Dunkard Group coal beds: Palynology, coal petrography and geochemistry

Callipterid peltasperms of the Dunkard Group, Central Appalachian Basin

“…Physical evidence strongly points in this direction, such as the association of these plants with sequences dominated by Calcisols and Vertisols, both in the Washington and Greene formations, and the steep decline in coal bed frequency and thickness coinciding with the appearance of callipterids (Eble et al, 2013). As Darrah (1969, p. 68) noted, significantly, "…the Callipteris Permian flora…appears to be indicative of physiologically xerophytic conditions.…”

“…An association of two callipterid species and a conifer is consistent with a subhumid climatic setting, based on their occurrences elsewhere in equatorial Pangea. In the upper parts of the Greene Formation, compared to the Washington and lower Greene formations, coals are thinner and less numerous, indicators of climatic seasonality are stronger (Cecil et al, 2011;Eble et al, 2013), and red beds become predominant. Such indicators are broadly consistent with the presence, at some times during glacial-interglacial cycles, of plants more tolerant of seasonal drought.…”

Response of Soils and Soil Ecosystems to the Pennsylvanian–Permian Climate Transition in the Upper Fluvial Plain of the Dunkard Basin, Southeastern Ohio, USA

“…Autunia conferta is an extinct pteridosperm common in Dunkard Group flora where seasonally dry conditions occurred [44]. Calamites, a giant horsetail, is commonly found in Dunkard Group coal beds and was a likely component of wet floral assemblages [19,45]. Fossil burrows (Palaeophycus and cf.…”

“…The goal of this study was to use the small-scale study approach to identify the average response of soils and soil ecosystems to climatic variation in the Dunkard Basin during the Late [15,16,19,23]; (B) Stratigraphic column showing general lithologies of the Upper Monongahela and Dunkard groups modified from [14]. …”

Late Paleozoic continental warming of a cold tropical basin and floristic change in western Pangea

“…During this time interval a major vegetational change occurred, from floras characteristic of "wet" habitats to those typical of seasonally dry habitats (DiMichele et al, 2006;Montañez et al, 2007;Opluštil, 2013). This change parallels similar shifts in vegetation throughout central and western Pangea during this time (Broutin et al, 1990;DiMichele and Aronson, 1992;Kerp, 1996), and occurs contemporaneously with the changes in vegetation documented in Dunkard strata of eastern North America Eble et al, 2013).…”