Reconstruction of changes in the Amundsen Sea and Bellingshausen Sea sector of the West Antarctic Ice Sheet since the Last Glacial Maximum

• Published in: Quaternary Science Reviews
• Main Authors: Larter, Robert D., Anderson, John B., Graham, Alastair G.C., Gohl, Karsten, Hillenbrand, Claus-Dieter, Jakobsson, Martin, Johnson, Joanne S., Kuhn, Gerhard, Nitsche, Frank O., Smith, James A., Witus, Alexandra E., Bentley, Michael J., Dowdeswell, Julian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2014
• Subjects: Ice sheet; Last Glacial Maximum; Holocene; Ice stream; Grounding line; Radiocarbon; Cosmogenic isotope; Surface exposure age; Multibeam swath bathymetry; Sediment; Glacimarine; Diamicton; Continental shelf; Circumpolar deep water; Subglacial meltwater; Sea level; Antarctic; West Antarctica; Amundsen Sea; West Antarctic Ice Sheet; Bellingshausen Sea; Antarc*; Antarctica; ice core; Ice Sheet
• Online Access: https://hdl.handle.net/1911/88244; https://doi.org/10.1016/j.quascirev.2013.10.016

Marine and terrestrial geological and marine geophysical data that constrain deglaciation since the Last Glacial Maximum (LGM) of the sector of the West Antarctic Ice Sheet (WAIS) draining into the Amundsen Sea and Bellingshausen Sea have been collated and used as the basis for a set of time-slice reconstructions. The drainage basins in these sectors constitute a little more than one-quarter of the area of the WAIS, but account for about one-third of its surface accumulation. Their mass balance is becoming increasingly negative, and therefore they account for an even larger fraction of current WAIS discharge. If all of the ice in these sectors of the WAIS were discharged to the ocean, global sea level would rise by ca 2 m. There is compelling evidence that grounding lines of palaeo-ice streams were at, or close to, the continental shelf edge along the Amundsen Sea and Bellingshausen Sea margins during the last glacial period. However, the few cosmogenic surface exposure ages and ice core data available from the interior of West Antarctica indicate that ice surface elevations there have changed little since the LGM. In the few areas from which cosmogenic surface exposure ages have been determined near the margin of the ice sheet, they generally suggest that there has been a gradual decrease in ice surface elevation since pre-Holocene times. Radiocarbon dates from glacimarine and the earliest seasonally open marine sediments in continental shelf cores that have been interpreted as providing approximate ages for post-LGM grounding-line retreat indicate different trajectories of palaeo-ice stream recession in the Amundsen Sea and Bellingshausen Sea embayments. The areas were probably subject to similar oceanic, atmospheric and eustatic forcing, in which case the differences are probably largely a consequence of how topographic and geological factors have affected ice flow, and of topographic influences on snow accumulation and warm water inflow across the continental shelf. Pauses in ice retreat are recorded where ...