A record of Holocene relative sea-level changes on Nelson Island, South Shetland Islands, Antarctica

Abstract

Understanding past relative sea level (RSL) is important for constraining the timing and magnitude of changes in the cryosphere, providing critical benchmarks for models used to project future sea-level change, and supplying a datum for constraining past vertical motion. Past sea-level records from Antarctica can help determine the extent to which small or large changes in ice cover induce a response of the solid Earth in tectonically active settings. Here, we examine raised beaches located at Duthoit Point, Nelson Island, Antarctica. We combine geomorphic mapping and high-resolution topographic surveys to reconstruct RSL change and glacial fluctuations during the Holocene. Our study is the first record from Duthoit Point and identifies sea-level changes associated with up to four Holocene ice advances, likely occurring between ∼7000 and ∼4800 cal yr BP, at ∼2000 cal yr BP, at ∼500 cal yr BP, and during a more recent advance younger than ∼500 cal yr BP. Our findings support assertions that uplift rates are primarily driven by glacial isostatic adjustment and changes in ice extent modulate isostatic responses at centennial to millennial timescales. Improved constraints on Holocene uplift histories provide important benchmarks for evaluating isostatic adjustment models used to reconstruct past ice-sheet change and project future sea-level change.