CHANNEL-FILL COAL BEDS ALONG THE WESTERN MARGIN OF THE EASTERN KENTUCKY COAL FIELD

Four channel-filling coal beds from the lower part of the Breathitt Fo rmation (lower Middle Pennsylvanian, late Westphalian A) were examined palynologically, petrographically and geochemically to determine the paleoenvironmental conditions under which these peats accumulated. The se results were then compared with detailed sedimentological analyses of the strata overlying the coal in the channels to see if any genetic relationship between coal composition and the origin of the overburde n could be drawn. All four of the coal beds used in this study are loc ated in the western-most part of the Eastern Kentucky Coal Field and o ccur at, or near, the Early Pennsylvanian unconformity (0-30 m). Lycos pora and Densosporites (and related crassicingulate taxa, e.g. Cristat isporites, Cingulizonates and Radiizonates) dominate the studied assem blages, with Granulatisporites (and related trilete, sphaerotriangular genera, e.g. Leiotriletes and Lophotriletes), Laevigatosporites and S chulzospora being common accessory genera. Petrographically, all four coals contain high percentages of vitrinite macerals (avg. 78.6% miner al matter free), moderate amounts of Liptinite (or exinite) macerals ( avg. 14.9%, mmf) and low percentages of inertinite macerals (avg. 6.5% , mmf). Strata above the coals consist of dark, carbonaceous shales, a nd heterolithic strata that exhibit varying degrees of bioturbation. C ommonly occurring trace fossils include Arenicolites, Monocraterion, P lanolites and Skolithos. Although marine-influenced strata, as determi ned from detailed sedimentology and ichnology (the study of trace foss ils), covers all four coal beds, they are not uniformly high in total total sulfur content as might be expected. Rather they are extremely v ariable, ranging from 1-9% (dry basis) total sulfur. Ash yields are al so variable ranging from 6.2-54.3% (dry basis). It is probable that th e origin of the very first sediments covering the peat, as well as the amount of brackish water influence during peat accumulation, were imp ortant factors in determining the total sulfur content of the resultan t coal. Initial sedimentation of fresh water clays and silts may have acted as a barrier to downward percolation/diffusion of sulfate bearin g waters, or may have served as a site for sulfide formation, thereby keeping the total sulfur content of the underlying coal low. If initia l sedimentation was of brackish or marine origin, as indicated by biot urbated laminae directly above the coal, or if the peat was subject to frequent brackish or marine water influence during accumulation, then sulfide generation might proceed unchecked, resulting in high sulfur coal.