exploration efforts. Our study has shown that integrating airborne gamma data with C-A fractal modeling can effectively identify U anomalies and determine their genesis. The CAFM software and the FSMAE method offer valuable tools for U exploration.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106445"},"PeriodicalIF":3.1,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221475","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":"Natural kaolin minerals with varying iron contents reduced cattle's enteric methane generation in vitro","authors":"Md. Rashidul Islam ,&nbsp;Ravi Naidu ,&nbsp;Bhabananda Biswas","doi":"10.1016/j.apgeochem.2025.106459","DOIUrl":"10.1016/j.apgeochem.2025.106459","url":null,"abstract":"<div><div>Kaolin, a dominant mineral group in geophagic soil, often contains iron impurities that incur purification costs. Valorizing kaolin for livestock applications like ruminant methane (CH₄) suppression without purification is promising but not well studied. This study used two kaolin clay samples collected from a Western Australia deposit, and tested their inclusion in a basal diet for CH₄ inhibition in an <em>in vitro</em> animal model using viable cattle rumen fluid and paunch. Physicochemical characterization showed that one clay sample (Kao) had kaolinite as the dominant mineral species and a trace of halloysite, while another one had additional minerals and impurities such as iron oxides and illite/mica (KaoFe). Regardless of the CH₄ produced by the basal diet, an approximately 5 % inclusion of clays significantly reduced enteric CH_4, with reductions of 23 % (Kao) and 37 % (KaoFe) compared to the control. On average, the <em>in vitro</em> digestibility (IVD), coefficient of fermentation efficiency (CFE), microbial crude protein (mCP), and ammonia nitrogen (NH₃–N) were 64 %, 77 %, 144 g/kg DM, and 21 g/kg DM, respectively. These results showed no significant differences between clay-treated and control groups, which indicates the clay's non-toxic nature in the rumen. Biochemical and physicochemical parameters and their correlations suggest that clay inclusion in the basal diet increased hydrogen sinkers, such as propionic acid and CH₄ inhibitory ions, such as Al³⁺, Si⁴⁺, Fe²⁺/Fe³⁺, and K⁺. And the inclusion of the KaoFe sample contributed to more of these. Given that the cattle naturally ingest soil minerals through geophagy with good palatability, this study emphasizes the potential valorization of natural kaolin clays as feed supplements. It advances a cost-effective and biocompatible feed additive for rumen CH₄ abatement without adversely affecting the digestive system.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106459"},"PeriodicalIF":3.1,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144203181","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":"Precise U–Pb chronology of tooth enamels of index fossils of Miocene fauna","authors":"Pu Zhang ,&nbsp;Yangfan Li ,&nbsp;Guoqi Liu ,&nbsp;Zhe Zhang","doi":"10.1016/j.apgeochem.2025.106457","DOIUrl":"10.1016/j.apgeochem.2025.106457","url":null,"abstract":"<div><div>Five fossil beds containing fossil specimens of <em>Hipparion chiai,</em> which is the most widespread index fossil in Late Miocene strata in northern China, were identified. The biological apatite (carbonated hydroxyapatite) in the teeth fossils of <em>Hipparion chiai</em> has a high μ value (initial ²³⁸U/²⁰⁴Pb_i) and limited Th content. The fossilized tooth enamels remain relatively unchanged due to their resistance to diagenetic alterations. Here, for the first time, we precisely dated six fossil teeth of <em>Hipparion chiai</em> from the Wangdafuliang section in Fugu, Shaanxi Province, using <strong>the</strong> LA-ICP-MS U–Pb geochronology method. The U–Pb dates obtained from the six fossil teeth of <em>Hipparion chiai</em> range from 6.87 ± 0.13 Ma to 7.71 ± 0.39 Ma (2 s), with an average of 7.26 Ma. <strong>The a</strong>ges of the tooth enamels of a <em>Samotherium</em> sp. and a <em>Rhinocerotidae</em> (genus and species unidentified) are consistent with the ages of the tooth enamels of the <em>Hipparion chiai</em>. The analytical method developed for this study provides a new benchmark for dating Neogene fossils.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106457"},"PeriodicalIF":3.1,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144166203","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":"Comparing open versus closed system weathering experiments using lithium isotopes","authors":"Philip A.E. Pogge von Strandmann ,&nbsp;Xiaoqing He ,&nbsp;Ying Zhou ,&nbsp;David J. Wilson","doi":"10.1016/j.apgeochem.2025.106458","DOIUrl":"10.1016/j.apgeochem.2025.106458","url":null,"abstract":"<div><div>Chemical weathering of silicate rocks represents a critical part of the carbon cycle, and also a potential method for the artificial drawdown of atmospheric CO₂ (“enhanced weathering”). However, weathering and particularly the resulting secondary minerals (especially clays) have proven hard to measure and quantify. Here we use lithium isotopes to examine and compare two different types of laboratory weathering experiments, using the same initial water and rock, in order to determine their similarities and differences. Specifically, we compare “open system” experiments, where the reacting water drips through the rock powder, with “closed system” experiments, where the reacting water and rock are in contact in a closed beaker. The results (elemental ratios, mobility calculations, saturation indices) suggest that closed experiments, with their longer water-rock interactions times, exhibit more secondary minerals formation. This finding is confirmed by their higher “equilibrium” solution δ⁷Li values (δ⁷Li = 35.7 versus 29.5 ‰, respectively). The determination of their observed fractionation factors (α = 0.983 ± 0.004 and 0.977 ± 0.003 for the open and closed experiments, respectively) and partition coefficients between water and secondary minerals yields a test case, to determine whether the amount of clays that form during weathering can be calculated solely from Li isotope ratios, giving values similar to the amount of basalt dissolved. Based on potassium concentration (here the most mobile element), 1.9–3.2 g of rock was dissolved. Based on the Li isotopes, 1.6–2.0 g of clay was precipitated during the month-long experiment. This result agrees with other estimates from isotope systems, which suggest that clay formation is rapid, which in turn has consequences for weathering processes, and especially for the efficiency of enhanced weathering.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106458"},"PeriodicalIF":3.1,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144166202","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":"Fugitive dust from exposed tailings at an inactive gold mine in Québec, Canada, using the Pas-DD dust capture method","authors":"E.J. Berryman ,&nbsp;A. Cleaver ,&nbsp;J.P. Coumans ,&nbsp;N.R. Zagrtdenov ,&nbsp;C. Martineau ,&nbsp;N.J. Fenton ,&nbsp;P. Huntsman","doi":"10.1016/j.apgeochem.2025.106449","DOIUrl":"10.1016/j.apgeochem.2025.106449","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Fugitive mine dust (i.e., particulate emissions) is a ubiquitous waste stream at all mine sites, including active, inactive, and abandoned. Although dust emissions can reasonably be expected to diminish after the cessation of mining activities, any waste products left uncovered have the potential to continue to emit dust to the near-mine environment. In this study, we capture and characterize dust using the Pas-DD dustfall method around the inactive gold-mine site of Joutel in the Abitibi-Témiscamingue region of Québec. The site has been inactive for 30 years, during which time the tailings storage area has been left mostly uncovered, with previously unknown amounts of dust entering the near-mine environment. The quantity of dust captured by our samplers was generally low and did not exceed 0.5 mg/dm&lt;sup&gt;2&lt;/sup&gt;day. Areas of the bottom ∼2 mm of the polyurethane foam (PUF) disks used as a sampling substrate in the Pas-DD method partially degraded following deployment for 284–285 days in the field, resulting in a mass loss of up to 0.57 mg/dm&lt;sup&gt;2&lt;/sup&gt;day. The low dust deposition rates and variable amounts of PUF degradation precluded net mass flux of the PUF disks providing meaningful insight into spatial variability of dust deposition. In contrast, element deposition rates and quantitative mineralogy of the dust are not impacted by PUF degradation and were the most useful datasets in this low-dust setting, allowing us to distinguish background environmental dust from local anthropogenic dust sources, including the tailings as well as other activities in the area. The major (average &gt; 5 vol%) minerals in the dust are: muscovite (21 ± 6 vol%), quartz (22 ± 16 vol%), feldspars (18 ± 4 vol%), chlorite (13 ± 3 vol%), and olivine or serpentine (5 ± 3 vol%). All of these minerals except olivine or serpentine were also common in the tailings, in similar abundance except for reduced muscovite (3.9 ± 0.6 vol% muscovite, 27 ± 7 vol% quartz, 19 ± 3 vol% feldspars, 10 ± 5 vol% chlorite). The tailings also had iron (hydr)oxides (21 ± 8 vol%) and sometimes pyrite (14 ± 19 vol%) as major minerals. The minerals that were identified as being derived mainly from the tailings site are iron (hydr)oxides, ankerite, and pyrite whereas olivine or serpentine, amphibole, calcite, and dolomite originate primarily from the background Abitibi Greenstone Belt environment. Dust with the highest proportion of tailings-sourced minerals was captured downwind of the site and decreased in abundance with distance, pointing to wind as the primary control on dust dispersion from the tailings, with other activity in the forest near the site or along the roads producing discreet dust-generating events. The captured dust contained distinctly less Fe and As than the tailings, reflecting the much lower proportion of iron (hydr)oxides and pyrite in the dust compared to the tailings. Differences in the relative proportion of minerals in the dust compared to the tailings reflec","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"189 ","pages":"Article 106449"},"PeriodicalIF":3.1,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144166106","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}