PALYNOLOGY, PETROLOGY AND GEOCHEMISTRY OF SOME UNIQUE BRECCIATED AND MINERALIZED COALS FROM WESTERN KENTUCKY

Brecciated and mineralized coals from two exploratory drill cores (B-2 and B-3) in Union County, Kentucky were examined for palynomorph and maceral content and geochemical composition. The cores were drilled in a heavily faulted area of the Western Kentucky Coal Field, which represents the southern tip of the Eastern Interior (Illinois) Basin.

Core B-2 intercepted four coal beds. The top coal is dominated by tree fern spores and is completely devoid of Lycospora, indicating that it probably is Late Pennsylvanian in age. Relatively high percentages of Endosporites further suggest that it may be from a postion near the Middle/Late Pennsylvanian boundary. Coal two is co-dominated by Lycospora and tree fern spores, and contains abundant Thymospora and infrequent Schopfites and Densosporites. This type of assemblage indicates a stratigraphic placement in the lower part of the Carbondale Formation. Coal three contains abundant Lycospora and Florinites, as well as infrequent Densosporites and Thymospora, indicating a stratigraphic placement near the Carbondale/Tradewater Formation boundary. Coal four, the basal coal in core B-2, contains a variable palynoflora co-dominated by Lycospora, Densosporites, and tree fern spores. The occurrence of Radiizonates indicates a stratigraphic placement in the middle part of the Tradewater Formation.

Core B-3 intercepted three coals, two of which yielded palynomorphs. One coal had a heterogeneous palynoflora co-dominated by Crassispora and tree fern spores, with subdominant calamite spores and cordaite pollen. The other coal was strongly dominated by tree fern spores. Both coals contained no Lycospora and are interpreted to be Late Pennsylvanian in age.

All but one of the coals from both cores contained high percentages of vitrinite macerals (>80%), moderate ash yields (10 to 20%), and moderate to high sulfur contents (1.5 to 4%), all of which is typical for western Kentucky coals. The basal coal in B-2 is enigmatic in that it contains very high amounts of inertinite (>50%) and is low in ash and sulfur. In addition, all of the studied coals showed elevated levels of metamorphism and secondary mineralization (mainly carbonate), presumably caused by the accelerated migration of hydrothermal fluids along fault traces.