The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
James C. Hower - One of the best experts on this subject based on the ideXlab platform.
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Mineralogy of a rare earth element-rich Manchester coal lithotype, Clay County, Kentucky
International Journal of Coal Geology, 2020Co-Authors: James C. Hower, Dali Qian, Nicolas J. Briot, Madison M. Hood, Cortland F. EbleAbstract:Abstract Many Eastern Kentucky coals have high-REE contents, with Lithotypes of the Pennsylvanian-age Manchester coal rivaling some of the richest concentrations in the Fire Clay coal, arguably the premier resource in terms of concentration and aerial extent. A > 2000-ppm-REE + Y (REY; ash basis; 2.13% ash) Manchester coal lithotype, analyzed first by scanning electron microscopy, was selected for detailed transmission electron microscopy/ energy dispersive x-ray spectroscopy/ fast Fourier transform/ selected area electron diffraction investigation (TEM/EDS/FFT/SAED). The mineral grains extracted from the coal, seemingly fragments of one or more 2- to 3-μm spherical nodules, proved to have a phosphate (rhabdophane?) rim with a light REE (La through Sm) and Gd association. The core of the nodule and the region surrounding the nodule is Al Si rich but the mineralogy could not be determined. The nodule may be a mineralized coprolite, the product of the microfauna inhabiting the peat.
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submicron scale mineralogy of Lithotypes and the implications for trace element associations blue gem coal knox county kentucky
International Journal of Coal Geology, 2018Co-Authors: James C. Hower, Debora Berti, Michael F Hochella, Susan M Rimmer, Darrell N TaulbeeAbstract:Abstract Transmission electron microscopy accompanied by energy-dispersive spectroscopy and selected area electron diffraction of density-gradient separates from two Lithotypes of the low-ash, low-sulfur Blue Gem coal, eastern Kentucky, revealed an array of previously unrecognized (in this coal, and arguable in most others) sub-micron minerals, some Fe, Cu Fe S, Fe Zn-S, and Pb; and areas, probably comprising agglomerates of several grains, if not several minerals, with concentrations of Mg, Ca, Ti, Fe, Zn, Zr, and Mo. The sample representing the 1.30–1.31 specific gravity fraction of the basal lithotype has aggregates of particles enriched in Mg, Ca, Ti, and Fe. Individual grains not specifically quantified include Cr Ni Mn Cu Fe S, Ag S, and Cu S. Detailed investigation of one area (most of the variation within a Co Ge and Ag Cd Bi, the latter with a more evident S association than the former; metallic Bi; nisnite (Ni3Sn); silver cadmium; manganosite (MnO); and siderite. Some minerals, such as the monazite, are most likely of detrital or tuffaceous origin. Many of the other assemblages could be of hydrothermal origin, a hypothesis supported by known regional geochemical and coal rank trends, but not previously demonstrated in mineral assemblages at the 10's of nm scale in this region.
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Coal modeling using Markov Chain and Monte Carlo simulation: Analysis of microlithotype and lithotype succession
Sedimentary Geology, 2015Co-Authors: Saeid R. Dindarloo, James C. Hower, Amirhossein Bagherieh, John H. Calder, Nicola J. WagnerAbstract:Abstract Markov Chain analysis was applied to the description of the megascopic lithologic transitions in Pennsylvanian-age eastern Kentucky coals. Coal lithology modeling can be problematic as individual Lithotypes can represent near-instantaneous events (vitrain), prolonged degradation (durain), or fire-induced loss of previously deposited lithologies (fusain). Each of the latter Lithotypes, potentially representing vastly different amounts of time, could be of the same thickness. Therefore, equal thickness does not necessarily imply equal time. Probability transform matrices that employ uniform lithotype thicknesses were used, allowing transitions between like Lithotypes; embedded Markov Chains, thereby only considering transitions between different Lithotypes; and continuous-time Markov Chains were employed in the assessment of a section of the No. 5 Block coal (Pennsylvanian Breathitt Group, Martin County, Kentucky). Embedded Markov Chains could successfully simulate the lithologic transitions. A Monte Carlo random process was programmed to simulate thickness variations of Lithotypes between the transitions. The proposed hybrid model of Monte Carlo–Markov Chain was able to predict the random pattern that underlies Lithotypes transitions and thickness. The hybrid Monte Carlo–Markov Chain technique proved to be effective in the case study in simulating both the lithologic thickness variations and transitions.
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Notes on the origin of the resinite-rich “pine needle” lithotype of the Cretaceous Cambria coal, Weston County, Wyoming
International Journal of Coal Geology, 2014Co-Authors: Michelle N. Johnston, James C. Hower, Fredrick J. RichAbstract:Abstract The Cretaceous Cambria coal, located in the western part of the Black Hills in Weston County, Wyoming, was mined in the late-1800's and early-1900's primarily to serve the Burlington and Missouri River Railroad on its route from Lincoln, Nebraska to Billings, Montana. The coal bed contains a distinctive resinite-rich lithotype, commonly known as the “pine needle coal.” The coal is characterized by a collodetrinite/inertodetrinite/liptodetrinite lithotype, and the liptodetrinite including the resinite, represents a degraded residue of what was originally a deposit with a greater representation of wood-derived material.
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Tales from a distant swamp: Petrological and paleobotanical clues for the origin of the sand coal lithotype (Mississippian, Valley Fields, Virginia)
International Journal of Coal Geology, 2008Co-Authors: James C. Hower, Jennifer M.k. O’keefe, Cortland F. EbleAbstract:Abstract Tournasian (Mississippian) Price Formation semianthracites ( R max = 2.40%) in the Valley Fields of southwestern Virginia contain a lithotype described in an early-20th-century report as a “sand” coal. The Center for Applied Energy Research inherited a collection of coals containing sand coal specimens, making it possible to study the lithotype from the long-closed mines. The sand coal consists of rounded quartz sand and maceral assemblages (secretinite, corpogelinite, and rounded collotelinite) along with banded collotelinite, vitrodetrinite, and inertodetrinite assemblages. The association of rounded macerals and similar-size quartz grains suggests transport. Oxidation rims surrounding the rounded collotelinite provides further evidence for transport. Due to the semianthracite rank, palynology could not be performed. Stratigraphic evidence indicates that the Lepidodendropsis flora would have been the dominant mire vegetation. Pteridosperms in this assemblage could have contributed resin rodlets, subsequently metamorphosed to collogelinite or secretinite. While a resin rodlet origin is an intriguing possibility for the origin of the rounded macerals (at least some of the rounded maceral, the rounded collotelinite clearly has a different origin), we cannot definitively prove this origin.
R.b. Johns - One of the best experts on this subject based on the ideXlab platform.
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differentiation of victorian brown coal Lithotypes as revealed by thermally desorbable biomarkers
Journal of Analytical and Applied Pyrolysis, 1991Co-Authors: Maowen Li, R.b. JohnsAbstract:Abstract TD/GC/MS analyses of a profile of Victorian brown coal Lithotypes are reported. Specifically, weight loss on TD, triterpenoid and diterpenoid hydrocarbons, and trimethylnaphthalene isomers are considered as lithotype differentiators. In this initial use of biomarkers released by thermal desorption to characterise Lithotypes, evidence is reported for differences in angiosperm/gymnosperm contributions, variations in higher plant inputs and for distinct variations of bacterial biomass content of the liththotypes. Trimethylnaphthalenes also differentiate coal seams in the samples reported in this study.
Ian R K Sluiter - One of the best experts on this subject based on the ideXlab platform.
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sequence stratigraphic analysis and the origins of tertiary brown coal Lithotypes latrobe valley gippsland basin australia
International Journal of Coal Geology, 1995Co-Authors: G R Holdgate, A P Kershaw, Ian R K SluiterAbstract:Abstract The methods of sequence analysis have been applied to the onshore Gippsland Basin and in particular to the Latrobe Valley Group coal measures which include up to five coal seams each exceeding 100 m in thickness. The methods appear to provide new depositional concepts to the evolution of these seams, and the development of coal Lithotypes. In the eastern half of the Latrobe Valley evidence for marine transgressions into the coal measures are recorded in most of the interseam sediment splits by the presence of contained foraminifera and dinoflagellates. To the west (inland) these splits pinch out into continuous coal. However, they can be followed westwards as enhanced organic sulphur levels along sharply defined boundaries between light coal Lithotypes below and dark coal Lithotypes above. The dark lithotype immediately overlying each of these boundaries contains the highest sulphur value and warmer climate pollen assemblages (Sluiter et al., 1995, this volume). Colorimeter and lithotype logging strongly supports an upwards lightening cyclicity to coal colour at 12–20 m intervals through the approx. 100 m thick seams, with cycle boundaries defined at sharp planar to undulating surfaces. The lightening upward lithotype cycles together with their unique boundary conditions (i.e. enhanced organic sulphur levels, warm climatic indicators and laterally equivalent marine clay splits) are interpreted as parasequences and parasequence boundaries respectively. Each major coal seam can comprise up to five parasequences and is interpreted to represent deposition during an outbuilding high stand systems tract at one of several maximum periods of Tertiary coastal onlap. The top of each major seam shows evidence of truncation (erosion?) on a regional scale and these surfaces are interpreted to represent the sequence boundaries. The major seams are usually conformably underlain by marine clays and extensive aquifer sands, being deposits of the late transgressive systems tracts. The low stands and early parts of the transgressive systems tracts appear not to be represented in the Latrobe Valley due to its (more) basin margin location, but are probably present down-dip in the equivalent marine facies of the Seaspray Group. Stratigraphic correlation of the sequence boundaries identified in the coal measures to the adjacent, internationally dated marine Seaspray Group, provides a basis for chronostratigraphic correlation of the coal successions to the coastal onlap charts of Haq et al. (Exon Mesozoic-Cenozoic chronostratigraphic chart, version January 1988, and August 1989). From this dating it appears that each major seam is confined to high stands of third order eustatic cycles. It therefore follows that the lithotype cycles (parasequences) that comprise each seam are related to fourth order eustatic cycles. By analogy all the coal cycles may have developed under subtropical conditions as ombrogenous forested peat swamps in a similar manner to the Holocene, though tropical, swamps of Indonesia.
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the nature and evolution of Lithotypes in the tertiary brown coals of the latrobe valley southeastern australia
International Journal of Coal Geology, 1991Co-Authors: A P Kershaw, P F Bolger, Ian R K Sluiter, J G Baird, M WhitelawAbstract:Abstract Lithotype banding, identified on colour and texture of the coal, occurs in all seams covering the period Mid Eocene to Late Miocene in the Latrobe Valley. Preliminary palaeobotanical studies on both pollen and plant macrofossil components of the youngest seams indicated strong relationships between lithotype, vegetation and inferred depositional environment with the lithotype gradient from lightest to darkest coals corresponding with hydroseral stages from unvegetated open water-through swamp forest-to raised bog communities. Subsequent studies on the older seams failed to show such close correspondence between lithotype and vegetation. The analysis of palynological and petrological data from all seams in this paper adds support to the original hypothesis of lithotype formation. However, it also demonstrates a gradual differentiation of Lithotypes through the coal-forming period. This most likely involved the progressive development of vegetation communities adapted to the range of swamp environments with the peatforming environment. Of particular significance is the development of a community with a significant sclerophyll component within the predominant rainforest vegetation, which colonised the raised bogs of the youngest seams. The process may have been facilitated or accelerated by an increasingly variable climate and the increased importance of fire within the region.
N Shopova - One of the best experts on this subject based on the ideXlab platform.
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investigation of low temperature autooxidation processes in bituminous coal Lithotypes
Thermochimica Acta, 1995Co-Authors: K Markova, N Shopova, Sevdalina P ValcevaAbstract:Abstract The kinetics of autooxidation processes in sub-bituminous (vitrain and clarain) and high-bituminous (clarain) coal Lithotypes has been calculated by the method of Coats and Redfern. The differences in the E a values of the thermooxidative processes show structural changes in the investigated Lithotypes. Their macerallar compositions and the temperature affect the reactivity of the coal samples during oxidation by atmospheric oxygen. The results obtained suggest differences between the mechanism of the autooxidation processes occurring both in the homogeneous lithotype vitrain and in the heterogeneous clarain of equal coalification degrees, and between the clarain samples of various coalification degrees.
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investigation of low temperature autooxidation processes of low rank coal Lithotypes by dta and tg
Journal of Thermal Analysis and Calorimetry, 1993Co-Authors: K Markova, N ShopovaAbstract:The autooxidation processes in the temperature range 50 o -150 o C in the low rank coal Lithotypes (xylain, humovitrain, semifusain, fusain and liptain) were studied. The activation energy of the processes for the investigated temperature range was calculated by Coats and Redfern method. The established differences between the activation energies of the initial and oxidized Lithotypes are connected with the structure peculiarities of the Lithotypes, and with the varieties in the mechanism of the autooxidation processes
Maowen Li - One of the best experts on this subject based on the ideXlab platform.
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differentiation of victorian brown coal Lithotypes as revealed by thermally desorbable biomarkers
Journal of Analytical and Applied Pyrolysis, 1991Co-Authors: Maowen Li, R.b. JohnsAbstract:Abstract TD/GC/MS analyses of a profile of Victorian brown coal Lithotypes are reported. Specifically, weight loss on TD, triterpenoid and diterpenoid hydrocarbons, and trimethylnaphthalene isomers are considered as lithotype differentiators. In this initial use of biomarkers released by thermal desorption to characterise Lithotypes, evidence is reported for differences in angiosperm/gymnosperm contributions, variations in higher plant inputs and for distinct variations of bacterial biomass content of the liththotypes. Trimethylnaphthalenes also differentiate coal seams in the samples reported in this study.
