COAL RESOURCES AS A TOOL FOR BASIN ANALYSIS COBB, James C., BRANT, Russell A., and CHESNUT, Donald R., Jr., Kentucky Geological Survey, University of Kentucky, Lexington, KY 40506 Original coal resources in the Eastern Kentucky Coal Field are estimated to have been nearly 60 billion tons. Resources have been estimated for about 40 coal beds and splits over 14 inches in thickness. Analyses of coal-resource trends with respect to stratigraphic position reveal two cycles of greatly differing magnitude. The larger scale cycle shows that resources increase and decrease dramatically through Pennsylvanian time. The smaller scale cycles that are superimposed on the larger cycle show that coal resources increase and decrease within each of eight regressive depositional sequences in the Lee, Breathitt, and Conemaugh Formations. The regressive depositional sequences are bounded above and below by laterally extensive marine transgressive units. These sequences contain from 1 to 7 coal beds and range from 30 to 300 feet in thickness. The coal resources within each regressive sequence increase from the base progressively upward to a maximum at approximately the midpoint, and from there they decline progressively to the next marine transgression. Mapped areal distributions of coals within regressive sequences show the changing patterns of peat-swamp development from highly localized following transgression, to widespread and well protected at the midpoint of regression, to localized again prior to the succeeding transgression. Mean sulfur values of coal beds also reflect this trend; values are high at the tops and bottoms of each regressive sequence and are at a minimum near the midpoints. The large-scale cycle has been attributed to tectonics and paleoclimate by other authors. The small-scale cycles are attributed to transgressions and regressions within the basin and the progressive development and destruction of favorable environments for peat accumulation within each regressive sequence.