Basal terraces on melting ice shelves

Ocean waters melt the margins of Antarctic and Greenland glaciers, and individual glaciers' responses and the integrity of their ice shelves are expected to depend on the spatial distribution of melt. The bases of the ice shelves associated with Pine Island Glacier (West Antarctica) and Peterma...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Dutrieux, Pierre, Stewart, Craig, Jenkins, Adrian, Nicholls, Keith W., Corr, Hugh F J., Rignot, Eric, Steffen, Konrad
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2014
Subjects:
Antarctic
West Antarctica
Greenland
Pine Island Glacier
Antarc*
Antarctica
glacier
Ice Shelf
Ice Shelves
Petermann glacier
Pine Island
Online Access:http://nora.nerc.ac.uk/id/eprint/508581/
https://nora.nerc.ac.uk/id/eprint/508581/1/grl51949.pdf
https://doi.org/10.1002/2014GL060618
Description
Summary:Ocean waters melt the margins of Antarctic and Greenland glaciers, and individual glaciers' responses and the integrity of their ice shelves are expected to depend on the spatial distribution of melt. The bases of the ice shelves associated with Pine Island Glacier (West Antarctica) and Petermann Glacier (Greenland) have similar geometries, including kilometer-wide, hundreds-of-meter high channels oriented along and across the direction of ice flow. The channels are enhanced by, and constrain, oceanic melt. New meter-scale observations of basal topography reveal peculiar glaciated landscapes. Channel flanks are not smooth, but are instead stepped, with hundreds-of-meters-wide flat terraces separated by 5–50 m high walls. Melting is shown to be modulated by the geometry: constant across each terrace, changing from one terrace to the next, and greatly enhanced on the ~45° inclined walls. Melting is therefore fundamentally heterogeneous and likely associated with stratification in the ice-ocean boundary layer, challenging current models of ice shelf-ocean interactions.

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