International Journal of Coal Geology最新文献

{"title":"Corrigendum to “From abandoned mines to carbon sinks: Assessing the CO2 storage capacity of Austrian low-rank coal deposits” [International Journal of Coal Geology 286 (2024) 1–13/104495]","authors":"Majid Safaei-Farouji , David Misch , Reinhard F. Sachsenhofer , Max Rauscher , Nikolaos Kostoglou","doi":"10.1016/j.coal.2024.104520","DOIUrl":"https://doi.org/10.1016/j.coal.2024.104520","url":null,"abstract":"","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0166516224000776/pdfft?md5=5cb227760ddf2b50eacf2fc4ff0ec435&pid=1-s2.0-S0166516224000776-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140825708","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":"Structure and morphology of chars and activated carbons obtained from thermal treatment of coal and biomass origin materials, including their wastes: Results from the ICCP Microscopy of Carbon Materials Working Group","authors":"G. Predeanu ,&nbsp;M. Wojtaszek-Kalaitzidi ,&nbsp;I. Suárez Ruiz ,&nbsp;M.N Bălănescu ,&nbsp;A. Gómez Borrego ,&nbsp;M.D. Ghiran ,&nbsp;P.C. Hackley ,&nbsp;S. Kalaitzidis ,&nbsp;J. Kus ,&nbsp;M. Mastalerz ,&nbsp;M. Misz-Kennan ,&nbsp;S. Pusz ,&nbsp;S. Rodrigues ,&nbsp;G. Siavalas ,&nbsp;A. Varma ,&nbsp;A. Zdravkov ,&nbsp;D. Životić","doi":"10.1016/j.coal.2024.104519","DOIUrl":"10.1016/j.coal.2024.104519","url":null,"abstract":"<div><p>This paper describes the evaluation of petrographic textures in char and activated carbon derived from coal, coal by-products and biomass, formed during carbonization and activation processes. This work represents the results of interlaboratory exercises from 2016 to 2022 of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology. The interlaboratory exercises were run on photomicrograph samples. For textural characterization of carbon materials, the existing American Society for Testing and Materials (ASTM) classification system for metallurgical coke was applied. Morphological differences were evaluated in 29 carbon material types, including 22 char samples, and 7 activated carbon (AC) samples obtained experimentally using conventional direct/indirect and microwave heating technologies. This approach gives an extended view on the identification of microporous carbons, and how a certain heat treatment develops a certain optical texture and structure in a raw material. The requested evaluation of carbon materials was related to their porosity, origin, extent, and characteristics, which are particular to each carbon material type. Because carbon matrices can form a wide range of optical textures during heat treatment it is important to demonstrate which carbon occurrences will have a crucial role in industrial applications dominated by adsorption phenomena.</p><p>The interlaboratory exercises included 17 participants from 14 laboratories. Four sets of digital black and white and colour photomicrographs were distributed, which in total comprised 184 fields of different types of carbon material. The results were evaluated based on four levels: (i) optical texture (isotropic/anisotropic), (ii) optical type and size (punctiform, mosaic, fiber, ribbon, domain), iii) morphology (porous, non-porous/massive), and (iv) particle origin (precursor type).</p><p>The statistical method applied to evaluate the results was based on “raw agreement indices”. Comparative analyses of the average values of the level of overall agreement showed homogeneity in the results, the mean value was 89%, with a minimum value of 87% and a maximum value of 91% for those who participated in at least three out of four exercises.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141058217","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":"Methane diffusion in coal matrix considering heterogeneity of micromechanical properties by nanoindentation","authors":"Yidong Cai ,&nbsp;Ding Jia ,&nbsp;Dameng Liu ,&nbsp;Ranjith Pathegama Gamage ,&nbsp;Qian Li ,&nbsp;Yingfang Zhou ,&nbsp;Zhentao Li","doi":"10.1016/j.coal.2024.104518","DOIUrl":"https://doi.org/10.1016/j.coal.2024.104518","url":null,"abstract":"<div><p>The coal matrix exhibits significant heterogeneity at the micro-scale. In this study, a heterogeneous mechanical model of coal matrix from different coal ranks was constructed by using nanoindentation. Additionally, a fluid-solid coupling model was developed to consider matrix shrinkage and stress sensitivity, enabling the incorporation of porosity changes during methane diffusion. The methane concentration and matrix deformation characteristics in the simulation area at different times was obtained. The effects of matrix shrinkage and stress sensitivity on porosity changes and matrix deformation were compared. And the deformation of the matrix under different micromechanical properties was compared. The findings indicate that the nanoindentation method effectively characterizes the micromechanical heterogeneity of coal matrices. Furthermore, during the diffusion process, we observed an initial increase followed by a decrease in matrix deformation, with matrix shrinkage leading to more pronounced deformation. Notably, harder coal matrices exhibited reduced deformation. This study enhances the understanding of the dynamic changes in the matrix during coalbed methane extraction.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140822814","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":"Depositional setting and sequence stratigraphy of Upper Mississippian coal-bearing paralic cyclothems in Upper Silesian foreland","authors":"S. Opluštil ,&nbsp;J. Laurin ,&nbsp;J. Jureczka ,&nbsp;W. Nadłonek ,&nbsp;B. Naglik ,&nbsp;J. Horák ,&nbsp;A. Kędzior ,&nbsp;R. Lojka ,&nbsp;R. Nádaskay ,&nbsp;M. Sivek","doi":"10.1016/j.coal.2024.104516","DOIUrl":"10.1016/j.coal.2024.104516","url":null,"abstract":"<div><p>The upper Serpukhovian Poruba Member (c. 325–324 Ma) is a coal-bearing “paralic” succession deposited in the Upper Silesian Coal Basin located along the eastern foreland of the Moravo-Silesian segment of the Variscan fold and thrust belt. The basin formed an &gt;150 km long, tectonically controlled embayment open to the north and northeast, with estuarine circulation, predominance of fluvial discharge and a limited tidal influence. A high-accommodation depocentre (possibly up to 1100 m/Myr) was filled by shallowing-upward successions related to the progradation of river dominated (bay-head) deltas, with subordinate fluvial and marine sediments. These strata form two orders of transgressive-regressive cycles, or genetic sequences, both overlapping with the Milankovitch band. Intervals of maximum transgression, marked by marine or brackish faunal horizons, immediately overlie coal beds, suggesting non-accretionary transgression in a low energy setting. Six medium-term genetic sequences (cyclothems) are recognized, each consisting of 4 to 6 elementary sequences and a number of smaller scale units of possible autocyclic origin. The medium-term sequences are attributed to a combined influence of relative sea-level change and changes in sediment input, both possibly as a far field response to Gondwanan glaciation through glacioeustasy and attendant changes in climatic seasonality.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140756311","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":"Enrichment mechanisms of Nb, Zr, and REY in the Late Permian coal-bearing strata in western Guizhou, SW China","authors":"Wei Deng ,&nbsp;Hanjie Wen ,&nbsp;Kunyue Ling ,&nbsp;Shengjiang Du ,&nbsp;Chongguang Luo ,&nbsp;Yang Yang","doi":"10.1016/j.coal.2024.104517","DOIUrl":"10.1016/j.coal.2024.104517","url":null,"abstract":"<div><p>Niobium, Zr, REE, and Y are widely enriched in the Upper Permian coal-bearing strata in southwestern China and are regarded as a substantial resource. To better understand the occurrence modes and enrichment mechanisms of these rare metals, comprehensive heavy-mineral separation, Micro-Raman spectroscopy, EPMA, and LA-ICP-MS analyses of primary and secondary metal minerals were conducted in the polymetallic beds in western Guizhou. In addition, the XRD, XRF, and ICP-MS analyses of bulk rocks were carried out. Our results suggest that Nb is primarily hosted in secondary TiO₂ polymorphs which converted from primary Nb-rich rutile, and occurs as minor ilmenorutile and columbite-(Fe). The Zr is sequestered in both detrital zircon and secondary microcrystalline zircon. REE and Y (REY) are mainly incorporated into secondary florencite-(Ce), rhabdophane-(Ce), churchite-(Y), and zircon, also partially adsorbed by clay minerals. The assemblage of detrital zircon, Nb-rich rutile, and discrete Nb minerals reveals that rare metals are preconcentrated during the waning-stage Emeishan alkaline magmatisms. Complex zonings in rutile crystals may result from the diffusion of Nb⁵⁺ and Fe²⁺, and these grains are further overprinted by magmatic-hydrothermal and enveloped by ilmenorutile and columbite-(Fe). Furthermore, magmatic rutile is commonly converted into anatase, brookite, and leucoxene under supergene conditions, and then persisted as stable phases. Authigenic REY-rich (Al)-phosphates and zircon are sourced from the leaching, even decomposition of primary REY-phosphates and zircons. Their colloidal aggregates are precipitated from the acidic and oxidizing low-temperature fluids, which are superposed onto clay matrix. The mineralogical and geochemical features suggest that the polymetallic beds are enriched by both alkaline magmatic-hydrothermal processes in source rocks and supergene fluid alterations in sediments. This study gives new insights into the enrichment processes and conditions, and further extraction of critical metals in the coeval coal-bearing strata in southwestern China.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140778758","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":"Geochemical characteristics and formation mechanism of organic-rich source rocks of mixed sedimentary strata in continental saline lacustrine basin: A case study of Permian Pingdiquan formation in the Shishugou Sag, Junggar Basin, Northwest China","authors":"Wenren Zeng ,&nbsp;Boran Wang ,&nbsp;Xuan Chen ,&nbsp;Guobin Fu ,&nbsp;Zhihuan Zhang ,&nbsp;Zhilong Huang","doi":"10.1016/j.coal.2024.104508","DOIUrl":"https://doi.org/10.1016/j.coal.2024.104508","url":null,"abstract":"<div><p>The Permian Pingdiquan Formation (P₂p) in Shishugou Sag, Junggar Basin, Northwest China, is a typical example of mixed sedimentary strata formed in a saline lacustrine environment, characterized by complex lithological assemblages and extensive distribution of organic-rich source rocks. To further investigate the differences in oil-source contribution and hydrocarbon generation characteristics of source rocks with different lithologies, studying the difference of their geochemical characteristics and the formation mechanism of organic-rich source rocks is the top priority. Based on a comprehensive analysis of lithologic types, geochemical characteristics, and hydrocarbon generation potential of source rocks using organic petrology, molecular geochemistry and element geochemistry, this paper reveals the formation background and organic matter enrichment mechanism of the P₂p organic-rich source rocks. The results show that the mixed sedimentary rocks of the P₂p were deposited under relatively arid and saline lacustrine conditions. Paleoclimatic conditions tended to be more arid and hydrothermal activity became more frequent during the sedimentation process from mudstone, dolomitic mudstone to argillaceous dolomite. Consequently, the water column salinity elevated, leading to an increased proportion of salt-tolerant green algae and slight salt-tolerant cyanobacteria compared to salt-intolerant algae. Frequent changes in paleoclimate and hydrothermal activity control the interbedding deposition of mudstone, dolomitic mudstone and argillaceous dolomite, and the resulting salinity fluctuations contribute to variations in the proportion of salt-tolerant and intolerant algae in source rocks with different lithologies. Furthermore, the source rocks within the mixed sedimentary strata (mudstone, dolomitic mudstone and argillaceous dolomite) all exhibit substantial hydrocarbon generation potential, and there exists heterogeneity among source rocks of the same lithology. The key factor influencing the development of these organic-rich source rocks is the enhancement of palaeoproductivity driven by volcanic activity. Additionally, the water stratification caused by saline water promotes anoxic water columns, also contributing to organic matter enrichment in the source rocks.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140558101","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":"Petrology and organic geochemistry of the Middle Devonian cutinitic liptobioliths from Luquan region, Yunnan Province, China","authors":"Daofu Song ,&nbsp;Tieguan Wang ,&nbsp;Hao Wang ,&nbsp;Honghe Xu ,&nbsp;Zhengang Lu ,&nbsp;Yue Liu","doi":"10.1016/j.coal.2024.104507","DOIUrl":"https://doi.org/10.1016/j.coal.2024.104507","url":null,"abstract":"<div><p>The majority of Middle Devonian coal samples from Wujing (WJ), Damo (DM), and Batang (BT) areas in the Luquan region of China have cutinite content exceeding 50%, classifying them as typical cutinitic liptobioliths. These coals are notable for their thinly-bedded texture, which allows them to split readily into leaf-like laminae. However, coals from these areas display distinct macroscopic, microscopic, and geochemical features. The split laminae from WJ and DM coals are black and ribbon-like, with those from WJ being notably longer and wider. In contrast, BT coal laminae are irregular, small fragments with golden or brown hues. Correspondingly, the cutinite in WJ coals is predominantly thick-walled, DM coals primarily contain a medium-walled type, and BT coals are characterized by a thin-walled type. Additionally, BT coals are rich in sporinite, with some classified as sporinite-rich durain or sporinitic liptobiolith. Abundant tetracyclic diterpenoids were detected in the maltene fraction of all the coal extracts. The concentration and composition of these diterpenoids are influenced by the content and type of cutinite present in the coals. The presence of tetracyclic diterpenoids, with beyerane, atisane and kaurane skeletons, had already evolved in early land plants. This implies that the precursors of these compounds were likely significant components of the cuticles of early land plants or, at least coexisted alongside plant cuticles. The spore assemblages in coals and the microscopic features of cutinite suggest that the coal-forming plants of the Luquan cutinitic liptobioliths were early land plants, predominantly herbaceous lycopsids, rhyniopsids, <em>Orestovia</em> and <em>Spongiophyton</em>. However, it is important to note that the specific types of these coal-forming plants may vary by areas. This variation leads to the distinctive macroscopic and microscopic characteristics observed in coals from different locations.</p><p>Cutinitic liptobiolith appears to have been exclusive to the Middle Devonian period, especially during the Givetian. The emergence of this distinct coal type is likely due to the unique structure of Devonian land plants. Specifically, the combination of well-developed cuticles and less developed woody tissues in these early land plants might have played a key role in the formation of cutinitic liptobioliths.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140342284","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":"Genesis and accumulation mechanism of external gas in deep coal seams of the Baijiahai Uplift, Junggar Basin, China","authors":"Bin Zhang ,&nbsp;Shu Tao ,&nbsp;Bin Sun ,&nbsp;Shuling Tang ,&nbsp;Shida Chen ,&nbsp;Yijie Wen ,&nbsp;Jincheng Ye","doi":"10.1016/j.coal.2024.104506","DOIUrl":"https://doi.org/10.1016/j.coal.2024.104506","url":null,"abstract":"<div><p>Coal seams are typically self-sourced reservoirs. However, in certain special cases, the coal seams also contain large amounts of external gas from other source rocks. Successful development strategies in relation to Jurassic coalbed methane (CBM) in recent years have confirmed the presence of large amounts of external gas within the coal seams of the Baijiahai Uplift, Junggar Basin, China, which has important exploration and development prospects. However, the genesis and source of Jurassic CBM in the area remain unclear, limiting our understanding of its formation and accumulation as well as the planning of further development strategies. Based on a comprehensive analysis of the geochemical characteristics of Jurassic CBM, combined with research on the burial and thermal evolution history of the Jurassic coal seams, this study discusses the production curves of typical wells as well as regional tectonic styles, genesis, source, and accumulation of Jurassic CBM in the Baijiahai Uplift. Depending on the genesis, Jurassic CBM in the study area is divided mainly into coal-type (humic-type) gas, oil-type (sapropelic-type) gas, and mixtures of them, all of which are thermogenic gases of medium to high maturity. There are two main sources of Jurassic CBM in the Baijiahai Uplift. On the one hand, it comes from the vertical migration of gas generated by Permian and Carboniferous source rocks in the Baijiahai Uplift directly. On the other hand, it comes from the regional lateral migration from the Dongdaohaizi and Fukang Sags. Gas generated by source rocks in the Dongdaohaizi and Fukang Sags is driven by pressure, migrates towards the Baijiahai Uplift through sandstone channels, and accumulates in the Jurassic coal seams through faults. Compared with common self-sourced coal seams, enrichment of the coal seams with large amounts of external gases requires two necessary conditions: (1) Other layers of gas-generating source rocks are present at levels deeper than those of the coal seams, constituting additional gas sources for the coal seams, and (2) an open fault system is developed regionally, providing pathways for gas from other layers to enter the coal seams.</p></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140330623","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":"Pyrolysis of macroalgae: Insight into product yields and biochar morphology and stability","authors":"H.I. Petersen ,&nbsp;H. Deskur ,&nbsp;A. Rudra ,&nbsp;S.B. Ørberg ,&nbsp;D. Krause-Jensen ,&nbsp;H. Sanei","doi":"10.1016/j.coal.2024.104498","DOIUrl":"https://doi.org/10.1016/j.coal.2024.104498","url":null,"abstract":"<div><p>Pyrolysis of biomass residues into biochar is seen as a feasible way to mitigate climate change by biological carbon storage (carbon dioxide removal, CDR) and to substitute fossil fuel with sustainable biofuel. This study applies a combination of flash and ramp heating pyrolysis, and organic petrography to investigate the hydrocarbon (biofuel) potential and biochar stability and morphotypes of eight brown, red, and green macroalgal species of different tissue complexity. The carbon stability of biochar derived from macroalgae has not previously been assessed using organic petrography (reflectance measurements) and evaluated in the context of the geological carbon cycle. The biochar, hydrocarbon, and CO + CO₂ yields vary due to different chemical composition of the macroalgal species, but the product yield variations are not related to the brown, red, or green macroalgal groups. The total biofuel yield shows an inverse trend with biochar yield. A slower heating rate produces more biochar and higher CO + CO₂ and lower biofuel yields than the combined flash pyrolysis and faster heating rate. The morphotype composition of the biochar was qualitatively examined by reflected light microscopy while carbon stability was assessed by random reflectance (R_o) measurements. The diverse morphotype compositions observed in biochar formed under similar pyrolysis conditions likely stem from variations in the original algal composition. While some biochar samples show morphologies resembling the original macroalgal structure, porous morphotypes predominantly characterize the biochar samples overall. Despite a maximum pyrolysis production temperature (PT) of 650 °C, the highest mean R_o value among all biochar samples is 2.91%, corresponding to a carbonization temperature (CT) of 526 °C. This observation is tentatively related to the less lignocellulosic structure of the macroalgae compared to terrigenous biomass. Four biochar samples have their entire R_o distribution range above the inertinite benchmark (IBR_o2%) of R_o = 2% indicating high carbon stability. Conversely, the remaining four biochar samples exhibit R_o distributions extending below IBR_o2%, indicating the presence of a carbon fraction with lower long-term stability in soil. The statistically significant inverse relationship observed between the mean R_o values and the peak hydrocarbon generation temperature (T_max) can be attributed to the behavior of residual macromolecules within the biochar. When these macromolecules reach peak biofuel generation at a lower temperature, they undergo carbonization over a more extended time interval during pyrolysis. Consequently, this prolonged exposure to the pyrolysis process leads to higher degrees of carbonization, as reflected by higher R_o values. In conclusion, the findings from pyrolysis and organic petrography reveal: (1) Macr","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0166516224000557/pdfft?md5=0d65373d62f36defcafced7d9787f013&pid=1-s2.0-S0166516224000557-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140321530","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":"High-cellulose content of in-situ Miocene fossil tree stumps and trunks from Lusatia lignite mining district, Federal Republic of Germany","authors":"J. Kus ,&nbsp;M. Dolezych ,&nbsp;W. Schneider ,&nbsp;J.C. Hower ,&nbsp;T. Hofmann ,&nbsp;E. Visiné Rajczi ,&nbsp;A. Bidló ,&nbsp;B. Bolodár-Varga ,&nbsp;R.F. Sachsenhofer ,&nbsp;A. Bechtel ,&nbsp;K. Stojanović ,&nbsp;D. Životić ,&nbsp;I. Kojić ,&nbsp;M. Mastalerz ,&nbsp;T. Graupner ,&nbsp;W.E. Lukens ,&nbsp;L. Donaldson","doi":"10.1016/j.coal.2024.104494","DOIUrl":"10.1016/j.coal.2024.104494","url":null,"abstract":"<div><p>Second Miocene Seam Complex (2nd MFK; <em>germ.:</em> 2. Miozäner Flözkomplex) holds many <em>in-situ,</em> not permineralised fossil tree stumps and trunks with high-cellulose contents. The state of preservation of a set of <em>in-situ</em> fossil trees (<em>Taxodioxylon cryptomerioides</em>, <em>Sciadopityoxylon wettsteinii</em>, and <em>Quasisequoioxylon piskowitzense</em>) collected from three open-cast mines (Welzow-Süd, Meuro, and Piskowitz) in Lusatia lignite mining district, Federal Republic of Germany was investigated using a multi-method research schema.</p><p>Examination of preservation state of thermally immature fossil woods revealed: (1) well-preserved (non-deformed, non-degraded, and non-flattened) textinite, (2) a retained structural integrity represented by multilayered (multi-zoned) cells with primary, secondary cell wall, and middle lamella, (3) microfracturing restricted to secondary walls only, (4) preservation of polyphenolic parenchyma cells (PP cells), (5) excellent preservation of pits in ray tracheids, (6) presence of amorphous silica (opal-A) coating, and (7) crystalline silica (opal-CT) fillings of small-bladed crystals.</p><p>Thermogravimetric analysis results showed dissimilar gelification status of fossil samples, supporting chlorite holocellulose assay results. The latter indicated anomalously high-cellulose values (15.6–37.6% holocellulose). The micro-FTIR data obtained revealed an excellent preservation of both hemicellulose (bands at 1740 and 1245 cm⁻¹) and cellulose (bands at 1110 and 1040 cm⁻¹). Micro-FTIR spectrometry indicated lack of preferential hydrolytic removal of polysaccharides in examined samples.</p><p>Biomarker patterns in lignite revealed forested and prevailing reed-mire vegetation. The results indicated lower contribution of Cupressaceae and emergent macrophyta to precursor organic matter of Welzow-Süd in comparison to Piskowitz lignite. Piskowitz lignite formed in permanent mire with stable water table under reducing, mesotrophic conditions. In contrast, more pronounced water level fluctuations (reducing to slightly oxic settings) and/or post-depositional events are postulated for Welzow-Süd samples.</p><p>Biomarker assemblages obtained from fossil wood show a distinct dominance of diterpenoids and δ¹³C values (−24.6 ‰ to −20.3 ‰) that clearly confirm gymnosperm sources. Distributions of diteprenoids and sesquiterpenoids, as well as fatty acids indicate the higher amount of saturated diterpenoids (pimarane, abietane) in fossil than in modern wood. This indicates reducing conditions promoting hydrogenation reactions. In addition to low Eh, preservation of cellulose in fossil wood was also favored by acidic conditions, very low degrees of aerobic fungal degradation, and protection of wood by Cupressaceae-derived resins.</p><p>While δ¹³C values of fossil wood are generally consistent with stratigraphic trends and chemotaxonomical classification, ","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S016651622400051X/pdfft?md5=7962ebc6d65adfe24913c93fee7a4a1d&pid=1-s2.0-S016651622400051X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140270566","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}