59th Annual Report on Research 2014

The purpose of this project is to study the paleosols of the Upper Pennsylvanian to Lower Permian Dunkard Group in southeastern Ohio to develop a better understanding of the relationships between paleosol properties and local scale variations in hydrology, topography, parent material, and biota. In addition, these studies will be used to reconstruct the Late Paleozoic landscapes of the Dunkard foreland basin and improve the understanding of the changing climate over this transitional interval.

During this first year of the project my students and I have undertaken field and laboratory work focused on field sites within two areas with excellent exposures of multiple paleosols through the lower half of the Dunkard Group in eastern Athens County, Ohio and western Wood County, West Virginia. Both areas have provided unique opportunities to investigate coeval paleosols across wide distances in several directions due to the size and nature of the road cuts. Stratigraphic control has been provided by the location of key coal beds. We have constructed 13 detailed stratigraphic sections from these localities and described twelve different types of paleosols from the outcrop and hand sample descriptions. We have collected samples for thin sections as well as geochemical and clay mineralogical analyses to improve these descriptions. The preparation and analysis of these samples is currently underway. The field work has also resulted in the description of numerous continental trace fossils, plant fossils, invertebrate, and vertebrate fossils from the localities. Many of the trace fossils include previously undescribed forms or those not known from the region such as Camborygma. The fossil specimens provide a critically important view of the fauna and flora that occupied the landscape surface and the subsurface. The body fossils also provide additional stratigraphic control for each of the field sites.

From the field areas investigated we have identified nine subenvironments and their associated paleosol orders including palustrine (Histosols), interfluve (Vertisols), distal levee (Inceptisols), proximal floodplain (Entisols and Inceptisols), distal floodplain (Vertisols), backswamp (Vertisols), marsh (Vertisols), marsh channel overbank (Inceptisols), and seasonally dry fen (Vertisols). The paleosols have shown strong influence by local processes; this has been recognized from lateral variation in coeval paleosol properties within and between outcrops. These variations include development of horizons, development of peds and cutans, presence and composition of nodules and concretions, and depth of rooting and burrowing. Changes in topographic relief, drainage conditions, and soil organisms appear to have played major roles in altering paleosol properties. Despite these variations, however, major features of the paleosols, including those that help define their paleosol orders, appear consistent across coeval units. A few paleosols, including those currently interpreted as forming on interfluves, have shown consistent physical properties across several hundred meters suggesting possible utility as stratigraphic markers.

In the first year this grant has supported two undergraduate students and one graduate student. The students conducted research at the field localities, measuring sections, describing hand samples, and collecting samples for laboratory analyses. Results of this research will be presented in two talks, one given by my current graduate student, at the 2014 Geological Society of America Annual Meeting in Vancouver.