1Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
2School of Geography, Politics & Sociology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
3British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
4School of GeoSciences, University of Edinburgh, Edinburgh EH8 9XP, UK
5School of Geography, University of Exeter, Exeter EX4 4RJ, UK
6Environment Department, University of York, York YO10 5DD, UK
7Grantham Institute and Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK
Received: 16 Jun 2014 – Discussion started: 15 Jul 2014
Abstract. We present ice-penetrating radar evidence for ancient (pre-glacial) and extensive erosion surfaces preserved beneath the upstream Institute and Möller ice streams, West Antarctica. Radar data reveal a smooth, laterally continuous, gently sloping topographic block, comprising two surfaces separated by a distinct break in slope. The erosion surfaces are preserved in this location due to the collective action of the Pirrit and Martin–Nash hills on ice sheet flow, resulting in a region of slow flowing, cold-based ice downstream of these major topographic barriers. Our analysis reveals that smooth, flat subglacial topography does not always correspond to regions of either present or former fast ice flow, as has previously been assumed. We discuss the potential origins of the erosion surfaces. Erosion rates across the surfaces are currently low, precluding formation via present-day glacial erosion. We suggest that fluvial or marine processes are most likely to have resulted in the formation of these surfaces, but we acknowledge that distinguishing between these processes with certainty requires further data.
Revised: 28 Jan 2015 – Accepted: 02 Feb 2015 – Published: 16 Feb 2015
Rose, K. C., Ross, N., Jordan, T. A., Bingham, R. G., Corr, H. F. J., Ferraccioli, F., Le Brocq, A. M., Rippin, D. M., and Siegert, M. J.: Ancient pre-glacial erosion surfaces preserved beneath the West Antarctic Ice Sheet, Earth Surf. Dynam., 3, 139-152, doi:10.5194/esurf-3-139-2015, 2015.