Massive subsurface ice formed by refreezing of ice-shelf melt ponds.
Surface melt ponds form intermittently on several Antarctic ice shelves. Although implicated in ice-shelf break up, the consequences of such ponding for ice formation and ice-shelf structure have not been evaluated. Here we report the discovery of a massive subsurface ice layer, at least 16 km across, several kilometres long and tens of metres deep, located in an area of intense melting and intermittent ponding on Larsen C Ice Shelf, Antarctica. We combine borehole optical televiewer logging and radar measurements with remote sensing and firn modelling to investigate the layer, found to be ∼10 °C warmer and ∼170 kg m(-3) denser than anticipated in the absence of ponding and hitherto used in models of ice-shelf fracture and flow. Surface ponding and ice layers such as the one we report are likely to form on a wider range of Antarctic ice shelves in response to climatic warming in forthcoming decades.
Centre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, UK.
Bryn
http://orcid.org/0000-0002-3565-3875
B
Hubbard
Glaciology Group, Department of Geography, Swansea University, Swansea SA2 8PP, UK.
Adrian
http://orcid.org/0000-0002-9618-5905
A
Luckman
Centre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, UK.
David W
DW
Ashmore
Glaciology Group, Department of Geography, Swansea University, Swansea SA2 8PP, UK.
Suzanne
S
Bevan
Glaciology Group, Department of Geography, Swansea University, Swansea SA2 8PP, UK.
Bernd
B
Kulessa
Glaciology Group, Department of Geography, Swansea University, Swansea SA2 8PP, UK.
Peter
P
Kuipers Munneke
Laboratoire de Glaciologie, Département Géosciences, Environnement et Société, Université Libre de Bruxelles, Bruxelles 1050, Belgium.
Morgane
M
Philippe
Alfred Wegener Institut, Helmholtz-Zentrum für Polar- und Meeresforschung D-27568, Bremerhaven, Germany.
Daniela
D
Jansen
School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
Adam
A
Booth
Department of Arctic Geology, University Centre in Svalbard, N-9171 Longyearbyen, Norway.
Heidi
H
Sevestre
Laboratoire de Glaciologie, Département Géosciences, Environnement et Société, Université Libre de Bruxelles, Bruxelles 1050, Belgium.
Jean-Louis
JL
Tison
Glaciology Group, Department of Geography, Swansea University, Swansea SA2 8PP, UK.
Martin
M
O'Leary
Glaciology Group, Department of Geography, Swansea University, Swansea SA2 8PP, UK.
Ian
I
Rutt