TECTONICALLY CONTROLLED DISTRIBUTION OF THICK MINEABLE BODIES OF THE BECKLEY SEAM COAL IN SOUTHERN WEST VIRGINIA (STRUCTURE, PEAT, STRATIGRAPHY, SULFUR, SEDIMENTOLOGY)

An interval of Upper Carboniferous strata approximately 150 feet (50m) thick near Beckley, West Virginia, has been studied in order to determine facies types and distribution as they reflect direction of sediment transport and mechanisms of sediment distribution and coal accumulation.;The basic control of sediment distribution seems to have been a large northeast-southwest oriented fault or narrow zone of faults that, for the most part, restricted thick fluvial deltaic sediments to the southeastern part of the area and the thinner orthoquartzite facies to the northwestern part. Within blocks subsidence was not uniform and in the southeastern block slower subsidence is reflected by offset positions of greywacke sandstone in contrast to stacked sandstones produced by more rapid subsidence. Persistence of this structural feature both before and after Beckley deposition is indicated by similar patterns of sediment and coal distribution in the Pocahontas No. 3 Seam 300 to 400 feet (100 to 130m) below and the Sewell Seam 250 to 400 feet (80 to 130m) above the Beckley.;There are two principal facies; (1) a fluvial deltaic facies which is composed of greywacke sandstone, siltstone, shale and coal, some of which is very thick, and (2) a shoreline facies which is dominated by orthoquartzite sandstone with some siltstone and shale and thin coal seams. Greywacke sandstone occurs as tabular northeast-southwest oriented linear bodies with mainly southwest directed crossbeds presumably indicating a direction of longshore transport. The major coal seams occur on the crests or flanks of sandstone bodies and suggest that the thickest peats developed on topographic highs which were produced by less compactable substrate and which protected peats from detrital influx in the topographic lows. Where adjacent topographic lows contained marine or brackish water, the sulfur content of the coal is higher than where the lows contained fresh water. The general pattern of deposition appears to have been characterized by episodic detrital influx and intense shoreline reworking similar to that in the modern Burdekin, Irrawaddy and Mekong deltas.