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Science. 2014 Sep 12;345(6202):1354-8. doi: 10.1126/science.1256697.

Boundary condition of grounding lines prior to collapse, Larsen-B Ice Shelf, Antarctica.

Author information

1
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/C-34010, Sgonico (TS) Italy.
2
Department of Geosciences, Hamilton College, Clinton, NY 13323, USA. College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, FL 33701-5016, USA. edomack@usf.edu.
3
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/C-34010, Sgonico (TS) Italy. Centre for Environmental and Marine Studies/Department of Geosciences, University of Aveiro, Aveiro 3810-193, Portugal.
4
Department of Geology, Colgate University, Hamilton, NY 13346, USA.
5
Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, USA.
6
International Cooperation, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung. Am Handelshafen 12, 27570 Bremerhaven, Germany.
7
Earth and Planetary Sciences, McGill University, Montreal, Quebec H3A 2A7, Canada.
8
Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
9
National Snow and Ice Data Center, University of Colorado, Boulder, CO 80309, USA.
10
British Antarctic Survey, Cambridge CB3 0ET, UK.
11
Department of Geosciences, 900 Yukon Drive, Room 308, Post Office Box 755780, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.

Abstract

Grounding zones, where ice sheets transition between resting on bedrock to full floatation, help regulate ice flow. Exposure of the sea floor by the 2002 Larsen-B Ice Shelf collapse allowed detailed morphologic mapping and sampling of the embayment sea floor. Marine geophysical data collected in 2006 reveal a large, arcuate, complex grounding zone sediment system at the front of Crane Fjord. Radiocarbon-constrained chronologies from marine sediment cores indicate loss of ice contact with the bed at this site about 12,000 years ago. Previous studies and morphologic mapping of the fjord suggest that the Crane Glacier grounding zone was well within the fjord before 2002 and did not retreat further until after the ice shelf collapse. This implies that the 2002 Larsen-B Ice Shelf collapse likely was a response to surface warming rather than to grounding zone instability, strengthening the idea that surface processes controlled the disintegration of the Larsen Ice Shelf.

PMID:
25214629
DOI:
10.1126/science.1256697
[Indexed for MEDLINE]
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