PALYNOSTRATIGRAPHY OF THE LOWER PALEOGENE MARGARET FORMATION AT STENKUL FIORD, ELLESMERE ISLAND, NUNAVUT, CANADA

The late Paleocene-early Eocene Margaret Formation at Stenkul Fiord on southern Ellesmere Island, Nunavut, Canada represents a nearly continuous terrestrial succession of palynomorph-rich deposits of clastic sediments and coals. The sediments were deposited at a time where the Arctic was undergoing extensive tectonic activity related to Eurekan deformation. The Margaret Formation, part of the Eureka Sound Group, at Stenkul Fiord has been affected by pronounced folding and faulting during deposition, but precise ages of these tectonic events and their chronology are still rather unknown. In addition, the greenhouse climate of the late Paleocene-early Eocene was punctuated by several episodic hyperthermal events such as the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM2). Fossil evidence of high-latitude Arctic forests is preserved at Stenkul Fiord in high stratigraphic detail. Current radiometric dating at Stenkul Fiord provides a U-Pb detrital zircon age of 53.7 ± 0.6 Ma, which suggests these deposits record the ETM2 hyperthermal. Prior palynostratigraphic studies at Stenkul Fiord suggested a late Paleocene age for some sediments. In order to provide greater temporal resolution for both tectonic and climatic events preserved at Stenkul Fiord, a palynostratigraphic framework was constructed. This framework includes four pollen zones that were defined based on temporally unique floral assemblages, compositional shifts in floral communities in response to intervals of major climatic change, and stratigraphic ranges of occurrence of pollen and spore taxa. These data show that the character of vegetation (e.g. shifts in species dominance) shifted during, and after, the PETM and ETM2 hyperthermals. The palynostratigraphy was integrated with section-specific lithostratigraphy and facilitates the correlation of early Paleogene sediments at Stenkul Fiord. Furthermore, these results will be integrated with carbon isotope stratigraphy for paleoenvironmental reconstructions and to assist with the interpretation of the chronology of Eurekan deformation events at Stenkul Fiord.