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John V Ross - One of the best experts on this subject based on the ideXlab platform.
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neo mineral formation during artificial Coalification of low ash mineral free peat material from tropical malaysia potential explanation for low ash Coals
International Journal of Coal Geology, 2008Co-Authors: Raphael A J Wust, John V RossAbstract:Abundant Coal Deposits have very low inorganic contents (ash yield; < 2%) and hence are almost ash-free. Inexplicable to date is that the precursor of Coal, modern peat Deposits, almost nowhere have such low ash yields as a result of both the inorganic mineral and biogenic phytolith contents. However, despite the common occurrence of phytoliths in modern peats, they are invariably absent in Coals. It has thus been hypothesized by some investigators that modern environments are not ideal analogues for the formation of low ash Coal Deposits. Here we present new evidence to suggest that mineral diagenesis during Coalification can transform biogenic inorganics to new minerals and that a substantial component of these new minerals could be removed in solution during expulsion of moisture with Coalification resulting in low ash precursors of Coal. This study presents results from artificial Coalification experiments of modern tropical forest peat material with ash yields between 2-4.3 wt.%. The inorganic material of the peat consists almost exclusively of Al-Si-and Si-rich phytoliths and other bioliths; no other inorganic mineral matter is present. Compressed pellets of dried peat were deformed in a Griggs constant strain rate apparatus at a constant confining pressure of 5 kb and constant strain rate of 10- 5 s - 1 at variable temperatures from 350 [degree sign]C to 550 [degree sign]C. The samples, exposed to artificial Coalification processes, were then analysed by SEM, EDS, and XRD for semi-quantitative chemical analyses. The deformed material showed a lack of any biogenic silica and Al-Si-phytoliths, but contained neoformed idiomorphic quartz crystals and clays. We conclude that modern peat forming environments that have low-ash peats containing biogenic silica and other biogenic Al-Si-material can represent precursors of very low-ash Coal Deposits. Our experiments illustrate that during Coalification, it is likely all or almost all biogenic material is transformed into new minerals, mainly quartz and clay minerals, such as kaolinite. Because natural systems are not confined to the same degree as our experiments, it is likely that part or all of the inorganic fraction migrates in solutions out of the peat or Coal seam with available fluids, resulting in an almost ash-free Coal deposit.
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neo mineral formation during artificial Coalification of low ash mineral free peat material from tropical malaysia potential explanation for low ash Coals
International Journal of Coal Geology, 2008Co-Authors: Raphael A J Wust, Marc R Bustin, John V RossAbstract:Abundant Coal Deposits have very low inorganic contents (ash yield; < 2%) and hence are almost ash-free. Inexplicable to date is that the precursor of Coal, modern peat Deposits, almost nowhere have such low ash yields as a result of both the inorganic mineral and biogenic phytolith contents. However, despite the common occurrence of phytoliths in modern peats, they are invariably absent in Coals. It has thus been hypothesized by some investigators that modern environments are not ideal analogues for the formation of low ash Coal Deposits. Here we present new evidence to suggest that mineral diagenesis during Coalification can transform biogenic inorganics to new minerals and that a substantial component of these new minerals could be removed in solution during expulsion of moisture with Coalification resulting in low ash precursors of Coal. This study presents results from artificial Coalification experiments of modern tropical forest peat material with ash yields between 2-4.3 wt.%. The inorganic material of the peat consists almost exclusively of Al-Si-and Si-rich phytoliths and other bioliths; no other inorganic mineral matter is present. Compressed pellets of dried peat were deformed in a Griggs constant strain rate apparatus at a constant confining pressure of 5 kb and constant strain rate of 10- 5 s - 1 at variable temperatures from 350 [degree sign]C to 550 [degree sign]C. The samples, exposed to artificial Coalification processes, were then analysed by SEM, EDS, and XRD for semi-quantitative chemical analyses. The deformed material showed a lack of any biogenic silica and Al-Si-phytoliths, but contained neoformed idiomorphic quartz crystals and clays. We conclude that modern peat forming environments that have low-ash peats containing biogenic silica and other biogenic Al-Si-material can represent precursors of very low-ash Coal Deposits. Our experiments illustrate that during Coalification, it is likely all or almost all biogenic material is transformed into new minerals, mainly quartz and clay minerals, such as kaolinite. Because natural systems are not confined to the same degree as our experiments, it is likely that part or all of the inorganic fraction migrates in solutions out of the peat or Coal seam with available fluids, resulting in an almost ash-free Coal deposit.
Raphael A J Wust - One of the best experts on this subject based on the ideXlab platform.
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neo mineral formation during artificial Coalification of low ash mineral free peat material from tropical malaysia potential explanation for low ash Coals
International Journal of Coal Geology, 2008Co-Authors: Raphael A J Wust, John V RossAbstract:Abundant Coal Deposits have very low inorganic contents (ash yield; < 2%) and hence are almost ash-free. Inexplicable to date is that the precursor of Coal, modern peat Deposits, almost nowhere have such low ash yields as a result of both the inorganic mineral and biogenic phytolith contents. However, despite the common occurrence of phytoliths in modern peats, they are invariably absent in Coals. It has thus been hypothesized by some investigators that modern environments are not ideal analogues for the formation of low ash Coal Deposits. Here we present new evidence to suggest that mineral diagenesis during Coalification can transform biogenic inorganics to new minerals and that a substantial component of these new minerals could be removed in solution during expulsion of moisture with Coalification resulting in low ash precursors of Coal. This study presents results from artificial Coalification experiments of modern tropical forest peat material with ash yields between 2-4.3 wt.%. The inorganic material of the peat consists almost exclusively of Al-Si-and Si-rich phytoliths and other bioliths; no other inorganic mineral matter is present. Compressed pellets of dried peat were deformed in a Griggs constant strain rate apparatus at a constant confining pressure of 5 kb and constant strain rate of 10- 5 s - 1 at variable temperatures from 350 [degree sign]C to 550 [degree sign]C. The samples, exposed to artificial Coalification processes, were then analysed by SEM, EDS, and XRD for semi-quantitative chemical analyses. The deformed material showed a lack of any biogenic silica and Al-Si-phytoliths, but contained neoformed idiomorphic quartz crystals and clays. We conclude that modern peat forming environments that have low-ash peats containing biogenic silica and other biogenic Al-Si-material can represent precursors of very low-ash Coal Deposits. Our experiments illustrate that during Coalification, it is likely all or almost all biogenic material is transformed into new minerals, mainly quartz and clay minerals, such as kaolinite. Because natural systems are not confined to the same degree as our experiments, it is likely that part or all of the inorganic fraction migrates in solutions out of the peat or Coal seam with available fluids, resulting in an almost ash-free Coal deposit.
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neo mineral formation during artificial Coalification of low ash mineral free peat material from tropical malaysia potential explanation for low ash Coals
International Journal of Coal Geology, 2008Co-Authors: Raphael A J Wust, Marc R Bustin, John V RossAbstract:Abundant Coal Deposits have very low inorganic contents (ash yield; < 2%) and hence are almost ash-free. Inexplicable to date is that the precursor of Coal, modern peat Deposits, almost nowhere have such low ash yields as a result of both the inorganic mineral and biogenic phytolith contents. However, despite the common occurrence of phytoliths in modern peats, they are invariably absent in Coals. It has thus been hypothesized by some investigators that modern environments are not ideal analogues for the formation of low ash Coal Deposits. Here we present new evidence to suggest that mineral diagenesis during Coalification can transform biogenic inorganics to new minerals and that a substantial component of these new minerals could be removed in solution during expulsion of moisture with Coalification resulting in low ash precursors of Coal. This study presents results from artificial Coalification experiments of modern tropical forest peat material with ash yields between 2-4.3 wt.%. The inorganic material of the peat consists almost exclusively of Al-Si-and Si-rich phytoliths and other bioliths; no other inorganic mineral matter is present. Compressed pellets of dried peat were deformed in a Griggs constant strain rate apparatus at a constant confining pressure of 5 kb and constant strain rate of 10- 5 s - 1 at variable temperatures from 350 [degree sign]C to 550 [degree sign]C. The samples, exposed to artificial Coalification processes, were then analysed by SEM, EDS, and XRD for semi-quantitative chemical analyses. The deformed material showed a lack of any biogenic silica and Al-Si-phytoliths, but contained neoformed idiomorphic quartz crystals and clays. We conclude that modern peat forming environments that have low-ash peats containing biogenic silica and other biogenic Al-Si-material can represent precursors of very low-ash Coal Deposits. Our experiments illustrate that during Coalification, it is likely all or almost all biogenic material is transformed into new minerals, mainly quartz and clay minerals, such as kaolinite. Because natural systems are not confined to the same degree as our experiments, it is likely that part or all of the inorganic fraction migrates in solutions out of the peat or Coal seam with available fluids, resulting in an almost ash-free Coal deposit.
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low ash peat Deposits from a dendritic intermontane basin in the tropics a new model for good quality Coals
International Journal of Coal Geology, 2001Co-Authors: Raphael A J Wust, Marc R BustinAbstract:Many good quality, thick, low-ash Carboniferous, Cretaceous and Tertiary Coal Deposits have dulling-upward sequences that have been interpreted to be of ombrotrophic, lowland, coastal origin. Previous studies of potential modern analogues for thick, dulling-upward Coal sequences have focused on tropical, ombrotrophic coastal peats. However, most modern coastal ombrotrophic Deposits would yield all bright Coal seams. New evidence from peat Deposits of the southern intermontane Tasek Bera Basin, Western Malaysia, reveals that thick, low-ash, low-sulfur peat may originate in narrow tributary valleys with moderately steep flank gradients. These Deposits may be favorable precursors to dulling-upward Coals, in that they contain high wood and low-ash content at depth and medium wood and slightly increasing ash content in the upper parts. Peat accumulation in the Tasek Bera Basin began in Mid-Holocene time. During the past 4500 years, 500 cm of low-ash ( 40 cm) white, fluvial silty clay with wood fragments was deposited. The clay-rich sediments are overlain by limnic black mud, sandy clay and dark-brown mud-rich peat up to 70 cm thick. The ash content of the mud-rich peat is as high as 31 wt.%. The high-ash peat is overlain by low-ash, sapric to hemic peat up to 5 m thick. The basal 3 m of the peat Deposits contain abundant logs and large woody fragments, whereas the top 2 m have less hard wood, but more arborescent fragments of palmae, such as roots from Pandanus atrocarpus. The acrotelm (top 50 cm) has a low-to-medium ash content ( < 10 wt.%). With burial, the Deposits of southern Tasek Bera Basin would yield a dendritic sediment pattern of sandstone, shale, carbonaceous shale and a dulling-upward, vitrain-rich Coal, overlain by carbonaceous shale. Because of the dendritic nature of the Tasek Bera Basin, Coal seams would most likely have a similar pattern as the Carboniferous humic Coal Deposits of the Black Warrior Basin in Alabama (USA). However, the good quality Coals with dulling-upward characteristics would be concentrated in the southern tributaries of the basin.
Marcello Ruta - One of the best experts on this subject based on the ideXlab platform.
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cranial anatomy ontogeny and relationships of the late carboniferous tetrapod gephyrostegus bohemicus jaekel 1902
Journal of Vertebrate Paleontology, 2014Co-Authors: Jozef Klembara, Jennifer A Clack, Andrew R Milner, Marcello RutaAbstract:ABSTRACT We review the cranial morphology of the Late Carboniferous terrestrial tetrapod Gephyrostegus bohemicus from the Coal Deposits of the Nýřany Basin in the Czech Republic. Gephyrostegus is known from several skulls ranging in length from about 25 mm to about 58 mm (holotype). The narrow skull is about twice as long as wide and shows a well-ossified quadrate and articular, but no evidence of braincase ossification. Autapomorphic features include a pustular ornamentation on some skull table bones, and a plate-like tabular process exhibiting a fine dorsal pitting. Gephyrostegus shares with Bruktererpeton fiebigi (Late Carboniferous, Germany) the presence of low, anteromedially to posterolaterally orientated sharp ridges on the posteroventral surface of the vomer. It shares with seymouriamorphs a rectangular, transverse pterygoid process and closely packed, radially arranged rows of small denticles on the palate. A phylogenetic analysis retrieves Gephyrostegidae (Gephyrostegus, Bruktererpeton) as siste...
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Cranial anatomy, ontogeny, and relationships of the Late Carboniferous tetrapod Gephyrostegus bohemicus Jaekel, 1902
2014Co-Authors: Jennifer A Clack, Jozef Klembara, Marcello Ruta, Andrew R MilnerAbstract:ABSTRACTWe review the cranial morphology of the Late Carboniferous terrestrial tetrapod Gephyrostegus bohemicus from the Coal Deposits of the Nýřany Basin in the Czech Republic. Gephyrostegus is known from several skulls ranging in length from about 25 mm to about 58 mm (holotype). The narrow skull is about twice as long as wide and shows a well-ossified quadrate and articular, but no evidence of braincase ossification. Autapomorphic features include a pustular ornamentation on some skull table bones, and a plate-like tabular process exhibiting a fine dorsal pitting. Gephyrostegus shares with Bruktererpeton fiebigi (Late Carboniferous, Germany) the presence of low, anteromedially to posterolaterally orientated sharp ridges on the posteroventral surface of the vomer. It shares with seymouriamorphs a rectangular, transverse pterygoid process and closely packed, radially arranged rows of small denticles on the palate. A phylogenetic analysis retrieves Gephyrostegidae (Gephyrostegus, Bruktererpeton) as sister group to Seymouriamorpha, although this wider clade receives low bootstrap support.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP
Marc R Bustin - One of the best experts on this subject based on the ideXlab platform.
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neo mineral formation during artificial Coalification of low ash mineral free peat material from tropical malaysia potential explanation for low ash Coals
International Journal of Coal Geology, 2008Co-Authors: Raphael A J Wust, Marc R Bustin, John V RossAbstract:Abundant Coal Deposits have very low inorganic contents (ash yield; < 2%) and hence are almost ash-free. Inexplicable to date is that the precursor of Coal, modern peat Deposits, almost nowhere have such low ash yields as a result of both the inorganic mineral and biogenic phytolith contents. However, despite the common occurrence of phytoliths in modern peats, they are invariably absent in Coals. It has thus been hypothesized by some investigators that modern environments are not ideal analogues for the formation of low ash Coal Deposits. Here we present new evidence to suggest that mineral diagenesis during Coalification can transform biogenic inorganics to new minerals and that a substantial component of these new minerals could be removed in solution during expulsion of moisture with Coalification resulting in low ash precursors of Coal. This study presents results from artificial Coalification experiments of modern tropical forest peat material with ash yields between 2-4.3 wt.%. The inorganic material of the peat consists almost exclusively of Al-Si-and Si-rich phytoliths and other bioliths; no other inorganic mineral matter is present. Compressed pellets of dried peat were deformed in a Griggs constant strain rate apparatus at a constant confining pressure of 5 kb and constant strain rate of 10- 5 s - 1 at variable temperatures from 350 [degree sign]C to 550 [degree sign]C. The samples, exposed to artificial Coalification processes, were then analysed by SEM, EDS, and XRD for semi-quantitative chemical analyses. The deformed material showed a lack of any biogenic silica and Al-Si-phytoliths, but contained neoformed idiomorphic quartz crystals and clays. We conclude that modern peat forming environments that have low-ash peats containing biogenic silica and other biogenic Al-Si-material can represent precursors of very low-ash Coal Deposits. Our experiments illustrate that during Coalification, it is likely all or almost all biogenic material is transformed into new minerals, mainly quartz and clay minerals, such as kaolinite. Because natural systems are not confined to the same degree as our experiments, it is likely that part or all of the inorganic fraction migrates in solutions out of the peat or Coal seam with available fluids, resulting in an almost ash-free Coal deposit.
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low ash peat Deposits from a dendritic intermontane basin in the tropics a new model for good quality Coals
International Journal of Coal Geology, 2001Co-Authors: Raphael A J Wust, Marc R BustinAbstract:Many good quality, thick, low-ash Carboniferous, Cretaceous and Tertiary Coal Deposits have dulling-upward sequences that have been interpreted to be of ombrotrophic, lowland, coastal origin. Previous studies of potential modern analogues for thick, dulling-upward Coal sequences have focused on tropical, ombrotrophic coastal peats. However, most modern coastal ombrotrophic Deposits would yield all bright Coal seams. New evidence from peat Deposits of the southern intermontane Tasek Bera Basin, Western Malaysia, reveals that thick, low-ash, low-sulfur peat may originate in narrow tributary valleys with moderately steep flank gradients. These Deposits may be favorable precursors to dulling-upward Coals, in that they contain high wood and low-ash content at depth and medium wood and slightly increasing ash content in the upper parts. Peat accumulation in the Tasek Bera Basin began in Mid-Holocene time. During the past 4500 years, 500 cm of low-ash ( 40 cm) white, fluvial silty clay with wood fragments was deposited. The clay-rich sediments are overlain by limnic black mud, sandy clay and dark-brown mud-rich peat up to 70 cm thick. The ash content of the mud-rich peat is as high as 31 wt.%. The high-ash peat is overlain by low-ash, sapric to hemic peat up to 5 m thick. The basal 3 m of the peat Deposits contain abundant logs and large woody fragments, whereas the top 2 m have less hard wood, but more arborescent fragments of palmae, such as roots from Pandanus atrocarpus. The acrotelm (top 50 cm) has a low-to-medium ash content ( < 10 wt.%). With burial, the Deposits of southern Tasek Bera Basin would yield a dendritic sediment pattern of sandstone, shale, carbonaceous shale and a dulling-upward, vitrain-rich Coal, overlain by carbonaceous shale. Because of the dendritic nature of the Tasek Bera Basin, Coal seams would most likely have a similar pattern as the Carboniferous humic Coal Deposits of the Black Warrior Basin in Alabama (USA). However, the good quality Coals with dulling-upward characteristics would be concentrated in the southern tributaries of the basin.
Jozef Klembara - One of the best experts on this subject based on the ideXlab platform.
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cranial anatomy ontogeny and relationships of the late carboniferous tetrapod gephyrostegus bohemicus jaekel 1902
Journal of Vertebrate Paleontology, 2014Co-Authors: Jozef Klembara, Jennifer A Clack, Andrew R Milner, Marcello RutaAbstract:ABSTRACT We review the cranial morphology of the Late Carboniferous terrestrial tetrapod Gephyrostegus bohemicus from the Coal Deposits of the Nýřany Basin in the Czech Republic. Gephyrostegus is known from several skulls ranging in length from about 25 mm to about 58 mm (holotype). The narrow skull is about twice as long as wide and shows a well-ossified quadrate and articular, but no evidence of braincase ossification. Autapomorphic features include a pustular ornamentation on some skull table bones, and a plate-like tabular process exhibiting a fine dorsal pitting. Gephyrostegus shares with Bruktererpeton fiebigi (Late Carboniferous, Germany) the presence of low, anteromedially to posterolaterally orientated sharp ridges on the posteroventral surface of the vomer. It shares with seymouriamorphs a rectangular, transverse pterygoid process and closely packed, radially arranged rows of small denticles on the palate. A phylogenetic analysis retrieves Gephyrostegidae (Gephyrostegus, Bruktererpeton) as siste...
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Cranial anatomy, ontogeny, and relationships of the Late Carboniferous tetrapod Gephyrostegus bohemicus Jaekel, 1902
2014Co-Authors: Jennifer A Clack, Jozef Klembara, Marcello Ruta, Andrew R MilnerAbstract:ABSTRACTWe review the cranial morphology of the Late Carboniferous terrestrial tetrapod Gephyrostegus bohemicus from the Coal Deposits of the Nýřany Basin in the Czech Republic. Gephyrostegus is known from several skulls ranging in length from about 25 mm to about 58 mm (holotype). The narrow skull is about twice as long as wide and shows a well-ossified quadrate and articular, but no evidence of braincase ossification. Autapomorphic features include a pustular ornamentation on some skull table bones, and a plate-like tabular process exhibiting a fine dorsal pitting. Gephyrostegus shares with Bruktererpeton fiebigi (Late Carboniferous, Germany) the presence of low, anteromedially to posterolaterally orientated sharp ridges on the posteroventral surface of the vomer. It shares with seymouriamorphs a rectangular, transverse pterygoid process and closely packed, radially arranged rows of small denticles on the palate. A phylogenetic analysis retrieves Gephyrostegidae (Gephyrostegus, Bruktererpeton) as sister group to Seymouriamorpha, although this wider clade receives low bootstrap support.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP