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C428: Architecture and dynamics of ice flow in the Wilkes Subglacial Basin, a key to the last glacial cycle (Lead Supervisor: Tom A. Jordan, British Antarctic Survey)

Supervisors: Tom A. Jordan (British Antarctic Survey), Julian A. Dowdeswell (Geography/SPRI) and Louise Sime (British Antarctic Survey)

Importance of the area of research:

Parts of the Antarctic Ice Sheet were likely lost during the Last Interglacial period, 116-129 thousand years ago. The dating, magnitude, and location of this mass loss remains unresolved. Our overarching objective is to reconstruct the behaviour of Wilkes Subglacial Basin ice during the Last Interglacial. This vast 500 to 1500m deep subglacial basin extends >800 km into the interior of the East Antarctic Ice Sheet. Knowledge of the evolution of this region will allow better constraint of physics in ice sheet models, and understanding of the magnitude and rates of Wilkes Subglacial Basin mass loss that have occurred in the past.

Until recently the East Antarctic Ice Sheet was considered to be relatively stable and unchanging, compared to the smaller but more dynamic marine-based West Antarctic Ice Sheet. Recent models challenging this view suggest that East Antarctic marine embayments such as the Wilkes Subglacial Basin may be prone to significant change. Today ice flow is relatively slow, but the architecture of ice sheet internal layers may preserve the signature of former enhanced ice flow, providing a key to understanding the evolution of this region through glacial cycles.

Project summary:

This project will test the hypothesis that the Wilkes Subglacial Basin hosted significantly faster ice flow during previous glacial cycles, particularly during the Last Interglacial. Techniques to evaluate, quantify and trace internal radar-derived stratigraphy of the ice sheet will be developed. Products such as layer continuity, conformity with the bedrock topography and the location of palaeo-shear margins will be used to identify regions of past enhanced flow. Tracing layers from dated ice cores at Talos Dome, and potentially Dome C, will enable dating of changes in flow. In addition it may be possible to identify and quantify variations in snow accumulation in space and time.

What the student will do:

To reveal the ice sheet's internal architecture the student will investigate and develop techniques to identify and quantify the patterns of internal radio-echo layers. This may include using commercial seismic processing software, and/or developing their own routines, e.g. in Matlab or Python. The internal stratigraphy will be integrated with navigation information to reveal the spatial pattern of layer variability and continuity, allowing identification of regions of former enhanced ice flow. By understanding the correlation with subglacial topography and present ice flow the student will constrain the critical factors which controlled ice flow during past glacial cycles, and how it has changed. Links to the Talos Dome ice core will allow the student to date the changes in ice flow. In addition there may be the opportunity to apply 1D ice sheet modelling techniques to investigate if past variations in accumulation and ice flow were coupled. The primary data source will be information from the 2005/2006 WISE/ISODYN radar survey flown by BAS. The student will be the first to use this dataset to evaluate the internal architecture and past ice flow of this critical region.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Dutton et al., (2015) Sea-level rise due to polar ice-sheet mass loss during past warm periods. Science. 349, doi:10.1126/science.aaa4019.

Bingham et al., (2007) Organized flow from the South Pole to the Filchner-Ronne ice shelf: An assessment of balance velocities in interior East Antarctica using radio echo sounding data. J. Geophys. Res. doi:10.1029/2006JF000556.

Sime, et al., (2011) Automated processing to derive dip angles of englacial radar reflectors in ice sheets. Journal of Glaciology, 57. 260-266.

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

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