Modelled stress distributions at the Dome Summit South borehole, Law Dome, East Antarctica: a comparison of anisotropic ice flow relations

• Published in: Journal of Glaciology
• Main Authors: Treverrow, A, Warner, RC, Budd, WF, Jacka, TH, Roberts, JL
• Format: Article in Journal/Newspaper
• Language: English
• Published: Int Glaciol Soc 2015
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; East Antarctica; Law Dome; Antarc*; Antarctica; Journal of Glaciology
• Online Access: https://doi.org/10.3189/2015JoG14J198; http://ecite.utas.edu.au/104646

In this study we compare the anisotropic flow relations for polycrystalline ice of Azumaand Goto-Azuma (1996), Thorsteinsson (2002), Placidi and others (2010) and Budd and others (2013).Observations from the Dome Summit South (DSS) ice-coring site at Law Dome, East Antarctica, areused to model the vertical distribution of deviatoric stress components at the borehole site. The flowrelations in which the anisotropic rheology is parameterized by a scalar function, so that the strain-rateand deviatoric stress tensor components are collinear, provide simple shear and vertical compressiondeviatoric stress profiles that are most consistent with laboratory observations of tertiary creep incombined stress configurations. Those flow relations where (1) the anisotropy is derived from themagnitude of applied stresses resolved onto the basal planes of individual grains and (2) themacroscopic deformation is obtained via homogenization of individual grain responses provide stressestimates less consistent with laboratory observations. This is most evident in combined simple shearand vertical compression flow regimes where shear is dominant. Our results highlight the difficultiesassociated with developing flow relations which incorporate a physically based description ofmicrodeformation processes. In particular, this requires that all relevant microdeformation,recrystallization and recovery processes are adequately parameterized.