Past ice-sheet behaviour: retreat scenarios and changing controls in the Ross Sea, Antarctica
Studying the history of ice-sheet behaviour in the Ross Sea, Antarctica's largest drainage basin can improve our understanding of patterns and controls on marine-based ice-sheet dynamics and provide constraints for numerical ice-sheet models. Newly collected high-resolution multibeam bathymetry...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-05-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/10/1003/2016/tc-10-1003-2016.pdf |
| Summary: | Studying the history of ice-sheet behaviour in the Ross Sea,
Antarctica's largest drainage basin can improve our understanding of
patterns and controls on marine-based ice-sheet dynamics and provide
constraints for numerical ice-sheet models. Newly collected high-resolution
multibeam bathymetry data, combined with two decades of legacy multibeam and
seismic data, are used to map glacial landforms and reconstruct palaeo
ice-sheet drainage.
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During the Last Glacial Maximum, grounded ice reached the continental shelf
edge in the eastern but not western Ross Sea. Recessional geomorphic
features in the western Ross Sea indicate virtually continuous back-stepping
of the ice-sheet grounding line. In the eastern Ross Sea, well-preserved
linear features and a lack of small-scale recessional landforms signify
rapid lift-off of grounded ice from the bed. Physiography exerted a
first-order control on regional ice behaviour, while sea floor geology played
an important subsidiary role.
<br><br>
Previously published deglacial scenarios for Ross Sea are based on
low-spatial-resolution marine data or terrestrial observations; however,
this study uses high-resolution basin-wide geomorphology to constrain
grounding-line retreat on the continental shelf. Our analysis of retreat
patterns suggests that (1) retreat from the western Ross Sea was complex
due to strong physiographic controls on ice-sheet drainage; (2) retreat was
asynchronous across the Ross Sea and between troughs; (3) the eastern Ross Sea
largely deglaciated prior to the western Ross Sea following the formation of
a large grounding-line embayment over Whales Deep; and (4) our glacial
geomorphic reconstruction converges with recent numerical models that call
for significant and complex East Antarctic ice sheet and West Antarctic ice
sheet contributions to the ice flow in the Ross Sea. |
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| ISSN: | 1994-0416 1994-0424 |