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The evolution of deformation mechanisms during the mechanical weakening of polycrystalline ice: a quantitative microstructural study

A talk by Otago Geology PhD candidate Sheng Fan

Flowing glaciers and ice sheets play key roles in shaping planetary surfaces, and form important feedbacks with climate, both on Earth and elsewhere in the solar system. Ice deformation is a significant component of ice flow. Ice becomes mechanically weaker during the deformation—the rate of ice flow accelerates as the deformation progresses from low to high strain, at a constant temperature. Such mechanical weakening is controlled by microstructural changes such as grain size reduction and alignment of ice crystallographic axes.

Therefore, we have to understand the mechanisms that lead to the ice microstructural changes during the deformation, in order to improve the current ice sheet dynamic models. This research includes ice deformation experiments coupled with cryogenic electron backscattered diffraction (cryo-EBSD) analyses. We quantified the ice microstructural evolution from cryo-EBSD data, and these data were used to predict the activity of deformation mechanisms that are responsible for the mechanical weakening of ice.

Date Monday, 25 January 2021
Time 1:00pm - 1:50pm
Audience All University
Event Category Sciences
Event Type Academic
Departmental Seminar
CampusDunedin
DepartmentGeology
LocationBenson Common Room (Gn9), Geology Building, University of Otago, Dunedin
CostFree
Contact NameSheng Fan
Contact Emailsheng.fan@postgrad.otago.ac.nz

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