Terrestrial paleoecology of distal deltaic environments of the upper Mississippian Bluefield, Hinton and Bluestone formations of southwestern Virginia and southern West Virginia

Abstract

Multiple sections at 13 localities in West Virginia and Virginia, that expose the Early Carboniferous (Late Mississippian) Bluefield, Hinton, and Bluestone Formations, were measured. Geological structures and paleontological occurrences were recorded. In situ rooted plants were compared with transported plant and animal assemblages from fluvially dominated terrestrial beds and interdistributary channel-dominated, bay-fill, marine beds in order to interpret the paleoecology of this subtropical Early Carboniferous coastal landscape. Interdistributary wetlands of the Bluefield, Hinton and Bluestone Formations resemble earlier swamps more than those of the younger Pennsylvanian. In both Hampshire (Late Devonian, Famennian) and Price Formation (Early Carboniferous, Toumaisian) coal swamps, diversity is so low that only one taxon of plant is present: Rhacophyton ceratangium in the Late Devonian and Lepidodendropsis vandergrachtii in the Early Mississippian. The presence of Lepidodendron veltheimii as the apparent sole occupant of these younger Early Carboniferous plant communities makes them most similar to the arborescent lycopod-dominated Price Formation swamps. Although many Pennsylvanian (Late Carboniferous) swamps were also dominated by tree lycopods, including species of Lepidodendron sensu lato, other plants were present as well. Thus, these Late Mississippian communities incorporate some features of both younger and older swamps and can be considered ecologically transitional between them. Swamps have been stressful environments for plant growth for as long as they have existed. This is manifested by their low diversity since the Paleozoic and continues to be true today.