Sedimentary processes on the continental slope north of Kvitøya (northern Barents Sea) – preliminary results from regional bathymetry and sediment cores

The continental margin of the northern Barents Sea is a key area for understanding the behavior and dynamics of the northern Barents Sea Ice Sheet, as well as the Arctic ocean circulation pattern during the Last Glacial Maximum, the deglaciation, and the Holocene.

In this study, we investigate the continental slope north of Kvitøya and Nordaustlandet (Svalbard) by analyzing the seabed morphology of the improved IBCAO 4.0 bathymetric grid (Jakobsson et al., 2020) and high-resolution sub-bottom profiles (CHIRP), one giant piston core and three gravity cores (4.61 to 18 m long). We present results from the multi-proxy analysis of the sediment cores, including lithostratigraphy, physical properties, grain-size distribution, XRF core scanning data, and radiocarbon dates.

The morphology of the Kvitøya Trough-Mouth Fan is generally smooth, with furrows 500 m wide and 200-500 m deep stretching from the shelf edge at around 250 m water depth to at least 3000 m water depth into the Arctic Ocean. The morphology of the continental slope east and west of the trough-mouth fan is smooth in the upper parts, and characterized by 3-5 km wide and 200-500 m deep channels and canyons cutting into the slope from a water depth of around 1000 to 3000 m.

The observations from the bathymetric data show that the trough-mouth fan buries channels and canyons, smoothing the morphology of the continental slope. The furrows are likely erosional features resulting from downslope activity such as debris flows and turbidity currents. In the inter-fan areas to the east and west, we interpret that the uppermost smooth morphology results from suspension fallout of sediments from the ocean currents flowing along-slope, indicating that these accumulations are contourites. The rugged topography further downslope possibly represents channel and canyon systems that are only partially buried, likely due to reduced influence from ocean currents at greater water depths. Analysis of the cores provides insight on the sediment properties of the contourites, debris flows, and turbidites, and radiocarbon dates shed light on the interplay and timing of the ocean current regime and the glacial dynamics.

 

Jakobsson, M., Mayer, L.A., Bringensparr, C. et al. The International Bathymetric Chart of the Arctic Ocean Version 4.0. Sci Data 7, 176 (2020). https://doi.org/10.1038/s41597-020-0520-9