Late Quaternary West Antarctic Ice Sheet Dynamics: Remote Sensing and Substrate Studies of Palaeo-Ice Sheet Beds on the Amundsen Sea Shelf

Abstract

The Amundsen Sea sector of the largely marine-based West Antarctic Ice Sheet is currently subject to the most rapid changes in the global cryosphere. Ice streams here are marine-based on slopes that significantly deepen inland, thus are susceptible to increased future ice mass loss, directly resulting in a rising sea-level of up to 3.4 m (Fretwell et al. 2013). However, state-of-the-art ice sheet models that aim to elucidate these future scenarios are only initialised with observational data covering the past 30-40 years (e.g. Favier et al. 2014), thus excluding long-term empirical data of ice sheet change spanning the Last Glacial Maximum and the subsequent deglacial period. To test the reliability of predicted future scenarios it is essential to validate models against past ice sheet configurations confirmed by empirical data from palaeo-ice sheet beds on modern Antarctic continental shelves. Attempts at reproducing the LGM ice sheet (Golledge et al. 2013), have revealed considerable mismatches between model simulations and empirical data, mainly due a lack of comprehensive palaeo-glaciological data particularly from outer continental shelves and regions in between the large palaeo-ice stream troughs, regions known as inter-ice stream ridges. This thesis presents the mapping and detailed analysis of new marine geophysical and geological data from three formerly unstudied regions on the Amundsen Sea shelf that significantly improve our understanding of Antarctic palaeo-ice sheet dynamics and will ultimately help to better understand West Antarctic Ice Sheet dynamics during and since the Last Glacial Maximum. The new information will significantly add to a hitherto sparse database of previous work, helping to test, validate, and improve ice sheet models in the vital region of the Amundsen Sea. Only by enhancing their ability to simulate past ice sheet configurations more accurately will more reliable predictions of the future evolution of these dramatically changing parts of the West Antarctic Ice Sheet be possible.