HIGH-RESOLUTION LITHOLOGY AND STRATIGRAPHY OF AN OUTCROP WITHIN THE GRUNDY FORMATION, BREATHITT GROUP (PENNSYLVANIAN), SOUTHEAST KENTUCKY
The outcrop is comprised of mudstone, siltstone, and sandstone with thin intervals of coal in the Grundy (formerly Hance) Formation (Lower Pennsylvanian). We measured 81 meters of stratigraphic section using a Jacob’s staff, and sampled pertinent rock units for detailed examination. The stratigraphic section shows several coarsening-upward sequences from 6 to 20 meters in thickness, capped by coal and/or organic-rich shale about a decimeter thick. Clastic lithologies pervasively exhibit lamination in mudstones and fine cross-lamination in siltstones and sandstones. Woody fragments and plant material are common in several units. The lithology and sedimentary structures of marine mudstone are consistent with deposition in shelf (prodelta?) depositional environments. Overlying sandstones are deposited in probable deltaic and tidal systems, which are capped by coal and/or organic-rich mudstone that likely formed in coastal, freshwater environments.
Ultimately, contextual information, lithologic descriptions, the measured stratigraphic column, and photographs of key features and samples will be posted on the Kentucky Geological Survey (KGS) website as a story map. Samples will be archived at the KGS Earth Analysis Research Laboratory (EARL). An undergraduate thesis detailing this research is available in the digital archive of the Eastern Kentucky University library.