International Journal of Coal Geology最新文献

{"title":"Matrix permeability anisotropy of organic-rich marine shales and its geological implications: Experimental measurements and microscopic analyses","authors":"Yong Ma ,&nbsp;Huiting Hu ,&nbsp;Zhejun Pan ,&nbsp;Ningning Zhong ,&nbsp;Fujie Jiang ,&nbsp;Chengyu Yang ,&nbsp;Jianbin Ma ,&nbsp;Binhao Feng","doi":"10.1016/j.coal.2024.104670","DOIUrl":"10.1016/j.coal.2024.104670","url":null,"abstract":"<div><div>Due to the presence of natural and/or preparation-related fractures, the anisotropy of the matrix permeability of shales is usually difficult to characterize. In this study, we used X-ray micro-computed tomography (XRμCT) imaging to select samples from the Lower Cambrian and Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation of the Upper Yangtze Platform, China, showing no natural or artificial fractures. From these samples, cubic specimens were prepared with a wire saw and then re-inspected for fractures. Using a specially developed sample holder, the matrix permeability of these specimens were measured in the three principal directions using the pulse decay method with N₂ as the flowing fluid. To analyze the microscopic lithological and structural controls on shale matrix permeability anisotropy, we employed a combined methodology using thin sections, focused ion beam-scanning electron microscopy (FIB-SEM), and permeability simulation.</div><div>The matrix permeability of the 15 shale samples ranged from 19.6 to 189.4 nD (19.6–189.4 × 10⁻²¹ m²) parallel to bedding and from 2.4 to 24.7 nD (2.4–24.7 × 10⁻²¹ m²) perpendicular to bedding, at a constant confining pressure of 1500 psi (10.3 MPa). Tectonic stress resulting from structural deformation leads to the deformation of OM pores within solid bitumen, which is the main factor controlling the matrix permeability. The ratio of the matrix permeability coefficients parallel and perpendicular to bedding (k_x/k_z) varied from 3.4 to 29.6, primarily due to cleavage zones along the bedding-parallel platy mica and clay altered from mica. The matrix permeability ratio in the two orthogonal horizontal directions (k_x/k_y) typically did not exceed a value of 2, but for samples with oriented graptolites and siltstone layers ratios as high as 2.9 and 2.3, respectively, were observed. The microfractures between graptolite and minerals, together with the elongated pores within the graptolites, enhance the permeability and facilitate gas flow along the bedding planes. The higher proportion of brittle minerals in siltstone renders it more prone to cracking compared to shale, which causes the anisotropy in the parallel-to-bedding directions.</div><div>For three shales from the strongly deformed northeast Chongqing with high-angle fractures parallel to the lamination, permeability parallel to bedding varied between 627.2 and 6820.3 nD, while permeability perpendicular to bedding ranged between 11.3 and 27.8 nD. The presence of microfracture parallel to the lamination in three shale samples resulted in a permeability higher by factors of 34 to 348 than the matrix permeability, leading to a higher anisotropy ratio between both horizontal and vertical directions.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"297 ","pages":"Article 104670"},"PeriodicalIF":5.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825341","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":"Staged evolutionary features of the aromatic structure in high volatile A bituminous coal (hvAb) during gold tube pyrolysis experiments","authors":"Wenbin Yang ,&nbsp;Pal Toth ,&nbsp;Yu Song ,&nbsp;Wu Li","doi":"10.1016/j.coal.2024.104660","DOIUrl":"10.1016/j.coal.2024.104660","url":null,"abstract":"<div><div>Low-temperature pyrolysis of coal is a crucial step in the coal thermal conversion process and involves very complex physical and chemical reactions that can have different effects on the coal's structure. The thermal evolution behavior and transformation mechanism of the coal microstructure are not yet fully understood, which also limits the efficient utilization of coal to a certain extent. The aromatic structural features (including size, molecular ordering, nematic symmetry, stacking, and curvature) of the char produced from low-temperature pyrolysis of high volatile A bituminous coal (hvAb) from the Xutuan coal mine, China, were quantitatively assessed via high-resolution transmission electron microscopy (HRTEM) image processing and analytical techniques. The thermal transformation process and the mechanisms controlling it were explored. The results show that, except for the unexpected slight growth of aromatic sheets at 440 °C, the lower pyrolysis temperature (&lt; 521 °C) contributed weakly to their size growth, whereas at higher temperatures (561–600 °C), it significantly increased their size. The aromatic molecular ordering tended to gradually change in three stages: increasing between 340 and 440 °C, decreasing between 440 and 521 °C and increasing again between 521 and 600 °C. The nematic symmetry strength of aromatic fringes also followed a similar pattern with temperature at different scales. Additionally, in addition to a very minor development trend at 440 °C, the stacking did not significantly change at temperatures below 521 °C but developed appreciably further with increasing temperatures at 561–600 °C; however, the average spacing of the stacks did not appear to be significantly reduced at all temperatures. The curvature of the aromatic sheets also varied in different temperature stages, i.e., initially slightly increasing (340–380 °C), then gradually decreasing (380–480 °C), later increasing again (480–521 °C), and eventually decreasing (521–600 °C). The properties of the chemical composition and structure of the initial coal play important roles in the thermal reaction behavior, and the physical and chemical reactions that dominate at the different temperature stages may be responsible for such wiggly trends in the evolution of the aromatic structure. Notably, the properties of the mesophase (approximately 440 °C) strongly influence the subsequent structural transformation. These findings could provide useful information for the microstructure–property relationships and preparation of coal-based carbon materials.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"297 ","pages":"Article 104660"},"PeriodicalIF":5.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874792","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":"Noble gases in Paleozoic shale fluids document tectonic events and fluid migration in the Upper Yangtze Block","authors":"Rui Liu ,&nbsp;Tao Wen ,&nbsp;Daniele L. Pinti ,&nbsp;Rui Xu ,&nbsp;Fang Hao ,&nbsp;Shang Xu ,&nbsp;Zhiguo Shu","doi":"10.1016/j.coal.2024.104671","DOIUrl":"10.1016/j.coal.2024.104671","url":null,"abstract":"<div><div>Major and noble gases of natural gas extracted from the low-permeability Paleozoic Wufeng-Longmaxi shale were measured to reconstruct the multi-stage, spatially varying tectonic evolution of the Upper Yangtze Block, China, one of the oldest parts of the Earth continents. The high gas dryness ratio [C₁/(C₂ + C₃)] and high carbon isotopic ratios (δ¹³C-C₁, δ¹³C-C₂, δ¹³C-CO₂) suggest a late mature thermogenic origin of shale gas. The highly fractionated atmospheric ²⁰Ne/³⁶Ar and ⁸⁴Kr/³⁶Ar ratios in our gas samples suggest they result from solubility-based partitioning of noble gases between oil and water followed by gas-water partitioning. Calculated volume ratios of oil, water, and gas phases vary spatially and temporally. In particular, the western Yangtze Block shows a lower reconstructed oil/water ratio, suggesting oil leakage promoted by the Triassic exhumation of Paleozoic shale, while a low gas/water ratio in the central-eastern Yangtze Block suggests gas leakage promoted by basin-wide Jurassic fold-thrust faulting. The lowest C₁/³⁶Ar volume ratio around faults at the basin edges indicates extensive gas expulsion. Delineated radiogenic ⁴He in gas samples are several orders lower than calculated in-situ produced radiogenic ⁴He, likely suggesting widespread ⁴He loss. Spatially-varying ⁴He/nucleogenic ²¹Ne ratios in the shale indicated that ⁴He loss in the western Yangtze Block predated that in the central-eastern portion. Such He loss was also coupled with the Triassic exhumation and the Jurassic fold-thrust faulting episodes. In summary, noble gas in pore fluids extracted from low-permeability shale can preserve reliable records of tectonic events produced during upper crust evolution.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"297 ","pages":"Article 104671"},"PeriodicalIF":5.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874791","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":"Elemental geochemical insights into sediment sources, influx variations and depositional environment changes in the Eocene–Miocene Lark Formation, Danish North Sea","authors":"Zhiheng Zhou ,&nbsp;Qingyong Luo ,&nbsp;Niels Hemmingsen Schovsbo ,&nbsp;Henrik Ingermann Petersen ,&nbsp;Arka Rudra ,&nbsp;Hamed Sanei","doi":"10.1016/j.coal.2024.104673","DOIUrl":"10.1016/j.coal.2024.104673","url":null,"abstract":"<div><div>The Lark Formation in the Danish North Sea holds great paleoenvironmental interest for understanding climatic and tectonic impacts on sediment supply and depositional environment during the latest Eocene to the Middle Miocene. This study investigates sediment provenance, variations in sediment flux, chemical weathering intensity, and redox conditions in relation to these climatic and tectonic events. A dataset of 86 cuttings and one core from six wells in the Danish North Sea was analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The recently published maceral composition of these samples was also included in this research.</div><div>Provenance investigation indicates that the sediment originated from felsic sources within a continental arc tectonic setting. Such a source area is currently located in southern Norway and Sweden on the southwest margin of the Baltic Shield. During the Eocene–Miocene progressive filling of the eastern North Sea Basin, climatic conditions primarily controlled chemical weathering intensity and sediment influx. This is evidenced by higher Chemical Index of Alteration (CIA) and Zr concentrations in the Lower Miocene compared to other series deposited under cooler and less humid climates. Additionally, elemental proxies (Ce_anom, V/(V + Ni), Th/U), along with organic petrological and geochemical evidence, indicate that the Lark Formation was deposited in dysoxic-anoxic environments. Variations of these proxies further reveal that sea-level changes primarily controlled fluctuations in redox condition, resulting in more oxic environments. Moreover, the impact of marine productivity on U and Mo is revealed by the positive correlations between the enrichment factors of U (U_EF) and Mo (Mo_EF) and the abundances of liptinite and Cd. Increased productivity, combined with bottom water anoxia, led to the enrichment of U and Mo in the sediment, with upwelling further enhancing this process.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"297 ","pages":"Article 104673"},"PeriodicalIF":5.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901786","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":"The geochemical and organic petrological characteristics of kolm (upper Cambrian, Sweden): Implications for genesis","authors":"Anji Liu ,&nbsp;Niels Hemmingsen Schovsbo ,&nbsp;Arne Thorshøj Nielsen ,&nbsp;Qingyong Luo ,&nbsp;Ningning Zhong ,&nbsp;Leibo Bian ,&nbsp;Xiaowei Zheng ,&nbsp;Rasmus Andreasen ,&nbsp;Hamed Sanei","doi":"10.1016/j.coal.2025.104687","DOIUrl":"10.1016/j.coal.2025.104687","url":null,"abstract":"<div><div>Kolm refers to uraniferous (1280–7100 ppm) and organic-rich (25–71 wt%) lenses occurring exclusively within the Furongian part of the Alum Shale Formation in south-central Sweden. It typically less than 7 cm thick and forms thin discontinuous layers. This study investigates the geochemical and organic petrological characteristics of kolm, and it is shown that the organic matter likely represents secondarily formed solid bitumen rather than a primary organic-rich component. The high uranium content is concentrated in specific uranium‑yttrium‑zinc-rich (U-Y-Zn-rich) particles. A model for kolm formation is presented, suggesting that during sedimentation, initial uranium-enriched particles were formed and then became concentrated, probably by winnowing at the sea floor under euxinic conditions. This lag deposit rich in uranium particle subsequently formed the radioactive nuclei (U-Y-Zn-rich particles) for the kolm nodules that grew during the early diagenesis. Initial kolm was apparently formed by in-situ accumulation of diagenetically formed solid bitumen (R_o &lt; 0.5 %) onto these strongly radioactive U-Y-Zn-rich particles. The more abundant development of kolm in the Billingen area of Västergötland, compared to other regions in south-central Sweden where kolm occurs, is likely due to increased generation of solid bitumen associated with localized heating from Permo-Carboniferous intrusions.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"299 ","pages":"Article 104687"},"PeriodicalIF":5.6,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990607","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":"Wood-degrading fungal origin of perylene in peatlands of southern Poland: A molecular and statistical approach","authors":"J. Smolarek-Lach,&nbsp;E. Szram,&nbsp;K.J. Wójcicki,&nbsp;L. Marynowski","doi":"10.1016/j.coal.2025.104685","DOIUrl":"10.1016/j.coal.2025.104685","url":null,"abstract":"<div><div>Perylene is a polycyclic aromatic hydrocarbon (PAH) whose origin remains enigmatic. It has been thought to be derived from hydrocarbons, however much uncertainty remains over whether it is natural or anthropogenic. In this study, a comprehensive study of peat was conducted in the Osobłoga and Kłodnica River Valleys of southern Poland. Here, we show a significant advance in our understanding of the source of perylene using a detailed analysis of macro and minor elements along with its correlation with other PAHs and biogenic compounds. Based on principal component analysis (PCA), a negative correlation between perylene and combustion-derived PAHs was demonstrated, suggesting different origins for these compounds. Diagnostic ratios, such as %Pe/∑PAH and %Pe/∑PAI above 10 %, and a Py/Pe ratio below 9, indicate that the perylene present in these peat samples is of natural origin, formed from terrestrial organic matter. Furthermore, perylene is associated with a dominance of long-chain <em>n</em>-alkanes, which exhibit a strong odd-over-even preference, further supporting its biogenic source. The analysis revealed a weak correlation between total organic carbon (TOC) and perylene content, indicating that perylene concentration does not directly depend on the overall organic carbon content in peat. In contrast, a strong correlation was observed between perylene and wood-type biogenic compounds, specifically periderm (correlation coefficient of 0.2) and wood (correlation coefficient of 0.3). This finding suggests that perylene formation is closely linked to woody biomass. The Conifer Wood Degradation Index (CWDI) was calculated for samples containing conifer wood phytoclasts, providing insights into the degradation processes affecting these components and their relation to perylene formation. Further molecular and statistical studies on Vistulian and Holocene peats in our study also confirm the hypothesis of a natural, specifically fungal, origin of perylene. A comprehensive analysis of peat deposits, combined with advances in molecular and statistical techniques, continues to elucidate on the complex biogeochemical processes that contribute to the presence of perylene in natural environments.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"299 ","pages":"Article 104685"},"PeriodicalIF":5.6,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143050021","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":"Horgen-Käpfnach, the largest Swiss coal deposit: Geology, petrology and geochemistry","authors":"R.F. Sachsenhofer ,&nbsp;V. Aghayeva ,&nbsp;S. Ajuaba ,&nbsp;I. Kojić ,&nbsp;D. Misch ,&nbsp;K. Stojanović","doi":"10.1016/j.coal.2025.104684","DOIUrl":"10.1016/j.coal.2025.104684","url":null,"abstract":"<div><div>The Miocene Käpfnach seam is only about 0.5 m thick but offers interesting insights into the depositional environments during the early stages (∼16 Ma) of the deposition of the Upper Freshwater Molasse in the Swiss part of the North Alpine Foreland Basin. It is also the most important coal deposit in Switzerland. The study focused on the coal seam, which includes a marly parting (“Stinkstein”), but the underlying and overlying sediments were also investigated.</div><div>The coal seam, which is separated by the “Stinkstein” parting into a lower and an upper part, was investigated using bulk geochemical data, biomarker composition, isotope data and organic petrography. The coal accumulated in a freshwater environment. High sulphur contents and the presence of carbonate shells in the upper part of the seam reflect a high pH value related to a carbonate-rich environment. A significant part of sulphur in the upper part of the seam is organically bound. Petrographical investigations show that herbaceous plants rather than big trees contributed to the organic matter. Biomarker data show the presence of ferns, angiosperms and gymnosperms, albeit in highly variable proportions across the seam. Representatives of the Cupressaceae, Taxaceae and Sciadopityaceae families contributed to the peat-forming vegetation during the early stages of peat accumulation. Open water areas, colonized by freshwater gastropods, existed during deposition of the upper part of the seam. High contents of inertinite macerals in this part of the seam reflect frequent wildfires in the paleomire surroundings.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"299 ","pages":"Article 104684"},"PeriodicalIF":5.6,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990608","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":"Organic petrology and geochemistry of the late Neogene Shizigou Formation in the Qaidam Basin, China: Characteristics of a prospective microbial gas source rock","authors":"Jinqi Qiao ,&nbsp;Qingyong Luo ,&nbsp;Shouxin Guo ,&nbsp;Xianglu Tang ,&nbsp;Ludmila Kopaevich ,&nbsp;Ralf Littke","doi":"10.1016/j.coal.2024.104658","DOIUrl":"10.1016/j.coal.2024.104658","url":null,"abstract":"<div><div>The discovery of natural gas trapped in the late Neogene Shizigou Formation in the Yikeyawuru anticline indicates the potential for additional microbial gas reservoirs outside of the primary exploration targets for microbial gas in the younger, i.e., the Pleistocene sediments of the Qaidam Basin. In this study, a detailed investigation is presented on the bulk geochemistry and organic petrography of the potential microbial source rocks as well as on molecular organic geochemistry of the solvent extracts obtained from the late Neogene Shizigou Formation of the Yiliping Depression. The objectives are to elucidate i) the depositional environment, ii) biological sources of organic matter (OM), and iii) biodegradation levels in these microbial gas source rocks.</div><div>The samples from the well situated at the center of the Yiliping Depression (the H 1 well) exhibit minor variations in total organic carbon (TOC) and total sulfur contents, whereas the samples from the well located at the margin of the depression (the Y 3 well) show large variations in these values. All these samples are presently thermally immature. The kerogen of the TOC-rich Y 3 well samples is mainly composed of mixed types II–III kerogen and characterized by a complex maceral composition (i.e., a mixture of large fragments of huminite, semifusinite, fusinite, resinite/fluorinite, lamalginite, and liptodetrinite). In contrast, samples from the H 1 well contain typically type III kerogen with a less complex maceral composition consisting of huminite, lamalginite, and liptodetrinite. The molecular data illustrates that the OM is predominantly derived from bacterial and algal biomass as well as aquatic higher plants (primarily in the Y 3 well samples), while angiosperms are the primary source of the subordinate terrestrial OM in the samples. The marginal area is characterized by salinity levels akin to normal marine conditions with bottom-water paleoredox conditions ranging from dyoxic (samples with high TOC content) to oxic, whereas the central area developed a mesosaline environment with oxic bottom-water conditions prevailing. In contrast to the primary microbial gas producing layer, the Pleistocene Qigequan Formation, the late Neogene Shizigou Formation exhibits a higher contribution of emergent macrophytes but a reduced abundance of lower aquatic organisms in the OM as well as a higher salinity level in the water column. Despite the late Neogene Shizigou Formation demonstrating a lower potential for hydrocarbon generation and a lower degree of biodegradation of OM than the Qigequan Formation, it still shows generally favorable geological and geochemical conditions that are conducive to the development of microbial gas reservoirs, which is underscored by the biodegradation levels between 3 and 4 for the studied samples.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"296 ","pages":"Article 104658"},"PeriodicalIF":5.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747671","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":"Anomalies in Vicker's microhardness of subbituminous and high volatile bituminous coals","authors":"Saeed Chehreh Chelgani ,&nbsp;James C. Hower ,&nbsp;Maria Mastalerz ,&nbsp;Susan M. Rimmer","doi":"10.1016/j.coal.2024.104659","DOIUrl":"10.1016/j.coal.2024.104659","url":null,"abstract":"<div><div>Vickers microhardness (MH) of coal is known to be strongly correlated with coal rank. To examine coal rank and other coal quality parameters, such as organic sulfur, that might influence MH, a suite of more than 300 samples from the Penn State Coal Quality database with vitrinite R_max &lt; 1.1 % were examined. The data set was narrowed down to 296 coals with moisture (as-received basis) &lt; 20 %. As MH is a parameter measured on vitrinite, vitrinite R_max was used as the rank parameter. The Eocene Big Dirty coal (Washington state) stood out as a high MH/high-moisture coal while Hanna and Green River basin coals (Wyoming) had low atomic H/C values and K Unita Basin (Utah) coals had high H/C. Organic S did not show a correlation with MH within discrete rank ranges. With respect to vitrinite R_max vs. MH, the Big Dirty coal and some Illinois and Iowa coals lie on the high-MH/low-R_max side and the Pennsylvanian Tioga (West Virginia) and the Indiana Brazil Formation coals, all dominated by dull lithotypes, lie on the low-MH/high-R_max side of the main data trend. Overall, the quadratic regression of vitrinite R_max vs. MH yields an R² of 0.55, indicating a significant correlation at the 95 % level.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"296 ","pages":"Article 104659"},"PeriodicalIF":5.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696909","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":"Corrigendum to “Characteristics of the low-pressure spatial and temporal distributions of oil- and gas-bearing layers in the Ordos Basin, China” [Int. J. Coal Geol. 2024 (285) 104476].","authors":"Yang Qin ,&nbsp;Chiyang Liu ,&nbsp;Lei Huang ,&nbsp;Jianqiang Wang ,&nbsp;Junfeng Zhao ,&nbsp;Deyong Shao ,&nbsp;Lihua Yang ,&nbsp;Xiaochen Zhao ,&nbsp;Ehsan Khalaf ,&nbsp;Shaohua Zhang ,&nbsp;Nan Du","doi":"10.1016/j.coal.2024.104622","DOIUrl":"10.1016/j.coal.2024.104622","url":null,"abstract":"","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104622"},"PeriodicalIF":5.6,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670370","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}