International Journal of Coal Geology最新文献

{"title":"Characterization and upgrading of a new Mozambican graphite ore for the production of graphene materials","authors":"Salvador Mondlane Jr. ,&nbsp;Yuliesker Yaque ,&nbsp;Adrián Vigil ,&nbsp;Isabel Suárez-Ruiz ,&nbsp;Uriel Sierra ,&nbsp;Marcos Granda ,&nbsp;Amadeu Carlos Dos Muchangos ,&nbsp;Alfonso Mercado ,&nbsp;Patricia Álvarez","doi":"10.1016/j.coal.2025.104773","DOIUrl":"10.1016/j.coal.2025.104773","url":null,"abstract":"<div><div>This study investigates the mineralogical characteristics of Mozambique graphite, with a particular focus on the Ancuabe deposit, located in the Cabo Delgado Province of northern Mozambique. Analysis of the mineralogy of the ore shows the presence of large flakes of graphite in parallel veinlets that follow the strike of the main foliation and in a disseminated form with structures that feature massive, highly foliated schists. The ore's mineral composition, as determined by XRF is dominated by SiO₂ (∼75 %), containing &lt;0.5 wt% of critical raw materials as Ti, V_, Ni, and Cr. Approximately 30 % of the ore is carbon, which is attributed to graphite as determined by XRD, Raman spectroscopy and optical microscopy.</div><div>The potential of these graphite deposits to serve as a raw material in the production of graphene was examined. For that, the graphite ore was purified through size fractionation, employing standard graphite purification methods. The total graphite, along with the graphite fractions, were utilised as raw material for the preparation of graphene oxide (GO) via standard chemical oxidation and exfoliation methods. The monolayers of GO obtained from the whole graphite fraction exhibited the typical oxidation of basal planes and edges but were obtained at a low yield. However, this yield was enhanced by subjecting the three graphite fractions to an optimized procedure, which involved employing longer reaction times with the larger-sized graphite fractions. Consequently, the overall process yield was significantly increased, and it was also possible to obtain GO sheets of controlled lateral size, ranging from very large to small.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104773"},"PeriodicalIF":5.6,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deciphering the Douro Carboniferous Basin (Pejão Coalfield, Portugal): Geochemical, petrological, and mineralogical evidence of depositional, diagenetic, and hydrothermal processes","authors":"Mariana Costa ,&nbsp;Ary Pinto de Jesus ,&nbsp;Eduardo Ferreira da Silva ,&nbsp;Isabel SuárezRuiz ,&nbsp;Fernando Rocha ,&nbsp;Deolinda Flores","doi":"10.1016/j.coal.2025.104771","DOIUrl":"10.1016/j.coal.2025.104771","url":null,"abstract":"<div><div>The Douro Carboniferous Basin (DCB) in Portugal hosts significant coal deposits, with the Pejão Coalfield being among the most important. This study integrates petrographic, geochemical, and mineralogical analyses to investigate the sedimentation, hydrothermal influences, and paleoclimatic conditions of the DCB. Petrographic analysis classifies these coals as high-rank anthracite A, with vitrinite as the dominant maceral (&gt;90 %). Geochemical analyses reveal trace element enrichments (Ag, As, Pb, Sb, and V), suggesting a combination of primary sedimentary input and later hydrothermal overprinting, as indicated by the presence of REE-bearing phosphates (florencite, monazite, xenotime) and sulfosalts (tetrahedrite, bournonite).</div><div>Paleoweathering indices (CIA, PIA, WIP, MIA) suggest intense weathering and subtle sediment recycling, while paleosalinity proxies indicate periodic evaporation events linked to ephemeral lacustrine zones, possibly playa-type systems. The REE distribution patterns and provenance indicators suggest a limited zircon enrichment, supporting minimal sedimentary recycling, especially intracarboniferous breccia and sandstone lithologies. These findings provide new insights into the basin's depositional environment, diagenetic history, and hydrothermal alteration, contributing to a broader understanding of Carboniferous intermontane basins.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104771"},"PeriodicalIF":5.6,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The K isotopic signatures of coals: A reconnaissance study","authors":"Zhihan Ji ,&nbsp;Jun Mu ,&nbsp;Suping Yao ,&nbsp;Weiqiang Li","doi":"10.1016/j.coal.2025.104770","DOIUrl":"10.1016/j.coal.2025.104770","url":null,"abstract":"<div><div>Potassium (K) isotopes are significantly fractionated in sediments, with biological samples exhibiting even greater K isotopic variability than geological samples. Coal is a unique type of sedimentary rock composed of organic matter and minerals, both of which are K-rich. Therefore, K isotopes hold the potential for tracing the origin of coal and understanding coal-forming processes. However, our knowledge of K isotopes in coals is limited due to the scarcity of K isotopic studies on coals. In this study, we conducted the first detailed investigation of K isotopes in 12 coal samples of varying ranks by analyzing the abundance and isotopic compositions of K in different phases. We ashed the coals and sequentially leached K from the ashes with deionized water (DW), ammonium acetate (AA), HCl, and HF, followed by elemental and isotopic analyses. The majority of K occurs in DW-leached and HF-leached fractions of these coal samples, representing the K associated with organic matter and the K that exists in the silicate phase, respectively. The bulk K content of the twelve studied coals ranges from 0.004 to 1.308 wt%, with the HF-leached K holding the dominant K budget. The δ⁴¹K values vary from −1.19 ‰ to 0.52 ‰ in the DW-leached phase, and from −1.27 ‰ to −0.22 ‰ in the HF-leached phase of the low temperature coal ashes. The large variations in δ⁴¹K values of DW leachate are attributed to the plants decay and diffusion in pore fluids in the early stage of diagenesis. The K isotope compositions of the HF-leached K in coals are variable and lighter than average igneous rocks (δ⁴¹K_BSE = −0.43 ‰). Pore fluid exchanges likely caused the preference for ³⁹K in the silicate phase of coal. The K isotope compositions of coals overall reflect ³⁹K enrichment during diagenesis or organic matter inheritance.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104770"},"PeriodicalIF":5.6,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"micro-Raman indicates biochar has similar stability and structural features as natural fusinite and semifusinite","authors":"H.I. Petersen ,&nbsp;M.R. Stokes ,&nbsp;P.C. Hackley ,&nbsp;A. Rudra ,&nbsp;Z. Zhou ,&nbsp;H. Sanei","doi":"10.1016/j.coal.2025.104769","DOIUrl":"10.1016/j.coal.2025.104769","url":null,"abstract":"<div><div>Semifusinite and fusinite macerals are formed through carbonization of plant material in naturally occurring wildfires. Both macerals, belonging to the inertinite maceral group, are carbon-rich and oxygen-poor, and are typical constituents of charcoal. The charring of plant material into charcoal is a naturally occurring process that effectively stores carbon over geological timescales. The stability of carbon in biochar formed by pyrolysis of biomass are determined by its degree of carbonization, and long-term storage in soil assumes that the biomass has been completely transformed into inertinite biochar. Inertinite biochar is thought to have a structural composition comparable to highly stable natural fusinite, whereas less carbonized biochar is similar to less stable semifusinite. In this study, micro-Raman spectroscopy was employed to examine the structural composition of 16 biochar samples produced at different temperatures from various lignocellulosic feedstocks, as well as one natural semifusinite isolated from a coal deposit. The estimated carbonization temperatures, representing the actual internal heating temperatures experienced by the biomass, ranged from 326 to 825 °C. The micro-Raman results of the biochar samples were compared with previously published micro-Raman data on naturally formed semifusinite and fusinite. The findings show that biochar, semifusinite, and fusinite likely undergo similar structural evolution with increasing temperatures, suggesting that the process of pyrolyzing biomass into biochar may mimic the natural charring process that occurs during wildfires. Though additional work could help to validate benchmarks, these results support the idea that biochar stability is similar to that of fusinite and semifusinite and indicate its potential as a long-term storage solution in the context of the geological carbon cycle. Furthermore, the results indicate that in addition to the established inertinite benchmark (IBR_o2%; R_o = 2 %) for determining biochar stability, up to four new micro-Raman benchmarks can be used to define inertinite biochar: (1) D3-band position: 1460 cm^‐1 or higher, (2) D1/G amplitude ratio: 0.80 or higher, (3) Raman band separation (RBS): 250 cm^‐1 or higher, and possibly (4) G-FWHM (full width at half maximum): 72 cm^‐1 or lower. The availability of multiple benchmarks that can indicate biochar stability could provide tools for evaluating biochar long-term storage potential, thus reinforcing carbon dioxide removal (CDR) via biomass waste pyrolysis as a viable technique to mitigate climate change.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104769"},"PeriodicalIF":5.6,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A lithofacies-coupled palynofacies model for meandering river floodplains in the Late Cretaceous: Insights from the Dinosaur Park Formation, Alberta, Canada","authors":"Muditha Goonetilleke ,&nbsp;Ricardo L. Silva ,&nbsp;João G. Mendonça-Filho ,&nbsp;Paul R. Durkin","doi":"10.1016/j.coal.2025.104768","DOIUrl":"10.1016/j.coal.2025.104768","url":null,"abstract":"<div><div>Alluvial floodplains accommodate various sub-environments that preserve evidence of fluvial dynamics, aiding in the reconstruction of terrestrial paleoenvironments. While floodplains serve as major sources and sinks for organic matter, characterizing sub-environments within ancient floodplains using fossil organic matter (kerogen) is sparsely applied due to its unclear relationship with organic matter dynamics in modern fluvial settings. This study develops a lithofacies-coupled palynofacies model for fluvial environments to address this gap and reveal organic matter dynamics in paleo-floodplains. The sedimentary successions of the Upper Cretaceous Dinosaur Park Formation in Dinosaur Provincial Park, Alberta, Canada, offer an ideal fluvial setting to develop this model, compare it across geological time intervals, and refine paleoenvironmental reconstructions of the Dinosaur Park Formation.</div><div>A floodplain-dominated stratigraphic section of the Dinosaur Park Formation comprises six recurring lithofacies and two facies associations representing channel-belt and floodplain deposits. All observed kerogen assemblages originated from terrestrial environments. Channel-belt deposits are characterized by sandstones containing opaque and amorphous non-biostructured phytoclasts, as well as amorphous organic matter. Levee deposits are characterized by sandy mudstones, while proximal floodplains are characterized by gray mudstones. Despite these distinctions, kerogen assemblages are relatively similar and heterogeneous, with opaque phytoclasts remaining prevalent. Backswamps (carbonaceous mudstones and shales) and distal floodplain environments (brown mudstones) exhibit a high abundance of cuticles, membranes, sporomorphs and amorphous non-biostructured phytoclasts. Total organic carbon content discriminates between different sub-environments, with higher organic carbon content found in backswamp and distal floodplain environments. The results show that lithofacies and kerogen assemblages (i.e. palynofacies) in the Dinosaur Park Formation's floodplains were mainly influenced by channel proximity and floodplain topography. When compared with modern and deep-time fluvial examples, the model supports palynofacies analysis as a robust proxy for distinguishing floodplain sub-environments and demonstrating its applicability in understanding fluvial dynamics over geological timescales.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104768"},"PeriodicalIF":5.6,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancing shale geochemistry: Predicting major oxides and trace elements using machine learning in well-log analysis of the Horn River Group shales","authors":"Ammar J. Abdlmutalib ,&nbsp;Korhan Ayranci ,&nbsp;Umair Bin Waheed ,&nbsp;Nicholas B. Harris ,&nbsp;Tian Dong","doi":"10.1016/j.coal.2025.104767","DOIUrl":"10.1016/j.coal.2025.104767","url":null,"abstract":"<div><div>This study evaluates machine learning algorithms for predicting geochemical compositions in the Middle to Upper Devonian Horn River Group shales. The minor textural variations within shale successions necessitate a detailed understanding of their geochemical composition for accurate interpretation of depositional environments and stratigraphic relationships. Geochemical analysis is essential for unconventional reservoir shales but is traditionally labor-intensive. Machine learning offers a cost-effective alternative, streamlining geochemical interpretation and stratigraphic correlation. Five models, Random Forest Regressor, Gradient Boosting Regressor, XGBoost, Support Vector Regressor, and Artificial Neural Networks (ANN), were assessed using well-log data to predict major oxides and trace elements. Training and validation used data from two wells, with model performance tested on an unseen well to evaluate generalizability. Tree-based models, particularly Random Forest Regressor, demonstrated high accuracy for major oxides such as K₂O and CaO, while Gradient Boosting Regressor excelled for Al₂O₃ and TiO₂. However, SiO₂ and Na₂O were less predictable due to their complex origins and low concentrations. For trace elements, Random Forest Regressor effectively predicted Th, Zr, Co, and total rare earth elements (∑REE). Redox-sensitive elements such as Mo, Cu, U, and Ni had lower accuracy due to their weaker correlation with well-log data; however, Random Forest Regressor still achieved the best performance among the models for these elements. Blind tests confirmed the generalizability of the models, with tree-based models maintaining strong predictive performance for several major oxides, trace elements, and REEs, while ANN and Support Vector Regressor exhibited robustness in Al₂O₃, K₂O, and TiO₂ predictions. This study highlights tree-based models as reliable tools for predicting geochemical compositions, supporting chemostratigraphy and reservoir characterization. Integrating machine learning with well-log data offers a promising solution for efficient geochemical analysis and subsurface characterization in Devonian shale reservoirs.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104767"},"PeriodicalIF":5.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstructing the late Permian-early Triassic environment of a coal-bearing succession in the Maniamba Basin, Mozambique (Central Gondwana): A multiproxy palynological and geochemical approach","authors":"N. Nhamutole ,&nbsp;M.K. Bamford ,&nbsp;P.A. Souza ,&nbsp;C.M. Felix ,&nbsp;E. Pereira ,&nbsp;L. Bastos ,&nbsp;L. Mendes ,&nbsp;O. Deus ,&nbsp;M. Nopeia ,&nbsp;D.A. Carmo","doi":"10.1016/j.coal.2025.104755","DOIUrl":"10.1016/j.coal.2025.104755","url":null,"abstract":"<div><div>The Maniamba Basin is an intracratonic, Karoo-aged basin located in northern Mozambique. Recent studies have reported the occurrence of organic-rich units in the Maniamba Basin, based on Rock Eval data. However, detailed characterization of the palaeoenvironments in the basin is still lacking. In this study, detailed palynological, palynofaciological, XRD and organic geochemical techniques (TOC, total sulphur, and biomarkers) were performed in order to understand past environments that prevailed in the basin. The palynological data reveal the dominance of gymnosperm taxa (striate and non-striate bisaccate, and praecolpate pollen grains) followed by lycopsids, sphenopsids and ferns suggesting hypautochthonous sedimentation characterized by warm and humid palaeoclimate. The palynological results indicate a Permian and Triassic age for the strata. The organic-rich units unveiled a dominance of phytoclasts and palynomorphs, and to a lesser extent by terrestrial and bacterially derived organic matter with no fluorescence, indicating high maturity. Swamp, river and lake dominated environments with oxic-suboxic-anoxic conditions, reflecting shifting of depositional conditions overtime, are inferred in the Maniamba Basin. The deposition and accumulation of organic-rich units were mainly controlled by palaeoredox conditions linked to basin infill during different rifting episodes. The biomarkers mainly consist of saturated compounds that suggest terrestrial organic matter with freshwater algal contribution.</div><div>Overall, the integration of mineralogical composition with palynofacies, biomarkers and palynology indicate the presence of potential source rocks that were thermally influenced. Additionally, the petroleum fluids known from younger strata in the Rovuma and Mozambique basins did not show any link with the source rock reported previously.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104755"},"PeriodicalIF":5.6,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Domestic combustion of biomass pellets: Example from Poland","authors":"Agnieszka Drobniak ,&nbsp;Zbigniew Jelonek ,&nbsp;Kamila Widziewicz-Rzońca ,&nbsp;Maria Mastalerz ,&nbsp;Arndt Schimmelmann ,&nbsp;Iwona Jelonek","doi":"10.1016/j.coal.2025.104757","DOIUrl":"10.1016/j.coal.2025.104757","url":null,"abstract":"<div><div>In the context of the European Union's intensified efforts to curb greenhouse gas emissions and meet climate targets, wood pellets have emerged as a pivotal element in the renewable energy strategy. Yet, biomass pellet combustion has been linked to a range of pollutants impacting air quality and public health. As biomass utilization gains popularity as a fuel for residential heating, it is important to determine this impact and enhance sustainable practices throughout the entire biomass energy production cycle.</div><div>This study investigates the intricate dynamics of biomass pellet properties on their combustion emissions, with a specific focus on the differences observed between pellets of woody and non-woody origins. The data reveal a variation in pellet characteristics, especially regarding their ash yield and fines contents, mechanical durability, and impurity levels, and significant differences in the type and amount of utilization emissions. The results highlight potential health risks posed by the combustion of biomass fuels, particularly non-woody (agro) pellets, due to elevated concentrations of emitted particulate matter (PM), carbon monoxide (CO), nitrogen dioxide (NO₂), hydrogen sulfide (H₂S), ammonia (NH₃), chlorine (Cl₂), sulfur dioxide (SO₂), and formaldehyde (HCHO), all surpassing recommended limits.</div><div>Moreover, the study reveals that emissions from pellet combustion could be partially predicted by analyzing pellet characteristics. Statistical analysis identified several key variables—including bark content, fines content, mechanical durability, bulk density, heating value, net calorific value, sulfur, and nitrogen content—that impact emissions of CO, NO₂, H₂S, SO₂, HCHO, and respiratory tract irritants. These findings underscore the need for proactive measures, including the implementation of stricter standards for fuel quality and emissions, alongside public education initiatives promoting the cleanest and safest fuels possible.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104757"},"PeriodicalIF":5.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"","authors":"Gregory Smith","doi":"10.1016/j.coal.2025.104756","DOIUrl":"10.1016/j.coal.2025.104756","url":null,"abstract":"","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"304 ","pages":"Article 104756"},"PeriodicalIF":5.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of geological fluids on the distribution of lithium in anthracite, an example from the Yangquan Mining District, Qinshui Basin, northern China","authors":"Huidi Hao ,&nbsp;Bo Jiu ,&nbsp;Wenhui Huang ,&nbsp;Chunlan Yu ,&nbsp;Zhaoguo Wang ,&nbsp;Binchao Qin ,&nbsp;Linghao Huang","doi":"10.1016/j.coal.2025.104754","DOIUrl":"10.1016/j.coal.2025.104754","url":null,"abstract":"<div><div>Coal with abundant kaolinite and illite has become an important target for the exploration of potential coal-hosted lithium deposits. The No.15 coal from the Xinjing Mine, northern China, is rich in kaolinite, illite, and NH₄-illite. This study comprehensively applied multi-scale mineral analysis and in-situ micro-regional characterization methods to analyze the lithium content distribution in clay minerals, while elucidating the genetic mechanisms of clay minerals and their interactions with geological fluids. The genesis of these minerals and their interaction with geological fluids during thermal evolution were analyzed using whole-rock and in-situ geochemical methods. Lithium is enriched in the No.15 coal (42.2 μg/g). The Li concentration in clay minerals in the No.15 coal seam follows a descending order of: cryptocrystalline kaolinite (649.9 μg/g) &gt; detrital kaolinite (366.1 μg/g) &gt; cell-filling kaolinite (94.8 μg/g) &gt; illite (16.1 μg/g) and NH₄-illite (21.1 μg/g). Cryptocrystalline and detrital kaolinite are thus the primary hosts of Li. Whole-rock and mineral geochemical data indicate detrital input as the main source of Li. The similarities in the REE distribution patterns between kaolinite in coal and Yinshan granite suggest that kaolinite, a key weathering product of acidic magmatic rocks in humid sedimentary systems, may have originated from the Yinshan Mountain granite. The presence of seawater and organic acids within coal-bearing strata collectively facilitate the illitization of kaolinite at temperatures of 120–140 °C. The negative correlation between Gd anomalies and Sr/Ba ratios indicates that the interaction between groundwater and seawater has established a geochemical barrier, which facilitates the enrichment of Li in coal.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"303 ","pages":"Article 104754"},"PeriodicalIF":5.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}