Preprints
https://doi.org/10.5194/tc-2022-172
https://doi.org/10.5194/tc-2022-172
 
14 Sep 2022
14 Sep 2022
Status: this preprint is currently under review for the journal TC.

Reversible ice sheet thinning in the Amundsen Sea Embayment during the Late Holocene

Greg Balco1,, Nathan Brown2,, Keir Nichols3,, Ryan A. Venturelli4,, Jonathan Adams3,6, Scott Braddock5, Seth Campbell5, Brent Goehring7, Joanne S. Johnson6, Dylan H. Rood3, Klaus Wilcken8, Brenda Hall5, and John Woodward9 Greg Balco et al.
  • 1Berkeley Geochronology Center, Berkeley CA USA
  • 2University of Texas, Arlington, Arlington TX USA
  • 3Imperial College London, London, UK
  • 4Colorado School of Mines, Golden CO USA
  • 5University of Maine, Orono ME USA
  • 6British Antarctic Survey, Cambridge, UK
  • 7Tulane University, New Orleans LA USA
  • 8ANSTO, Lucas Heights NSW, Australia
  • 9Northumbria University, Newcastle UK
  • These authors contributed equally to this work. Listed in alphabetical order.

Abstract. Cosmogenic-nuclide concentrations in subglacial bedrock cores show that the West Antarctic Ice Sheet (WAIS) at a site between Thwaites and Pope Glaciers was at least 35 m thinner than present in the past several thousand years, and subsequently thickened. This is important because of concern that present thinning and grounding line retreat at these and nearby glaciers in the Amundsen Sea Embayment may be irreversible, potentially leading to decimeter- to meter-scale sea level rise within decades to centuries. A past episode of ice sheet thinning, which took place in a similar although not identical climate, was not irreversible. We propose that the past thinning-thickening cycle was due to a glacioisostatic rebound feedback, similar to that invoked as a possible stabilizing mechanism for current grounding line retreat, in which isostatic uplift caused by early Holocene thinning led to relative sea level fall favoring grounding line advance.

Greg Balco et al.

Status: open (until 09 Nov 2022)

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Greg Balco et al.

Greg Balco et al.

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Short summary
Samples of bedrock recovered from below the West Antarctic Ice Sheet show that part of the ice sheet was thinner than it is now several thousand years ago, and subsequently thickened. This is important because of concern that present ice thinning in this region may lead to rapid, irreversible sea level rise. The past episode of thinning at this site, which took place in a similar although not identical climate, was not irreversible. However, reversal required at least 3000 years to complete.