Terrestrial vs. marine depositional model—A new assessment of subsurface Lower Pennsylvanian rocks of southwestern Virginia

A reinterpretation of the origin of subsurface rocks in southwestern Virginia and southeastern Kentucky suggests that, contrary to commonly accepted ideas, the Mississippian-Pennsylvanian Systemic boundary is an unconformity and the Lower Pennsylvanian quartz arenite sequences were deposited in a fluvial environment. Because Pennsylvanian strata of the Pocahontas and Lee Formations appear to have been deposited at the same time in adjacent valleys, the Pocahontas, which generally has been considered to be older and to underlie the Lee, is considered here to be equivalent to the basal part of the Middlesboro Member of the Lee Formation.