Hard rock landforms generate 130 km ice shelf channels through water focusing in basal corrugations

• Published in: Nature Communications
• Main Authors: Jeofry, H, Ross, N, Le Brocq, A, Graham, A, Li, J, Gogineni, P, Morlighem, M, Jordan, T, Siegert, MJ
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Nature 2018
• Subjects: Foundation Ice Stream; Ice Sheet; Ice Shelf
• Online Access: http://hdl.handle.net/10871/34105; https://doi.org/10.1038/s41467-018-06679-z

This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this record. Airborne radar data used in this study are freely available at the CReSIS website; [https://data.cresis.ku.edu/]. The digital elevation model of the Foundation Ice Stream, and radar data used to build it, are available at [https://doi.org/10.5194/essd-10-711-2018]. In addition, all relevant data are also available from the corresponding author. Satellite imagery reveals flowstripes on Foundation Ice Stream parallel to ice flow, and meandering features on the ice-shelf that cross-cut ice flow and are thought to be formed by water exiting a well-organised subglacial system. Here, ice-penetrating radar data show flow parallel hard-bed landforms beneath the grounded ice, and channels incised upwards into the ice shelf beneath meandering surface channels. As the ice transitions to flotation, the ice shelf incorporates a corrugation resulting from the landforms. Radar reveals the presence of subglacial water alongside the landforms, indicating a well-organised drainage system in which water exits the ice sheet as a point source, mixes with cavity water and incises upwards into a corrugation peak, accentuating the corrugation downstream. Hard-bedded landforms influence both subglacial hydrology and ice-shelf structure and, as they are known to be widespread on formerly glaciated terrain, their influence on the ice-sheet-shelf transition could be more widespread than thought previously. CReSIS radar data were collected as a part of NASA grant # NNX10AT68G and a significant resources for processing these data were provided through ANT # NT-0424589, and with additional support from the University of Kansas. IMAFI radar data were collected through UK NERC AFI grant NE/G013071/1 to MJS.