Pub Date : 2025-06-20Epub Date: 2025-05-30DOI: 10.1016/j.coal.2025.104815
Jia Song , Beilei Sun , Sandra Rodrigues , Chao Liu , Zhanming Guo , David French
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), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transform-Infrared Spectroscopy (FTIR), and Confocal Raman Microscopy (Raman). Results reveal that kaolinite is the primary host of Li, with concentrations exceeding 1516 μg/g. Lithium isotopic compositions (δ7Li) in kaolinite from high-rank coals exhibit narrow ranges, suggesting Li isotopic homogenization as a result of the elevated paleotemperature. In contrast, δ7Li values in lower-rank coals show greater variability, influenced by pore fluids and depth-dependent fractionation processes. Organic material, characterized by lower lithium concentrations (mostly <100 μg/g) and highly variable δ7Li values, exhibits a heavier lithium isotopic composition in high-rank coal compared to δ7Li values in low-rank coal. These findings highlight the role of kaolinite in this isotopic fractionation. and emphasize the role of kaolinite as a major Li carrier. This study provides critical insights into Li enrichment mechanisms and isotopic fractionation during coalification, contributing to a better understanding of Li sources and mobility in coal-bearing strata.
{"title":"Li concentration and isotopes in kaolinite and organic of coals determined by secondary ion mass spectrometry","authors":"Jia Song , Beilei Sun , Sandra Rodrigues , Chao Liu , Zhanming Guo , David French","doi":"10.1016/j.coal.2025.104815","DOIUrl":"10.1016/j.coal.2025.104815","url":null,"abstract":"<div><div>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), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transform-Infrared Spectroscopy (FTIR), and Confocal Raman Microscopy (Raman). Results reveal that kaolinite is the primary host of Li, with concentrations exceeding 1516 μg/g. Lithium isotopic compositions (δ<sup>7</sup>Li) in kaolinite from high-rank coals exhibit narrow ranges, suggesting Li isotopic homogenization as a result of the elevated paleotemperature. In contrast, δ<sup>7</sup>Li values in lower-rank coals show greater variability, influenced by pore fluids and depth-dependent fractionation processes. Organic material, characterized by lower lithium concentrations (mostly <100 μg/g) and highly variable δ<sup>7</sup>Li values, exhibits a heavier lithium isotopic composition in high-rank coal compared to δ<sup>7</sup>Li values in low-rank coal. These findings highlight the role of kaolinite in this isotopic fractionation. and emphasize the role of kaolinite as a major Li carrier. This study provides critical insights into Li enrichment mechanisms and isotopic fractionation during coalification, contributing to a better understanding of Li sources and mobility in coal-bearing strata.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"306 ","pages":"Article 104815"},"PeriodicalIF":5.6,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184395","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}
Pub Date : 2025-06-20Epub Date: 2025-05-10DOI: 10.1016/j.coal.2025.104807
J.E. Ogala , K. Perleros , E. Kyriazaki , M. Angelopoulos , O.I. Ejeh , M. Wojtaszek-Kalaitzidi , S. Kalaitzidis , K. Christanis
<div><div>Twenty eight (7 coal, 12 organic-rich and 9 inorganic) cutting samples obtained from six boreholes drilled over a <em>c</em>. 60-km<sup>2</sup>-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 of the palaeoenvironmental conditions during the Oligocene-Miocene peat accumulation.</div><div>As the samples were received a long time after sampling, moisture could not be determined. The ash and the volatile matter yields of the samples vary from 19.9 to 88.5 wt% (db) and 63.5–67.9 wt% (daf), respectively. Huminite is the dominant maceral group ranging from 60.6 to 90.6 vol% (on mineral matter-free basis), with detrohuminite being the major sub-group. The inertinite content is very low (<1.5 %), whereas liptinite macerals are frequent to quite enriched (8.8–37.9 %) with alginite and liptodetrinite being the most common. The mean random huminite reflectance of all the coal samples varies between 0.32 % and 0.39 %.</div><div>As mainly sandstones, intercalated with siltstones and claystones are the main sedimentary rocks deposited in the Niger-River alluvial plain, the inorganic part of all the studied coaly and carbonaceous samples consists primarily of quartz and kaolinite, whereas goethite, mixed clay layers (illite-montmorillonite), anatase and gypsum occur in minor amounts. Accordingly, SiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> display values ranging from 9 to 58 % and up to 23 wt%, respectively, while Fe<sub>2</sub>O<sub>3</sub> up to 12 wt% and TiO<sub>2</sub> up to 2 wt%.</div><div>Palaeoenvironmental geochemical proxies indicate a mixed source area for the siliciclastic facies, with significant recycling and weathering, deposited under a pure freshwater regime. The carbonaceous layers seem to have been deposited in a relative semi-arid climate, while the palaeomires were established under a more humid regime, promoting anaerobic conditions, which is in agreement with the observed very low inertinite content. Facies diagrammes based on the maceral contents were applied to reconstruct the environmental conditions in the palaeomires. According to the TPI <em>vs.</em> GI diagramme, the peat-forming vegetation was mostly herbaceous yielding low TPI and medium GI values, and the conditions were fluvial-limnotelmatic. The GWI <em>vs.</em> VI diagramme points to herbaceous vegetation on the palaeomire surface and mesotrophic water conditions with intense mineral matter influx from palaeo-Niger River. The area received frequent rainfall along with river flooding; thus, peat remained water-logged. Within the several hundred metres thick alluvial sediments, only short periods of limnotelmatic conditions prevailed in the area, yielding coal beds less than 17 m thick. The small number of the available cores distribut
{"title":"Palaeoenvironmental reconstruction of the coal-forming conditions during Oligocene in Niger Delta, Southern Nigeria: Implications for organic matter preservation and hydrocarbons potential","authors":"J.E. Ogala , K. Perleros , E. Kyriazaki , M. Angelopoulos , O.I. Ejeh , M. Wojtaszek-Kalaitzidi , S. Kalaitzidis , K. Christanis","doi":"10.1016/j.coal.2025.104807","DOIUrl":"10.1016/j.coal.2025.104807","url":null,"abstract":"<div><div>Twenty eight (7 coal, 12 organic-rich and 9 inorganic) cutting samples obtained from six boreholes drilled over a <em>c</em>. 60-km<sup>2</sup>-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 of the palaeoenvironmental conditions during the Oligocene-Miocene peat accumulation.</div><div>As the samples were received a long time after sampling, moisture could not be determined. The ash and the volatile matter yields of the samples vary from 19.9 to 88.5 wt% (db) and 63.5–67.9 wt% (daf), respectively. Huminite is the dominant maceral group ranging from 60.6 to 90.6 vol% (on mineral matter-free basis), with detrohuminite being the major sub-group. The inertinite content is very low (<1.5 %), whereas liptinite macerals are frequent to quite enriched (8.8–37.9 %) with alginite and liptodetrinite being the most common. The mean random huminite reflectance of all the coal samples varies between 0.32 % and 0.39 %.</div><div>As mainly sandstones, intercalated with siltstones and claystones are the main sedimentary rocks deposited in the Niger-River alluvial plain, the inorganic part of all the studied coaly and carbonaceous samples consists primarily of quartz and kaolinite, whereas goethite, mixed clay layers (illite-montmorillonite), anatase and gypsum occur in minor amounts. Accordingly, SiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> display values ranging from 9 to 58 % and up to 23 wt%, respectively, while Fe<sub>2</sub>O<sub>3</sub> up to 12 wt% and TiO<sub>2</sub> up to 2 wt%.</div><div>Palaeoenvironmental geochemical proxies indicate a mixed source area for the siliciclastic facies, with significant recycling and weathering, deposited under a pure freshwater regime. The carbonaceous layers seem to have been deposited in a relative semi-arid climate, while the palaeomires were established under a more humid regime, promoting anaerobic conditions, which is in agreement with the observed very low inertinite content. Facies diagrammes based on the maceral contents were applied to reconstruct the environmental conditions in the palaeomires. According to the TPI <em>vs.</em> GI diagramme, the peat-forming vegetation was mostly herbaceous yielding low TPI and medium GI values, and the conditions were fluvial-limnotelmatic. The GWI <em>vs.</em> VI diagramme points to herbaceous vegetation on the palaeomire surface and mesotrophic water conditions with intense mineral matter influx from palaeo-Niger River. The area received frequent rainfall along with river flooding; thus, peat remained water-logged. Within the several hundred metres thick alluvial sediments, only short periods of limnotelmatic conditions prevailed in the area, yielding coal beds less than 17 m thick. The small number of the available cores distribut","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"306 ","pages":"Article 104807"},"PeriodicalIF":5.6,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942439","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}
Pub Date : 2025-06-20Epub Date: 2025-04-21DOI: 10.1016/j.coal.2025.104777
Ifeanyi Valerian Nwankwo , Morteza Dejam , Scott Austin Quillinan
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, which affects fluid flow. Furthermore, non-Darcy flow mechanisms exist thereby making flow in shale a complex phenomenon. Nonetheless, many studies have recently focused on the geophysical and geomechanical characterization of shale. Various works have equally examined the complexity of fluid flow. Numerous studies were particularly interested in the influence of non-linear flow parameters and stress sensitivity on apparent permeability, intrinsic permeability, and porosity during pressure depletion. However, relatively few works, mostly theoretical, have been carried out on coupled flow and geomechanical reactions. This review thus includes a report on fluid flow and geomechanical characterization of shale formation, as well as an identification of the factors that influence rock deformation and fluid flow during production. The review showed that flow regimes are predominantly dependent on pore pressure and pore size, whereas flow regimes regulate apparent permeability. For example, at low pressures and pore radius less than 10 nm, flow regims were found to significantly increase the apparent permeability. However, at higher bulk modulus (>10 GPa), pore radius has essentially no impact, hence, pore pressure becomes the dominant factor influencing flow. In addition, the review shows that during depressurization, geophysical metrics are more sensitive to pressure changes than geomechanical properties. Finally, some results in literature revealed that the impact of geomechanical characteristics on cumulative production can be ignored in competent formations with high Young's modulus (about 6 × 106-10 × 106 psi). In conclusion, recovery from shale could be optimized by integrating experimental studies with hydromechanical models during initial reservoir studies.
{"title":"A critical review of experimental and theoretical studies on shale geomechanical and deformation properties, fluid flow behavior, and coupled flow and geomechanics effects during production","authors":"Ifeanyi Valerian Nwankwo , Morteza Dejam , Scott Austin Quillinan","doi":"10.1016/j.coal.2025.104777","DOIUrl":"10.1016/j.coal.2025.104777","url":null,"abstract":"<div><div>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, which affects fluid flow. Furthermore, non-Darcy flow mechanisms exist thereby making flow in shale a complex phenomenon. Nonetheless, many studies have recently focused on the geophysical and geomechanical characterization of shale. Various works have equally examined the complexity of fluid flow. Numerous studies were particularly interested in the influence of non-linear flow parameters and stress sensitivity on apparent permeability, intrinsic permeability, and porosity during pressure depletion. However, relatively few works, mostly theoretical, have been carried out on coupled flow and geomechanical reactions. This review thus includes a report on fluid flow and geomechanical characterization of shale formation, as well as an identification of the factors that influence rock deformation and fluid flow during production. The review showed that flow regimes are predominantly dependent on pore pressure and pore size, whereas flow regimes regulate apparent permeability. For example, at low pressures and pore radius less than 10 nm, flow regims were found to significantly increase the apparent permeability. However, at higher bulk modulus (>10 GPa), pore radius has essentially no impact, hence, pore pressure becomes the dominant factor influencing flow. In addition, the review shows that during depressurization, geophysical metrics are more sensitive to pressure changes than geomechanical properties. Finally, some results in literature revealed that the impact of geomechanical characteristics on cumulative production can be ignored in competent formations with high Young's modulus (about 6 × 10<sup>6</sup>-10 × 10<sup>6</sup> psi). In conclusion, recovery from shale could be optimized by integrating experimental studies with hydromechanical models during initial reservoir studies.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"306 ","pages":"Article 104777"},"PeriodicalIF":5.6,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917670","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}
Pub Date : 2025-06-20Epub Date: 2025-05-01DOI: 10.1016/j.coal.2025.104792
J. Kus, L. Richter, G. Scheeder, C. Ostertag-Henning, M. Blumenberg, M. Mertineit
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 and distinctively. 405 nm based excitation allowed for in-situ CLSM-associated acquisitions and distinction of HCFI emission spectra for both sites. In contrast to transmitted light microscopy equipped with barrier filter >515 nm, the CLSM-related emission >410 nm employed full emission spectra essential for observation of the entire emission spectrum of HCFI. While maximum emission intensity (λmax) of HCFI at the Gorleben site peaks at 455–456 nm, the corresponding λmax at the Morsleben site ranges from 485 to 495 nm, indicating that emission spectra of HCFI at Gorleben site are “blue-shifted” in comparison to those at Morsleben. It is implied that the blue-shift is caused by a shift to a less aromatic/polar composition of the HCFI at Gorleben site. Both, HCFI and petroleum differ noticeably in spectral properties from epoxy resins indicating no contamination of epoxy resin in the examined thick sections. Coarse approximations of °API (a standard for petroleum liquid density), based on red/green coefficient (Qmax) and empirical correlation equation as well as direct measurements of °API, suggested markedly different °API gravities for Gorleben and Morsleben sites with higher °API values, of up to 52.4 for the first. Collectively, the results of this research study demonstrated the applicability and adaptability of CLSM as a well-advanced method to acquire in-situ spectral properties of HCFI in salt rock, as a basis for understanding hydrocarbon generation and migration in sedimentary environments.
{"title":"Characterizing hydrocarbon-bearing fluid inclusions using CLSM-based microspectrometry with application to the Upper Permian rock salt in the Gorleben and Morsleben sites, Germany","authors":"J. Kus, L. Richter, G. Scheeder, C. Ostertag-Henning, M. Blumenberg, M. Mertineit","doi":"10.1016/j.coal.2025.104792","DOIUrl":"10.1016/j.coal.2025.104792","url":null,"abstract":"<div><div>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 and distinctively. 405 nm based excitation allowed for in-situ CLSM-associated acquisitions and distinction of HCFI emission spectra for both sites. In contrast to transmitted light microscopy equipped with barrier filter >515 nm, the CLSM-related emission >410 nm employed full emission spectra essential for observation of the entire emission spectrum of HCFI. While maximum emission intensity (λ<sub>max</sub>) of HCFI at the Gorleben site peaks at 455–456 nm, the corresponding λ<sub>max</sub> at the Morsleben site ranges from 485 to 495 nm, indicating that emission spectra of HCFI at Gorleben site are “blue-shifted” in comparison to those at Morsleben. It is implied that the blue-shift is caused by a shift to a less aromatic/polar composition of the HCFI at Gorleben site. Both, HCFI and petroleum differ noticeably in spectral properties from epoxy resins indicating no contamination of epoxy resin in the examined thick sections. Coarse approximations of °API (a standard for petroleum liquid density), based on red/green coefficient (Q<sub>max</sub>) and empirical correlation equation as well as direct measurements of °API, suggested markedly different °API gravities for Gorleben and Morsleben sites with higher °API values, of up to 52.4 for the first. Collectively, the results of this research study demonstrated the applicability and adaptability of CLSM as a well-advanced method to acquire in-situ spectral properties of HCFI in salt rock, as a basis for understanding hydrocarbon generation and migration in sedimentary environments.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"306 ","pages":"Article 104792"},"PeriodicalIF":5.6,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912502","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}
Pub Date : 2025-06-20Epub Date: 2025-05-08DOI: 10.1016/j.coal.2025.104804
José A. D'Angelo , James C. Hower , Gerardo Camí , Maiten A. Lafuente Diaz
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 seam (Asturian-Cantabrian boundary; vitrinite reflectance Ro% = 0.65) at Brogan's pit locality, Cape Breton Island, Nova Scotia, Canada. Well-preserved compressions of pinnules (rachises were not preserved) are analyzed by Fourier transform infrared (FTIR) spectroscopy. These data are examined with the purpose of (i) calculating pinnular density (δ) and associated biomechanical and physiological properties, i.e., tensile strength (TS = resistance to fracture), tensile modulus of elasticity (TME = stiffness), and leaf mass per area (LMA = biomass investment and construction cost); (ii) comparing the data for δ, TS, TME, and LMA of O. cantabrica and O. schlotheimii at two levels: interspecific differences and intraspecific variations between pinnules representing different (proximal and distal) parts of each frond; (iii) comparing data for δ, TS, TME, and LMA of O. cantabrica and O. schlotheimii with those of previously studied medullosalean frond taxa, namely Alethopteris ambigua and Neuropteris ovata var. simonii; and (iv) obtaining new insights into the possible growth habit of both fronds. Results indicate that pinnular density, resistance to fracture, stiffness, and leaf mass per area vary continuously throughout the fronds and indicate biomechanical resistance and physiological efficiency. ANOVA tests show that the pinnules of O. cantabrica and O. schlotheimii are not significantly different in terms of density and biomechanical/physiological characteristics overall. However, within each species, proximal pinnules exhibit statistically higher density, stiffness, resistance to fracture, and metabolic construction cost compared to distal pinnules. The δ, TS, TME, and LMA data for O. cantabrica and O. schlotheimii are notably lower than those of N. ovata var. simonii and A. ambigua. The order of values for δ, TS, TME, and LMA follows: N. ovata var. simonii > A. ambigua > O. cantabrica = O. schlotheimii. Considering the values for δ, TS, TME, LMA, and general morphology, it is possible that O. cantabrica and O. schlotheimii had a semi-self-supporting to self-supporting (arborescent) growth form.
作为正在进行的研究项目“石炭纪植物的化学、生物力学和生理学”的一部分，本研究调查了两个最大的加拿大标本，1969年（22厘米长）的cantabrica Wagner和1828-1831年（7厘米长）的Odontopteris schlotheimii Brongniart，来自宾夕法尼亚悉尼煤田。在劳埃德湾煤层（阿斯图里—坎塔布连边界）顶板页岩中，这两种样品共存；加拿大新斯科舍省布雷顿角岛布罗根坑地区镜质组反射率Ro% = 0.65)。用傅立叶变换红外光谱分析了保存完好的小叶压缩（小叶未保存）。对这些数据进行检查的目的是：(1)计算叶尖密度（δ）和相关的生物力学和生理特性，即抗拉强度（TS =抗断裂）、抗拉弹性模量（TME =刚度）和每面积叶质量（LMA =生物量投资和建设成本）；（ii）在两个水平上比较了甘布兰和石竹的δ、TS、TME和LMA数据：代表每叶不同部分（近端和远端）的小叶之间的种间差异和种内差异；(3)与已有研究的延髓纲前叶类群Alethopteris ambigua和Neuropteris ovata var. simonii的δ、TS、TME和LMA数据进行比较；（iv）对两种叶子可能的生长习性有了新的认识。结果表明，叶尖密度、断裂阻力、刚度和单位面积叶质量在整个叶片中呈连续变化，表明了生物力学阻力和生理效率。方差分析结果表明，在密度和生物力学生理特征方面，两种植物的小叶总体上没有显著差异。然而，在每个物种中，与远端小叶相比，近端小叶在统计上表现出更高的密度、刚度、抗骨折性和代谢构建成本。坎塔布兰和施罗氏稻的δ、TS、TME和LMA数据均显著低于紫斑稻和双歧稻。δ、TS、TME和LMA的取值顺序为：N. ovata var. simonii >；A.歧义；O. cantabrica = O. schlotheimii。综合δ、TS、TME、LMA值和总体形态特征，推测其生长形态可能为半自立型到自立型（乔木型）。
{"title":"Biomechanics and physiology of Odontopteris cantabrica and Odontopteris schlotheimii (Medullosales, Pennsylvanian, Canada)","authors":"José A. D'Angelo , James C. Hower , Gerardo Camí , Maiten A. Lafuente Diaz","doi":"10.1016/j.coal.2025.104804","DOIUrl":"10.1016/j.coal.2025.104804","url":null,"abstract":"<div><div>As part of the ongoing research project “<em>Chemistry, Biomechanics, and Physiology of Carboniferous plants</em>”, this study investigates two of the largest Canadian specimens of <em>Odontopteris cantabrica</em> <span><span>Wagner, 1969</span></span> (22-cm long) and <em>Odontopteris schlotheimii</em> <span><span>Brongniart, 1828-1831</span></span> (7-cm long) from the Pennsylvanian Sydney Coalfield. Specimens of both species co-occur in the roof shale of the Lloyd Cove coal seam (Asturian-Cantabrian boundary; vitrinite reflectance Ro% = 0.65) at Brogan's pit locality, Cape Breton Island, Nova Scotia, Canada. Well-preserved compressions of pinnules (rachises were not preserved) are analyzed by Fourier transform infrared (FTIR) spectroscopy. These data are examined with the purpose of (i) calculating pinnular density (δ) and associated biomechanical and physiological properties, i.e., tensile strength (TS = resistance to fracture), tensile modulus of elasticity (TME = stiffness), and leaf mass per area (LMA = biomass investment and construction cost); (ii) comparing the data for δ, TS, TME, and LMA of <em>O. cantabrica</em> and <em>O. schlotheimii</em> at two levels: interspecific differences and intraspecific variations between pinnules representing different (proximal and distal) parts of each frond; (iii) comparing data for δ, TS, TME, and LMA of <em>O. cantabrica</em> and <em>O. schlotheimii</em> with those of previously studied medullosalean frond taxa, namely <em>Alethopteris ambigua</em> and <em>Neuropteris ovata</em> var. <em>simonii</em>; and (iv) obtaining new insights into the possible growth habit of both fronds. Results indicate that pinnular density, resistance to fracture, stiffness, and leaf mass per area vary continuously throughout the fronds and indicate biomechanical resistance and physiological efficiency. ANOVA tests show that the pinnules of <em>O. cantabrica</em> and <em>O. schlotheimii</em> are not significantly different in terms of density and biomechanical/physiological characteristics overall. However, within each species, proximal pinnules exhibit statistically higher density, stiffness, resistance to fracture, and metabolic construction cost compared to distal pinnules. The δ, TS, TME, and LMA data for <em>O. cantabrica</em> and <em>O. schlotheimii</em> are notably lower than those of <em>N. ovata</em> var. <em>simonii</em> and <em>A. ambigua</em>. The order of values for δ, TS, TME, and LMA follows: <em>N. ovata</em> var. <em>simonii</em> > <em>A. ambigua</em> > <em>O. cantabrica</em> = <em>O. schlotheimii</em>. Considering the values for δ, TS, TME, LMA, and general morphology, it is possible that <em>O. cantabrica</em> and <em>O. schlotheimii</em> had a semi-self-supporting to self-supporting (arborescent) growth form.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"306 ","pages":"Article 104804"},"PeriodicalIF":5.6,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947695","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}
Pub Date : 2025-06-20Epub Date: 2025-05-10DOI: 10.1016/j.coal.2025.104809
Maria Mastalerz , Agnieszka Drobniak , Bei Liu , Peter E. Sauer
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.
This study investigates the relationship between reflectance and the chemical composition (elemental ratios and organic functional groups) of biochar produced from sycamore wood, wheat straw, and peanut shells across well-controlled pyrolysis temperatures ranging from 300 °C to 700 °C, aiming to assess the potential of biochar reflectance as an indicator of biochar permanence.
The results demonstrate strong correlations between biochar reflectance and H/C and O/C molar ratios and show that the reflectance increases systematically with pyrolysis temperature. A strong correlation between the elemental O/C ratio and the FTIR-derived ratio of oxygenated groups to aromatic carbon across different pyrolysis temperatures provides additional valuable insights for predicting biochar stability.
The findings point to pyrolysis temperature as the dominant factor influencing biochar longevity and reinforce the suggestion that biochars with reflectance values above 2.0 % are non-reactive and are expected to be stable in the environment for a very long time. The results highlight biochar reflectance as a rapid and effective proxy for predicting biochar permanence, supporting its utility in carbon sequestration and environmental management.
{"title":"Reflectance as an indicator of biochar permanence","authors":"Maria Mastalerz , Agnieszka Drobniak , Bei Liu , Peter E. Sauer","doi":"10.1016/j.coal.2025.104809","DOIUrl":"10.1016/j.coal.2025.104809","url":null,"abstract":"<div><div>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.</div><div>This study investigates the relationship between reflectance and the chemical composition (elemental ratios and organic functional groups) of biochar produced from sycamore wood, wheat straw, and peanut shells across well-controlled pyrolysis temperatures ranging from 300 °C to 700 °C, aiming to assess the potential of biochar reflectance as an indicator of biochar permanence.</div><div>The results demonstrate strong correlations between biochar reflectance and H/C and O/C molar ratios and show that the reflectance increases systematically with pyrolysis temperature. A strong correlation between the elemental O/C ratio and the FTIR-derived ratio of oxygenated groups to aromatic carbon across different pyrolysis temperatures provides additional valuable insights for predicting biochar stability.</div><div>The findings point to pyrolysis temperature as the dominant factor influencing biochar longevity and reinforce the suggestion that biochars with reflectance values above 2.0 % are non-reactive and are expected to be stable in the environment for a very long time. The results highlight biochar reflectance as a rapid and effective proxy for predicting biochar permanence, supporting its utility in carbon sequestration and environmental management.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"306 ","pages":"Article 104809"},"PeriodicalIF":5.6,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070582","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}
Pub Date : 2025-05-26Epub Date: 2025-04-18DOI: 10.1016/j.coal.2025.104785
Bo Jiu , Zhijun Jin , Huidi Hao , Zhaoguo Wang , Wenhui Huang , Zhenguang Shang , Runchao Liu , Yang Li , Linhao Huang , Binchao Qin , Zixuan Huang , Li Long , Wenzhong Zhang , Yian Wang
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 in-situ analytical techniques. This study focused on the in-situ distribution of REY in the selected subbituminous coals from the Jungar Coalfield as well as in their associated mudstone and tonstein partings and the widely distributed calcite veins inside the coal seam, using LA-ICP-MS spot and mapping analysis. The results showed that in the subbituminous coal, La and Ce as well as other light REY (LREY) are concentrated in the minerals such as bastnasite and monazite. Small amounts of Pr, Nd, and Sm can be associated with organic matter including vitrinite and liptinite. Medium REY (MREY) and heavy REY (HREY) are highly enriched in vitrinite in the subbituminous coal. In terrigenous mudstone of the subbituminous coal, La and Ce are concentrated in monazite. Other LREY are present in Ti-oxides, while HREY tend to occur in zircon. MREY can be associated with both Ti-oxides and zircon. The calcite veins in the coal seam are classified into three types based on their morphology and occurrence features: bedding calcite veins in the upper part of the coal, vertical calcite veins in the middle, and vertical calcite veins with a high Sr value in the lower part of the coal. Polarization and crystal size of calcite crystals in these veins exhibit multistage growth. LA-ICP-MS spot analysis shows that the bedding and vertical calcite veins are characterized by positive Y and Gd anomalies, suggesting their formation under meteoric water leaching. The vertical calcite vein in the lower part of the coal seam displays a positive Gd anomaly and high Sr concentrations, indicating formation under seawater injection. The concentration of REY in all epigenetic calcite veins increases with depth. For calcite veins with multi-stage growth, the REY content in the late-stage calcite is consistently higher than in the early stages. It is proposed that leaching of meteoric water and seawater on the coal seams is the key factor for the association of REY with organic matter, influenced by the chemical composition and pH value of the leaching fluids. In particular, MREY and HREY are preferentially associated with organic matter, mainly vitrinite, and the over-leached MREY and HREY in coal were concentrated in epigenetic minerals, with calcite being the primary phase in this study.
{"title":"Modes of occurrence of rare earth elements and yttrium in the subbituminous coal of the Jungar Coalfield, Ordos Basin, North China","authors":"Bo Jiu , Zhijun Jin , Huidi Hao , Zhaoguo Wang , Wenhui Huang , Zhenguang Shang , Runchao Liu , Yang Li , Linhao Huang , Binchao Qin , Zixuan Huang , Li Long , Wenzhong Zhang , Yian Wang","doi":"10.1016/j.coal.2025.104785","DOIUrl":"10.1016/j.coal.2025.104785","url":null,"abstract":"<div><div>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 in-situ analytical techniques. This study focused on the in-situ distribution of REY in the selected subbituminous coals from the Jungar Coalfield as well as in their associated mudstone and tonstein partings and the widely distributed calcite veins inside the coal seam, using LA-ICP-MS spot and mapping analysis. The results showed that in the subbituminous coal, La and Ce as well as other light REY (LREY) are concentrated in the minerals such as bastnasite and monazite. Small amounts of Pr, Nd, and Sm can be associated with organic matter including vitrinite and liptinite. Medium REY (MREY) and heavy REY (HREY) are highly enriched in vitrinite in the subbituminous coal. In terrigenous mudstone of the subbituminous coal, La and Ce are concentrated in monazite. Other LREY are present in Ti-oxides, while HREY tend to occur in zircon. MREY can be associated with both Ti-oxides and zircon. The calcite veins in the coal seam are classified into three types based on their morphology and occurrence features: bedding calcite veins in the upper part of the coal, vertical calcite veins in the middle, and vertical calcite veins with a high Sr value in the lower part of the coal. Polarization and crystal size of calcite crystals in these veins exhibit multistage growth. LA-ICP-MS spot analysis shows that the bedding and vertical calcite veins are characterized by positive Y and Gd anomalies, suggesting their formation under meteoric water leaching. The vertical calcite vein in the lower part of the coal seam displays a positive Gd anomaly and high Sr concentrations, indicating formation under seawater injection. The concentration of REY in all epigenetic calcite veins increases with depth. For calcite veins with multi-stage growth, the REY content in the late-stage calcite is consistently higher than in the early stages. It is proposed that leaching of meteoric water and seawater on the coal seams is the key factor for the association of REY with organic matter, influenced by the chemical composition and pH value of the leaching fluids. In particular, MREY and HREY are preferentially associated with organic matter, mainly vitrinite, and the over-leached MREY and HREY in coal were concentrated in epigenetic minerals, with calcite being the primary phase in this study.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"305 ","pages":"Article 104785"},"PeriodicalIF":5.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855308","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}
Pub Date : 2025-05-26Epub Date: 2025-04-28DOI: 10.1016/j.coal.2025.104790
Eugene Donskoi , Andrei Poliakov , Lauren Williamson , Oliver Scholes
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.
The study showed that, NH cokes had coarser structure, including larger porosity pockets, coagulated nodes and connecting walls. However, AU cokes had more connections/walls per unit area which in total were thicker. Inert Maceral Derived Components (IMDC) in NH cokes were smaller, more rounded and less elongated. The IMDC boundary smoothness was higher in NH cokes. There are fewer voids within Reacted Maceral Derived Components on the IMDC boundary in NH cokes, and the average size of these voids is significantly larger. Porosity in AU cokes was more tortuous and there was less fine optically recordable porosity in NH cokes.
For all 26 structural parameters where the difference between NH and AU cokes was significant and where the correlation of each parameter with RMax obtained from a large set of Australian cokes was also significant, the difference was such that the structure of Australian cokes was corresponding to higher RMax than matched NH cokes.
{"title":"Systematic differences in the microstructure of cokes made from medium/high-reflectance Northern hemisphere and Australian coals","authors":"Eugene Donskoi , Andrei Poliakov , Lauren Williamson , Oliver Scholes","doi":"10.1016/j.coal.2025.104790","DOIUrl":"10.1016/j.coal.2025.104790","url":null,"abstract":"<div><div>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.</div><div>The study showed that, NH cokes had coarser structure, including larger porosity pockets, coagulated nodes and connecting walls. However, AU cokes had more connections/walls per unit area which in total were thicker. Inert Maceral Derived Components (IMDC) in NH cokes were smaller, more rounded and less elongated. The IMDC boundary smoothness was higher in NH cokes. There are fewer voids within Reacted Maceral Derived Components on the IMDC boundary in NH cokes, and the average size of these voids is significantly larger. Porosity in AU cokes was more tortuous and there was less fine optically recordable porosity in NH cokes.</div><div>For all 26 structural parameters where the difference between NH and AU cokes was significant and where the correlation of each parameter with RMax obtained from a large set of Australian cokes was also significant, the difference was such that the structure of Australian cokes was corresponding to higher RMax than matched NH cokes.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"305 ","pages":"Article 104790"},"PeriodicalIF":5.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902060","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}
Pub Date : 2025-05-26Epub Date: 2025-04-27DOI: 10.1016/j.coal.2025.104788
David A. Wood
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 (India) associated with a wide range of thermal maturity and petrology are evaluated using optical microscopy, N2 and CO2 low pressure gas adsorption analysis, and single-heating rate and multi-heating rate Rock-Eval pyrolysis. The results reveal distinctive relationships between pore volumes, specific surface area (SSA), fractal dimensions, reaction kinetic distributions, and S2 pyrogram features that differ for the micropore and mesopore PSDs. The most thermally mature coals exhibit the highest micropore volumes, SSA and fractal dimensions but the PSD characteristics are also influenced by maceral fractions, particularly liptinite/vitrinite ratio. Difference in PSD characteristics are observed between the micropores and mesopores. The complexity of the kinetic distributions increases with thermal maturity. Clear relationships exist between the weighted average standard deviation of activation energies and micropore fractal dimensions and SSA. Similar but less well-defined relationships exist between single-heating rate transformation fraction temperature ranges and micropore fractal dimensions and SSA. The significance of these results is that it opens the possibility to use Rock-Eval analysis to estimate coal PSD characteristics. Once calibrated with low-pressure gas adsorption (LPGA) analysis, Rock-Eval pyrograms could be generated more rapidly and at lower costs on multiple samples to better delineate the best coal zones for gas recovery and gas storage. No published studies have previously identified or addressed relationships between reaction kinetics distributions and PSD.
{"title":"Complex interactions between coal maceral fractions, thermal maturity, reaction kinetics, fractal dimensions and pore-size distributions: Implications for gas storage","authors":"David A. Wood","doi":"10.1016/j.coal.2025.104788","DOIUrl":"10.1016/j.coal.2025.104788","url":null,"abstract":"<div><div>Characterizing pore-size distributions (PSD) of coals is required to identify optimum zone for gas recovery and suitable sites to store carbon dioxide (CO<sub>2</sub>) 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 (India) associated with a wide range of thermal maturity and petrology are evaluated using optical microscopy, N<sub>2</sub> and CO<sub>2</sub> low pressure gas adsorption analysis, and single-heating rate and multi-heating rate Rock-Eval pyrolysis. The results reveal distinctive relationships between pore volumes, specific surface area (SSA), fractal dimensions, reaction kinetic distributions, and S2 pyrogram features that differ for the micropore and mesopore PSDs. The most thermally mature coals exhibit the highest micropore volumes, SSA and fractal dimensions but the PSD characteristics are also influenced by maceral fractions, particularly liptinite/vitrinite ratio. Difference in PSD characteristics are observed between the micropores and mesopores. The complexity of the kinetic distributions increases with thermal maturity. Clear relationships exist between the weighted average standard deviation of activation energies and micropore fractal dimensions and SSA. Similar but less well-defined relationships exist between single-heating rate transformation fraction temperature ranges and micropore fractal dimensions and SSA. The significance of these results is that it opens the possibility to use Rock-Eval analysis to estimate coal PSD characteristics. Once calibrated with low-pressure gas adsorption (LPGA) analysis, Rock-Eval pyrograms could be generated more rapidly and at lower costs on multiple samples to better delineate the best coal zones for gas recovery and gas storage. No published studies have previously identified or addressed relationships between reaction kinetics distributions and PSD.</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"305 ","pages":"Article 104788"},"PeriodicalIF":5.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143888090","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}
Pub Date : 2025-05-26Epub Date: 2025-04-14DOI: 10.1016/j.coal.2025.104772
M. Zielińska , J. Kus , J.G. Mendonça Filho , E. Szram , M. Blumenberg , M. Fabiańska
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 the Pieniny Klippen Belt of the Western Carpathians in Poland and Slovakia. In addition, a reconstruction of paleoenvironmental conditions and dinoflagellate cyst biochronology were performed. The presence of first-cycle vitrinite was well-discerned from phyllovitrinite and a reworked vitrinite population. It allowed for determination of thermal maturity at 0.74 % VRo (0.04–0.10 % SD). Although a comparison between measured and calculated λmax and Q650/500 for sporinite and alginite yielded a marked discrepancy, both spectral fluorescence parameters illustrate a clear similarity between lamalginite and dinoflagellate cysts. The samples contain predominantly thermally mature organic-lean Type III kerogen of terrigenous-derived macerals of first-cycle vitrinite, phyllovitrinite, reworked vitrinite, and liptinite (sporinite) with admixture of Type II kerogen associated with lamalginite. This is in line with Rock-Eval and biomarker data as well as the palynofacies composition, the latter indicating predominance of phytoclasts kerogen groups over palynomorphs and amorphous components. The occurrence of reworked, oxidized, and fragmented terrigenous OM is attributed to weathered and eroded sedimentary rocks from the Upper Carboniferous to Triassic and Lower Jurassic periods as well as from the lowermost Middle Jurassic cover. Together with predominant primarily indigenous terrigenous OM, the reworked sedimentary strata served as a source for siliciclastic sedimentation and formation of turbiditic deposits in marine slope to abyssal plain settings. In the extensional active tectonic setting, sediment flux and runout in turbidity currents were derived from overstepped margin slopes, fault-bounded tilt blocks, and the Czorsztyn Ridge. In addition, organic contributions to pelagic deposits included planktonic microorganisms such as dinoflagellate cysts, foraminiferal test linings, and, to a lesser extent, prasinophytes and acritarchs. It is likely that the deposition of Middle Jurassic black shales occurred in a predominantly heterolithic-oxic shelf and dysoxic-suboxic shelf to basin transition. The Szlachtowa Formation yielded dinoflagellate cysts indicative of the Middle Jurassic Aalenian to Bajocian stages, with a few species also appearing in the Toarcian and Bathonian stages. Significant changes in OM preservation influenced hydrocarbon generative potential of studied black shales, accounting for its low to fair source rock generative potential (avg. ∼0.6 wt% TOC; Hydrogen Index avg. ∼100).
采用显微鉴定分析、显微光度法、荧光显微光谱法、孢粉相分析、岩石热解和生物标志物地球化学等综合方法，确定了波兰和斯洛伐克西喀尔巴阡盆地Pieniny Klippen带中侏罗统Szlachtowa组有机质类型、物源、热成熟度和油气潜力的变化来源。此外，还重建了古环境条件和鞭毛藻囊生物年代学。从层状镜质组和改造镜质组群中可以很好地识别出第一旋回镜质组。它允许在0.74% VRo （0.04 - 0.10% SD）下测定热成熟度。虽然将孢子石和藻褐石的测量值与计算值λmax和Q650/500进行比较，结果存在明显差异，但两者的光谱荧光参数均表明藻褐石和鞭毛藻囊具有明显的相似性。样品中主要含有热成熟的有机贫型III型干酪根，由陆源的第一轮镜质组、层状镜质组、改造镜质组和脂质组（孢子质组）组成，并混合有与板藻质组相关的II型干酪根。这与岩石评估和生物标志物数据以及孢粉相组成一致，后者表明植物碎屑干酪根群优于孢粉和非晶组分。上石炭统至三叠纪、下侏罗统以及中侏罗统最下部盖层的风化侵蚀沉积岩，形成了改造、氧化、破碎的陆源有机质。与主要的本土陆源有机质一起，改造后的沉积地层为海相斜坡到深海平原的硅屑沉积和浊积沉积的形成提供了来源。在伸展活动构造背景下，沉积通量和浊流跳动来源于越级边缘斜坡、断界倾斜块体和恰尔什丁海脊。此外，对远洋沉积物的有机贡献包括浮游微生物，如鞭毛藻囊、有孔虫试验衬里，以及在较小程度上的裸生植物和关键生物。中侏罗统黑色页岩沉积可能发生在以杂岩-含氧陆架和缺氧-缺氧陆架为主的盆地过渡时期。Szlachtowa组的鞭毛藻囊显示了中侏罗世阿勒世至巴约西亚期的特征，在托瓦西亚和Bathonian期也出现了一些鞭毛藻囊。有机质保存的显著变化影响了研究的黑色页岩的生烃潜力，导致其低至中等的烃源岩生烃潜力（平均TOC为~ 0.6 wt%）；氢指数平均值为~ 100)。
{"title":"Middle Jurassic black shale deposits from the Pieniny Klippen Belt, Western Carpathians: Insights into organic matter composition, thermal maturity, depositional, and palaeoenvironmental variations","authors":"M. Zielińska , J. Kus , J.G. Mendonça Filho , E. Szram , M. Blumenberg , M. Fabiańska","doi":"10.1016/j.coal.2025.104772","DOIUrl":"10.1016/j.coal.2025.104772","url":null,"abstract":"<div><div>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 the Pieniny Klippen Belt of the Western Carpathians in Poland and Slovakia. In addition, a reconstruction of paleoenvironmental conditions and dinoflagellate cyst biochronology were performed. The presence of first-cycle vitrinite was well-discerned from phyllovitrinite and a reworked vitrinite population. It allowed for determination of thermal maturity at 0.74 % VR<sub>o</sub> (0.04–0.10 % SD). Although a comparison between measured and calculated λ<sub>max</sub> and Q<sub>650/500</sub> for sporinite and alginite yielded a marked discrepancy, both spectral fluorescence parameters illustrate a clear similarity between lamalginite and dinoflagellate cysts. The samples contain predominantly thermally mature organic-lean Type III kerogen of terrigenous-derived macerals of first-cycle vitrinite, phyllovitrinite, reworked vitrinite, and liptinite (sporinite) with admixture of Type II kerogen associated with lamalginite. This is in line with Rock-Eval and biomarker data as well as the palynofacies composition, the latter indicating predominance of phytoclasts kerogen groups over palynomorphs and amorphous components. The occurrence of reworked, oxidized, and fragmented terrigenous OM is attributed to weathered and eroded sedimentary rocks from the Upper Carboniferous to Triassic and Lower Jurassic periods as well as from the lowermost Middle Jurassic cover. Together with predominant primarily indigenous terrigenous OM, the reworked sedimentary strata served as a source for siliciclastic sedimentation and formation of turbiditic deposits in marine slope to abyssal plain settings. In the extensional active tectonic setting, sediment flux and runout in turbidity currents were derived from overstepped margin slopes, fault-bounded tilt blocks, and the Czorsztyn Ridge. In addition, organic contributions to pelagic deposits included planktonic microorganisms such as dinoflagellate cysts, foraminiferal test linings, and, to a lesser extent, prasinophytes and acritarchs. It is likely that the deposition of Middle Jurassic black shales occurred in a predominantly heterolithic-oxic shelf and dysoxic-suboxic shelf to basin transition. The Szlachtowa Formation yielded dinoflagellate cysts indicative of the Middle Jurassic Aalenian to Bajocian stages, with a few species also appearing in the Toarcian and Bathonian stages. Significant changes in OM preservation influenced hydrocarbon generative potential of studied black shales, accounting for its low to fair source rock generative potential (avg. ∼0.6 wt% TOC; Hydrogen Index avg. ∼100).</div></div>","PeriodicalId":13864,"journal":{"name":"International Journal of Coal Geology","volume":"305 ","pages":"Article 104772"},"PeriodicalIF":5.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143842696","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}
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