Solid Earth change and the evolution of the Antarctic Ice Sheet

Abstract

Recent studies suggest that Antarctica has the potential to contribute up to ~15 m of sea-level rise over the next few centuries. The evolution of the Antarctic Ice Sheet is driven by a combination of climate forcing and non-climatic feedbacks. In this review we focus on feedbacks between the Antarctic Ice Sheet and the solid Earth, and the role of these feedbacks in shaping the response of the ice sheet to past and future climate changes. The growth and decay of the Antarctic Ice Sheet reshapes the solid Earth via isostasy and erosion. In turn, the shape of the bed exerts a fundamental control on ice dynamics as well as the position of the grounding line—the location where ice starts to float. A complicating issue is the fact that Antarctica is situated on a region of the Earth that displays large spatial variations in rheological properties. These properties affect the timescale and strength of feedbacks between ice-sheet change and solid Earth deformation, and hence must be accounted for when considering the future evolution of the ice sheet.

Paleogene Marine and Terrestrial Development of the West Antarctic Rift System

“…The absence of Neogene fossils at Site 1 therefore implies deeper glacial erosion than at the other sites, with ongoing unroofing and removal of younger strata. Because Miocene and younger marine strata must have accumulated there during periods of reduced ice, the lack of young fossils implies significantly more uplift at Site 1 than the others; a conclusion consistent with tectonic interpretations (Whitehouse et al, 2019;Winberry & Anandakrishnan, 2004;Begeman et al, 2017;Nield et al, 2018;Barletta et al, 2018;Fisher et al, 2015;Spiegel et al, 2016).…”

“…Additionally, the Marie Byrd Land region has a higher uplift potential as a result of a thinner crust with a low viscosity, responsive mantle (Whitehouse et al, 2019) likely influenced by an inferred mantle plume (Winberry & Anandakrishnan, 2004;Begeman et al, 2017;Nield et al, 2018;Barletta et al, 2018;Fisher et al, 2015). Spiegel et al (2016) suggest the uplift arising from plume activity occurred~20 Ma.…”

“…Based on thermal subsidence estimates, plate movement and glacial erosion inferred from seismically defined offshore sedimentary bodies (Paxman et al, ; Wilson et al, , ), models reconstructing the Antarctic landmass suggest that extensive uplands and coastal lowlands existed in the Ross Embayment sector of West Antarctica during Late Eocene time. Evaluating Late Paleogene paleotopographic conditions is important because one of two alternate published paleolandscape models (Wilson et al, ) has been widely applied in paleoglaciological (Levy et al, ) and paleotectonic (Whitehouse et al, ) studies. Uncertainties associated with model input data led the authors (Wilson et al, , ) to present two alternative reconstructions for the end of the Eocene: a “minimum” reconstruction, characterized by coastal lowlands, and a “maximum” reconstruction that includes a broad landmass with uplands reaching 1,000‐m above sea level across the southern Ross Embayment (a term we will use to encompass the entire study area; Figure b).…”

Major Ice Sheet Change in the Weddell Sea Sector of West Antarctica Over the Last 5,000 Years

“…GIA model predictions of present-day uplift rates across the WS sector vary significantly in both spatial pattern and magnitude (Whitehouse et al, 2019). The majority of models predict maximum present-day uplift rates in the region of the HIR, KIR, and BIR, with predicted rates peaking at >10 mm/year (Argus et al, 2014;Whitehouse, Bentley, Milne, et al, 2012).…”

“…However, a significant limitation of this approach, aside from the uncertainty associated with climate forcing, is the need to know the correct Earth rheology. Upper mantle viscosity across Antarctica is thought to vary by >3 orders of magnitude (Hay et al, 2017;van der Wal et al, 2015;Whitehouse et al, 2019). The associated range in mantle relaxation times significantly perturbs the strength of the feedback between isostatic deformation and ice dynamics in different regions of Antarctica (Gomez et al, 2015;Konrad et al, 2015;Pollard et al, 2017) and motivates the need for a coupled ice sheet-GIA model that incorporates 3-D Earth structure.…”