1Department of Geosciences, Eberhard Karls University Tübingen,
72074 Tübingen, Germany
2Alfred Wegener Institute Helmholtz Centre for Polar and Marine
Research, 27568 Bremerhaven, Germany
3Departament de Geologia, Universitat Autònoma de Barcelona, 08193
Bellaterra (Barcelona), Spain
Received: 01 Jul 2016 – Discussion started: 11 Jul 2016
Abstract. We performed numerical simulations on the microdynamics of ice with air inclusions as a second phase. Our aim was to investigate the rheological effects of air inclusions and explain the onset of dynamic recrystallization in the permeable firn. The simulations employ a full-field theory crystal plasticity code coupled to codes simulating dynamic recrystallization processes and predict time-resolved microstructure evolution in terms of lattice orientations, strain distribution, grain sizes and grain-boundary network. Results show heterogeneous deformation throughout the simulations and indicate the importance of strain localization controlled by air inclusions. This strain localization gives rise to locally increased energies that drive dynamic recrystallization and induce heterogeneous microstructures that are coherent with natural firn microstructures from EPICA Dronning Maud Land ice coring site in Antarctica. We conclude that although overall strains and stresses in firn are low, strain localization associated with locally increased strain energies can explain the occurrence of dynamic recrystallization.
Revised: 11 Nov 2016 – Accepted: 02 Dec 2016 – Published: 21 Dec 2016
Steinbach, F., Bons, P. D., Griera, A., Jansen, D., Llorens, M.-G., Roessiger, J., and Weikusat, I.: Strain localization and dynamic recrystallization in the ice–air aggregate: a numerical study, The Cryosphere, 10, 3071-3089, doi:10.5194/tc-10-3071-2016, 2016.