Variations in Glacial Erosion over Multiple Glacial-Interglacial Cycles
Abstract
Glacial erosion plays an important role in the construction and development of many mountain ranges. When modeling orogenic development, the choice of ice-flow physics can have an influence on developing topography, though many simple models can still produce the distinctive geomorphological features associated with glaciated topography. However, detailed comparisons at orogenic-time and length scales hold potential for quantifying the influence of glacial physics in landscape evolution models. Within a modified version of the ICE-Cascade landscape evolution model, we present results from a comparison between two different numerical models of glacial flow. This orogenic model calculates not only glaciological processes but also hillslope and fluvial erosion, sediment transport, isostasy, and temporally and spatially variable orographic precipitation. Over single and multiple glaciations and in a variety of climate scenarios, glacial erosion rates and topographic evolution are analyzed. We compare the predicted erosion patterns using a modified SIA as well as a nested, 3D Stokes-flow model calculated using COMSOL Multiphysics. The time-averaged erosion rates differ between the two models of ice physics. In addition, these results and the amount of variation between the models are sensitive to the climate and the ice temperature. For warmer climates with more sliding, the higher-order model leads to larger erosion rates, by almost an order of magnitude, also with more variance. Additionally, as the erosion, basal topography and the ice deformation are all interconnected through the glacial dynamics, comparisons of large-scale and glacier-wide properties can also be instructive. For these properties, particularly the ice thickness and extent, the higher-order glacial model can lead to variations between the ice flow models that are greater than 30%, again with larger differences for temperate ice. When compared after multiple glaciations and long-time scales, these results suggest that consideration of higher-order glacial physics may be necessary, particularly in regions with extensive temperate or polythermal glaciers.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMEP41B0799H
- Keywords:
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- 0720 CRYOSPHERE Glaciers;
- 0774 CRYOSPHERE Dynamics;
- 8175 TECTONOPHYSICS Tectonics and landscape evolution