PALYNOLOGY, PETROGRAPHY, SEDIMENTOLOGY AND INFERRED PALEOECOLOGY OF A MIDDLE PENNSYLVANIAN AGE MIRE TO MIRE TRANSECT, PEACH ORCHARD COAL ZONE, CENTRAL APPALACHIAN BASIN

In the eastern Kentucky coal field, the Peach Orchard coal zone includes the Hazard #7 and #8 coal beds. These two economically important coal beds are separated by an interval of clastic sediments that ranges from 10 to 30m in the Hazard, Kentucky study area. Samples of coal from the Peach Orchard coal zone were analyzed palynologically and petrographically to determine the miospore and maceral composition of each coal bed. These data were then used to infer the type of paleomires the coal originated from. Clastic samples were analyzed palynologically to document changes in miospore composition that were occurring in the intervening clastic environments. Sedimentologic analysis of the clastic interval was used to determine the environments of deposition within the clastic interval. Collectively, all three data sets were incorporated into a paleoecological model to describe the origin of the Peach Orchard coal zone.

Based on spores and pollen, the Peach Orchard coal zone is Middle Pennsylvanian (Bolsovian) in age. Stratigraphically important taxa include Radiizonates difformis, R. rotatus, Laevigatosporites globosus and Triquitrites sculptilis. Coal palynology indicates that both coal beds are co-dominated by Lycospora, Densosporites (and related crassicingulate taxa, e.g., Radiizonates), and several taxa that were produced by tree ferns (e.g., Laevigatosporites globosus, Punctatisporites minutus and Punctatosporites minutus). Clastic palynology records higher percentages of Calamospora, Laevigatosporites minor and Florinites, than were typically found in the coal. Coal petrology indicates that both coal beds contain significant amounts of inertinite and liptinite macerals, which collectively contribute to an abundance of “splint” coal lithotypes.

Sedimentologically, the clastic interval between the Hazard No. 7 and No. 8 coal beds contains fluvial channel, splay, floodplain and lacustrine facies. Clastic swamps in this interval include a standing lycopsid forest in distal splay and floodplain facies, and calamite wetland environments in more proximal splay positions.