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SUMMARY:Where might we find evidence of a Last Interglacial West Antarctic
  ice sheet collapse in Antarctic ice core records? - Sarah Bradley\, Depar
 tment of Earth Sciences\, University of Bristol\, Bristol\, UK
DTSTART:20120529T143000Z
DTEND:20120529T153000Z
UID:TALK37421@talks.cam.ac.uk
CONTACT:Dr. Ailsa Benton
DESCRIPTION:Despite numerous studies exploring the evolution of the West A
 ntarctic Ice sheet (WAIS) during the Last Interglacial (LIG)\, when it is 
 widely believed to have significant reduced in size compared to the Holoce
 ne\, major uncertainties and unknowns are still left unresolved: Did the W
 AIS fully collapse and if so\, what caused and how rapid was this collapse
 ? What would be the impact and its contribution to the higher than present
  global mean sea level?\n\nUnderstanding and constraining the spatial and 
 temporal history of the WAIS during this period is complicated due to spar
 se amount of direct evidence. Most previous studies have relied upon indir
 ect data records\, such as far-field sea level data (Kopp et al.\, 2009) o
 r paleoclimatic data (oceanic or δ180 record) (McKay et al.\, 2011\; Menv
 iel et al.\, 2010). However\, these data records are sensitive not only to
  the impact of changes in the WAIS but to multiple signals/processes in th
 e climate system and this suggests that a new approach is needed to addres
 s many of these remaining questions.\n\nThis study uses a different method
 ology to explore these issues by comparing for the first time\, East Antar
 ctic stable isotope ice core records (δD) for the LIG with the output fro
 m a glacial-isostatic adjustment (GIA) model. Results of a sensitivity stu
 dy are presented which investigated if isostatically driven changes in sur
 face elevation from a number of idealised models for the WAIS retreat will
  generate a resolvable and significant δD signal at these ice core sites.
  This is the first time this approach has been taken to seek evidence for 
 the evolution of the WAIS during the LIG. \n\nIt will be shown that a simu
 lated collapse of the WAIS does not generate a significant elevation-drive
 n δD signal at the East Antarctic LIG ice core sites and as such\, these 
 ice core records cannot be used to assess WAIS stability over this period.
  However\, treasure maps of the predicted δD and associated change in sur
 face elevation are presented to identify regions which are sensitive to th
 e isostatic signal associated with the WAIS collapse. These maps could be 
 used by the wider community/field scientists to highlight sites where new 
 data records obtained from geological studies (such as exposure ages) and/
 or new paleoclimatic data (such as ice core reconstructions) could constra
 in the evolution of the WAIS during the LIG. \n\nKopp\, R.E.\, Simons\, F.
 J.\, Mitrovica\, J.X.\, Maloof\, A.C. and Oppenheimer\, M.\, 2009. Probabi
 listic assessment of sea level during the last interglacial stage. Nature\
 , 462(7275)\, 863-867.\nMcKay\, N.P.\, Overpeck\, J.T. and Otto-Bliesner\,
  B.L.\, 2011. The role of ocean thermal expansion in Last Interglacial sea
  level rise. Geophysical Research Letters\, 38\, 6.\nMenviel\, L.\, Timmer
 mann\, A.\, Timm\, O.E. and Mouchet\, A.\, 2010. Climate and biogeochemica
 l response to a rapid melting of the West Antarctic Ice Sheet during inter
 glacials and implications for future climate. Paleoceanography\, 25\, 12\n
LOCATION:room 307\, British Antarctic Survey\, High Cross\, Cambridge\, CB
 3 0ET
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