CONODONTS AND THE FRASNIAN-FAMENNIAN BOUNDARY (UPPER DEVONIAN) IN THE NEW ALBANY SHALE, ILLINOIS BASIN, WESTERN KENTUCKY

The Frasnian-Famennian (F-F) boundary is recognized in the subsurface within a 5 cm interval based on the last occurrence of Palmatolepis wincelli, in high Frasnian strata that also contain Pa. extensa and Pa. hassi, followed by the first occurrence of Palmatolepis subperlobata and Pa. triangularis which define the base of the Famennian. Higher Famennian taxa in the 3.5 m interval above the boundary include Pa. delicatula, Pa. perlobata, Pa. regularis, Pa. tenuipunctata, and Ancyrognathus sinelamina. The boundary interval is preserved in strata of the New Albany Shale in the transition from the Selmier Member to the organic-rich Grassy Creek Member in the eastern Illinois Basin of western Kentucky. There is no notable lithological change or evidence of a disconformity at the boundary. Bulk magnetic susceptibility, collected at 1 cm intervals though the boundary interval, has a + 0.1 δMS shift just after the last Frasnian conodont.