Applied Geochemistry最新文献

{"title":"Hydrochemical evolution and response mechanisms in multiple aquifers affected by coal mining activities: Insights from machine learning and inverse geochemical modeling","authors":"Chang Lu ,&nbsp;Huiyong Yin ,&nbsp;Wenju Cheng ,&nbsp;Fangying Dong ,&nbsp;Weijie Zhang ,&nbsp;Biao Li ,&nbsp;Yankun Jia","doi":"10.1016/j.apgeochem.2026.106683","DOIUrl":"10.1016/j.apgeochem.2026.106683","url":null,"abstract":"<div><div>Extensive coal mining has significantly altered hydrogeological systems by enhancing aquifer connectivity and changing groundwater chemistry, which poses environmental and health risks. Traditional hydrochemical methods often fail to fully capture these mining-induced impacts. To better capture mining impacts, 127 groundwater samples from three aquifers were analyzed using hydrochemical techniques and clustering algorithms including SOM and K-Means. The results show that ion exchange, carbonate and silicate dissolution, and water–rock interactions drive groundwater evolution under mining disturbances. Major ions such as Na⁺, HCO₃⁻, and SO₄²⁻ display clear spatial variation and enrichment patterns. Clustering divided the samples into seven hydrochemical types, reflecting differences in aquifer connectivity and geochemical processes. PHREEQC inverse modeling further quantified mineral transformations, confirming the combined roles of pyrite oxidation, carbonate dissolution, and cation exchange. Mining-enhanced hydraulic connections between the Sandstone and 3# Limestone aquifers led to similar hydrochemical features, while the deeper Ordovician aquifer maintained distinct signatures due to limited disturbance. These results support a conceptual model of “mining disturbance–fracture connectivity–hydraulic linkage–hydrochemical evolution,” providing a scientific basis for mitigating acid mine drainage and advancing sustainable groundwater and mineral resource management in mining regions.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106683"},"PeriodicalIF":3.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145904064","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 common ontology for stable isotope data","authors":"Nina Welti ,&nbsp;Steph Hawkins ,&nbsp;Kathryn Waltenberg ,&nbsp;Cath Hughes ,&nbsp;Jagoda Crawford ,&nbsp;Yanfeng Shu ,&nbsp;Regina Campbell ,&nbsp;Alex Leslie ,&nbsp;Athina Puccini ,&nbsp;Christoph Gerber ,&nbsp;Axel Suckow ,&nbsp;Geoff Fraser ,&nbsp;Lian Flick","doi":"10.1016/j.apgeochem.2026.106682","DOIUrl":"10.1016/j.apgeochem.2026.106682","url":null,"abstract":"<div><div>Stable isotope data has broad applicability across multiple science domains. As more datasets are published and stable isotope data systems are built, the findability and accessibility of stable isotope data increases. However, due to a lack of a common reporting framework, the interoperability of these data systems is limited. A common ontology is needed so stable isotope data systems and published datasets can be translated into a common format without disrupting existing data models or introducing complex workflows. This common ontology for stable isotope data and associated metadata offers a methodology to achieve cross-domain interoperability of environmental stable isotope data. It functions as a straightforward data stewardship tool to enhance the findability, accessibility, interoperability, and reuse (FAIR principles) of stable isotope data across disciplines. Ultimately, this ontology aims to make existing data systems cohesive, interoperable, and discoverable across the entire measurement pipeline, encompassing publicly accessible repositories, peer-reviewed literature, and grey literature.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106682"},"PeriodicalIF":3.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974373","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":"Behaviour of Mo(VI), Eu(III) and U(VI) in calcium-silicate-hydrate phases: Immobilisation and dynamic remobilisation under repository-relevant conditions","authors":"Aaron Haben,&nbsp;Nico Bachmann,&nbsp;Jan Jakob Langer,&nbsp;Ralf Kautenburger","doi":"10.1016/j.apgeochem.2026.106684","DOIUrl":"10.1016/j.apgeochem.2026.106684","url":null,"abstract":"<div><div>Calcium-silicate-hydrate (C–S–H) phases play an essential role as a geotechnical barrier in high-level nuclear waste (HLW) repositories. To guarantee the long-term safety of a HLW disposal site, it is important to know how and to which degree radionuclides are retained by C–S–H phases. To this date, only little to no data on the remobilisation dynamics of the repository-relevant elements Mo(VI), Eu(III) and U(VI) under realistic conditions are available. In this study, C–S–H phases incorporating these elements were synthesised, the element immobilisation was quantified via ICP-QQQ and their structure was investigated via X-ray diffractometry. All C–S–H phases had a calcium-silicon ratio (C/S) of 1.066 ± 0.003 and no relevant structural influences of the studied elements could be observed. In all cases, quantitative immobilisation was observed for Eu(III) and U(VI), whereas Mo(VI) was retained/incorporated to only about 50 %. Afterwards, their leaching behaviour with ultrapure water was studied in batch and mini-column experiments (MCE). Mo(VI) was remobilised quickly, while Eu(III) and U(VI) were retained nearly quantitatively. Due to the more realistic and therefore more representative conditions, further experiments to investigate the effects of three repository-relevant parameters were conducted only using MCE. A higher ionic strength significantly enhanced U(VI) remobilisation, while Eu(III) and Mo(VI) remained nearly unaffected. The displacement agents Fe(III) and Tb(III) only affected Mo(VI)'s remobilisation by retarding it. The addition of a complexing agent (2-phosphonobutane-1,2,4-tricarboxylic acid; PBTC) led to a delayed remobilisation of Mo(VI), while Eu(III) and U(VI) were remobilised to some degree after sufficient PBTC eluation. Overall, this work delivers important information on key processes relevant to nuclear waste disposal.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106684"},"PeriodicalIF":3.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923855","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 mechanisms and advances in the significant carbon sequestration potential of karst water","authors":"Fan Xia ,&nbsp;Guanxia Cai ,&nbsp;Min Zhao ,&nbsp;Haibo He ,&nbsp;Roohollah Noori ,&nbsp;Qian Bao ,&nbsp;Bo Chen ,&nbsp;Yongqiang Zhou","doi":"10.1016/j.apgeochem.2026.106678","DOIUrl":"10.1016/j.apgeochem.2026.106678","url":null,"abstract":"<div><div>Carbon sequestration and stabilization and their regulatory mechanisms are key issues in studies of inland water carbon cycles, especially in karst areas. Biological carbon pump transforms the timescales for carbon storage from short to long durations through photosynthesis. However, carbon sequestration is not equal to carbon storage. The research on refractory dissolved organic matter (RDOM) in inland water bodies has not been widely conducted. Here, the formation mechanism, environmental factors, temporal and spatial patterns and carbon sink effect of RDOM are discussed. Our review indicates that dissolved inorganic carbon (DIC) and calcium in the water are important factors affecting the composition of DOM, and they also have an indirect impact on the chemical and biological community structure, regulating the strength of the biological carbon pump (BCP) and microbial carbon pump (MCP). We also estimated the production rate of autochthonous RDOM in karst water bodies to be varied from 0.92 to 23.00 mg m⁻²∙d⁻¹, which is greater than that in marine ecosystems (<em>i.e.</em>, 1.55 mg m⁻²∙d⁻¹ in the South China Sea). It indicates that karst surface water, which is rich in DIC, is conducive to the accumulation and preservation of DOM. The research provides a new perspective for understanding the role of karst water in the global carbon cycle and emphasizes the importance of microorganisms in carbon storage in inland water bodies.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106678"},"PeriodicalIF":3.4,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974772","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":"Chromium isotope fractionation in the redox-stratified Chesapeake Bay","authors":"Debbrota Mallick ,&nbsp;Xiangli Wang ,&nbsp;Marzia Miletto ,&nbsp;Jeffrey W. Krause ,&nbsp;Daniel C. Ohnemus ,&nbsp;Noah J. Planavsky ,&nbsp;George W. Luther ,&nbsp;Timothy W. Lyons ,&nbsp;Bradley M. Tebo","doi":"10.1016/j.apgeochem.2025.106671","DOIUrl":"10.1016/j.apgeochem.2025.106671","url":null,"abstract":"<div><div>The chromium (Cr) stable isotope compositions of sedimentary rocks have been used to track the evolution of oxygen levels in Earth's ocean-atmosphere system. However, the Cr isotope fractionation during transfer of dissolved Cr to sediments is still unclear. The Chesapeake Bay is a seasonally redox-stratified estuary (oxic surface water overlying euxinic, or sulfide-bearing, deep water) and thus provides a good opportunity to investigate Cr isotope fractionation in euxinic systems. Here we report total dissolved Cr concentrations and stable isotope compositions (δ⁵³Cr) of a water column in this estuary. As salinity increases from 7.51 in the oxic surface water to 19.22 in the euxinic deep water, total dissolved Cr concentration decreases from 1.21 nmol kg⁻¹ to 0.51 nmol kg⁻¹, while δ⁵³Cr decreases from 0.60 ‰ to −0.41 ‰. Explaining these data requires partial reduction of Cr(VI) to Cr(III) followed by incomplete scavenging of Cr(III) from solution, which leads to isotope fractionation during removal of Cr from seawater to anoxic sediments. An extensive compilation of redox-stratified systems suggests that Cr isotope fractionation during removal from anoxic water column is a common phenomenon. This has major implications for using the δ⁵³Cr of anoxic sediments to reconstruct paleo-seawater δ⁵³Cr values. Correcting for such fractionation will require better understanding of its governing factors, which would need more data for sediment trap, porewater, and redox-specific water column samples from anoxic settings.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"197 ","pages":"Article 106671"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881535","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":"Biogenic sphalerite signatures and pH-dependent precipitation pathways","authors":"Chris Ingles ,&nbsp;John Mavrogenes ,&nbsp;Yue Wang ,&nbsp;Maria Cherdantseva ,&nbsp;David Saxey ,&nbsp;Denis Fougerouse","doi":"10.1016/j.apgeochem.2026.106677","DOIUrl":"10.1016/j.apgeochem.2026.106677","url":null,"abstract":"<div><div>Biogenic ore formation has long required clarification of depositional mechanisms and textural characteristics such as carbonate dissolution and ‘snow on the roof’. This research explored evidence for microbial sulfate reduction and biogenic mineralisation associated with sulfide ore deposits, using sphalerite from eight locations. Sulfur isotopic and microtextural analyses were conducted on sphalerites from Navan (Ireland), Wiesloch (Germany), Broken Hill supergene, Century and Cadjebut (Australia), Pomorzany (Poland), Balmat (USA) and Geco (Canada), using Sensitive High-Resolution Ion Microprobe, X-ray Fluorescence Microscopy, fluorination, cathodoluminescence, and atom probe tomography. Results correlated microbial sulfate reduction to stromatolitic zonation accompanied by strongly negative δ³⁴S (−10 to −40) and δ³³S (−5 to −20). Mississippi Valley-type sphalerites were classified as either MVTa (abiotic) or MVTb (biotic). The colloform banding suggest cyclic ore deposition, which led to the construction of pH dependent precipitation pathways that begin with acidic fluids and evolve into alkaline conditions with ongoing microbial activity. While sulfate reducing bacteria are the most likely organisms associated with sulfide mineralisation, syntrophic microbial communities are also suggested as avenues to process organic compounds such as hydrocarbons and aid sulfate reduction. The distinct isotopic signatures indicate that sphalerite from Navan, Wiesloch and the supergene Broken Hill ores formed from biogenic sulfate reduction. Rayleigh-type closed system isotopic fractionation was identified in abiotic sphalerite from Pomorzany and mass-independent fractionation (resemblant of pre-Great Oxidation Event conditions) in sphalerite from Geco.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"197 ","pages":"Article 106677"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922382","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":"Negligible isotope ratio variation assumption: Significant errors in mixing model but minimal impact on Rayleigh distillation model","authors":"Yuyang He","doi":"10.1016/j.apgeochem.2025.106668","DOIUrl":"10.1016/j.apgeochem.2025.106668","url":null,"abstract":"<div><div>Isotope geochemistry examines the geochemical properties of isotopes within the same element, which are influenced by subtle mass differences. A common assumption in traditional isotope theories is that variations in isotope ratio (<em>R</em>) are sufficiently small to be considered negligible, expressed as 1+<em>R</em>_X ≈ 1+<em>R</em>_Y, named Negligible Isotope Ratio Variation Assumption. Here, X and Y represent sample and standard in the <em>delta</em> notations, distinct endmembers in mixing models, or residual components at progressive stages in Rayleigh distillation models. While this assumption simplifies theoretical models, it may fail when dealing with isotopically enriched or depleted samples, such as synthetic tracers (e.g., ¹⁸O-enriched water), or extraterrestrial samples (e.g., hydrogens in solar wind). Moreover, in Rayleigh distillation processes, the <em>R</em> value of residual phases can theoretically approach infinity, significantly deviating from the initial <em>R</em>₀ value, rendering an important simplification in classical Rayleigh distillation model invalid. To quantify errors arising from this assumption, this study conducted rigorous mathematical analyses. The results demonstrate that the error in binary mixing models depends on the <em>R</em> value differences between endmembers, while Rayleigh distillation models exhibit a maximum error of ∼1‰ under isotope fractionation factors of 0.9 to 1.1, independent of isotope abundance. These findings highlight the robustness of certain approximations while emphasizing the need to consider model limitations in specific scenarios.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"197 ","pages":"Article 106668"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881089","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":"Mineralogical constraints on carbon deportment in phosphate ores: Implications for decarbonizing ore processing","authors":"Abdelaziz Zine ,&nbsp;Abdellatif Elghali ,&nbsp;Radouan El Bamiki ,&nbsp;Nouhaila Attalir ,&nbsp;Mustapha Mouflih ,&nbsp;Jérémie Aubineau ,&nbsp;Fleurice Parat ,&nbsp;Manuel Munoz ,&nbsp;Oussama Khadiri Yazami ,&nbsp;Jean-Louis Bodinier","doi":"10.1016/j.apgeochem.2025.106672","DOIUrl":"10.1016/j.apgeochem.2025.106672","url":null,"abstract":"<div><div>The release of CO₂ from carbon-bearing minerals during phosphate ore processing contributes to industrial emissions but remains poorly quantified. This study examines the Bouchane phosphate deposit, part of the Gantour Basin in Morocco, which consists of Upper Cretaceous–Paleogene sedimentary phosphates. The objective is to constrain the proportions and deportment of carbon within its mineral phases and assess their contribution to CO₂ release during beneficiation and acidulation. For this purpose, 20 representative samples from a stratigraphic section of the deposit were analyzed for petrographic composition, bulk mineralogy by X-ray diffraction, bulk geochemistry by inductively coupled plasma optical emission spectroscopy (ICP-OES), and total carbon by induction furnace, complemented by in-situ microanalyses using an electron probe micro-analyzer (EPMA) and quantitative automated mineralogy with a TESCAN Integrated Mineral Analyzer (TIMA). Moreover, the modal composition of the studied samples was determined using various approaches such as quantitative X-ray diffraction (QXRD), quantitative automated mineralogy (QAM), element-to-mineral conversion (EMC), and total inversion (TI). The studied samples were predominantly composed of phosphatic coated grains, peloids, coprolites, and skeletal particles. The chemistry of these sediments varied along the stratigraphic section, marked by a dominance of inorganic carbon compared to organic carbon, with a mean content of 11.38 ± 4.58 wt% and 0.68 ± 0.03 wt%, respectively. The developed calculated mineralogy techniques (EMC, TI) proved successful in accurate quantification of the modal composition of the phosphate sediments. Automated mineralogy by TIMA provided a quantification of the percentage of problematic locked carbonates within phosphatic grains, with values below 3 %. These grains were predicted to hold 11 % of the CO₂ in carbonate fluorapatite (CFA), and 0.3 % and 0.1 % in calcite and dolomite, respectively. The remaining carbonate phases are removed during washing and flotation. This study shows that adopting holistic approaches in phosphate mining is efficient for developing rapid, low-cost techniques for mineralogical characterization (EMC, TI) and indicates that phosphate rock processing results in limited in situ CO₂ release from carbonate minerals.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"197 ","pages":"Article 106672"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881534","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":"Impact of salinity on nitrogen cycling and microbial community functional potential in groundwater of the Yellow river delta","authors":"Huan Wang ,&nbsp;Chuanshun Zhi ,&nbsp;Yufei Jiao ,&nbsp;Dan Xu ,&nbsp;Wenfeng Gao ,&nbsp;Yawei Kou ,&nbsp;Xiancang Wu ,&nbsp;Jing Bai ,&nbsp;Hui Mu ,&nbsp;Houliang Lu ,&nbsp;Xiaonong Hu","doi":"10.1016/j.apgeochem.2025.106669","DOIUrl":"10.1016/j.apgeochem.2025.106669","url":null,"abstract":"<div><div>Microorganisms in shallow groundwater of river deltas play a key role in nitrogen cycling, yet little is known about this process in high-salinity regions. This study examines how salinity affects nitrogen cycling and microbial function in the Yellow River Delta's high-salinity groundwater. Through combined hydrochemical, microbial, and genetic analyses, the study reveals that groundwater is high saline, mainly of the Na–Cl type, with ammonium as the dominant nitrogen form under reducing conditions. Microbial communities vary with salinity and redox conditions, and nitrogen cycling is mainly driven by DNRA and denitrification. Functional genes related to nitrogen metabolism strongly correlate with ammonium levels, emphasizing ammonium's regulatory role. Different hydrochemical factors shape nitrogen cycling at varying salinities: pH, I⁻, and Mg²⁺ at low salinity; K⁺ and sulfide at medium salinity; and TDS, Cl⁻, SO₄²⁻, and Na⁺ at high salinity. Overall, reductive pathways dominate, with denitrification (35.88 %) and DNRA (31.03 %) as the main processes. Under varying salinity conditions, nitrogen cycling pathways shift significantly: low-salinity favors nitrogen fixation, nitrification and DNRA, promoting both nitrogen input and loss; medium-salinity supports active nitrogen turnover through enhanced nitrification, denitrification, and ANRA; while high salinity leads to DNRA dominance, ammonium accumulation, and reduced nitrogen removal due to suppressed nitrification and denitrification. High-salinity selects for DNRA-performing, salt-tolerant microbes, enriching DNRA genes (<em>narGHI, nirBD</em>), while denitrification genes (<em>nosZ, nirK</em>) are more abundant at lower salinities.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"197 ","pages":"Article 106669"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881129","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":"Resolving false positive Eu anomaly in seep carbonates with high Ba/Sm ratio using DGA resin separation","authors":"Xudong Wang ,&nbsp;Lanlan Zhang ,&nbsp;Tongtong Bai ,&nbsp;Jean-Alix Barrat ,&nbsp;Zhaoyang Wang ,&nbsp;Zice Jia ,&nbsp;Dong Feng","doi":"10.1016/j.apgeochem.2025.106670","DOIUrl":"10.1016/j.apgeochem.2025.106670","url":null,"abstract":"<div><div>The contents and distribution patterns of rare earth elements (REEs) are powerful tools for reconstructing fluid sources and redox conditions in marine sedimentary environments. However, their accurate determination in carbonate rocks is often complicated by low REE abundances and high barium (Ba) contents, which cause severe isobaric interference with europium (Eu) during conventional ICP-MS analysis due to the formation of BaO⁺ or BaOH⁺ polyatomic ions. In this study, we applied a validated DGA resin separation technique to analyze REEs from 30 Ba-rich authigenic carbonate samples from nine seep sites in the Gulf of Mexico. Before and after DGA separation, REE analyses were conducted on both bulk carbonate rock and carbonate fraction of carbonate rock (hereafter carbonate fraction). Ba contents ranged from 201 ppm to 91200 ppm in the bulk carbonate rock, and from 28 ppm to 1700 ppm in the carbonate fraction. Prior to separation, Eu/Eu∗ values ranged from 1.40 to 80.49 in bulk rock and from 1.44 to 17.65 in the carbonate fraction, with strong correlation to Ba/Sm ratios, indicating Ba-induced analytical artifacts. After DGA resin separation, Eu/Eu∗ values decreased to 1.10–1.16 in bulk rock and 1.11–1.22 in the carbonate fraction, confirming the elimination of false Eu anomaly. These results demonstrate that Ba-related interference can lead to substantial misinterpretation of REE data in Ba-rich samples. We advocate for routine chemical separation of REEs from matrix elements prior to ICP-MS analysis to ensure accurate paleoenvironmental reconstructions in seep and other Ba-enriched sedimentary settings.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"197 ","pages":"Article 106670"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881090","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}