A centuries-long delay between a paleo-ice-shelf collapse and grounding-line retreat in the Whales Deep Basin, eastern Ross Sea, Antarctica

Recent thinning and loss of Antarctic ice shelves has been followed by near synchronous acceleration of ice flow that may eventually lead to sustained deflation and significant contraction in the extent of grounded and floating ice. Here, we present radiocarbon dates from foraminifera that constrain...

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Bibliographic Details
Published in:Scientific Reports
Main Authors: Bart, Philip J., DeCesare, Matthew, Rosenheim, Brad E., Majewski, Wojceich, McGlannan, Austin
Format: Text
Language:English
Published: Nature Publishing Group UK 2018
Subjects:
Article
Antarctic
Ross Sea
West Antarctic Ice Sheet
Antarc*
Antarctica
Ice Sheet
Ice Shelf
Ice Shelves
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6098127/
http://www.ncbi.nlm.nih.gov/pubmed/30120261
https://doi.org/10.1038/s41598-018-29911-8
Description
Summary:Recent thinning and loss of Antarctic ice shelves has been followed by near synchronous acceleration of ice flow that may eventually lead to sustained deflation and significant contraction in the extent of grounded and floating ice. Here, we present radiocarbon dates from foraminifera that constrain the time elapsed between a previously described paleo-ice-shelf collapse and the subsequent major grounding-line retreat in the Whales Deep Basin (WDB) of eastern Ross Sea. The dates indicate that West Antarctic Ice Sheet (WAIS) grounding-line retreat from the continental shelf edge was underway prior to 14.7 ± 0.4 cal kyr BP. A paleo-ice-shelf collapse occurred at 12.3 ± 0.2 cal kyr BP. The grounding position was maintained on the outer-continental shelf until at least 11.5 ± 0.3 cal kyr BP before experiencing a 200-km retreat. Given the age uncertainties, the major grounding-line retreat lagged ice-shelf collapse by at least two centuries and by as much as fourteen centuries. In the WDB, the centuries-long delay in the retreat of grounded ice was partly due to rapid aggradational stacking of an unusually large volume of grounding-zone-wedge sediment as ice-stream discharge accelerated following ice-shelf collapse. This new deglacial reconstruction shows that ongoing changes to ice shelves may trigger complex dynamics whose consequences are realized only after a significant lag.

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