Lithium (Li) enrichment in coal has attracted significant attention due to its economic potential and complex geochemical behavior during coal formation. This study investigates the concentration and isotopic composition of Li in kaolinite and organic matter from three high-Li coals from North China using Secondary Ion Mass Spectrometry (SIMS), complemented by TESCAN Integrated Mineral Analyzer (TIMA)

The Bogatyr Komin open-pit mine in the Ekibastuz Basin, located in north-east Kazakhstan, is one of the largest coal mines in the world. It is based on three Lower Carboniferous seams (from bottom to top: seams 3, 2, and 1), which together form a 150 m thick, uniform seam complex. At the study site on the western basin edge, the seams dip steeply. Organic petrological and geochemical investigations

Solid bitumen constitutes a predominant organic component in thermally mature source rocks, yet its role in shale reservoirs remains poorly constrained. This study integrated hydrocarbon expulsion simulation via sequential solvent extraction with isothermal pyrolysis experiments conducted on an early mature bituminite-rich shale sample from the Mesoproterozoic Xiamaling Formation in North China. Organic

Coals from southern Brazil are preserved in the Lower Permian postglacial Rio Bonito Formation of the Paraná Basin. Previous studies on the Candiota Coalfield have shown intervals with significant accumulations of inertinite macerals in the Banco Louco and S9 coal seams. Aiming to understand the causes of these anomalous inertinite accumulations, this study analyzed coal samples from the anomalous

The coal-bearing basal section of the Late Eocene Socka Beds in northeastern Slovenia exhibits iron sulfide mineralization associated with coal. Detailed petrographic analyses have identified five distinct textural and geochemical varieties of pyrite and marcasite. Geochemical analyses reveal that pyrite is notably enriched in Cu, Zn, and Mo, while marcasite shows enrichment in Co, Ni, As, Se, and

Biochar, a carbon-rich product of biomass pyrolysis, holds considerable potential for carbon sequestration, soil amendment, and environmental remediation. Its effective application, however, hinges on understanding biochar permanence and on employing robust methodologies to reliably assess its stability and reactivity.

Twenty eight (7 coal, 12 organic-rich and 9 inorganic) cutting samples obtained from six boreholes drilled over a c. 60-km2-large area in the alluvial plain of Niger River between Obomkpa and Issele-Azagba, southern Nigeria, were examined and evaluated by means of coal-petrography, mineralogical (XRD) and geochemical (CHNS, Rock Eval, XRF) analyses. This study aimed to provide an initial assessment

Geothermal exploration can be complicated by the presence of hydrocarbons in the subsurface. This is a well-known issue in Switzerland, where geothermal projects were affected by the consequences of an unexpected finding of hydrocarbons during drilling operations. This was the case of the Schlattingen-1 well in 2011 and the St. Gallen-GT-1 well in 2013, both located in the north-eastern part of the

As part of the ongoing research project “Chemistry, Biomechanics, and Physiology of Carboniferous plants”, this study investigates two of the largest Canadian specimens of Odontopteris cantabricaWagner, 1969 (22-cm long) and Odontopteris schlotheimiiBrongniart, 1828-1831 (7-cm long) from the Pennsylvanian Sydney Coalfield. Specimens of both species co-occur in the roof shale of the Lloyd Cove coal

Surficial low-temperature sedimentary clay-type Li deposit is one of three major types of Li deposits in the world; however, its formation and corresponding Li isotope fractionation mechanisms are still unclear. In this study, we demonstrate an unusually high Li concentration (89.1 ppm to 520 ppm) within a Late Triassic coal-hosted clay Li deposit from the Sichuan Basin, China. In-situ mapping of the

The composition of sedimentary organic matter (OM) is an important parameter that determines the hydrocarbon potential and reveals the depositional conditions of organic-rich shales. Several automated analysis methods have been developed to determine the maceral composition of coals, but few studies have applied these techniques to assess the composition of OM in source rocks. This research developed

A series of gold tube pyrolysis experiments (72 h, 300–550 °C, 50 MPa) conducted on a graptolite-rich lower Paleozoic marine shale generated pyrolysis residues for a comprehensive evaluation of the molecular and structural variability of three types of graptolite periderm. Organic petrology, Raman spectroscopy, and field emission scanning electron microscopy (FE-SEM) with energy dispersive spectroscopy

Hydrocarbon-bearing fluid inclusions (HCFI) in halite from the Gorleben and Morsleben sites (Germany), petroleum from Gorleben, and epoxy resins have been analysed in-situ using a combined approach of confocal laser-scanning microscopy (CLSM), incident light, and transmitted light fluorescence microscopy. The HCFI contain vapour and liquid hydrocarbon phases and their optical appearance varies widely

This study presents a pioneering investigation into the behaviour of biocoke, particularly its biogenic component (biochar), during ferromanganese production. Employing μCT scanning, micro-Raman spectrometry, and organic petrology, the research explores the transformation of organic matter throughout different zones of a pilot ferroalloy furnace. The results reveal that the degradation of biocoke and

Cokes prepared from Northern Hemisphere (NH) and Australian coals (AU) were characterised by structural/textural parameters obtained using automated optical image analysis. Comparison of matched cokes from NH and AU with similar parent coal rank and amount of vitrinite revealed significant differences between their structural parameters.

Whether the coals in Western Siberia generated commercial volumes of liquid hydrocarbons is an important issue that remains controversial because it has not yet been definitively resolved. Organic petrography and geochemical investigations including Rock-Eval pyrolysis, elemental, isotope, and biomarker analyses were carried out to characterize in detail the hydrocarbon generation potential, type of

Characterizing pore-size distributions (PSD) of coals is required to identify optimum zone for gas recovery and suitable sites to store carbon dioxide (CO2) or hydrogen. Micropore and mesopore PSD characteristics vary with differences in thermal maturity, maceral fractions, and as this study novelly identifies, bulk-rock reaction kinetic distributions. Five coal samples from the Damodar Coal Province

Flow in shale differs substantially from that in conventional reservoirs due to unfavorable reservoir features such as ultra-low permeability and very poor porosity. Shale also exhibits considerable anisotropy and heterogeneity, with clay laminae and bedding angle being the primary variables influencing anisotropy. As a result, shale is subjected to high stress sensitivity and deformation during depressurization

A sequence of Upper Ordovician black shales from the Casal de Alge area, Figueiró dos Vinhos, in the Central Iberian Zone, with unusually high organic matter content, is studied for the first time. These black shales rich in organic matter (31.21–41.29 %), also contain quartz (30–61 %) and illite (26–62 %), revealing the contribution of siliciclastic and detrital elements to their composition. The

Modes of occurrence of rare earth elements (REE; if including Y, REY) in coal have attracted much attention owing to the extraction potential of REY from coal fly ash. Although previous studies have explored the associations of REY in coals with different ranks and the affinities of light, medium, and heavy REY associated with organic matter, challenges remain due to the limitations of indirect or

Coal combustion and coal fires occur globally, and pyrometamorphic rocks produced by coal combustion and coal fires are widely distributed in the northeastern Ordos Basin, China. Studies on the characteristics and genetic environment of pyrometamorphic rocks within the study area remain limited. In this light, the paper explored the petrological, mineralogical, and geochemical properties of pyrometamorphic

The northeastern Ordos Block, a pivotal transition zone between the stable North China Craton and the reactivated Yinshan Orogenic Belt, preserves critical records of intra-cratonic responses to the closure of the Paleo-Asian Ocean. However, the Permo-Carboniferous tectonic evolution of the northeastern Ordos Block is debated due to the conflicting sediment source interpretations. This study reports

An integrated multi-method research study, employing maceral identification and analysis, microphotometry, fluorescence microspectrometry, palynofacies analysis, Rock-Eval pyrolysis and biomarker geochemistry, and was applied to determine sources of variation of organic matter (OM) type, its provenance, thermal maturity, as well as hydrocarbon potential of the Middle Jurassic Szlachtowa Formation in

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

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

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

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

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

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

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

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

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

Vitrinite reflectance is a parameter of organic matter maturity considered of paramount importance to reconstruct the history of sedimentary basins (palaeotemperature, depth of burial, unconformities, tectonic overprinting, local thermal anomalies). Although sensitive to external factors (vitrinite alteration, maceral composition, lithology) that may harm its reliability, it is still the most robust

Coal-hosted critical metal deposits have emerged as a viable alternative to conventional critical metal resources and have garnered significant attention in recent years. Notable enrichments of critical metal assemblages, including aluminum, gallium, lithium, and rare earth elements and yttrium (REY) have been identified in several Permo-Carboniferous coal measures within the Jungar Coalfield and across

Peat deposits are highly sensitive to environmental changes and are well-suited to palaeobotanical investigations. Therefore, we assess the integration between organic petrology, palynology, and microcharcoal distributions to provide a robust interpretation on peatland dynamic and paleoenvironmental reconstruction. In addition, we propose a peat characterization using a quantitative color coordinate

The mechanical behavior and elastic anisotropy of coal under stress are critical to understanding its structural integrity and performance in subsurface environments. Despite its significance, limited research has systematically analysed the elastic anisotropic responses of coals under such conditions. This study investigates the elastic anisotropy of three anthracite-rank coals, Primrose, Lattimer

Deep source rocks are typically in a high-to-overmature stage, characterized by lower than original values of total organic carbon. Thus, resource evaluation is significantly influenced by the accuracy of the measured data and the restoration methods of original (pre-thermal maturation) values. Therefore, reliable data for assessing petroleum and natural gas resources generated during the burial process

Coal fly ashes (CFAs) are an alternative resource of rare earth elements and yttrium (REY). China is the largest producer of CFAs in the world and is likely to hold substantial reserves of CFA-REY resources, while nationwide research on REY resource in Chinese CFAs is lacking. In this work, CFA samples were collected from 118 coal - fired power plants (CFPPs), including eight subjected to long-term

Organic matter (OM) pores play a leading role in gas storage for many shale formations, and understanding their development mechanism is critical to evaluating the mechanisms of shale gas enrichment. However, an insufficient knowledge of OM compositional and structural complexity makes the origin of pore heterogeneity still unclear. This study correlates high-resolution scanning electron microscopy

The Barito Basin in southern Borneo contains large Eocene and Miocene coal deposits as well as a minor petroleum system. Previous authors have distinguished two oil families, termed Tanjung and Warukin. Coal has been discussed as the source for both, but there is no consensus on the lithology of the source rock of the Tanjung family.

Solid bitumen in Southwest China often coexists with metal deposits, indicating a genetic link between organic matter and ore formation. However, this linkage remains underexplored. This study investigated the relationship between sulfur origin and organic matter maturity through sulfur isotopes of metal sulfides. Organic petrology revealed that solid bitumen associated with minerals exhibited stronger

Fly ash derived from the combustion of an eastern Kentucky high volatile bituminous coal blend was, as discussed in previous studies, beneficiated to yield a − 75-μm product with a reduction in the carbon and spinels. The beneficiated fly ash was reacted with a strong acid in a pilot-scale unit to extract rare earth elements (REE) and other major and minor elements. In this study, polished, epoxy-bound

Chronostratigraphic calibration of the Westphalian and early Stephanian succession in the Saar-Lorraine Basin of Germany and France has been improved using high-precision UPb zircon dating of intercalated tonsteins (volcanic ashes) in coal seams. The clay mineralogy and elemental composition were determined to specify the source of these volcanic ashes and the post-depositional weathering processes

The evolution of pore structures in marine shale during thermal maturation was investigated using naturally matured samples (Ro 0.46–1.26 %) from the Upper Cretaceous Second White Speckled Shale and artificially matured samples in a semi-open system (200–450 °C). Analytical techniques, including Rock-Eval pyrolysis, FIB-FESEM, and nitrogen adsorption, revealed key trends in pore volume (PV) and specific

The black shale in the Upper Permian Dalong Formation in the Western Hubei (WH) Trough is characterized by its extreme organic matter accumulation (OMA), and its vertical heterogeneity necessitates more nuanced research. The characteristics of the lithology, conodont, total organic carbon (TOC), mineral composition, silica origin, palaeoenvironmental evolution, and the OMA mechanisms of the Dalong

Extensive coalbed gas exploration has been conducted in the Fukang area of the Junggar Basin in China, but no significant breakthroughs have yet to be achieved, partly due to the unclear origin of coalbed gas. In this study, the compositions and isotopes of coalbed, shale, and tight sandstone gases, along with the chemical characteristics of formation water are reported. The results indicate that the

Organic gases were collected at the Truman Shepherd and Lotts Creek coal fires, both developed in high volatile A bituminous coals, several times over the course of five to six months. Carbon dioxide and CO, exceeding 102,800 ppmv and 11,000 ppmv, respectively, at two of the vents studied, dominate the gas chemistry. Methane, ethane, and propane dominate the aliphatic gases and benzene dominates the

Correlations between metapelitic zones and organic proxies of thermal maturity, like coal rank, vitrinite reflectance and color alteration index in conodonts, were developed several decades ago and have been widely applied with satisfactory results. In contrast, comparisons between graptolite reflectance and metapelitic zones defined by Kübler Index values, clay mineral assemblages and chlorite geothermometry

Samples from the Senakin coal bed (Eocene age, Pasir Sub-basin) were analyzed to study the concentration of critical elements and investigate genetic types and enrichment processes. Of particular interest was to determine if an overlying mafic volcanic unit dated to the same age as the overlying Eocene sediments and tonstein layers withing the coal, affected the geochemical composition of the coal

Porosity, pore size distribution, and surface area are the main petrophysical characteristics indicative of gas storage capacity in shales. This paper investigates the influence of organic matter (OM) content on the evolution of these parameters at different stages of thermal maturity. Ninety-six samples of Silurian shales from the Baltic Basin ranging in maturity from immature to overmature were selected

Currently, demand for rare earth elements (REEs) increased significantly. Coal is actively evaluated as potential economic sources for extraction of REEs. In this work, laser-induced breakdown spectroscopy (LIBS) was evaluated for rapid estimation of REEs content and their distribution in the natural coal samples. The results were compared with similar laser ablation–inductively coupled plasma–mass

The eastern margin of the Ordos Basin in China holds substantial coalbed methane resources. Nevertheless, coalbed methane production in this region is significantly constrained due to the unclear characteristics of the in-situ stress field within the coal reservoirs. Drawing on extensive coal seam test data, including well testing and hydraulic fracturing, and uses hydraulic fracturing calculation

This study investigates the anthracite and graphite samples from the Hanpoao mining area in Hunan Province, China, to understand their structural deformation characteristics in relation to tectonic stress and magmatic intrusion. Despite previous research highlighting the influence of tectonic stress on the microcrystalline structure of organic matter, there remains a gap in comprehensively understanding

Recently, the demand for automatic coal maceral identification has gradually received much attention, and hence deep learning has been applied to the identification of coal macerals. However, a large number of labels are necessary for supervised learning, which imposes challenges for automatic coal maceral identification. In this study, the methods for identifying coal macerals were fully reviewed

The mechanical characteristics of naturally fractured coal under strain rate-dependent loadings can affect engineering activities such as coal seam gas production, gas drainage and CO2 sequestration. While the macro-(core) scale strain-rate dependent response of fractured coal has been investigated previously, the micro-scale mechanisms driving this core-scale behaviour particularly under recoverable

This study examines the effect of high water pressure (up to 900 bar) on hydrocarbon generation from Type-I kerogen-rich source rocks and compares the results with previously observed effects on Type-II and Type-III kerogens. An immature Type-I oil shale sample from the Duwi Formation, Egypt, was pyrolysed under anhydrous, low-pressure hydrous, and high water-pressure conditions at 320 °C (end of bitumen

The oil and gas industry are heavily dependent on hydrocarbon resources, and the identification of potential source rocks is a critical aspect of exploration. Accurate determination of the hydrocarbon generation potential (S1 and S2), thermal maturity (Tmax), and total organic carbon (TOC) of source rocks is essential for predicting both the quantity and quality of hydrocarbons. Traditional methods