Late Cenozoic erosion estimates for the northern Barents Sea: Quantifying glacial sediment input to the Arctic Ocean

Abstract

A compilation of seismic data has been used to characterize the Neogene – Quaternary sedimentary succession of the northwestern Barents Sea continental margin to better understand the paleoenvironmental evolution and the sedimentary processes involved. The Neogene strata are dominated by contourites related to the ocean circulation established from the opening of the Fram Strait connecting the Atlantic and the Arctic Oceans (< ~17.5 Ma). The upper Plio–Pleistocene strata (< ~2.7 Ma) are dominated by stacked gravity‐driven deposits forming trough‐mouth fans that were sourced from paleo‐ice streams. Within the inter‐fan areas, contouritic sedimentation prevailed. Thus, this margin provides an example of interaction of glacigenic debris flows, contour currents, and hemipelagic/glacimarine sedimentary processes. A total of ~29,000 km3 of sediments with an average sedimentation rate of about 0.24 m/Kyr were estimated. These numbers reflect the sediment input to this part of the Arctic Ocean from the northwestern Barents Sea shelf and adjacent land areas. For the first time, the average erosion and erosion rates for this source area are estimated using a mass balance approach. Approximately 410 – 650 m of erosion has on average occurred, corresponding to an average erosion rate of ~0.15 – 0.24 m/Kyr. These rates are comparable to those reported from other glaciated margins, including the western Svalbard and mid‐Norway margin, but up to only half the rates reported from the western Barents Sea margin. This variation is interpreted due to the size and bedrock types of the drainage area, ice dynamics, and the continental slope gradient.

<i>Plain Language Summary</i>: This study is about mapping the offshore glacial sediment by using seismic data in the northeastern Svalbard ‐ northern Barents Sea continental margin. The studied margin provides a unique opportunity to examine an interaction between down slope and along slope sediment processes.Development of Kvitøya glacial fan is highlighted and shows a major sediment delivery under ice streams that reached the shelf break. Prior to or at the onset of glaciation, a major slope failure likely occurred generating a large submarine slide, named "Body A".For the first time, the average erosion and erosion rates during the last ~2.7 Million years are estimated from this margin. We found out that 410 ‐ 650 m of sediments were removed from the source area. The erosion rates are estimated (0.15 ‐ 0.24 m/Kyr) and are comparable with other formerly glaciated margins. This study is an important scientific input for a better understanding of uplift and erosion in the Barents Sea shelf. The present contribution is highly relevant for future hydrocarbon exploration in the Barents Sea area and Arctic region. Finally, investigating such subsurface sediments is crucial for paleoenvironmental reconstruction in order to understand the climate dynamics in the past.