Applied Geochemistry最新文献

{"title":"The origin and evolution of waters in the Miocene formation of the Carpathian Foredeep","authors":"Marek Hajto ,&nbsp;Barbara Uliasz-Misiak ,&nbsp;Bogumiła Winid","doi":"10.1016/j.apgeochem.2026.106680","DOIUrl":"10.1016/j.apgeochem.2026.106680","url":null,"abstract":"<div><div>The autochthonous Miocene molasse sediments filling the Carpathian Foredeep (SE Poland) are rich in mineralised waters. This study aimed to determine the origin and hydrogeochemical evolution of these waters. The analysis of mineralisation, chemical composition, and selected hydrochemical indicators of groundwater was used to identify their genesis and the processes that influenced their composition over geological time.</div><div>More than 2000 water analyses from Miocene formations were compiled and verified according to hydrogeochemical standards. The analysed parameters included TDS, chloride, sulphate, bicarbonate, sodium, calcium, magnesium, and bromide. Waters were grouped by depth and geographic location to assess spatial and vertical variability, and key ion ratios were calculated.</div><div>Most of the waters occurring in Miocene formations are of the sodium–chloride type, typical of zones isolated from active circulation. Their mineralisation increases irregularly with depth. According to hydrochemical indicators, Miocene waters are primarily brines or chloride waters genetically related to seawater. However, variance in chemical composition indicates partial infiltration by meteoric waters. Waters at various depths may contain components of infiltration origin.</div><div>Ion exchange and the dissolution or precipitation of carbonate and sulphate minerals were the main factors shaping water chemistry, alongside seawater evaporation and halite dissolution. Although groundwater chemistry does not differ significantly between the eastern and western parts of the basin, deeper horizons (below 1000 m b.g.l.) show greater variation.</div><div>The complexity of processes affecting Miocene formation waters is reflected in the lack of clear correlations among parameters.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106680"},"PeriodicalIF":3.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023992","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 impact of a NaNO3 plume in a deep geological repository on the diffusion of dissolved gases in clay","authors":"Elke Jacops ,&nbsp;Chloé Roonacker ,&nbsp;Hannes Claes ,&nbsp;Lander Frederickx ,&nbsp;Anneleen Vanleeuw ,&nbsp;Quoc Tri Phung ,&nbsp;Jerry Peprah Owusu ,&nbsp;Sergey V. Churakov ,&nbsp;Jon Harrington ,&nbsp;Andrew Wiseall ,&nbsp;Christophe Bruggeman","doi":"10.1016/j.apgeochem.2026.106681","DOIUrl":"10.1016/j.apgeochem.2026.106681","url":null,"abstract":"<div><div>In the framework of the geological disposal of high and intermediate-level long-lived radioactive waste, the Boom Clay is considered as a potential host formation in Belgium. Boom Clay has suitable characteristics that limit the mass transport of dissolved species. Since gas generation in geological repositories is unavoidable, its dissipation needs to be evaluated. This study focuses on the gas diffusion properties in the case of a geochemical perturbation of the near field of Boom Clay, caused by NaNO₃ leaching from Eurobitumen bituminised waste. The diffusion of 4 gases (He, CH₄, Xe, and C₂H₆) was measured in intact and chemically (with NaNO₃) disturbed samples and the change in diffusion coefficients after perturbation was assessed. Intact and disturbed samples were petrographically and petrophysically characterised. Results of this study show that most of the clay properties are not altered by the chemical perturbation. The parameter which changed significantly is the specific surface area, which decreased 40–60 % in the chemically disturbed samples. Water transport (hydraulic conductivity) is not influenced by the perturbation. For diffusivity of dissolved gases and HTO, the differences are not significant as they are within the uncertainty boundaries. Molecular dynamics simulations in montmorillonite revealed that the clay interlayer might potentially shrink or even collapse due to the chemical and osmotic potential differences induced by geochemical perturbation (NaNO₃). The reduced volume of the interlayer porosity did not impact the diffusion of dissolved gases. The key message of this study is that a perturbation of clay with 1 M NaNO₃ will not significantly alter the transport properties of dissolved gases in the near field. This information is of relevance for the development of a geological disposal concept of bituminised waste in Boom Clay.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106681"},"PeriodicalIF":3.4,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923924","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":"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":"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":"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":"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}