EGU21-3266
https://doi.org/10.5194/egusphere-egu21-3266
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Recrystallization of ice enhances the creep and vulnerability to fracture of ice shelves 

Meghana Ranganathan1, Brent Minchew2, Colin Meyer3, and Matej Pec4
Meghana Ranganathan et al.
  • 1Massachusetts Institute of Technology, School of Science, Department of Earth, Atmospheric and Planetary Sciences, United States of America (meghanar@mit.edu)
  • 2Massachusetts Institute of Technology, School of Science, Department of Earth, Atmospheric and Planetary Sciences, United States of America (minchew@mit.edu)
  • 3Thayer School of Engineering, Dartmouth College, United States of America (Colin.R.Meyer@dartmouth.edu)
  • 4Massachusetts Institute of Technology, School of Science, Department of Earth, Atmospheric and Planetary Sciences, United States of America (mpec@mit.edu)

The initiation and propagation of fractures in floating regions of Antarctica has the potential to destabilize large regions of the ice sheet, leading to significant sea-level rise. While observations have shown rapid, localized deformation and damage in the margins of fast-flowing glaciers, there remain gaps in our understanding of how rapid deformation affects the creep and toughness of ice. Here we derive a model for dynamic recrystallization in ice and other rocks that includes a novel representation of migration recrystallization, which is absent from existing models but is likely to be dominant in warm areas undergoing rapid deformation within the ice sheet. We show that, in regions of elevated strain rate, grain sizes in ice may be larger than expected (~15 mm) due to migration recrystallization, a significant deviation from solid earth studies which find fine-grained rock in shear zones. This may imply that ice in shear margins deforms primarily by dislocation creep, suggesting a flow-law exponent of n=4 in these regions. Further, we find from existing models that this increase in grain size results in a decrease in tensile strength of ice by ~75% in the margins of glaciers. Thus, we expect that this increase in grain size makes the margins of fast-flowing glaciers less viscous and more vulnerable to fracture than we may suppose from standard model parameters.

How to cite: Ranganathan, M., Minchew, B., Meyer, C., and Pec, M.: Recrystallization of ice enhances the creep and vulnerability to fracture of ice shelves , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3266, https://doi.org/10.5194/egusphere-egu21-3266, 2021.

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