1,4,6- 1Loughborough University, Geography and Environment, Loughborough, Leicestershire, United Kingdom of Great Britain – England, Scotland, Wales (j.hillier@lboro.ac.uk)
- 2Royal Geographical Society, South Kensington, London, SW7 2AR, UK
- 3University of Aukland, Faculty of Science, Aukland, 1010, New Zealand
- 4Dept of Earth Sciences, Università Di Torino, 10124 Turin, Italy.
- 5School of Earth, Environment and Society. McMaster University.
- 6British Antarctic Survey, Cambridge, Madingley Rd, Cambridge CB3 0ET, UK.
For over 100 years, from school textbook to research, glacially sculpted landforms called drumlins have been considered asymmetrical, tear-drop shaped. Recent work has securely demonstrated that, in the absence of bedrock, this asymmetry is measurable but tiny – non-existent to visual inspection. High-resolution DEMs and a novel application of statistics to flow-sets demonstrate that a well-studied a Swedish site exhibits a transition from asymmetrical bedrock-cored drumlins to symmetrical till-cored ones within just a few 10s of m of till. We believe that this is the first direct observational constraint upon the thickness of till required to effectively decouple flowing ice from rough bedrock topography. Understanding where till lubrication has the potential to speed up ice flow has large implications for modelling current ice sheets and Antarctic deglaciation, so we are hoping for ideas of how to best assess this last part.
How to cite: Hillier, J. K., Smith, M., Dowling, T., Spagnolo, M., Maclachlan, J., and Martin, C.: Symmetrical till-cored drumlins highlight where past ice sheets flowed faster, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2751, https://doi.org/10.5194/egusphere-egu26-2751, 2026.
