2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 6
Presentation Time: 2:45 PM

Using Statistical Palynology to Describe Hydrologically-Controlled Variations in Plant Distribution in a Middle Eocene Wetland

O'KEEFE, Jen, Earth & Space Sciences, Morehead State University, 404-A Lappin Hall, Morehead, KY 40351, j.okeefe@moreheadstate.edu

Middle Eocene Claiborne Group lignites in western Kentucky overly clays that infill meander cut-offs in a paleofloodplain. In a Carlisle County, KY, deposit, the wedge-shaped lignite thins, becoming clay-rich toward the paleostream and thickens, becoming organic-rich toward the paleocutbank. This is similar to modern peat-forming wetlands in the region and on the Atlantic coastal plain. Palynomorphs preserved in the deposit record nine assemblages that can be roughly divided into gradational subsets of wet-tolerant and dry-tolerant clusters. Assemblage distributions are highly variable but follow a general trend of increasing wetness toward the paleostream. In general, repeating sequences of wet-tolerant assemblages followed by transitional to dry-tolerant assemblages occur throughout the deposit. Wet-tolerant assemblages can be correlated with flooding events that brought nutrient-rich clays into the deposit. Variations in which of the nine assemblages are present in a specific area reflect small-scale variations in depth to water-table in the system.