The dynamics of the West Antarctic Ice Sheet during the Cenozoic

Helmholtz Postdoc project PD-201, Dr. J. P. Klages, funding period 2015-2018

By investigating unprocessed geological and geophysical data from past RV Polarstern and RRS James Clark Ross (British Antarctic Survey, UK) cruises to the Amundsen Sea Embayment (ASE), as well as core material from the planned ASE-MeBo drilling campaign on RV Polarstern in early 2017, the Helmholtz Postdoc project aims to significantly improve insights into the long-term glacial history of the inherently-unstable marine-based West Antarctic Ice Sheet (WAIS; Fig. 1). Unopened gravity- and vibrocores from the ASE shelf as well as longer MeBo drill core records will

  • enable precise 'better-than-today' post-LGM retreat chronologies,
  • provide crucial information about the retreat pattern of the ice sheet, i.e. precise timing and duration of stabilization phases during general post-LGM WAIS retreat, and
  • put the recent rapid changes in the region into a long-term context spanning the Cenozoic.

These factors are still poorly known, although they are of highest relevance, in order to assess the threat of a partial or full future WAIS collapse more precisely, which would raise the global sea level by several metres. Previous studies modelled repeated WAIS collapses during the past ~5 million years, direct and definite geological evidence however still lacks as the only available sedimentary drill core record has been recovered from beneath the Ross Ice Shelf, thereby not providing a ‘pure’ WAIS signal. Finally, I aim to define the forcing mechanisms that may have led to ice sheet collapse during times that have been similar to today or were characterized by conditions that are predicted for the end of the 21st century.

Project collaborators

G. Kuhn and K. Gohl (AWI)

C.-D. Hillenbrand, J. A. Smith (British Antarctic Survey, UK)

A. G. C. Graham (University of Exeter, UK)

a) Modern topograhy of the Antarctic continent without ice. b) Profile of the Antarctic Ice Sheet (indicated by line AB in a) (modified from Fretwell et al. 2013, The Cryosphere). The figure illustrates inherent instability of the West Antarctic Ice Sheet (WAIS), as it is largely marine-based, in contrast to East Antarctic Ice Sheet (EAIS).