Geochemical and palynological indicators of the paleoecology of the River Gem coal bed, Whitley County, Kentucky

The River Gem coal bed (upper Westphalian A) was sampled at five sites in a single mine in Whitley County, Kentucky. Previous petrographic and sulfur analyses of the collected interval samples showed that the coal bed could be divided into a basal low-sulfur lithotype, a middle high-sulfur bone lithotype and an upper high-sulfur lithotype. At one location a high-sulfur rider unit is present. In this study we have conducted detailed palynological analyses on all of the interval samples and ash geochemistry on the upper high-sulfur lithotype intervals and two of the basal high-sulfur basal lithotype intervals.

Geochemical analyses show that As and Pb are generally high in the high-sulfur upper lithotypes from all five sites. Carbonates, having associated high levels of Ba and Sr, are important in the ash geochemistry of the lower, low-sulfur lithotypes. Ga, Ge and W are enriched in the higher vitrinite lithotypes among the low-sulfur samples. The basal lithotype at each of two sites, which was analyzed in detail, is enriched in yttrium plus the lighter rare earth elements.

The basal low-sulfur lithotypes are dominated by arboreous lycopod spores. The middle, low-sulfur portion of the bed is dominated by herbaceous lycopsids (Densosporites) at the base of the unit and becomes increasingly enriched in Lycospora towards the top of the unit indicating that the peat-forming environment became wetter. The greatest arboreous lycopod spore abundances in the upper, high-sulfur portion the bed, along with an overlying marine roof, indicates that peat deposition was terminated by a marine inundation.