CONODONTS IN MIDDLE AND UPPER DEVONIAN BLACK SHALES OF THE APPALACHIAN BASIN IN NEW YORK

Devonian black shales in the Appalachian Basin of New York first occur in the Lower Devonian Esopus Formation, from which conodonts have not been recovered. The first basin-wide black shales are in the Marcellus subgroup. Polygnathus costatus costatus and Po. linguiformis have been recovered from the Union Springs Formation; Icriodus stephensoni, Po. sp, and Tortodus sp. have been recovered from the Oatka Creek Formation in New York, while equivalent strata in Virginia have yielded Po. ensensis and Po. hemiansatus? in the absence of shallow water taxa. The Givetian Levanna Member black shale has yielded Po. pseudofoliatus and Icriodus latericrescens. In high Givetian through lower Famennian strata the Geneseo, Middlesex, Rhinestreet, Pipe Creek, and Dunkirk formations record significant deepening events that are represented globally and correlated by conodonts. The Geneseo contains a sparse high Givetian conodont fauna, the Middlesex records the lowest occurrence of Palmatolepis punctata? in association with Pa. transitans, Mesotaxis asymmetrica, Ancyrodella africana, and Ad. gigas. The thickest of the New York Upper Devonian black shales is the Rhinestreet Formation, which records two significant deepenings marked by Ancyrognathus ancyrognathoideus and Ozarkodina nonaginta near the base and the semichatovae-deepening near the top that yielded Pa. semichatovae and several other taxa. The Pipe Creek Formation yielded Palmatolepis winchelli, Pa. aff. Pa. hassi, and Polygnathus samueli and is recognized globally as the Lower Kellwasser Event; followed higher in the Hanover Formation by the Pt. Gratiot Bed, the Upper Kellwasser equivalent marked by the first occurrence of Famennian conodonts, notably Palmatolepis subperlobata and Pa. triangularis. The Dunkirk Formation, the last of the thick Upper Devonian black shales in New York marks the T-R cycle IIe flooding of Johnson et al. (1985), recognized across North America by other black shales or deeper water carbonates, occurs in the Pa. delicatula Zone. The black shales of the Huron Member and Cleveland Member of the Ohio Formation in the western Appalachian Basin and equivalent Gassaway Member of the Chattanooga Shale in the southern Appalachian Basin preserve a diverse offshore palmatolepid conodont fauna.