Structural Influence on Sedimentation Patterns in Lower to Middle Pennsylvanian Strata in Eastern Kentucky Coalfield

Ernie R. Slucher, Roy C. Keferle

Structural influence on sedimentation patterns in Lower to Middle Pennsylvanian strata in the Eastern Kentucky coalfield has been deduced from the study of 16 cores. These cores were analyzed for trends and patterns in sandstones, sand to shale ratios, sediment thickness, and marine beds.

Strata generally thin to the northwest. Sandstone bodies are either (1) south to southwest trending, linear to slightly sinuous, and characterized by coarse-grained sandstones with scattered quartz pebbles, or (2) westward trending, bifurcating, and lobate, and characterized by fine to medium-grained sandstones. The differences in sandstone texture and trends appear to represent a change from braided fluvial streams typical of the Lee Formation to fluvial-deltaic deposits characteristic of the overlying Breathitt Formation. This change in environment and depositional trends suggest that these rocks were deposited in a northwestward-prograding sequence.

Data generated indicate that the Eastern Kentucky syncline is post-Pennsylvanian. Thinning trends and sedimentation patterns strongly suggest that the Owsley County uplift-Rockcastle anticline was periodically positive during the Early to Middle Pennsylvanian. To the southeast, depositional strike and thickening trends suggest the presence of deep-seated faulting. However, local trends suggest the possible existence of a paleovalley at or near the base of the Pennsylvanian System. No evidence of a gradational Mississippian-Pennsylvanian systemic boundary was found in any of the cores.

AAPG Search and Discovery Article #91041©1987 AAPG Eastern Section Meeting, Columbus, Ohio, October 7-10, 1987.