The basis of modern fresh-water peatland (mire) classification, namely ground-water influence and source of ionic input, has been adopted in this study for ancient mire analysis. Trends that result from a modern mire’s evolution from a rheotrophic (ground-water influenced) planar to ombrotrophic (solely rain-fed), raised status, under decreasing influence of ground water, include decreasing pH levels, nutrient/ionic supply, ash content, species diversity, and ratio of arboreous to herbaceous vegetation. These attributes are inferred to give rise to the following upward trends within a coal seam: enhanced preservation and reduced biochemical geliflcation within similar tissues; decreasing abundance of liptinite macerals of aquatic affinity, sulfur (especially pyritic) content, and waterborne ash; and decreasing floral diversity. Reversals in these trends may signal change in the trophic status of the ancestral mire (e.g., deflation). The identification of such trends relies heavily upon the description of vitrinite in terms of relative geliflcation. The significance of Eh and the historical use of inertinite in paleomire analysis is questioned. The ancestral mire of the Westphalian B No. 3 seam of the Springhill coalfield, Cumberland Basin, Nova Scotia, formed between a piedmont of coalesced, retreating alluvial fans and the medial reaches of a basin-axis channel belt. The lithologically distinct piedmont, inner mire, and riverine zones of the seam reflect this geomorphic setting. Modeling of a maceral-based index of ground-water influence (strongly gelified tissues and mineral matter versus well preserved tissues) led to the deduction that the paleomire originated as a rheotrophic, and presumably planar, ecosystem that evolved progressively toward a less ground-water-influenced (mesotrophic) state, and possibly to an ombrotrophic, weakly domed system within the inner mire. This maceral-based method suggests a succession of mire types from swamp to fen (and questionably to bog) representing the classic hydroseral succession that forms by the autogenic process of terrestrialization. Contrary to the maceral-based evidence of progressive, albeit weak, raising of the mire surface, ash, sulfur, and miospore diversity increase, and lithotypes become duller upward within the upper third of the seam in the inner zone, suggesting that the mire may have ultimately reverted to a more ground-water-influenced state. A decrease in pH, inferred from an upward increase in tissue structure and decrease in geliflcation, accompanied inner mire development; elsewhere conditions were less acidic. The paleomire flora was dominated throughout by the arboreous lycopsids Lepidodendron hickii and Anabathra (cf. Paralycopodites ), confirming the rheotrophic nature of the ecosystem and the prevalence of flooded conditions. Floral succession of these arboreous lycopsids is evident within the inner mire. Groundwater discharge from alluvial fans at the piedmont margin favored conditions for the colonization of the forest flora. The feedback mechanism of lateral or upslope paludification was aided by the rapid, noncompetitive growth strategy of the arboreous lycopsids. At the riverine margin, autogenic evolution of the ecosystem was stymied by allogenic fluvial processes and by differential compaction about entombed multistory sandstone bodies. Lithotype trends record a general, but similar history of mire development. The ultimate demise of the mire is ascribed to allogenic change, potentially involving precession-induced climate change in concert with basin subsidence and sediment supply.

The Main Seam in the Greymouth coalfield (Upper Cretaceous Paparoa Coal Measures) is exceptionally thick (>25m) and occurs in three locally thick pods, termed north, middle, and south. These pods are separated by areas of thin or absent (“barren”) coal. The barren zone between the north and middle coal pods is characterized by a sequence that is 60 m thick comprising relatively thin (1–2.5 m thick) but laterally extensive (up to 500 m) sandstone units. The orientation of both the thin and the barren coal zones is approximately east to west. This is coincident with basement fault systems that occur in the region. Therefore, the stacked nature of the sandstones within this narrow zone may be a result of differential subsidence across basement fault blocks. The Main Seam, like the sandstone units in the “barren” zone, is inferred to represent a stacked sequence. Two zones of thin partings (<20 cm in thickness) occur in the coal, and even where these zones do not occur, an interval of abundant vitrain bands is present. As has been suggested for other coal beds, intervals with high vitrain content may represent a demarcation between different paleomire systems, or, as in the case of the Main Seam, periods where the paleomire was rejuvenated with plant nutrients, allowing continued aggradation of the mire. The low ash yield (<5% dry basis) indicates that the Main Seam was rarely affected by flood incursions. This may have been the result of both doming of the peat surface as well as restriction of the dominant sediment flow by syn-sedimentary faulting. Palynological analyses indicate that the Main Seam mire throughout most of its time was dominated by gymnosperms, particularly a relative of the Huron pine (Lagarostrobus franklinii). However, a distinct floral change to a Gleichenia -dominated mire occurs in the upper few meters of the Main Seam. This vegetation change may have resulted from basinwide environmental or climatic change. Gleichenia does not produce much biomass, and if it was the dominant mire plant it may not have been able to keep peat accumulation rates higher than subsidence. Whether the cause was a decrease in peat accumulation or a drying of mire, the result would have been lowering of the surface to a degree that flooding and final termination would be likely.

The Pittsburgh, Redstone, and Sewickley coal beds all occur in the Late Pennsylvanian Pittsburgh Formation of the Monongahela Group in the northern Appalachian Basin. The goal of this study is to compare and contrast the palynology, petrography, and geochemistry of the three coals, specifically with regard to mire formation, and the resulting impacts on coal composition and occurrence. Comparisons between thick (>1.0 m) and thin (<0.3 m) columns of each coal bed are made as well to document any changes that occur between more central and more peripheral areas of the three paleomires. The Pittsburgh coal bed, which is thick (>1m) and continuous over a very large area (over 17,800 km 2), consists of a rider coal zone (several benches of coal intercalated with clastic partings) and a main coal. The main coal contains two widespread bone coal, fusain, and carbonaceous shale partings that divide it into three parts: the breast coal at the top, the brick coal in the middle, and the bottom coal at the base. Thymospora thiessenii , a type of tree fern spore, is exceptionally abundant in the Pittsburgh coal and serves to distinguish it palynologically from the Redstone and Sewickley coal beds. Higher percentages of Crassispora kosankei (produced by Sigillaria , a lycopod tree), gymnosperm pollen, and inertinite are found in association with one of the extensive partings, but not in the other. There is little compositional difference between the thin and thick Pittsburgh columns that were analyzed. The Redstone coal bed is co-dominated by tree fern and calamite spores and contains no Thymospora thiessenii . Rather, Laevigatosporites minimus , Punctatisporites minutus , and Punctatisporites parvipunctatus are the most common tree fern representatives in the Redstone coal. Endosporites globiformis , which does not occur in the Pittsburgh coal, is commonly found near the base of the coal bed, and in and around inorganic partings. In this respect, Endosporites mimics the distribution of Crassispora kosankei in the Pittsburgh coal. Small fern spores are also more abundant in the Redstone coal bed than they are in the Pittsburgh coal. Overall, the Redstone coal bed contains more vitrinite, ash, and sulfur than the Pittsburgh coal. The distribution of the Redstone coal is much more podlike, indicating strong paleotopographic control on its development. Compositionally, there are major differences between the thin and thick Redstone columns, with higher amounts of Endosporites globiformis , gymnosperm pollen, inertinite, ash, and sulfur occurring in the thin column. The Sewickley coal bed is palynologically similar to the Redstone coal in that it is co-dominated by tree fern and calamite spores, with elevated percentages of small fern spores. Tree fern species distribution is different, however, with Thymospora thiessenii and T. pseudothiessenii being more prevalent in the Sewickley. The distribution of Crassispora kosankei in the Sewickley coal bed is similar to that in the Pittsburgh coal, i.e., more abundant at the base of the bed and around inorganic partings. By contrast, Endosporites is only rarely seen in the Sewickley coal. The Sewickley is more laterally continuous than the Redstone coal, but not nearly as thick and continuous as the Pittsburgh coal. Overall, the vitrinite content of the Sewickley coal is between that of the Pittsburgh (lowest) and Redstone (highest). Ash yields and sulfur contents are typically higher than in the Pittsburgh or Redstone. The thin and thick Sewickley columns are palynologically and petrographically very similar; ash and sulfur are both higher in the thin column.

Abstract Pennsylvanian (Atokan舑early Desmoinesian) parasequences in Indiana are thin (2舑13 m; 5舑40 ft) intervals that are composed of coal, siliciclastic, and carbonate-clastic units bounded by paleosols. Because the parasequences exhibit significant lateral and vertical lithologic variability and are so thin, they are difficult or impossible to discern on standard oil and gas geophysical logs. Therefore, in Indiana, regional correlations of this interval based primarily on geophysical logs and lithologic strip logs created from drill cuttings remain controversial. Detailed analyses of proprietary core from numerous locations in Daviess County in southwestern Indiana reveal that the most traceable of the parasequence facies in core are the paleosols which represent exposure surfaces that developed, in most cases, during apparent basinwide drops in relative sea level. Correlations are substantiated by detailed palynologic analyses of material collected from the bases of overlying marine-influenced flooding surfaces and by the use of thin, nearly continuous marker beds and the presence of certain biostratigraphically significant conodonts. Transgressive and regressive facies above the exposure surfaces are preserved with varying significance. The relative significance of the transgressive-regressive facies in a parasequence is, in part, related to the relative rates of changes in accommodation space and sea level. Detailed analyses of coal lithotypes and maceral compositions in two Atokan coal seams reveal that base-level rises during paleomire development were gradual in one and abrupt (catastrophic?) in another. Abrupt transgressions and the preservation of relatively thick transgressive sequences above the exposure surfaces were perhaps related to rates of mire collapse and compaction of the underlying peat (now coal) and soil (paleosol).