Abstract
AbstractThe development of a robust understanding of the response of the Antarctic Ice Sheet to present and projected future climatic change is a matter of key global societal importance. Numerical ice sheet models that simulate future ice sheet behaviour are typically evaluated with recourse to how well they reproduce past ice sheet behaviour, which is constrained by the geological record. However, subglacial topography, a key boundary condition in ice sheet models, has evolved significantly throughout Antarctica's glacial history. Since mantle processes play a fundamental role in the generation and modification of topography over geological timescales, an understanding of the interactions between the Antarctic mantle and palaeotopography is crucial for developing more accurate simulations of past ice sheet dynamics. This chapter provides a review of the influence of the Antarctic mantle on the long-term evolution of the subglacial landscape, through processes including structural inheritance, flexural isostatic adjustment, lithospheric cooling and thermal subsidence, volcanism and dynamic topography. The uncertainties associated with reconstructing these processes through time are discussed, as are important directions for future research and the implications of the evolving subglacial topography for the response of the Antarctic Ice Sheet to climatic and oceanographic change.
Highlights
Cin the generation and modification of topography over geological timescales, an understanding of S the interactions between the Antarctic mantle and palaeotopography is crucial for developing more accurate simulations of past ice sheet dynamics
The difference in the two-way travel times of these two reflectors gives the two-way travel time of the radar in the ice, which is multiplied by an assumed radar velocity in ice (~168 m/μs), with an additional small correction commonly made for the firn layer to give the ice thickness
M It is possible, but not conclusively demonstrated, that the long-wavelength, high-elevation domal topography of Marie Byrd Land, anomalous when compared to the adjacent West Antarctic Rift System (WARS), is in part supported by a hotspot-related thermal anomaly within the upper mantle
Summary
Ice sheet models aim to simulate the present dynamics of the AIS and predict the response of the ice. D sheet to future projected climatic change, and in turn evaluate likely changes in global sea levels E (DeConto and Pollard, 2016; Edwards et al, 2019; Golledge et al, 2015; Mengel and Levermann, T 2014). E the Aurora Subglacial Basin in East Antarctica, several hundred kilometres inland of the modern ice T margin (Aitken et al, 2016; Young et al, 2011) Such landforms likely formed near the margin of a P dynamic early ice sheet with a more restricted extent than at the present-day. C will be important boundary conditions for the modelling of older ice masses, regional ocean and A atmosphere circulation, and palaeoclimate
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