IODP Expedition 403, Eastern Fram Strait Paleo-Archive: challenges and achievements of the last IODP expedition

The Fram Strait gateway connecting the North Atlantic and Arctic Oceans is an area of high importance for understanding relationships between ocean currents and ice sheet dynamics during past climate transitions; such information is valuable for informing predictive models of future global change. IODP Expedition 403 was motivated by the necessity of retrieving continuous, high-resolution depositional sequences containing the record of the paleoceanographic characteristics of the warm, northward flowing West Spitsbergen Current (WSC) and the cryosphere evolution of the paleo-Svalbard Barents Sea Ice Sheet (SBSIS). Over 5.3 km of sediment records were recovered by drilling 7 sites located along the (S to N) pathway of the WSC, and at (E to W) proximal to distal settings relative to the paleo-SBSIS terminus. The initial age models based on paleomagnetic reversals and microfossils indicate the recovery of expanded Pleistocene and Pliocene sequences in the paleo-SBSIS proximal zone, and in the more distal setting, with recovery of 600+ m sequences that extend into to the mid-Pliocene and the early Pliocene/late Miocene. Preliminary comparisons between lithologies and well-established lithofacies from shallow piston cores of the western Svalbard margin, suggest that the Exp403 site records can be used to constrain the history of shelf edge glaciation, paleo-meltwater events, iceberg calving events, and warm periods dominated by persistent bottom water flow. Physical properties data support this tentative conclusion and suggest that orbital patterns and marine isotope stages (MIS) can be depicted in the records from all site locations despite the diagenetic overprint that complicates the identification of primary depositional signals and stratigraphy. We report also about the challenges faced during Exp-403, the last expedition of the RV JOIDES Resolution under the historical ODP/IODP international program.