International Journal of Coal Geology最新文献

{"title":"Deep syntectonic burial of the Anthracite belt, Eastern Pennsylvania","authors":"Mark A. Evans ,&nbsp;Aaron M. Jubb","doi":"10.1016/j.coal.2024.104646","DOIUrl":"10.1016/j.coal.2024.104646","url":null,"abstract":"<div><div>Fluid inclusion microthermometry and Raman spectroscopy of fluid inclusions in quartz veins from the Pennsylvanian rocks of the Anthracite belt, eastern Pennsylvania support a deep burial model of coalification in favor of focused orogenic hot fluid flow. High-temperature (250 to 255 °C) trapping of CH₄ ± CO₂ saturated aqueous fluids and CH₄ ± CO₂ inclusions indicate fluid trapping at depths of 11.5 to 13.4 km under a cover of Pennsylvanian to Permian(?) syntectonic load. In the folded rocks to the south of the Anthracite belt, CH₄ ± CO₂ fluid inclusions indicate a sediment load that was up to 16.3 km thick. <em>Re</em>-equilibrated aqueous fluid inclusions from veins in Silurian through Devonian rocks give the same range of trapping conditions but a wide range of fluid salinities suggesting that folding, fracturing, and meteoric recharge resulted in the intermixing of fluids from throughout the stratigraphic succession.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104646"},"PeriodicalIF":5.6,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661344","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":"Influence of tectonic evolution processes on burial, thermal maturation and gas generation histories of the Wufeng-Longmaxi shale in the Sichuan Basin and adjacent areas","authors":"Shuyong Shi ,&nbsp;Yunpeng Wang ,&nbsp;Chengsheng Chen ,&nbsp;Jinzhong Liu ,&nbsp;Ping'an Peng","doi":"10.1016/j.coal.2024.104642","DOIUrl":"10.1016/j.coal.2024.104642","url":null,"abstract":"<div><div>The Wufeng-Longmaxi (WL) shale is widely distributed in the Sichuan Basin and adjacent areas in southwest China. The basin experienced multiple-stage complex tectonic movements, whose influences on burial, thermal maturation and gas generation histories in different areas are poorly understood. Based on a detailed study of the denudation stages, strata thickness, and thermal history of the basin, burial and thermal maturation histories of seven wells in different areas were modelled using PetroMod software. Due to the high maturity of the WL shale, a low-maturity Silurian Polish Llandovery shale was used for gold tube closed-system pyrolysis experiments to obtain kinetic parameters for evaluating methane generation history. The Polish shale was selected due to its depositional age, sedimentary environment and organic type, which are similar to the WL shale. The burial history of the WL shale can be divided into five stages: I. Early to Middle Silurian rapid burial; II. Caledonian uplift and denudation; III. Permian to Triassic sustained burial and denudation; IV. sustained burial since the Late Triassic; and V. Late Cretaceous to present sustained uplift and denudation. The thermal maturity of the WL shale in all wells increased with burial depth during stage IV. In addition, high calculated reflectance increments in wells JY1 and N201 during stage III occurred due to the relatively high basal heat flow and deep burial depth, resulting in higher current thermal maturities than in the other wells. The late Permian–Early Triassic and the Middle Jurassic–Early (or Late) Cretaceous were the key methane generation periods for wells JY1 and N201. In contrast, the other five wells had a single methane generation stage, mainly determined by burial and thermal maturation processes. The time of uplift and the amount of denudation during stage V, the current burial depth, the development of faults and fractures, high proportion of retention and the seal capacity of the overlying caprock are key factors for shale gas preservation. Hence, this study will help guide future shale gas development in the Sichuan Basin.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104642"},"PeriodicalIF":5.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661343","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":"Devolatilization behaviour of Kolubara and Kostolac lignite (Serbia) during the combustion process: A case study","authors":"Miodrag Životić ,&nbsp;Nenad Nikolić ,&nbsp;Dragoslava Stojiljković ,&nbsp;Danica Bajuk-Bogdanović ,&nbsp;Dragana Životić","doi":"10.1016/j.coal.2024.104641","DOIUrl":"10.1016/j.coal.2024.104641","url":null,"abstract":"<div><div>In this study the devolatization behaviour of lignite samples, of various grain sizes, on a wire mesh reactor is evaluated. Lignite samples were rapidly heated at four different temperatures (300, 500, 700 and 900 °C). The feed lignite reveals a high content of huminite, a low inertinite and liptinite contents in the Kostolac samples and a slightly higher liptinite content in the Kolubara samples. The char obtained at 300 °C and 500 °C shows slight petrographic and chemical changes. The major changes in chemical and petrographic compositions were observed in char heated at higher temperatures (700 °C and 900 °C). FTIR spectral data for both Kolubara and Kostolac lignite samples reveal a decrease in aliphatic- and oxygen­containing structures with increase in temperatures from 300 to 700 °C. The lack of aliphatic and oxygen-containing structures, the breakdown of clay minerals and negligible amount of water are detected in samples devolatilized at 900 °C where aromatic structures dominate.</div><div>Huminite reflectance of initial samples confirms the low rank (lignite) of all the samples. Char of all grain sizes obtained at 300 °C and 500 °C showed very small changes in the maceral composition and reflectance value and still corresponded to lignite rank. A significant change in maceral composition and increase reflectance is observed in char obtained at 700 °C and 900 °C of all grain sizes.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104641"},"PeriodicalIF":5.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661345","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 effects of sample preparation on the interpretation of pyrolysis-based organic matter analysis in immature oil shale","authors":"Zibin Zhao ,&nbsp;Ralf Littke ,&nbsp;Christoph Hartkopf-Fröder","doi":"10.1016/j.coal.2024.104648","DOIUrl":"10.1016/j.coal.2024.104648","url":null,"abstract":"<div><div>Oil shale as well as shale oil and shale gas are significant energy resources with huge reserves present in different parts of the world. Various geochemical proxies have been applied to assess the petroleum potential of oil shales with samples pre-treated in various ways, e.g. as whole rock or demineralized sample or as solvent extracted rock/kerogen. In this respect, it is important to understand and quantify, how achieved geochemical parameters are influenced by pre-treatment. In this study, a systematic comparison is presented based on a study on i) whole rock, ii) extracted whole rock, iii) kerogen concentrate, and iv) extracted kerogen concentrate obtained after solvent extraction of demineralized shales. In total, seven immature, organic matter-rich samples from the Miocene lacustrine sediments of the Nördlinger Ries impact crater, Germany, were pretreated in this way leading to overall 28 samples. A set of elemental analysis (C, H, N), Rock-Eval pyrolysis, and Curie Point-pyrolysis–gas chromatography–mass spectrometry measurements were performed on these pretreated samples. Mineral matter removal leads to significant increase of total organic carbon, but also thermally evaporable and pyrolytically cracked organic matter (Rock-Eval S1 and S2 peaks). To some extent, labile organic matter represented in the original S2 peak can be destructed by mineral removal with hydrochloric and hydrofluoric acid, as shown by elevated values of PI [S1/(S1 + S2)] after demineralization. The organic matter type tends to be more petroleum-prone with raised hydrogen index (HI) and aliphaticity values after demineralization, while Rock-Eval T_max values commonly applied as parameters for thermal maturity tend to decrease, though not for all samples.</div><div>Reduced TOC, S1, S2 and PI values of extracted samples suggest that both thermally evaporable and additionally some non-evaporable but soluble organic matter hidden in the original S2 peak can be lost after solvent extraction. Increased values of HI, H/C and N/C of extracted samples indicate more oil-prone organic matter types than unextracted samples. Typical maturity-related parameters such as aliphaticity and Rock-Eval T_max decrease. Smectite and zeolites, which are abundant in the samples, are suggested to protect organic matter to some extent against solvent extraction, influencing a variety of geochemical proxies and the occurrence of metal cation-containing minerals. Zeolite invigorates the protection effect.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"296 ","pages":"Article 104648"},"PeriodicalIF":5.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670369","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":"Palynofacies as sea-level-sensitive proxy in Early Cretaceous marine mudstones – A critical evaluation","authors":"Hauke Thöle ,&nbsp;Ulrich Heimhofer ,&nbsp;André Bornemann ,&nbsp;Jochen Erbacher","doi":"10.1016/j.coal.2024.104645","DOIUrl":"10.1016/j.coal.2024.104645","url":null,"abstract":"<div><div>Stratigraphic distribution patterns of particulate organic matter (POM) have been widely used for facies recognition and paleoenvironmental interpretation as well as to decipher proximal to distal trends within fine-grained sediments. The Lower Cretaceous mudstone-dominated succession in the eastern Lower Saxony Basin (LSB) offers an excellent opportunity to critically evaluate such palynofacies parameters, commonly used to identify transgressive-regressive (T-R) cycles in marine sediments. For the seemingly monotonous succession, a robust sequence stratigraphic framework has been previously established by integrating high-resolution elemental intensity data from X-Ray Fluorescence (XRF) core scanning and biostratigraphy from four drill cores. In this study, the composition and distribution of the POM has been assessed by analysis of 220 strew mounts using transmitted-light microscopy. Overall, the POM composition indicates deposition in a mud-dominated proximal to distal shelf setting. The ratio of opaque versus translucent phytoclasts (OP/TR ratio) shows a distinct long-term increase from the Berriasian onwards with maximum values during the early Hauterivian, followed by a subsequent decrease in OP/TR ratio. This trend broadly reflects the overall T-R evolution of the succession interpreted from Si/Al changes. This also applies to the size and sorting of opaque phytoclasts, with the greatest amplitude changes in opaque particle size parameters being observed in the more proximal deposits of the studied succession. On the other hand, the ratio of terrestrial versus marine palynomorphs (T/M ratio), often applied as indicator of proximal to distal trends and distances from the coastline, shows no correlation with the T-R cycles. Systematic long- and short-term trends visible in T/M ratio correspond to variations in the XRF-derived Ca/Ti stratigraphic trend, which is interpreted to reflect variations in carbonate content. This may indicate that the T/M ratio in the LSB is largely controlled by variations in marine palynomorph flux, probably related to productivity changes of the organic-walled microplankton.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104645"},"PeriodicalIF":5.6,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661342","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":"Coke-based proppant for coalbed methane technology","authors":"Rafał Morga,&nbsp;Krzysztof Labus,&nbsp;Tomasz Suponik","doi":"10.1016/j.coal.2024.104647","DOIUrl":"10.1016/j.coal.2024.104647","url":null,"abstract":"<div><div>The production of ultra-light weight coke proppants for fracturing coal bed methane deposits is presented. The raw material is blast-furnace coke, foundry coke and a coke breeze. The method used obtains coke proppants that meet all the requirements of the ISO 13503-2:2006/Amd.1:2009 standard for proppants used in hydraulic fracturing, with the exception of crush resistance. They have porosity up to 40 % and they are mainly macroporous materials, containing predominantly cylindrical, less frequently bottle-shaped or wedge-shaped pores. The proppants with the lowest crush rate were obtained from the blast furnace coke (CSR &gt; 65 %).</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104647"},"PeriodicalIF":5.6,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661341","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":"Net primary productivity of paleo-peatlands linked to deep-time glacial periods in the late Carboniferous and early Permian icehouse interval","authors":"Yanwen Shao ,&nbsp;Fenghua Zhao ,&nbsp;Baruch Spiro ,&nbsp;Dehui Li ,&nbsp;Guangyuan Mu ,&nbsp;Jiangman Chu ,&nbsp;Jing Lu ,&nbsp;Longyi Shao","doi":"10.1016/j.coal.2024.104644","DOIUrl":"10.1016/j.coal.2024.104644","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Peatlands, an important organic carbon reservoir, play a crucial role in the global carbon cycle. The carbon accumulation of peatlands, reflected by net primary productivity (NPP), can have an impact on global carbon cycling and climate change. The late Carboniferous - early Permian is an icehouse period, during which numerous thick coal beds were accumulated in the North China Block (NCB) located within a low-latitude area, providing an opportunity for studying the carbon cycling under the glacial and interglacial climates. In this study, spectral analysis was performed on the natural gamma-ray (GR) logs of the Benxi, Taiyuan, and Shanxi formations of the late Carboniferous to early Permian in a borehole section located within the Ordos Basin in western NCB. Cyclic signals related to astronomical orbital parameters were identified, including long eccentricity (∼405 kyr), short eccentricity (∼125 kyr and ∼ 95 kyr), and obliquity (∼35.5 kyr). A floating astronomical time scale was established by using the long eccentricity signal, and this time scale was further used to constrain the durations of the accumulation of coal-forming paleo-peatlands. The paleo-peatland for the C&lt;sub&gt;8+9&lt;/sub&gt; coal seam (9 m thick) of the Taiyuan Formation lasted approximately 203 kyr, and the paleo-peatland for the C5 coal seam (4 m thick) of the Shanxi Formation lasted approximately 46 kyr. Using this timeframe and an estimation of carbon loss during coalification, the carbon accumulation rates of the late Carboniferous - early Permian low-latitude peatlands are calculated to be 104.7 ± 14.9 g·&lt;em&gt;C&lt;/em&gt;·m&lt;sup&gt;−2&lt;/sup&gt;·a&lt;sup&gt;−1&lt;/sup&gt;for the C&lt;sub&gt;8+9&lt;/sub&gt; coal seam and 192.6 ± 11.6 g·&lt;em&gt;C&lt;/em&gt;·m&lt;sup&gt;−2&lt;/sup&gt;·a&lt;sup&gt;−1&lt;/sup&gt;for the C&lt;sub&gt;5&lt;/sub&gt; coal seam. The NPP of the paleo-peatlands, which deducts a part of the carbon loss caused by the loss of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt;, can be calculated from the carbon accumulation rates. The calculated average NPP of the paleo-peatlands for the C&lt;sub&gt;8+9&lt;/sub&gt; seam was 199 ± 28 g·&lt;em&gt;C&lt;/em&gt;·m&lt;sup&gt;−2&lt;/sup&gt;·a&lt;sup&gt;−1&lt;/sup&gt;, and that of the C&lt;sub&gt;5&lt;/sub&gt; seam was 366 ± 22 g·&lt;em&gt;C&lt;/em&gt;·m&lt;sup&gt;−2&lt;/sup&gt;·a&lt;sup&gt;−1&lt;/sup&gt;. In combination with the absolute time scale calibrated by high-precision U&lt;img&gt;Pb dates from Palougou section in western NCB, the depositional time of the investigated strata was constrained to be from 300.1 ± 0.5 Ma to 294.3 ± 0.5 Ma. The coal seams of the late Carboniferous to early Permian in the NCB correspond to an interglacial interval around ∼298 Ma. The peatland with a lower NPP corresponds to the warming stage and the peatland with a higher NPP corresponds to the cooling stage. This implies that a lower NPP of paleo-peatland tends to be less efficient in carbon storage, and could not reduce the atmospheric CO&lt;sub&gt;2&lt;/sub&gt; substantially. In contrast, a higher NPP of paleo-peatland tends to accelerate carbon fixation, leading to temperature decrease and the termination of interglacial interval in ","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"296 ","pages":"Article 104644"},"PeriodicalIF":5.6,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656271","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":"Effects of thermal intrusion on biomarker distributions in the Alum Shale from south-central Sweden","authors":"Anji Liu ,&nbsp;Qingyong Luo ,&nbsp;Arka Rudra ,&nbsp;Niels Hemmingsen Schovsbo ,&nbsp;Xiaowei Zheng ,&nbsp;Zhiheng Zhou ,&nbsp;Hamed Sanei","doi":"10.1016/j.coal.2024.104643","DOIUrl":"10.1016/j.coal.2024.104643","url":null,"abstract":"<div><div>The middle (Miaolingian) to upper (Furongian) Cambrian Alum Shale Formation in the DBH15/73 core from south-central Sweden was exposed to local heat from a diabase intrusion, providing an opportunity to investigate the molecular geochemical response to thermal stress. Organic petrological observations and biomarker analyses were conducted to study changes in maturity-indicating parameters and the distribution of high molecular weight polycyclic aromatic hydrocarbons (PAHs) during the maturation process. The DBH15/73 samples exhibit a maturity gradient, ranging from immature at the base to mature in the upper part of the Alum Shale Formation. Multiple maturity-based biomarker parameters were analyzed, and Ts/(Ts + Tm), M₃₀/(M₃₀ + H₃₀), and Hopane H₃₂: 22S/(22S + 22R) of saturated hydrocarbon parameters are found to be more reliable. Ratios of alkylnaphthalenes, alkylphenanthrenes, and alkyldibenzothiophenes (MNR, DNR, TMNr, TeMNr, MPI-1, MPR, MDR, and DMDR) also showed consistent correlations with thermal maturity. Thermal maturation impacted the macromolecular structure, resulting in the aromatization and demethylation, leading to MPy/Py, MChy/Chy, and the sum of unsubstituted 5-ring/4-ring PAH ratios changes with maturity. The influence of thermal maturation outweighs that of uranium radiation in this study, and maturity varies mainly with depth.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104643"},"PeriodicalIF":5.6,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586647","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":"Disentangling causes of the limestone-marl bedding couplets in the Bridge Creek Limestone Member of the Greenhorn Formation through an integrated sedimentological and organic petrology analysis","authors":"Zhiyang Li ,&nbsp;Maria Mastalerz","doi":"10.1016/j.coal.2024.104640","DOIUrl":"10.1016/j.coal.2024.104640","url":null,"abstract":"<div><div>Although limestone-marl bedding couplets in the Cenomanian-Turonian Bridge Creek Limestone (BCL) have been widely attributed to changes in environmental conditions ultimately driven by Earth's orbital cycles, the causes of short-term variations in organic matter (OM) enrichment and composition (i.e., types and proportions of different macerals) in the bedding couplets through the BCL have rarely been examined in detail. To fill this gap, this study examined the BCL through an integrated sedimentological and organic petrology analysis. With the well-developed depositional context, organic petrology analysis was conducted on 17 samples from seven limestone-marl bedding couplets consisting of different sedimentary facies types in the USGS #1 Portland Core to systematically examine differences in the maceral composition among different expressions of the limestone-marl bedding couplets. The BCL in the #1 Portland Core has overall low thermal maturity (∼0.60 % vitrinite reflectance). All BCL samples contain dominant marine OM including bituminite (dominantly micrinized), alginite, and liptodetrinite and minor but persistently present terrigenous OM including vitrinite and inertinite. The OM composition and characteristics, combined with sedimentary facies characteristics and TOC data, suggest that the OM enrichment and preservation through the BCL is subject to various processes such as bottom current reworking and burial, bioturbation, early diagenesis, and pulses of volcanic ash input. The interplay of these processes led to changes in sedimentation rate, which can be associated with short-term relative changes in sea level and episodic volcanic input. Direct examinations of the composition and texture of OM in fine-grained sedimentary rocks can provide valuable insights into the causes of short-term variations in depositional conditions on a process basis, which should be integrated with other datasets (e.g., sedimentology, geochemistry) to fully resolve the specific mechanism(s) that modulated sedimentation in similar fine-grained marine systems characterized by apparently cyclic lithological alternations.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104640"},"PeriodicalIF":5.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578564","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":"Tungsten (W) geochemistry in north Asian coals (Siberia, Russian far east and Kazakhstan)","authors":"S.I. Arbuzov ,&nbsp;I.Yu. Chekryzhov ,&nbsp;V.I. Vyalov ,&nbsp;D.A. Spears ,&nbsp;A.S. Kholodov ,&nbsp;N.Yu. Popov","doi":"10.1016/j.coal.2024.104639","DOIUrl":"10.1016/j.coal.2024.104639","url":null,"abstract":"<div><div>This research discusses new data on the geochemistry of tungsten (W) in the coals of North Asia (Siberia, the Russian Far East, and Kazakhstan), based on analyses of over two thousand samples. In general, the studied coals are enriched in W in comparison with the average value for coals all over the world. In different regions of the studied area, coal deposits with anomalous W concentrations (up to commercially important concentrations) were found and the factors controlling the W content in these coals were investigated. Samples were selected in order to study both the vertical variation in W through the seams and laterally to determine its distribution across the coal basins. Seams with average W concentrations generally show some enrichment at the margins of the seam (Zilbermints law). In anomalously enriched seams, however, several patterns of W distribution are observed. Most commonly the base of the seam is enriched and concentrations decrease upwards, less commonly the reverse is the case and rarely the central parts of the seam are enriched. The results from the present work demonstrate that W is predominantly organically associated. In lignites, more than 80 % is concentrated in humic substances with the remainder in mineral matter. However, as the organic matter transforms during coalification some of the W passes into solution leading both to the formation of authigenic minerals and also loss from the seam. The nature of the W distributions in the coal seams indicates a predominantly hydrogenous (aqueous) mechanism of transport and accumulation. It is concluded that the composition of the rock types surrounding the coal-forming basins and the hydrogeochemical conditions of these basins and deposits are critical factors in determining the levels of W accumulation in the coals. The elevated and anomalous tungsten concentrations in coal and peat described in this work are due to the leaching of tungsten rich rocks, primarily granitoids and tungsten-bearing greisens and skarns.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"295 ","pages":"Article 104639"},"PeriodicalIF":5.6,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560685","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}