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 interfan 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.

Latitudinal variability in the Quaternary development of the Eurasian ice sheets—Evidence from the marine domain

“…2B), which suggest an extensive ice sheet in this region. This supports the earlier conclusions of Knies et al (2009) and Lasabuda et al (2018), who, based on IRD records and identification of GDFs, suggested an ice sheet with active ice streams covering Svalbard and the adjacent continental margins. Identification of glacial-derived sediments in shelf-edge wells (Knies et al, 2009) and the development of a well-defined upper-slope depocenter (Fiedler and Faleide, 1996) at the southwestern Barents Sea margin support the supposition that NHG phase I sedimentation rates (Fig.…”

“…2B) could suggest that the KBSIS did not extend to the shelf edge. However, identification of GDFs (Laberg et al, 2010;Lasabuda et al, 2018) implies that the KBSIS was located at the shelf edge and that ice streams were active also in NHG phase III. Fiedler and Faleide (1996) and Hjelstuen et al (1996) showed that the character of bedrock exposed to erosion in the catchment areas of the Bjørnøya and Storfjorden TMFs (Fig.…”

An Early Neogene—Early Quaternary Contourite Drift System on the SW Barents Sea Continental Margin, Norwegian Arctic

“…These first-order estimates allow us to compare different sediment sources and their relative influences on ocean basin sedimentation. The calculated sedimentation rates for this ocean current system are one order of magnitude lower than the average rates calculated for the subsequent deposits from the Quaternary Barents Sea Ice Sheet (Laberg et al, 2012) in the same area and on the Northern Barents Sea margin ( Figure 9) (Lasabuda et al, 2018a). These numbers therefore support the finding of Lasabuda et al (2018b), that is, that there was a pronounced increase in sedimentation rate on the SW Barents Sea continental margin following the establishment of Northern Hemisphere Glaciations in the Quaternary.…”

Pliocene–Pleistocene glacimarine shelf to slope processes in the south‐western Barents Sea

“…MTDs make up a significant component of the upper‐slope stratigraphy, suggesting that sediment slides and slumps contributed to the basinwards transfer of sediment in our study area (Figures 5b–d, 6a–d, and 7a). We do not discern any clear patterns in the magnitude or frequency of these events through the Pliocene–Pleistocene, which might have been expected given the inferred increased rate of sediment delivery to this margin from the Early to Middle Pleistocene (Faleide et al., 1996; Laberg & Andreassen, 2007; Laberg et al., 2010) and the accompanying changes in ocean circulation that could influence slope instability (Eiken & Hinz, 1993; Elger et al., 2017; Lasabuda et al., 2018; Osti et al., 2019). Furthermore, between H5 (~1.5 Ma) and H1 (~0.2 Ma), the outer‐shelf in the southern Barents Sea experienced net accumulation and shelf aggradation that may be related to differential subsidence in the shelf and outer shelf area (Faleide et al., 1993b, 1996, 2008), with sediment accumulation within each unit varying from 10 to 700 m in thickness (Figure 3a–e).…”