Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks. ...

• Main Authors: Wise, Matthew G, Dowdeswell, Julian A, Jakobsson, Martin, Larter, Robert D
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2017
• Subjects: 0406 Physical Geography and Environmental Geoscience; 0403 Geology; Antarctic; The Antarctic; West Antarctica; Island Bay; Pine Island Bay; Buttress; Antarc*; Antarctica; Ice Sheet; Ice Shelves; Iceberg*; Pine Island
• Online Access: https://dx.doi.org/10.17863/cam.22993; https://www.repository.cam.ac.uk/handle/1810/275729

Marine ice-cliff instability (MICI) processes could accelerate future retreat of the Antarctic Ice Sheet if ice shelves that buttress grounding lines more than 800 metres below sea level are lost. The present-day grounding zones of the Pine Island and Thwaites glaciers in West Antarctica need to retreat only short distances before they reach extensive retrograde slopes. When grounding zones of glaciers retreat onto such slopes, theoretical considerations and modelling results indicate that the retreat becomes unstable (marine ice-sheet instability) and thus accelerates. It is thought that MICI is triggered when this retreat produces ice cliffs above the water line with heights approaching about 90 metres. However, observational evidence confirming the action of MICI has not previously been reported. Here we present observational evidence that rapid deglacial ice-sheet retreat into Pine Island Bay proceeded in a similar manner to that simulated in a recent modelling study, driven by MICI. Iceberg-keel plough ...