PPT Slide
Carbondale Formation coals tend to occur in vertically repetitive sequences called cyclothems.
Cyclothems begin with an underclay / coal bed, followed by a fissile, black, marine shale sequence that becomes argillaceous toward the top of the unit. In some cases, the shale is capped by a limestone. Sediments then coarsen upward. Coals are very thick (ɱ ft), and laterally continuous; they also are usually high in sulfur (ɯ %). Nearly all of WKY coal production comes from Carbondale Fm coals.