A. Clara J. Henry

and 6 more

Ice rises situated around the perimeter of Antarctica buttress ice flow and contain information about the past climate and changes in flow regime. Moreover, ice rises contain convergent and divergent flow regimes, and both floating and grounded ice over comparatively small spatial scales, meaning they are ideal locations to study ice-flow dynamics. Here, we introduce a new modelling framework that permits the comparison between modelled and observed stratigraphy. A thermo-mechanically coupled, isotropic, full Stokes ice flow model with a dynamic grounding line is used (Elmer/Ice). The result is the simulated age-depth field of a three-dimensional, steady-state ice rise which is dynamically coupled to the surrounding ice shelf. Applying the model to Derwael Ice Rise, results show a good match between observed and modelled stratigraphy over most of the ice rise and predict approximately 8000 year old ice at a depth of 95 %. Differences in the prediction of age between simulations using Glen’s flow law exponents of n=3 and n=4 are generally small (<5 % over most areas). In the ice rise shear zones, large differences in shear strain rates in the velocity direction are found between the n=3 and the n=4 simulations. Our simulations indicate that a Glen’s flow law exponent of n=4 may be better suited when modelling ice rises due to a steady-state geometry which is closer to the observed geometry. Our three-dimensional modelling framework can easily be transferred to other ice rises and has relevance for researchers interested in ice core dating and understanding ice-flow re-organisation.