Spatiotemporal variations in the East Antarctic Ice Sheet during the Holocene

Abstract. The past changes in East Antarctic Ice Sheet (EAIS) are crucial for understanding the ice sheet dynamics and its response to the Earth’s climate system. Field-based geological data and various model simulations, such as ice sheet and glacial isostatic adjustment (GIA) modellings, provide significant insights into the behaviour of EAIS during the interglacial–glacial cycle. Recent in-situ cosmogenic nuclide surface exposure studies have revealed a large-scale thinning occurred in the Dronning Maud Land and Enderby Land of East Antarctica during 9–6 ka. However, the timing of this EAIS thinning event necessitates a revision of the ICE-6G model, which is a widely used GIA-based ice sheet history. To account for this temporal discrepancy, it is necessary to compare the sea levels calculated by GIA modelling with sea-level reconstructions to evaluate the validity of this refinement. The computed sea levels by GIA modelling are consistent with the relative sea-level reconstructions and indicate the spatial difference in the Holocene sea-level peaks, which is primarily due to the differences in the timings of ice-mass losses in the east and west of the Indian Ocean sector of East Antarctica. This finding challenges the prevailing assumption of synchronized ice-sheet growth and decay across this region, suggesting that the ice mass changes in the EAIS exhibit significant spatial differences.