Million-year Ice from Antarctica and the “Stagnant” Ice Zone: From Microstructure to Geochemistry (MIA:Mic2Geo) – linking BEOI’s “stagnant” ice, COLDEX’s Allan Hills blue ice, and Million Year Ice Core ice

Several international projects aim to retrieve million-year-old ice from Antarctica. Most focus on obtaining a continuous climate record. In the about-to-start 5-year project Million-year Ice from Antarctica (MIA), we will conduct an observation-based assessment of the potential of a preserved climate record older than 1.5 Myr in the European flagship ice core, BEOI. MIA will explore the “stagnant” ice zone, a roughly 200 m thick area of presumed stagnant ice that has not yet been characterised. In addition to exploiting its full paleoclimatic potential, MIA will advance our understanding of the ice dynamics of “stagnant" ice. This is highly relevant for ice sheets and glaciers and, thus, their impact on future sea level rise via solid ice discharge into the oceans. To accomplish these ambitious goals, we will apply a holistic approach. We will simultaneously analyse microstructural (e.g., grain size and shape, crystal-preferred orientation) and geochemical properties (e.g., impurity localisation) of solid ice samples using multiple methods. We will combine these measurements with the full-Stokes numerical ice flow model Underworld2, applying derived anisotropy data. We will also compare these results with the deepest sections of BEOI’s counterpart, the Million Year Ice Core (MYIC) project by the Australian Antarctic Division. MYIC is assumed to contain (almost) no “stagnant” ice. To fully exploit our interdisciplinary approach, we will analyse 2 COLDEX blue ice cores from the Allan Hills region, where the so-far-oldest ice on Earth was found. This contribution will outline the next five years of the MIA project and its potential to enhance our understanding of the oldest parts of the Antarctic Ice Sheet.