Preprints
https://doi.org/10.5194/cp-2021-7
https://doi.org/10.5194/cp-2021-7

  10 Feb 2021

10 Feb 2021

Review status: this preprint is currently under review for the journal CP.

Enhanced Moisture Delivery into Victoria Land, East Antarctica During the Early Last Interglacial: Implications for West Antarctic Ice Sheet Stability

Yuzhen Yan1,2, Nicole E. Spaulding3, Michael L. Bender1,4, Edward J. Brook5, John A. Higgins1, Andrei V. Kurbatov3, and Paul A. Mayewski3 Yuzhen Yan et al.
  • 1Department of Geosciences, Princeton University, Princeton NJ 08544, USA
  • 2Department of Earth, Environmental and Planetary Sciences, Rice University, Houston TX 77005, USA
  • 3Climate Change Institute, University of Maine, Orono ME 04469, USA
  • 4School of Oceanography, Shanghai Jiao Tong University, Shanghai 200240, China
  • 5College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis OR 97331, USA

Abstract. The S27 ice core, drilled in the Allan Hills Blue Ice Area of East Antarctica, is located in Southern Victoria Land ~80 km away from the present-day northern edge of the Ross Ice Shelf. Here, we utilize the reconstructed accumulation rate of S27 covering the Last Interglacial (LIG) period between 129 and 116 thousand years before present (ka) to infer moisture transport into the region. The accumulation rate is based on the ice age-gas age differences calculated from the ice chronology, which is constrained by the stable water isotopes of the ice, and an improved gas chronology based on measurements of oxygen isotopes of O2 in the trapped gases. The peak accumulation rate in S27 occurred at 128.2 ka, near the peak LIG warming in Antarctica. Even the most conservative estimate yields a six-fold increase in the accumulation rate in the LIG, whereas other Antarctic ice cores are typically characterized by a glacial-interglacial difference of a factor of two to three. While part of the increase in S27 accumulation rates must originate from changes in the large-scale atmospheric circulation, additional mechanisms are needed to explain the large changes. We hypothesize that the exceptionally high snow accumulation recorded in S27 reflects open-ocean conditions in the Ross Sea, created by reduced sea ice extent and increased polynya size, and perhaps by a southward retreat of the Ross Ice Shelf relative to its present-day position near the onset of LIG. The proposed ice shelf retreat would also be compatible with a sea-level high stand around 129 ka significantly sourced from West Antarctica. The peak in S27 accumulation rates is transient, suggesting that if the Ross Ice Shelf had indeed retreated during the early LIG, it would have re-advanced by 125 ka.

Yuzhen Yan et al.

Status: open (until 07 Apr 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Yuzhen Yan et al.

Data sets

Allan Hills Stable Water Isotopes Kurbatov, Andrei V., Spaulding, Nicole, Mayewski, Paul A., and Introne, Douglas https://doi.org/10.7265/N5NP22DF

Stable isotope composition of the trapped air in the Allan Hills S27 ice core Yan, Yuzhen, Bender, Michael, and Higgins, John https://doi.org/10.15784/601424

Greenhouse gas composition in the Allan Hills S27 ice core Yan, Yuzhen and Brook, Edward J. https://doi.org/10.15784/601425

Yuzhen Yan et al.

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Short summary
Here we reconstruct the rate of snow accumulation during the Last Interglacial Period in an East Antarctic ice core located near the present-day northern edge of the Ross Ice Shelf. We find a six-fold increase in the snow accumulation rate during the peak warming at the Last Interglacial. This large increase in mass accumulation is compatible with less ice cover in the Ross Sea, perhaps created by a partly collapsed West Antarctic Ice Sheet, whose stability in a warming world is uncertain.