Planar Mires Research Articles

Marine influence helps preserve the oil potential of coaly source rocks: Eocene Mangahewa Formation, Taranaki Basin, New Zealand

Many Cretaceous–Cenozoic coaly source rocks in Australasian and southeast Asian basins were deposited in coastal plain environments, yet the effect of early diagenetic marine influence on their oil potential is not well understood. An integrated organic geochemical and petrographic study of humic coals from the Eocene Mangahewa Formation (Taranaki Basin, New Zealand) was undertaken with coals predominantly from raised mire petrofacies, with subordinate proportions from planar mires. The total S content of 0.63–4.4% (dry, ash-free) indicated very slight to strong degrees of marine influence. Other than minor addition of inferred mangrove derived suberinite and associated liptodetrinite, the degree of marine influence had no obvious effect on maceral or plant tissue abundance. However, hydrogen index (HI) values were up to ca. 150% (109mgHC/gTOC) higher, and total (C6+) oil potential up to ca. 140% (43mg/gTOC) higher among the more strongly marine influenced coals. Correlation of organic S with solvent extract parameters pristane/phytane, C27–C29 diasteranes/steranes, C29 steranes/hopanes, C35/(C35+C34) homohopanes and oleanane index suggested that inundation of brackish water into the early diagenetic peat forming environment enhanced the bio-resistance of higher plant and other lipids through sulfurization, thereby helping to preserve more of the inherent H content and total oil potential of the original peat biomass. Conversely, marine influence had only a minor effect on the capacity of Mangahewa coals to generate paraffinic oil. Total (n-C6+) and non-volatile (n-C15+) paraffinic oil potentials were instead controlled primarily by the abundance of leaf derived cutinite and associated liptodetrinite. This, in turn, was dependent on the type of peat mire facies, with planar mire facies having better potential for preservation of leaf litter than raised mire facies because of their generally higher groundwater level. Marine influence is nonetheless beneficial for paraffinic oil charge from coaly source rock sequences in that the associated higher HIs enhance the efficiency and quantum of paraffinic oil expulsion through increased saturation of the coal pore system.

Conifer-dominated palynofloras in the Middle Pennsylvanian strata of the De Lutte-6 borehole, The Netherlands: Implications for evolution, palaeoecology and biostratigraphy

The evolutionary history of Pennsylvanian tropical dryland/upland communities remains enigmatic. In this paper, we describe conifer-dominated palynofloras in a facies context from the early to mid-Moscovian (Middle Pennsylvanian) interval of the De Lutte-6 borehole (the Netherlands) that shed light on this issue. Our data suggest that, in the upper Bolsovian–lowermost Asturian part of the borehole succession, Florinites-producing cordaitaleans with subordinate tree-ferns, pteridosperms, calamiteans, and lycopsids, covered low-lying braidplains draining the rising Variscan Orogen, while Cordaitina/Latensina-producing cordaitaleans, walchian conifers and enigmatic pteridosperms mostly grew in hinterland regions (Assemblage I). At one relatively brief interval, a mire dominated by calamiteans and arborescent lycopsids developed within this braidplain complex (Assemblage II). In the mid-Asturian part of the borehole succession, following a switch from humid to seasonally-dry climates (indicated by paleosols), palynofloras associated with a shallow, but extensive, lake deposit imply that communities of walchian conifers, Cordaitina/Latensina-producing cordaitaleans, and engimatic pteridosperms covered low-lying drylands, but were cyclically replaced by lycopsid ‘ephemerals’ during short-term pluvial events (Assemblage III). Across tropical Pangaea, the climate-driven migration of diverse conifers from Bolsovian hinterlands to mid-Asturian basins coincides with (1) the more frequent appearance of conifer megafloral remains in the fossil record, (2) a gradual increase in the frequency of tree-ferns in clastic swamps, (3) a decline in the abundance of arborescent lycopsids in mires, and (4) a change from perhumid raised mires to humid planar mires in cratonic areas. We therefore highlight that the mid-Asturian (mid-Moscovian) interval is an under-appreciated event in the evolution of Pennsylvanian tropical vegetation, on a par with the better-known climate-driven floral changeovers that occurred in the earliest Kasimovian and Gzhelian–Asselian. Our palaeoecological findings also clarify a long-running biostratigraphic controversy by showing that conifer dominance in the De Lutte-6 borehole is completely consistent with its Bolsovian–Asturian age, and does not require the invocation of an unconformity separating an inferred Westphalian part of the succession from an inferred upper Stephanian/Permian part of the succession, as suggested by some earlier workers. This, in turn, emphases the importance of selecting isotaphonomic (isoclimatic) samples for biostratigraphic purposes.

Petrography and depositional environment of the No. 308 coal seam (Upper Silesian Coal Basin, Poland)—a new approach to maceral quantification and facies analysis

Abstract Oriented block samples of coal representing the lower layer (2.1 m) of the No. 308 coal seam were collected in the Ziemowit mine. Microscope investigations were carried out using a self-developed, fast method of maceral quantification that enables obtaining a continuous petrographical profile (“microprofile”) of a seam and computer processing of the data. The contents of macerals and maceral groups distinguished along the profile were averaged using the method of moving averages to show trends of environmental changes in a mire. The facies diagram proposed is based on an assumption that oscillations of water table in the mire affect the coal petrographical composition, while stronger water influxes into the mire increase the mineral matter content of coal. The author has identified three major types of the mire environments in which plant material was deposited during deposition of the No. 308 coal seam. These are permanently inundated = planar mire (PM) with two sub-environments—PM “margin” and PM “central”; temporarily inundated = transitional mire (TM) with two sub-environments—TM “wet” and TM “dry”; and elevated = domed mire (DM) with two sub-environments—DM “progressive” and DM “regressive”.

06/00004 Petrology of subbituminous feed coal as a guide to the capture of mercury by fly ash-influence of depositional environment: Goodarzi, F. International Journal of Coal Geology, 2005, 61, (1–2), 1–12

Stratigraphy, palynology, petrography, and geochemistry of the Bon Air coal from the Armfield, Dotson, Rutledge, and Shakerag mine sites of Franklin County, Tennessee suggest that Bon Air seams at all sites were small (≤ 1.0 mile, 1.6 km), spatially distinct paleomires that evolved from planar to domed within the fluviodeltaic Lower Pennsylvanian Raccoon Mountain Formation. Of observed palynoflora, 88–97% are from lycopsids prevalent in the Westphalian. Densosporites palynomorphs of small lycopsids (e.g., Omphalophloios) dominate at the shale-hosted Armfield site, while Lycospora palynoflora of large arboreous lycopsids (especially Lepidodendron, with lesser Lepidophloios harcourtii and Lepidophloios hallii) dominate where intercalated siltstone/sandstone/shale hosts the coal (all other sites). Palynoflora of other lycopsids (Sigillaria and Paralycopodites), tree ferns, seed ferns, small ferns, calamites, and cordaites are generally minor. Genera of clastic-associated Paralycopodites are most common in Shakerag's coal (≥ 10%), yet quite rare in Rutledge or Dotson coals. Overall, the palynomorph assemblages suggest that the Bon Air paleomires were forest swamps, and Early Pennsylvanian in age (Westphalian A, Langsettian).Dominant macerals at all sites are vitrinites, with fine collodetrinite (from strongly decomposed plant debris) more common than coarser collotelinite (from well-preserved plant fragments), and with lesser inertinites (fusinite and semifusinite) and liptinites (dominantly sporinite). Shakerag's coal has greatest abundance (mineral-matter-free) of collotelinite (up to 47%) and total vitrinite (74–79%) of any sites, but lowest liptinite (12–14.5%) and inertinite (7–11%). The Dotson and Rutledge seams contain moderate liptinite (21–23%) and highest inertinite (36–37%), lowest vitrinite (≤ 41%), and lowest collotelinite (13–15%). Armfield's seam has relatively high liptinite (26–28%) and vitrinite (56.5–62%), but rather low inertinite (12–15%). Moderately high ash (11.0–20.0%) and low to moderate sulfur (1.24% avg.) are typical, but ash may locally be up to 38% and sulfur up to 2.9%. Volatile matter (32.1–41.3%), calorific value (33.3–34.9 MJ/kg MAF), moisture (2.2–3.4%), and vitrinite reflectance (0.70–0.84% Rmax; 0.64–0.79% Rrandom) place the Bon Air's rank as high-volatile-A bituminous (hvAb).The Armfield coal was probably a channel-distal paleomire, perhaps an oxbow lake or floodplain depression, which domed and then subsided back to planarity prior to burial. Features of its basal and uppermost benches suggest low-lying, often-flooded (but periodically dry) mires marked by fluvial influxes and diverse lycopsid growth. These include variable inertinite, common palynoflora of both small lycopsids (Omphalophloios-like) and large arboreous ones (Lepidophloios and Lepidodendron), minor but significant palynoflora of subaerial levee or levee/mire transition species (especially Paralycopodites), moderate to high ash, variable sulfur, and elevated levels of commonly fluvial trace elements (e.g., Al, Cr, REEs, Rb, Sr, Th, V, Y, and Zr). These benches also contain high total vitrinite, high collotelinite/collodetrinite ratios, and clays with moderate to low kaolinite/quartz ratios, all consistent with the near-neutral pH and limited peat degradation that typify such planar mires. By contrast, middle benches at Armfield reflect mires domed above the land surface, less-often flooded, less-preservational, and of lower pH: coals have lower ash, vitrinite, and collotelinite, less palynoflora of both large arboreous lycopsids and Paralycopodites, and high proportions of kaolinite, liptinite, and Densosporites.Similar data at Shakerag suggest that its mire also grew from planar to domed. However, more abundant Paralycopodites, a kaolinite-poor but quartz-and-illite-rich underclay, benches alternately ash-rich and ash-poor, and an upper bench truncated by channel sandstone, suggest that it was channel-proximal and prone to intermittent clastics. It is unclear if it returned to planarity prior to burial. The mires at Dotson and (especially) Rutledge, with more ferns, more inertinite, less Paralycopodites and less vitrinite, were probably topographically elevated or protractedly domed mires, more vulnerable to drought or fire.

Petrography, palynology, and paleoecology of the Lower Pennsylvanian Bon Air coal, Franklin County, Cumberland Plateau, southeast Tennessee

Abstract Stratigraphy, palynology, petrography, and geochemistry of the Bon Air coal from the Armfield, Dotson, Rutledge, and Shakerag mine sites of Franklin County, Tennessee suggest that Bon Air seams at all sites were small (≤ 1.0 mile, 1.6 km), spatially distinct paleomires that evolved from planar to domed within the fluviodeltaic Lower Pennsylvanian Raccoon Mountain Formation. Of observed palynoflora, 88–97% are from lycopsids prevalent in the Westphalian. Densosporites palynomorphs of small lycopsids (e.g., Omphalophloios) dominate at the shale-hosted Armfield site, while Lycospora palynoflora of large arboreous lycopsids (especially Lepidodendron, with lesser Lepidophloios harcourtii and Lepidophloios hallii) dominate where intercalated siltstone/sandstone/shale hosts the coal (all other sites). Palynoflora of other lycopsids (Sigillaria and Paralycopodites), tree ferns, seed ferns, small ferns, calamites, and cordaites are generally minor. Genera of clastic-associated Paralycopodites are most common in Shakerag's coal (≥ 10%), yet quite rare in Rutledge or Dotson coals. Overall, the palynomorph assemblages suggest that the Bon Air paleomires were forest swamps, and Early Pennsylvanian in age (Westphalian A, Langsettian). Dominant macerals at all sites are vitrinites, with fine collodetrinite (from strongly decomposed plant debris) more common than coarser collotelinite (from well-preserved plant fragments), and with lesser inertinites (fusinite and semifusinite) and liptinites (dominantly sporinite). Shakerag's coal has greatest abundance (mineral-matter-free) of collotelinite (up to 47%) and total vitrinite (74–79%) of any sites, but lowest liptinite (12–14.5%) and inertinite (7–11%). The Dotson and Rutledge seams contain moderate liptinite (21–23%) and highest inertinite (36–37%), lowest vitrinite (≤ 41%), and lowest collotelinite (13–15%). Armfield's seam has relatively high liptinite (26–28%) and vitrinite (56.5–62%), but rather low inertinite (12–15%). Moderately high ash (11.0–20.0%) and low to moderate sulfur (1.24% avg.) are typical, but ash may locally be up to 38% and sulfur up to 2.9%. Volatile matter (32.1–41.3%), calorific value (33.3–34.9 MJ/kg MAF), moisture (2.2–3.4%), and vitrinite reflectance (0.70–0.84% Rmax; 0.64–0.79% Rrandom) place the Bon Air's rank as high-volatile-A bituminous (hvAb). The Armfield coal was probably a channel-distal paleomire, perhaps an oxbow lake or floodplain depression, which domed and then subsided back to planarity prior to burial. Features of its basal and uppermost benches suggest low-lying, often-flooded (but periodically dry) mires marked by fluvial influxes and diverse lycopsid growth. These include variable inertinite, common palynoflora of both small lycopsids (Omphalophloios-like) and large arboreous ones (Lepidophloios and Lepidodendron), minor but significant palynoflora of subaerial levee or levee/mire transition species (especially Paralycopodites), moderate to high ash, variable sulfur, and elevated levels of commonly fluvial trace elements (e.g., Al, Cr, REEs, Rb, Sr, Th, V, Y, and Zr). These benches also contain high total vitrinite, high collotelinite/collodetrinite ratios, and clays with moderate to low kaolinite/quartz ratios, all consistent with the near-neutral pH and limited peat degradation that typify such planar mires. By contrast, middle benches at Armfield reflect mires domed above the land surface, less-often flooded, less-preservational, and of lower pH: coals have lower ash, vitrinite, and collotelinite, less palynoflora of both large arboreous lycopsids and Paralycopodites, and high proportions of kaolinite, liptinite, and Densosporites. Similar data at Shakerag suggest that its mire also grew from planar to domed. However, more abundant Paralycopodites, a kaolinite-poor but quartz-and-illite-rich underclay, benches alternately ash-rich and ash-poor, and an upper bench truncated by channel sandstone, suggest that it was channel-proximal and prone to intermittent clastics. It is unclear if it returned to planarity prior to burial. The mires at Dotson and (especially) Rutledge, with more ferns, more inertinite, less Paralycopodites and less vitrinite, were probably topographically elevated or protractedly domed mires, more vulnerable to drought or fire.

Peat biomass and early diagenetic controls on the paraffinic oil potential of humic coals, Canterbury Basin, New Zealand

Early mature, Pukeiwitahi Formation (Late Cretaceous) coals from Galleon-1 and Endeavour-1 wells in the Canterbury Basin, New Zealand have been analysed by petrographic, bulk chemical and thermal extraction- and pyrolysis-GC techniques and compared with similar coals in the Taranaki Basin to determine the primary controls on their paraffinic oil potential. The Pukeiwitahi coals, which are moderately perhydrous (HI 180–305 mgHC g −1 TOC), vitrinite-rich (73–95%) and relatively liptinite-poor (<10%), accumulated in gymnosperm-dominated, planar mires in a temperate, coastal plain environment. Pyrolysate compositions are representative of high-wax, paraffinic–naphthenic–aromatic crude oil-generating coals. Petrographic data and the n -alkyl chain length distributions of extracts and pyrolysates suggest that the long-chain aliphatic hydrocarbons are derived primarily from leaf-derived liptinites (cutinite and liptodetrinite). The paraffinic oil potential of the coals is accordingly dependent on the net amount of leaf biomass in the precursor peats, following partial degradation of the available leaf litter under generally high surface water levels and dilution with other, less paraffinic biomass, particularly wood. The coals in Endeavour-1 generally contain more leaf-derived liptinites than those in Galleon-1 and, thus, have greater paraffinic oil potentials despite commonly lower HI values. Brackish conditions within the depositional environment caused the Galleon-1 and Endeavour-1 coals to be variably enriched in hydrogen but not in aliphatics. HI is, therefore, not a reliable indicator of the paraffinic oil potential of marine-influenced coals.

Palaeoecological constraints of some Lepidostrobus cones and their parent plants from the Late Palaeozoic continental basins of the Czech Republic

About 60 strobilar specimens of six Lepidostrobus species ( Lepidostrobus sternbergii, Lepidostrobus nemejcii sp. nov., Lepidostrobus thomasii sp. nov., Lepidostrobus obovatus, Lepidostrobus ronnaensis sp. nov. and Lepidostrobus stephanicus) and their microspores from the Bohemian Late Palaeozoic continental basins were studied. The stratigraphical range of cones is from the Langsettian to the Stephanian B. Microspores isolated from six species of Lepidostrobus cones belong to six dispersed spore species of the genus Lycospora. Lepidostrobus crassus was synonymised with L. sternbergii based on identical spore content and closely similar morphology of the type specimens of both species. Lepidostrobus nemejcii, L. thomasii and L. ronnaensis have been erected as new species according to the cone morphology, spore content and parent plant. Ecological constraints of all the species are discussed. Two groups of species preferring different habitats were distinguished. The first group consists of species that preferred clastic to mixed peat/clastic substrates and high water table. Their parent plants grew either in clastic swamps along the lake margins and shallows or in planar mires frequently disturbed by clastic input during floodings. This group involves most of the studied species and their parent plants. Differences between habitats of the species of this group are indicated but their precise specifications needs further investigation. The second group involves only L. ronnaensis and its parent plant Lepidodendron ophiurus ( sensu Němejc). It preferred peat substrate of planar eutrophic mires with only minor clastic disturbances. The palynological comparison with in situ lycospores from compressed and petrified Lepidostrobus cones is made.

Palynology, petrography and geochemistry of the Sewickley coal bed (Monongahela Group, Late Pennsylvanian), Northern Appalachian Basin, USA

Forty-two bench samples of the Sewickley coal bed were collected from seven localities in the northern Appalachian Basin and analyzed palynologically, petrographically, and geochemically. The Sewickley coal bed occurs in the middle of the Pittsburgh Formation (Monongahela Group) and is of Late Pennsylvanian age. Palynologically, it is dominated by spores of tree ferns. Tree fern spore taxa in the Sewickley include Punctatisporites minutus, Punctatosporites minutus, Laevigatosporites minimus, Spinosporites exiguus, Apiculatasporites saetiger, and Thymospora spp. In fact, Punctatisporites minutus was so abundant that it had to be removed from the standard counts and recorded separately (average 73.2%). Even when Punctatisporites minutus is removed from the counts, tree fern spores still dominate a majority of the assemblages, averaging 64.4%. Among the tree fern spores identified in the Sewickley coal, Thymospora exhibits temporal and spatial abundance variation. Thymospora usually increases in abundance from the base to the top of the bed. Thymospora is also more abundant in columns that are thick (>100 cm) and low in ash yield (<12.0%, dry basis). Calamite spores (e.g. Calamospora spp., Laevigatosporites minor, and L. vulgaris) are the next most abundant plant group represented in the Sewickley coal, averaging 20%. Contributions from all other plant groups are minor in comparison. Petrographically, the Sewickley coal contains high percentages of vitrinite (average 82.3%, mineral matter-free (mmf)), with structured forms being more common than unstructured forms. In contrast, liptinite and inertinite macerals both occur in low percentages (average 7.7% and 10.0%, respectively). Geochemically, the Sewickley coal has a moderate ash yield (average 12.4%) and high total sulfur content (average 3.4%). Four localities contained a high ash or carbonaceous shale bench. These benches, which may be coeval, are strongly dominated by tree fern spores. Unlike the lower ash benches, they contain low percentages of vitrinite, which mainly occurs as unstructured vitrinite, and higher liptinite and inertinite contents. The accumulated data suggest that the Sewickley paleomire was probably a rheotrophic, planar mire that had a consistent water cover. This is supported by the high vitrinite contents, moderate ash yields, and high total sulfur contents. The high ash and carbonaceous shale benches probably represent either periods of dryness and substrate exposure, or flooding of the mire surface, the duration of which is unknown.

Marine flooding events and coal bed sequence architecture in southern West Virginia

Eight regional Lower to Middle Pennsylvanian coal beds (Namurian B/C to Westphalian C) in southern West Virginia were examined. Beds were divided into their component sedimentary parts or benches by identifying bounding surfaces and associated siliciclastic partings within beds. Bounding surfaces represent the cessation of peat accumulation. Paleo-peat mire morphology at the bench level was determined using shape analysis, petrographic indices and coal chemistry data. Planar and raised paleo-peat mire benches were identified. All gas coal and some splint coal benches were derived from raised mires. Heterolithic coal and the remaining splint coal benches were derived from planar mires. Most bounding surfaces are thin, composed of oxidized and degraded organic materials, high in ash and sulfur content, and contain clay minerals and silt-sized quartz. Vitrinite reflectance is suppressed in the upper part of some benches. The associated siliciclastic parting materials, when thick, show evidence of tidal influence and contain brackish water to marine trace fossil assemblages. Bounding surfaces and the associated sediments represent a sudden increase in water depth and the lateral continuity of these surfaces indicates regional to basinal extent. Bounding surfaces are the up-paleoslope expression of rapid (<1-ka duration) marine flooding events. A repeating sequence was identified within six of the eight thick, regional coal beds examined. It consists in its simplest expression of (1) planar mire formation, initially occurring on interfluvial sequence boundaries, (2) probable evolution of the planar mire into a raised mire, (3) marine flooding event and bounding surface formation, (4) planar mire reestablishment, and (5) bed termination. The hiatus between the interfluvial sequence boundary and overlying coal bed, based on comparisons with modern analogues, may represent more than 100 ka of missing time. Peat accumulation and basin subsidence estimates suggest that an additional 100 ka or more may have been involved in the formation of a single coal bed sequence. The geographic extent of these sequences and the fact that they repeat indicates that an allocyclic mechanism (climate and/or glacioeustacy) was responsible for their development.

Metalliferous coals of the Westphalian A Joggins Formation, Cumberland Basin, Nova Scotia, Canada: petrology, geochemistry, and palynology

Five coals of Westphalian A (early Middle Pennsylvanian) age were sampled from the Joggins Formation section exposed along Chignecto Bay at Joggins, Nova Scotia. Coal beds along the bay were mined beginning in the early 17th century, yet there have been few detailed published investigation of the coal beds of this classic section. The lowermost coal, the Upper Coal 28 (Upper Fundy), is a high-vitrinite coal with a spore assemblage dominated by arboreous lycopsid spores with tree ferns subdominant. The upper portions of the coal bed have the highest ratio of well-preserved to poorly-preserved telinite of any of the coals investigated. Coal 19 (“clam coal”) has 88% total vitrinite but, unlike the Fundy coal bed, the telinite has a poor preservation ratio and half the total vitrinite population comprises gelocollinite and vitrodetrinite. The latter coal bed is directly overlain by a basin-wide limestone bed. The Lower Kimberly coal shows good preservation of vitrinite with relatively abundant telinite among the total vitrinite. The Middle Kimberly coal, which underlies the tetrapod-bearing lycopsid trees found by Lyell and Dawson in 1852, exhibits an upward decrease in arboreous lycopod spores and an upward increase in the tree fern spore Punctatisporites minutus. Telinite preservation increases upwards in the Middle Kimberly but overall is well below the preservation ratio of the Upper Fundy coal bed. The coals all have high sulfur contents, yielding up to 13.7% total sulfur for the lower lithotype of the Upper Fundy coal bed. The Kimberly coals are not only high in total and pyritic sulfur, but also have high concentrations of chalcophile elements. Zinc, ranging up to 15,000 ppm (ash basis), is present as sphalerite in fusain lumens. Arsenic and lead each exceed 6000 ppm (ash basis) in separate lithotypes of the Kimberly coals. Together these data are consistent with elevated pH in planar mires. The source of the elemental enrichment in this presumed continental section is enigmatic.

Depositional history of the Fire Clay coal bed (Late Duckmantian), Eastern Kentucky, USA

More than 3800 coal thickness measurements, proximate analyses from 97 localities, and stratigraphic and sedimentological analyses from more than 300 outcrops and cores were used in conjunction with previously reported palynological and petrographic studies to map individual benches of the coal and document bench-scale variability in the Fire Clay (Hazard No. 4) coal bed across a 1860 km 2 area of the Eastern Kentucky Coal Field. The bench architecture of the Fire Clay coal bed consists of uncommon leader benches, a persistent but variable lower bench, a widespread, and generally thick upper bench, and local, variable rider benches. Rheotrophic conditions are inferred for the leader benches and lower bench based on sedimentological associations, mixed palynomorph assemblages, locally common cannel coal layers, and generally high ash yields. The lower bench consistently exhibits vertical variability in petrography and palynology that reflects changing trophic conditions as topographic depressions infilled. Infilling also led to unconfined flooding and ultimately the drowning of the lower bench mire. The drowned mire was covered by an air-fall volcanic-ash deposit, which produced the characteristic flint clay parting. The extent and uniform thickness of the parting suggests that the ash layer was deposited in water on a relatively flat surface without a thick canopy or extensive standing vegetation across most of the study area. Ash deposits led to regional ponding and establishment of a second planar mire. Because the topography had become a broadly uniform, nutrient-rich surface, upper-bench peats became widespread with large areas of the mire distant to clastic sources. Vertical sections of thick (>70 cm), low-ash yield, upper coal bench show a common palynomorph change from arborescent lycopod dominance upward to fern and densospore-producing, small lycopod dominance, inferred as a shift from planar to ombrotrophic mire phases. Domed mires appear to have been surrounded by wide areas of planar mires, where the coal was thinner (<70 cm), higher in ash yield, and dominated by arborescent lycopods. Rectangular thickness trends suggest that syndepositional faulting influenced peat accumulation, and possibly the position of the domed mire phase. Faulting also influenced post-depositional clastic environments of deposition, resulting in sandstone channels with angular changes in orientation. Channnels and lateral facies were locally draped by high-ash-yield rider coal benches, which sometimes merged with the upper coal bench. These arborescent-lycopod dominant rider coal benches were profoundly controlled by paleotopography, much like the leader coal benches. Each of the benches of coal documented here represent distinctly different mires that came together to form the Fire Clay coal bed, rather than a single mire periodically split by clastic influx. This is significant as each bench of the coal has its own characteristics, which contribute to the total coal characteristics. The large data set allows interpretation of both vertical and lateral limits to postulated domed phases in the upper coal bench, and to the delineation of subtle tectonic structures that allow for meaningful thickness projections beyond the limits of present mining.

99/00758 Methodology development to determine fine particle characteristics of coal combustion emissions

The Middle Pennsylvanian (Westphalian D) Stockton (also known as the Broas) coal bed of the Breathitt Formation is an important energy resource in Kentucky. Petrographic, geochemical and palynologic studies were undertaken from mine, core and highway exposures in Martin and northern Pike counies, Kentucky, in order to determine the influence of the Stockton depositional ecosystem on those parameters.Vitrinite-rich Stockton lithotypes are dominated by Lycospora. Dull lithotypes, including both high- and low-ash yield durains, generally have abundant Densosporites, suggesting that the parent plant inhabited a fairly wide range of environments. Lithologies having tree ferns as an important component also have high fusinite + semifusinite and a low telinite/gelocollinite ratio. The aerial root bundles of the tree ferns were susceptible to oxidation and, for tissue not oxidized to inertinite, to preservation as gelocollinite.In the initial stages of formation, the Stockton mire was discontinuous and had a rather restricted floral assemblage. The presence of durains higher in the Stockton section, particularly the low-ash yield durains having petrographic indicators of degradation, suggests that portions of the mire developed as a domed peat. The termination of the mire as a high-sulfur, arboreous lycopod-domimated mire is consistent with the return to more planar mire development.

97/02490 The changing particle size distribution in micronized coal and micronized coal water mixture flames: Its influence on heat transfer

Stratigraphy, palynology, petrography, and geochemistry of the Bon Air coal from the Armfield, Dotson, Rutledge, and Shakerag mine sites of Franklin County, Tennessee suggest that Bon Air seams at all sites were small (≤ 1.0 mile, 1.6 km), spatially distinct paleomires that evolved from planar to domed within the fluviodeltaic Lower Pennsylvanian Raccoon Mountain Formation. Of observed palynoflora, 88–97% are from lycopsids prevalent in the Westphalian. Densosporites palynomorphs of small lycopsids (e.g., Omphalophloios) dominate at the shale-hosted Armfield site, while Lycospora palynoflora of large arboreous lycopsids (especially Lepidodendron, with lesser Lepidophloios harcourtii and Lepidophloios hallii) dominate where intercalated siltstone/sandstone/shale hosts the coal (all other sites). Palynoflora of other lycopsids (Sigillaria and Paralycopodites), tree ferns, seed ferns, small ferns, calamites, and cordaites are generally minor. Genera of clastic-associated Paralycopodites are most common in Shakerag's coal (≥ 10%), yet quite rare in Rutledge or Dotson coals. Overall, the palynomorph assemblages suggest that the Bon Air paleomires were forest swamps, and Early Pennsylvanian in age (Westphalian A, Langsettian).Dominant macerals at all sites are vitrinites, with fine collodetrinite (from strongly decomposed plant debris) more common than coarser collotelinite (from well-preserved plant fragments), and with lesser inertinites (fusinite and semifusinite) and liptinites (dominantly sporinite). Shakerag's coal has greatest abundance (mineral-matter-free) of collotelinite (up to 47%) and total vitrinite (74–79%) of any sites, but lowest liptinite (12–14.5%) and inertinite (7–11%). The Dotson and Rutledge seams contain moderate liptinite (21–23%) and highest inertinite (36–37%), lowest vitrinite (≤ 41%), and lowest collotelinite (13–15%). Armfield's seam has relatively high liptinite (26–28%) and vitrinite (56.5–62%), but rather low inertinite (12–15%). Moderately high ash (11.0–20.0%) and low to moderate sulfur (1.24% avg.) are typical, but ash may locally be up to 38% and sulfur up to 2.9%. Volatile matter (32.1–41.3%), calorific value (33.3–34.9 MJ/kg MAF), moisture (2.2–3.4%), and vitrinite reflectance (0.70–0.84% Rmax; 0.64–0.79% Rrandom) place the Bon Air's rank as high-volatile-A bituminous (hvAb).The Armfield coal was probably a channel-distal paleomire, perhaps an oxbow lake or floodplain depression, which domed and then subsided back to planarity prior to burial. Features of its basal and uppermost benches suggest low-lying, often-flooded (but periodically dry) mires marked by fluvial influxes and diverse lycopsid growth. These include variable inertinite, common palynoflora of both small lycopsids (Omphalophloios-like) and large arboreous ones (Lepidophloios and Lepidodendron), minor but significant palynoflora of subaerial levee or levee/mire transition species (especially Paralycopodites), moderate to high ash, variable sulfur, and elevated levels of commonly fluvial trace elements (e.g., Al, Cr, REEs, Rb, Sr, Th, V, Y, and Zr). These benches also contain high total vitrinite, high collotelinite/collodetrinite ratios, and clays with moderate to low kaolinite/quartz ratios, all consistent with the near-neutral pH and limited peat degradation that typify such planar mires. By contrast, middle benches at Armfield reflect mires domed above the land surface, less-often flooded, less-preservational, and of lower pH: coals have lower ash, vitrinite, and collotelinite, less palynoflora of both large arboreous lycopsids and Paralycopodites, and high proportions of kaolinite, liptinite, and Densosporites.Similar data at Shakerag suggest that its mire also grew from planar to domed. However, more abundant Paralycopodites, a kaolinite-poor but quartz-and-illite-rich underclay, benches alternately ash-rich and ash-poor, and an upper bench truncated by channel sandstone, suggest that it was channel-proximal and prone to intermittent clastics. It is unclear if it returned to planarity prior to burial. The mires at Dotson and (especially) Rutledge, with more ferns, more inertinite, less Paralycopodites and less vitrinite, were probably topographically elevated or protractedly domed mires, more vulnerable to drought or fire.

Petrography, geochemistry and palynology of the Stockton coal bed (Middle Pennsylvanian), Martin County, Kentucky

The Middle Pennsylvanian (Westphalian D) Stockton (also known as the Broas) coal bed of the Breathitt Formation is an important energy resource in Kentucky. Petrographic, geochemical and palynologic studies were undertaken from mine, core and highway exposures in Martin and northern Pike counies, Kentucky, in order to determine the influence of the Stockton depositional ecosystem on those parameters. Vitrinite-rich Stockton lithotypes are dominated by Lycospora. Dull lithotypes, including both high- and low-ash yield durains, generally have abundant Densosporites, suggesting that the parent plant inhabited a fairly wide range of environments. Lithologies having tree ferns as an important component also have high fusinite + semifusinite and a low telinite/gelocollinite ratio. The aerial root bundles of the tree ferns were susceptible to oxidation and, for tissue not oxidized to inertinite, to preservation as gelocollinite. In the initial stages of formation, the Stockton mire was discontinuous and had a rather restricted floral assemblage. The presence of durains higher in the Stockton section, particularly the low-ash yield durains having petrographic indicators of degradation, suggests that portions of the mire developed as a domed peat. The termination of the mire as a high-sulfur, arboreous lycopod-domimated mire is consistent with the return to more planar mire development.

Coal-Bench Architecture as a Means of Understanding Regional Changes in Coal Thickness and Quality: ABSTRACT

Analysis of the Fire Creek (Westphalian B), Pond Creek (lower Westphalian B), and Stockton (Westphalian B) coals, three of the most heavily mined coals in the Central Appalachian Basin, shows that all have a similar multiple-bench architecture of at least two benches split by a regional clastic parting or durain. Coal benches beneath regionally extensive partings are generally less continuous, thinner, more palynologically variable, higher in ash yield, and higher in sulfur content than coal benches above regional partings in all three coals. Where thick, benches above regional partings tend to exhibit temporal palynological changes from lycopod- to fern-dominant. Where inertinite-rich/fern-dominant benches are overlain by additional benches, the upper benches are limited in extent, variable in thickness, high in sulfur content and ash yield, and split away from the coal. The multiple-bench architecture exhibited by these coals is interpreted to represent a cyclic mire succession that was common in the Middle Pennsylvanian. Peats began as planar mires infilling an irregular topography during rising base level. When the topography was infilled, unconfined flooding was possible and resulted in widespread partings. Ponding above these clay-rich flood deposits led to re-establishment of new planar mires with greater continuity than the underlying mires. Themore » extent of these mires provided buffers to clastic influx and, in many cases, allowed domed conditions to develop. Doming resulted in thick, high-quality coal benches. In some cases, a third stage of planar peats, with similar characteristics to the planar peats at the base of the beds, developed on the unevenly distributed clastics that buried underlying mires during continued base-level rise.« less

Mining Conditions and Deposition in the Amburgy (Westphalian B) Coal, Breathitt Group, Central Appalachian Basin: ABSTRACT

Carbonate concretions called clay balls are rare in the Central Appalachian Basin, but were found in the Amburgy coal overlain by the Kendrick Shale Member. In the study area, the Amburgy coal is 0.7 to 0.9 meters thick, moderate to high in sulfur content, moderate to high in ash yield, and mostly bright clarain, except at the top near the area of coal balls, where durain of limited extent occurs. The coal is co-dominated by lycopod and cordaites; tree spores, with subordinate Calamites. The local durain layer is dominated by Densosporites, produced by the shrubby lycopod Ompbalophloios. Coal balls were encountered where the durain is immediately overlain by a coquinoid hash of broken and whole marine fossils, along a trend of coal thinning. The coal balls contain permineralized cordaites, lycopods, calamites, and ferns. The Amburgy coal accumulated as a succession of planar mires. Local splits in the seam are common, indicating contemporaneous clastic influx. The abundance of Cordaites may indicate brackish mire waters related to a coastal position and initial eustatic rise of the marginal Kendrick seas. Near the end of the Amburgy mires, the high ash-Omphalopbloios association is interpreted as a local area that was being drowned by themore » Kendrick transgression. Ravinement within this local embayment, rapid inundation by marine waters, and concentration of carbonate-bearing waters within transgressive scours may have contributed to the formation of coal balls and pyritic concretions in the upper part of the coal bed.« less

95/05599 Quality variations in the high-sulfur lignite of the Neogene Beypazari Basin, Central Anatolla, Turkey

Stratigraphy, palynology, petrography, and geochemistry of the Bon Air coal from the Armfield, Dotson, Rutledge, and Shakerag mine sites of Franklin County, Tennessee suggest that Bon Air seams at all sites were small (≤ 1.0 mile, 1.6 km), spatially distinct paleomires that evolved from planar to domed within the fluviodeltaic Lower Pennsylvanian Raccoon Mountain Formation. Of observed palynoflora, 88–97% are from lycopsids prevalent in the Westphalian. Densosporites palynomorphs of small lycopsids (e.g., Omphalophloios) dominate at the shale-hosted Armfield site, while Lycospora palynoflora of large arboreous lycopsids (especially Lepidodendron, with lesser Lepidophloios harcourtii and Lepidophloios hallii) dominate where intercalated siltstone/sandstone/shale hosts the coal (all other sites). Palynoflora of other lycopsids (Sigillaria and Paralycopodites), tree ferns, seed ferns, small ferns, calamites, and cordaites are generally minor. Genera of clastic-associated Paralycopodites are most common in Shakerag's coal (≥ 10%), yet quite rare in Rutledge or Dotson coals. Overall, the palynomorph assemblages suggest that the Bon Air paleomires were forest swamps, and Early Pennsylvanian in age (Westphalian A, Langsettian).Dominant macerals at all sites are vitrinites, with fine collodetrinite (from strongly decomposed plant debris) more common than coarser collotelinite (from well-preserved plant fragments), and with lesser inertinites (fusinite and semifusinite) and liptinites (dominantly sporinite). Shakerag's coal has greatest abundance (mineral-matter-free) of collotelinite (up to 47%) and total vitrinite (74–79%) of any sites, but lowest liptinite (12–14.5%) and inertinite (7–11%). The Dotson and Rutledge seams contain moderate liptinite (21–23%) and highest inertinite (36–37%), lowest vitrinite (≤ 41%), and lowest collotelinite (13–15%). Armfield's seam has relatively high liptinite (26–28%) and vitrinite (56.5–62%), but rather low inertinite (12–15%). Moderately high ash (11.0–20.0%) and low to moderate sulfur (1.24% avg.) are typical, but ash may locally be up to 38% and sulfur up to 2.9%. Volatile matter (32.1–41.3%), calorific value (33.3–34.9 MJ/kg MAF), moisture (2.2–3.4%), and vitrinite reflectance (0.70–0.84% Rmax; 0.64–0.79% Rrandom) place the Bon Air's rank as high-volatile-A bituminous (hvAb).The Armfield coal was probably a channel-distal paleomire, perhaps an oxbow lake or floodplain depression, which domed and then subsided back to planarity prior to burial. Features of its basal and uppermost benches suggest low-lying, often-flooded (but periodically dry) mires marked by fluvial influxes and diverse lycopsid growth. These include variable inertinite, common palynoflora of both small lycopsids (Omphalophloios-like) and large arboreous ones (Lepidophloios and Lepidodendron), minor but significant palynoflora of subaerial levee or levee/mire transition species (especially Paralycopodites), moderate to high ash, variable sulfur, and elevated levels of commonly fluvial trace elements (e.g., Al, Cr, REEs, Rb, Sr, Th, V, Y, and Zr). These benches also contain high total vitrinite, high collotelinite/collodetrinite ratios, and clays with moderate to low kaolinite/quartz ratios, all consistent with the near-neutral pH and limited peat degradation that typify such planar mires. By contrast, middle benches at Armfield reflect mires domed above the land surface, less-often flooded, less-preservational, and of lower pH: coals have lower ash, vitrinite, and collotelinite, less palynoflora of both large arboreous lycopsids and Paralycopodites, and high proportions of kaolinite, liptinite, and Densosporites.Similar data at Shakerag suggest that its mire also grew from planar to domed. However, more abundant Paralycopodites, a kaolinite-poor but quartz-and-illite-rich underclay, benches alternately ash-rich and ash-poor, and an upper bench truncated by channel sandstone, suggest that it was channel-proximal and prone to intermittent clastics. It is unclear if it returned to planarity prior to burial. The mires at Dotson and (especially) Rutledge, with more ferns, more inertinite, less Paralycopodites and less vitrinite, were probably topographically elevated or protractedly domed mires, more vulnerable to drought or fire.

Facies development in the Lower Freeport coal bed, west-central Pennsylvania, U.S.A.

The Lower Freeport coal bed in west-central Pennsylvania is interpreted to have formed within a lacustrine-mire environment. Conditions of peat formation, caused by the changing chemical and physical environments, produced five coal facies and two mineral-rich parting facies within the coal bed. The coal bed facies are compositionally unique, having developed under varying conditions, and are manifested by megascopic, petrographic, palynologic and quality characteristics. The initial environment of the Lower Freeport peat resulted in a coal facies that is relatively high in ash yield and contains large amounts of lycopod miospores and moderate abundances of cryptotelinite, crypto-gelocollinite, inertinite and tree fern miospores. This initial Lower Freeport peat is interpreted to have been a topogenous body that was low lying, relatively nutrient rich (mesotrophic to eutrophic), and susceptible to ground water and to sediment influx from surface water. The next facies to form was a ubiquitous, clay-rich durain parting which is attributed to a general rise in the water table accompanied by widespread flooding. Following formation of the parting, peat accumulation resumed within an environment that inhibited clastic input. Development of doming in this facies restricted deposition of the upper shale parting to the margins of the mire and allowed low-ash peat to form in the interior of the mire. Because this environment was conducive to preservation of cellular tissue, this coal facies also contains large amounts of crypto-telinite. This facies development is interpreted to have been a transitional phase from topogenous, planar peat formation to slightly domed, oligotrophic (nutrient-poor) peat formation. As domed peat formation continued, fluctuations in the water table enabled oxidation of the peat surface and produced high inertinite concentrations toward the top of the coal bed. Tree ferns became an increasingly important peat contributor in the e upper facies, based on the palynoflora. This floral change is interpreted to have resulted from the peat surface becoming less wet or better drained, a condition that inhibited proliferation of lycopod trees. Accumulation of the peat continued until rising water levels formed a freshwater lake within which clays and silts were deposited. The development of the Lower Freeport peat from a planar mire through transitional phases toward domed peat formation may be an example of the type of peat formation of other upper Middle and Upper Pennsylvanian coal beds.