Dome C migration in Antarctica during the last 800,000 years

Abstract. The ice core extracted as part of the Beyond EPICA project is expected to provide the longest continuous climate record, reaching back at least 1.2 million years. However, the hypothesis that Dome C has remained stable over several glacial-interglacial cycles, which is a prerequisite for establishing a reliable age-depth relationship, remains unverified. Using the GRISLI2.0 ice sheet model, we perform an ensemble of 5 high-resolution nested simulations at 10 km × 10 km resolution to track the evolution of Dome C position over the past 800,000 years. Our results show that Dome C undergoes substantial displacements over time, strongly controlled by grounding line dynamics in the Aurora Subglacial Basin. Using a 1D ice flow model, we further demonstrate that these dome migrations can introduce age errors of several tens of thousands of years in the age-depth relationship, with the largest uncertainties affecting the oldest and deepest ice, precisely where the Beyond EPICA record is most critical.