ORGANIC PETROGRAPHY OF A MIDDLE EOCENE LIGNITE, TENNESSEE

The organic petrography of a low-rank, clay-rich lignite from Weakly Co., TN, is being examined using particulate pellets. It is thought that this lignite is part of the Clabornian-stage lignite outcrop belt. Petrographically, this deposit is similar in many aspects to known Claibornian-stage lignite deposits in Kentucky, in that it is composed primarily of clay and attrinite-rich horizons that are well-rooted, contain abundant liptinite, especially sporinite, and display evidence for extensive decay of original organic material prior to incorporation into the mire (funginite and damage attributed to fungi). Overall, petrography points toward organic deposition in a variably wet setting. Attrinite-rich horizons likely represent exposure and increased levels of aerobic decomposition while clay-rich horizons likely represent flooding surfaces. The high sporinite content in the clay horizons may indicate a spring flooding regime. Like similar deposits in Kentucky, the upper portions of the lignite contain blebs of anisotropic coke that are not associated with increased inertinite content in the coal. These particles likely represent remnants of crown fires in trees surrounding the mire.