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

Abstract

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 × 10 20 Pa s, and lower mantle viscosities of 6–80 × 10 21 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.