Glacio-isostatic Adjustment (GIA) in Marguerite Bay, Antarctic Peninsula: inferences from uplifted Holocene paleoshorelines

The primary indicators of relative sea-level change along the coasts of Antarctica are the uplifted paleoshorelines, which are documented with geomorphological and geochronological studies, particularly from the Antarctic Peninsula. Some of the most prominent examples are found along the shores of Marguerite Bay, situated in the central part of the Antarctic Peninsula. Here, we present that the shorelines of Calmette Bay, located within the research area, have experienced approximately 40 m of uplift over the past 7500 years. This study aims to quantify the amount of ice mass loss required to produce such a rapid uplift and to assess the magnitude of climate change necessary to drive this degree of ice mass reduction. In addition, our goal is to constrain the mantle rheology and viscosity conditions required to produce the observed crustal response in the region. Our approach integrates various Antarctic ice-deglaciation scenarios with crustal viscosity models. We employ the numerical code SELEN⁴ to compute the sea-level equation and generate theoretical uplift/subsidence curves. We compare our results with geological data to assess alternative ice deglaciation histories and to constrain the mantle-rheology parameters that most effectively reproduce the observed uplift pattern.