Talk by Kaitlin Keegan – Københavns Universitet

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Talk by Kaitlin Keegan

Basal ice folding of the Greenland ice sheet

New findings from deep Greenland ice cores and airborne radio echo sounding (RES) images show that basal ice flow is unstable, and that a basal layer of disturbed ice is often observed. At NEEM, Greenland this folding occurs at the boundary between the Eemian and glacial ice regimes, suggesting that differences in physical properties of the ice play a role in the disturbance. Here I will discuss our new project where we aim to study the structure of the NEEM deep ice core, across the unstable boundary, in order to understand the mechanisms causing this flow behavior. Past work in metallurgy (Burke, 1957) and ice (Hammer et al., 1978; Langway et al., 1988; Dahl-Jensen et al., 1997), suggests that impurity content controls grain evolution, and therefore deformation, which we hypothesize to be analogous to the differences in ice flow seen deep in the NEEM ice core.