GEOLOGY AND COAL-BENCH ARCHITECTURE OF THE LITTLE CANEY–VAN LEAR–UPPER ELKHORN NO. 3 COAL (BREATHITT GROUP, PENNSYLVANIAN) IN THE EASTERN KENTUCKY COAL FIELD, CENTRAL APPALACHIAN BASIN; A BASINWARD TRANSITION FROM SINGLE BED TO COAL ZONE

New roadcuts exposing the Little Caney coal bed on the western margin of the Eastern Kentucky Coal Field, Central Appalachian Basin, can be compared to its equivalents to the east, the Van Lear coal and the Upper Elkhorn No. 3 coal zone. The Little Caney coal is generally a single, thin bed, with simple bench architecture. It is laterally variable in thickness, tending to thicken into paleotopographic depressions. The equivalent Van Lear coal is similar, but tends to be thicker than the Little Caney for greater distances. Both coals are uniformly high (> 70 percent) in vitrinite content and dominated by Lycospora, the spore produced by Lepidophloios and Lepidodendron. Ash and sulfur contents also tend to be uniformly low to moderate (10-15 percent ash, 2-3 percent sulfur).

In southeastern Kentucky, these coals are stratigraphically equivalent to the Upper Elkhorn No. 3 coal bed, which becomes a zone consisting of multiple beds or benches. Each bed/bench in the zone may split or merge with overlying beds/benches locally. North of Pine Mountain, the Upper Elkhorn No. 3 zone can be divided into the Upper Elkhorn No. 3A and No. 3B coals, which consist of as many as four beds in a 15 to 20 m thick zone. On the Pine Mountain Overthrust Block, the Upper Elkhorn No. 3A and No. 3B coals are equivalent to the Darby and Kelioka coal beds, which can occur as multiple beds in a 20 to 30 m thick zone. Compositionally, the Upper Elkhorn No. 3 coal zone is more variable than the Little Caney coal to the west and Van Lear coal to the north. Although much of a mined Elkhorn No. 3 coal bed is also high in vitrinite and Lycospora content, a greater frequency of “splint” coal lithotypes are observed in the Upper Elkhorn No. 3 coal. These lithotypes contain higher percentages of inertinite, liptinite, and Densosporites. Ash and sulfur contents, though generally low (< 10 percent ash, < 1percent sulfur), also are more variable, both within and between individual beds/benches. Basinward zoning and general thickening of the Little Caney–Van Lear–Upper Elkhorn No. 3 coal provides insight into the influence of tectonic accommodation on coal distribution in a foreland basin.