Journal of Glaciology: Characterization of a glacial paleo-outburstflood using high-resolution 3-D seismic data: Bjørnelva River Valley, SW Barents Sea

B. Bellwald (VBPR), S. Planke (VBPR, UiT, UiO), S. Polteau (VBPR), N. Lebedeva-Ivanova (VBPR), J.I. Faleide (UiO, UiT), S.M. Morris  (VBPR), S. Morse (Lyme Bay Consulting, UK) and S. Castelltort (Univ. Geneve, Switzerland) have published the paper “Characterization of a glacial paleo-outburst flood using high-resolution 3-D seismic data: Bjørnelva River Valley, SW Barents Sea” in the Journal of Glaciology.

Abstract:

Proglacial braided river systems discharge large volumes of meltwater from ice sheets and trans- port coarse-grained sediments from the glaciated areas to the oceans. Here, we test the hypothesis if high-energy hydrological events can leave distinctive signatures in the sedimentary record of braided river systems. We characterize the morphology and infer a mode of formation of a 25 km long and 1–3 km wide Early Pleistocene incised valley recently imaged in 3-D seismic data in the Hoop area, SW Barents Sea. The fluvial system, named Bjørnelva River Valley, carved 20 m deep channels into Lower Cretaceous bedrock at a glacial paleo-surface and deposited 28 channel bars along a paleo-slope gradient of ∼0.64mkm−1. The landform morphologies and position relative to the paleo-surface support that Bjørnelva River Valley was formed in the proglacial domain of the Barents Sea Ice Sheet. Based on valley width and valley depth, we suggest that Bjørnelva River Valley represents a braided river system fed by violent outburst floods from a glacial lake, with estimated outburst discharges of ∼160 000 m3 s−1. The morpho- logical configuration of Bjørnelva River Valley can inform geohazard assessments in areas at risk of outburst flooding today and is an analogue for landscapes evolving in areas currently covered by the Greenland and Antarctic ice sheets.

Reference:

B. Bellwald, S. Planke, S. Polteau, N. Lebedeva-Ivanova, J.I. Faleide, S.M. Morris, S. Morse  and S. Castelltort (2021): Characterization of a glacial paleo-outburst flood using high-resolution 3-D seismic data: Bjørnelva River Valley, SW Barents Sea, Journal of Glaciology, pp. 1–17. [intranet], DOI: https://doi.org/10.1017/jog.2020.115