Mid Holocene rapid thinning and rethickening of the East Antarctic ice sheet suggested by glacial isostatic adjustment

Abstract

Understanding East Antarctic Ice Sheet dynamics during the mid-Holocene remains challenging due to complex climate interactions. Using Global Navigation Satellite System observations and glacial isostatic adjustment modeling, we investigate the ice-sheet history in the Lützow–Holmbukta region. Here we show that scenarios incorporating modest (65–100 m) ice-sheet re-thickening following previously documented rapid thinning of ~ 400 m between 9 and 6 ka provide improved agreement with geodetic observations compared with global deglaciation models. Our analysis constrains the rheological structure beneath East Antarctica, suggesting a lithospheric thickness of 50–70 km, upper mantle viscosities of 5–7 × 1020 Pa s, and lower mantle viscosities of 6–80 × 1021 Pa s, which show excellent agreement with independent constraints from effective elastic thickness studies and are broadly compatible with seismological estimates. These findings highlight the need to incorporate regional ice-sheet histories when investigating past ice-sheet dynamics, which is essential for understanding present-day behavior and predicting future responses to climate change.