IEDA
Project Information
EXPROBE-WAIS: Exposed Rock Beneath the West Antarctic Ice Sheet, A Test for Interglacial Ice Sheet Collapse
Short Title:
Subglacial evidence for ice-sheet collapse
Start Date:
2015-07-01
End Date:
2018-06-30
Project Location(s)
West Antarctic Ice Sheet
Pirrit Hills
Description/Abstract
This award supports a project to determine if the West Antarctic Ice Sheet (WAIS) has thinned and collapsed in the past few million years, and if so, when and how frequently this occurred. The principal aim is to identify climatic conditions or thresholds in the climate system that led to ice-sheet collapse in the past, and assess the threat of climate change to vulnerable ice sheets in the future. We recovered a subglacial bedrock core from beneath 150 m of ice cover in the Pirrit Hills, in West Antarctica, and measured cosmogenic nuclide profiles to determine the bedrock exposure history. Cosmic-ray-produced Be-10 and Al-26 in the core indicate: (i) Continuous Pleistocene ice cover averaging ~200 m; and (ii) One or more pre-Pleistocene deglaciations that exposed the core site for ~200-800 years in the Pliocene, or > 800 years, in the Miocene. Optically stimulated luminescence (OSL) dating of the core top precludes exposure to sunlight since ~450 ka, consistent with the Be-10 and Al-26 data. Trapped atmospheric argon in ice recovered from 80 cm above the bedrock surface indicates an age for the enclosing ice > 2 Ma (delta 40Ar/36Ar = -0.15 per-mil). Together, these results rule out any Pleistocene thinning of ice in the Pirrit Hills by more than 150 m.
Personnel
Person Role
Stone, John Investigator and contact
Funding
Antarctic Glaciology Award # 1341728
AMD - DIF Record(s)
Deployment
Deployment Type
Pirrit Hills subglacial drilling general deployment
Data Management Plan
Datasets
Repository Title (link) Status
Antarctica.Ice-D.org Cosmogenic nuclide data, Mt Axtell exists
Antarctica.Ice-D.org Cosmogenic nuclide data, Mt Tidd exists
Antarctica.Ice-D.org Cosmogenic nuclide data, Mt Turcotte exists
Antarctica.Ice-D.org Cosmogenic nuclide data, Mt Goodwin exists
Antarctica.Ice-D.org Cosmogenic nuclide data, Harter Nunatak exists
Antarctica.Ice-D.org Cosmogenic nuclide data, John Nunatak exists
USAP-DC Pirrit Hills subglacial bedrock core RB-2, cosmogenic Be-10, Al-26 data exists
Publications
  1. Spector, P., Stone, J., Pollard, D., Hillebrand, T., Lewis, C., & Gombiner, J. (2018). West Antarctic sites for subglacial drilling to test for past ice-sheet collapse. The Cryosphere, 12(8), 2741-2757. (doi:10.5194/tc-12-2741-2018)
  2. Spector, P., Stone, J., Pollard, D., Hillebrand, T., Lewis, C., & Gombiner, J. (2018). West Antarctic sites for subglacial drilling to test for past ice-sheet collapse. (doi:10.5194/tc-2018-88)