The opening of the Fram Strait and its influence on sediment transport, climate and ocean circulation between the Arctic Ocean and the North Atlantic

• Main Authors: Grützner, Jens, Geißler, Wolfram, Matthiessen, Jens, Gebhardt, Catalina, Schreck, Michael
• Format: Conference Object
• Language: unknown
• Published: 2022
• Subjects: Arctic; Arctic Ocean; Fram Strait; North Atlantic; Spitsbergen
• Online Access: https://epic.awi.de/id/eprint/57627/; https://epic.awi.de/id/eprint/57627/1/Gruetzner_Kolloquium2022.pdf; https://hdl.handle.net/10013/epic.e2aed823-a975-44ee-9830-45be15ad5252

It is known that during a long period of its Cenozoic history, the Arctic Ocean was isolated from any global thermohaline circulation system (e.g. Jakobsson et al., 2007). Thus, the opening and subsequent widening of the Fram Strait, the only deep-water connection between the Arctic and Atlantic oceans, was a fundamental tectonic process with extensive consequences for the global ocean circulation and paleoclimate evolution as well as for sedimentation processes in the adjacent ocean basins and along the continental margins. In order to reconstruct both the development of the ocean circulation within and the glacial history of the Arctic-Atlantic gateway we interpreted sediment packages imaged in reflection seismic profiles together with updated stratigraphic information from existing Ocean Drilling Program (ODP) holes (Fig. 1). Our new, high resolution seismic stratigraphy for the Molloy Basin (central Fram Strait) is based on a revised chronology for ODP Site 909 and on a seismic reflection pattern that is better resolved than in previous studies (e.g. Berger and Jokat, 2009). An improved core-log-seismic integration for ODP Site 909 and crossing seismic reflection profile AWI-20020300 (Fig. 2) was substantial in deriving the new seismic stratigraphy as well as characterizing the seismic units lithologically (Gruetzner et al., 2022). The core-seismic integration was combined with a revised magnetostratigraphy calibrated by new palynomorph bioevents which shifts previously used stratigraphies for ODP Site 909 (e.g. Myhre et al., 1995) to significantly younger ages in the time interval from c. 15 Ma to 3 Ma. The new stratigraphy implies that prominent maxima in coarse sand particles and kaolinite, often interpreted as evidence for ice rafting in the Fram Strait occur at c. 10.8 Ma, c. 3 Myr later as previously inferred. In the late Tortonian (< 7.5 Ma), sediment transport became current controlled, most probably through a western, recirculating branch of the West Spitsbergen Current. This current influence ...