FUSULINID BIOSTRATIGRAPHY OF MIDDLE PENNSYLVANIAN-LOWER PERMIAN CYCLOTHEMIC SEQUENCES IN MIDCONTINENT NORTH AMERICA

Fusulinid foramininfera are one of the primary index fossils used for Pennsylvanian-Permian biostratigraphic correlations. Fusulinid range charts plotted with Midcontinent Middle Pennsylvanian-Lower Permian (Desmoinesian-Wolfcampian) cyclothem stratigraphy enable comparison of biostratigraphic and glacioeustatic sealevel fluctuation patterns. The mid-Desmoinesian extinction of Wedekindellina and turnover of Beedeina species coincide with a widespread transgression and change in depositional and paleoclimatic patterns (e.g., decreasing coal beds). Near the marked Desmoinesian-Missourian sequence boundary, Beedeina-dominated faunas disappear and are succeeded by a thin Eowaeringella zone and then by Triticites-dominated faunas throughout the Upper Pennsylvanian. The lower and middle Missourian are characterized by small Triticites with plane septa. Upper Missourian strata are characterized by medium-sized Triticites with more complex fluting and Kansanella spp.. The uppermost Missourian and lower Virgilian are characterized by medium-sized evenly biconvex Triticites with weak septal fluting and the last Kansanella. The middle Virgilian is dominated by medium to large Triticites with complex fluting and Dunbarinella spp.. The upper Virgilian has large Triticites and the first Leptotriticites. The uppermost Virgilian (formerly lower Wolfcampian) is characterized by diverse Leptotriticites, the first primitive elongate Schwagerina, and a few species of Triticites. The lowest currently known Wolfcampian fusulinid fauna in the Neva Limestone contains large Leptotriticites spp. and the first inflated schwagerinid Paraschwagerina. The slightly higher Beattie Limestone has the first fusiform Schwagerina. Then there is a thick stratigraphic gap in faunas before the first occurrence of Pseudoschwagerina in the Florence and Gouldbusk limestones. Most significant faunal changes correlate with major cyclothem boundaries, but not all major cyclothem boundaries have significant faunal turnovers.