Numerical modeling of the past stability of the Wilkes Subglacial Basin (East Antarctica) continental margin: interplay between glacio-isostatic adjustment and ice-sheet dynamics.

The continental margin of the Wilkes Subglacial Basin (WSB) in East Antarctica presents a complex morphology, with overdeepened basins and articulated sedimentary architectures, which reflect an evolutionary history controlled by interactions between ice-sheet dynamics, ocean circulation, isostatic response, and sedimentary processes. The existing marine seismic data suggest a dynamic history of ice-sheet advances and retreats, with episodes of submarine continental-slope instability. The study focuses on the role of glacio-isostatic adjustment (GIA) in controlling the morphological changes of the Wilkes continental margin during the Late Pleistocene. To achieve this objective, we use a combination of two GIA models, TABOO (Spada et al., 2003) and the Sea-level Equation Solver SELEN4 (Spada et al., 2019) to reconstruct the temporal evolution of uplift and subsidence along the WSB continental margin. TABOO allows us to compute the general response of a spherically symmetric, incompressible, Maxwell viscoelastic and self-gravitating Earth to ice loads. SELEN4 solves the sea-level equation for a 1D spherically symmetric Earth with linear viscoelastic rheology, taking into account the migration of shorelines and the rotational feedback on sea level. Recent seismic tomography studies suggest that the lithosphere is thinner than previously thought in this sector and this also suggests that the mantle beneath could be less viscous than usually prescribed in ice-sheet models (Hansen et al., 2025). We set up idealised simulations of the WSB to understand the sensitivity of its continental margin to ice surface loads and rheological variations of the lithosphere and the Earth’s mantle. This work aims to highlight the role that GIA played in the morphological evolution of the WSB continental margin and the consequent influence on ice-sheet stability and on its potential contribution to global sea level during deglaciation phases.