GEOLOGY OF THE VANCLEVE COAL BED, BETSIE SHALE MEMBER, AND FROZEN SANDSTONE MEMBER (GRUNDY AND PIKEVILLE FORMATIONS) NEAR VANCLEVE, KENTUCKY

New roadcuts near Vancleve, Kentucky, on the western side of the Eastern Kentucky Coal Field expose the stratigraphic interval between the Vancleve coal bed near the top of the Grundy Formation (upper Lower Pennsylvanian), and Frozen Sandstone Member of the Pikeville Formation (lower Middle Pennsylvanian). The contact between these two formations is the Betsie Shale Member; a regionally extensive, coarsening-upward, marine interval. Deeper in the basin, the shale is thick and easily distinguishable. Here, closer to the basin margin, the shale is thin and difficult to distinguish from other shales, which complicates the stratigraphy.

The Van Cleve coal bed is 0 to 40 inches thick in the area, and is strongly-dominated by Lycospora (85.6 %). The bottom bench contains high percentages of Lycospora orbicula and L. micropapillata, both of which were produced by Paralycopodites. The remaining benches are more dominated by Lycospora pellucida, L. granulata (Lepidophloios) and L. pusilla (Lepidodendron). This shift reflects a transition from a Paralycopodites-dominated pioneering flora to a more mature flora with abundant Lepidophloios and Lepidodendron. Local thickness variation may record variation in paleotopography on the underlying Corbin Sandstone.

The base of the Betsie Shale represents a marine flooding surface. In some outcrops, bioturbated, slumped sandstones occur at the base of the shale. Thinning results from scouring at the base of the Frozen Sandstone. The sandstone is an incised valley fill, and the scour at its base represents a lowstand surface. Large paleoslumps (> 6m) in the shale beneath the sandstone contain fine-grained, bioturbated sandstones that are not preserved elsewhere in this area. These record part of the coarsening-upward sequence that is truncated laterally. Pervasive paleoslumping and minor faulting in this area could have resulted from normal depositional processes and loading, however, the outcrops are located on a structural hinge line across which there is dramatic thickening of the Lower Pennsylvanian and Mississippian sections southeastward into the basin. Basin-to-margin accommodation changes are interpreted to have influenced sedimentation and peat accumulation in this stratigraphic interval.