Mine level analysis of planar and raised peat deposition in a wave- and tide-influenced deltaic shoreline setting; Beckley bed (Westphalian A), southern West Virginia

Abstract

The Beckley bed of the New River Formation is known for difficult mining conditions. In the area examined the bed is composed of four coal benches separated by siliciclastic partings. Each bench represents a different episode of swamp development on a wave- and tide-influenced deltaic platform that had prograded to the northwest. Both planar swamps and raised mires developed in tidally influenced estuarine settings through time on this platform. These differing types of swamp morphology are superimposed, one upon the other, at the same geographic locations. These swamp environments were terminated by drowning, represented by a coarsening-upward sequence that overlies the bed. This sequence is tidally influenced and it represents the continuation of estuarine conditions. Most of this sequence is removed by an episode of incision by fluvial channels. This episode was followed by a return to sediment deposition in tidally influenced conditions. The distribution of all sediment types is influenced by faulting that was concurrent with sediment deposition. This faulting caused the localization and stacking of thick sandstones, thick coal areas, and the preservation of tidally influenced sediments that overlie the bed, all of which impact on the mineability of the bed.