Ice flow models and glacial erosion over multiple glacial–interglacial cycles

Abstract

Abstract. Mountain topography is constructed through a variety of interacting processes. Over glaciological timescales, even simple representations of glacial-flow physics can reproduce many of the distinctive features formed through glacial erosion. However, detailed comparisons at orogen time and length scales hold potential for quantifying the influence of glacial physics in landscape evolution models. We present a comparison using two different numerical models for glacial flow over single and multiple glaciations, within a modified version of the ICE-Cascade landscape evolution model. This model calculates not only glaciological processes but also hillslope and fluvial erosion and sediment transport, isostasy, and temporally and spatially variable orographic precipitation. We compare the predicted erosion patterns using a modified SIA as well as a nested, 3-D Stokes flow model calculated using COMSOL Multiphysics.Both glacial-flow models predict different patterns in time-averaged erosion rates. However, these results are sensitive to the climate and the ice temperature. For warmer climates with more sliding, the higher-order model yields erosion rates that vary spatially and by almost an order of magnitude from those of the SIA model. As the erosion influences the basal topography and the ice deformation affects the ice thickness and extent, the higher-order glacial model can lead to variations in total ice-covered area that are greater than 30 % those of the SIA model, again with larger differences for temperate ice. Over multiple glaciations and long timescales, these results suggest that higher-order glacial physics should be considered, particularly in temperate, mountainous settings.

Intermittent glacial sliding velocities explain variations in long-timescale denudation

“…Several other studies support using a simple sliding model in landscape evolution studies to drive glacial erosion (Harbor, 1992;Herman and Braun, 2008;MacGregor et al, 2000;Shuster et al, 2011; Tomkin and 1 7 Braun, 2002). The actual physical processes of glacial mechanics and erosion are much more complicated than encapsulated in the SIA approach (Egholm et al, 2012;Hallet, 1996Hallet, , 1979Headley and Ehlers, 2015;Herman et al, 2011). However, based on the results presented here, we suggest that sliding velocity derived erosion rates can capture the erosive potential of glaciers on geologic timescales.…”

Identifying spatial variations in glacial catchment erosion with detrital thermochronology

“…Detrital thermochronology offers a relatively new technique to trace the elevations from which sediment is sourced. In the context of glacial settings, this technique has potential to evaluate theoretical predictions for the distribution of erosion within glaciated catchments [e.g., Braun et al ., ; Egholm et al ., ; Herman and Braun , ; Yanites and Ehlers , ; Headley and Ehlers , ]. A comparison to glacial landscape evolution models is beyond the scope of this study, and we instead focus here on introducing how the detrital thermochronometer technique can be applied in glaciated catchments to quantify the distribution of erosion.…”

New chronological constraints on the timing of Late Pleistocene glacier advances in northern Switzerland

“…Haeberli and Schlüchter, 1987;Becker et al, 2016;Seguinot et al, 2018) and their potential to deeply erode into bedrock (e.g. Headly and Ehlers, 2015). Beside pure scientific interests, the question of possibly future glacial erosion is of high interest for the siting of nuclear waste disposal sites (Haeberli, 2010;McEvoy et al, 2016).…”