Petrology, palynology, and geochemistry of the Pond Creek coal (Pennsylvanian, Duckmantian), Pike County, Kentucky: Overprints of penecontemporaneous tectonism and peat doming

The petrographic, palynologic, and geochemical character of the high volatile A bituminous Pennsylvanian (Bashkerian, Duckmantian) Pond Creek coal was evaluated for a series of mine samples in the Lick Creek and Jamboree 7 ½’ quadrangles in Pike County, Kentucky. In its prime years of production, the Pond Creek coal was among the most important coal resources in the leading coal producing state in the U.S. The thickness and quality of the Pond Creek coal was closely related to its position relative to the northwestward-plunging, N20°E-trending Belfry anticline with the main bed of the coal thinning and the thickness of rock between the latter and the high-S Pond Creek rider bed thinning across the anticline. This suggests that the Belfry anticline and the Pond Creek mire were contemporaneous features, with the rising anticline influencing the lithology and chemistry of the peat. Within the study area, the lower three lithotypes fill the original topography and the next higher lithotype pinching out along the rise towards the anticline. The next three lithologies, a thick bright zone (zone 4 in the nomenclature of this study), a bone coal, and a thinner bright zone are continuous through the study area, although they all thin towards the anticline. The upper durain, the termination of the coal seam, also pinches out towards the anticline. Zone 4 shows a decrease in total vitrinite towards the uppermost bench of the zone, an upwards increase in ash yield, the upwards increase in the floral diversity, and a higher concentration of Mn, CaO, and Ba + Sr in the lower lithologies of the zone. Towards the anticline, there is a greater floral stability within zone 4 compared to the relatively subsiding area to the east. Within the zone 4 bright lithologies, peat growth outpaced the level of the water table, but at the cost of the turnover of the arborescent lycopod forest to a more diminutive flora, the collapse of the ombrogenous peat, and the influx of deeper water and the consequent deposition of the overlying relatively high-ash bone coal.