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

• Published in: Nature Communications
• Main Authors: Jeofry, Hafeez, Ross, Neil, Le Brocq, Anne, Graham, Alastair G.C., Li, Jilu, Gogineni, Prasad, Morlighem, Mathieu, Jordan, Thomas, Siegert, Martin J.
• Format: Text
• Language: English
• Published: Nature Publishing Group UK 2018
• Subjects: Article; Foundation Ice Stream; Ice Sheet; Ice Shelf
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212400/; http://www.ncbi.nlm.nih.gov/pubmed/30385741; https://doi.org/10.1038/s41467-018-06679-z

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.