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       t012-agu2021.txt (2031B)
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            1 Below is my recorded talk for the [1]American Geophysical Union 2021 Fall
            2 Meeting. Full abstract:
            3 
            4     Title: Process-based modeling of glacial till advection
            5 
            6     Anders Damsgaard(1), Jan A. Piotrowski(1), Ian Madden(2), Jenny Suckale(2),
            7     Kenny K. Sørensen(3)
            8 
            9     1: Department of Geoscience, Aarhus University, Denmark
           10     2: Department of Geophysics, Stanford University, CA, USA
           11     3: Department of Civil and Architectural Engineering, Aarhus University,
           12     Denmark
           13 
           14     Glacial flow can reshape the Earth surface through erosion and deposition.
           15     Many past and present ice sheets lie on soft beds, and till mobilization
           16     and transport is governed by the degree of basal coupling, fluctuations in
           17     thermal state, subglacial hydrology, and the mechanics of the basal till
           18     itself. Changes in basal topography due to ice movement could theoretically
           19     feed back onto ice-flow dynamics. For example, the buildup of sedimentary
           20     grounding-zone wedges at the marine termini of ice streams may stabilize
           21     their position against local sea-level change. However, modeling of
           22     subglacial till advection has previously relied on fluid-like rheologies,
           23     which contrasts the now established concensus of Mohr-Coulomb plasticity.
           24 
           25     In our work, we aim to improve the parameterization of till advection by
           26     glacial flow. We compare a new continuum model for till against laboratory
           27     consolidation and ring-shear experiments. We show how transient dynamics in
           28     porosity and strength affect the mechanics under non-steady forcings, such
           29     as glacier stick-slip or surge. We couple the till continuum model to an
           30     ice-stream model, and demonstrate how till transport varies when ice flows
           31     over simple soft-bed basal geometries, and affects ice-stream sensitivity
           32     to external forcings.
           33 
           34 Slides and video:
           35 
           36     - slides: gopher://adamsgaard.dk/9/npub/agu2021-damsgaard.pdf
           37     - video: https://adamsgaard.dk/video/agu2021-damsgaard.mp4
           38 
           39 References:
           40 
           41 [1] https://www.agu.org/Fall-Meeting
           42