STRATIGRAPHY OF THE FRASNIAN-FAMENNIAN MASS EXTINCTION INTERVAL (UPPER DEVONIAN) IN THE NORTHERN APPALACHIAN BASIN

The Frasnian-Famennian (Late Devonian) mass extinction occurred in two pulses: the Lower and Upper Kellwasser Events. In western New York, the Lower Kellwasser corresponds to the black shales of the Pipe Creek Formation and the Upper Kellwasser corresponds to the Point Gratiot Bed, a thin black shale in the upper Hanover Formation. Here, we discuss the correlation of these events into the shallow marine paleoenvironments of Allegany and Steuben counties in New York and Tioga County in north-central Pennsylvania. In previous work, we recorrelated the Wiscoy with the upper Angola Formation, the Canaseraga with the Hanover Formation, and the “Hume” with the Dunkirk Formation (Bush et al., Palaeo-cubed, 2015). We also began dividing the Canaseraga into members (Beard et al., Palaeo-cubed, 2017). Organic carbon isotope profiles verify our placement of the Lower Kellwasser Event in shallow marine sections and pinpoint the position of the Upper Kellwasser Event in the Canaseraga Formation. To facilitate discussions of the timing of faunal and paleoenvironmental changes during the Frasnian-Famennian transition, we suggest dividing the remaining portions of the Canaseraga Formation and the upper Wiscoy Formation into members. The ultimate purpose of this work is to examine paleoenvironmental and faunal changes associated with the extinctions along a depth transect. Numerous brachiopod species went extinct during the Lower Kellwasser extinction, although a few of these survived the deposition of the Pipe Creek Shale and died out some time later. Relatively few species died out during the Upper Kellwasser event. Ongoing geochemical analyses will provide additional information on paleoenvironmental conditions during the extinctions.