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Proglacial braided river systems discharge large volumes of meltwater from ice sheets and transport 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 ~0.64 m km−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 morphological 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. [ABSTRACT FROM AUTHOR]

The study by Thy, Tegner, and Lesher (Thy et al. 2009b) is based on whole-rock compositions in batch-melting experiments at one atmosphere that have a very large temperature variation for a very small plagioclase compositional variation. Their steep T-X slopes of up to 14 °C/An% contrast with the overall regression for the intrusion of <4 °C/An%. This paradox can be evaluated by using separate tests for equilibrium in temperature and composition. The issue of temperature is clouded by the presence of low-temperature components in the beginning of melting experiments. Compositions of plagioclase and liquid are too close to each other compared to expectations from other experiments at 1 atm and at pressure. A ruling hypothesis is perceived here to the effect that every T-X pair represents a valid equilibrium between a liquidus composition and a solidus composition. Therefore, by inversion, each solidus composition defines a valid temperature. Its corollary is that all such pairs receive equal weight and can therefore be legitimately regressed together. The Thy et al. (2009b) regression is passed through the center of gravity of the data rather than through the extrapolated maximum liquidus points. If the ruling hypothesis is falsified, these approaches lose their validity; upon testing, it is falsified. In temperature, testing leads to consequences known to be false. In composition, a test for reproducibility in results also fails, thereby falsifying the principle of stable equilibrium. The falsifications are repeated in at least three ways. The study results cannot furnish a valid thermal path for the fractional crystallization of Skaergaard magma. A selection of the highest-temperature results comes closer to a realistic result based on comparison with earlier experiments that melted out the trapped liquid component of the Skaergaard cumulates. New experimental approaches at the liquidus are needed to help define temperatures and fractionation progress in the Skaergaard intrusion. [ABSTRACT FROM AUTHOR]