Drilling in the Amundsen Sea Embayment: development and sensitivity of the West Antarctic Ice Sheet at its heart


Contact
gerhard.kuhn [ at ] awi.de

Abstract

The West Antarctic Ice Sheet (WAIS) is largely marine-based and, thus, highly sensitive to climatic and oceanographic changes. It probably had a very dynamic history over the last several million years. A complete collapse of the WAIS would result in a global sea-level rise of 3.3-4.3 m, yet, the world’s scientific community is not able to predict its future behavior. Moreover, knowledge about the past dynamics of the WAIS is poor, in particular during geological times with climatic conditions similar to those expected for the near and distant future. Reconstructions and quantifications of partial or complete WAIS collapses in the past are urgently needed for constraining and testing ice sheet models that aim to predict future WAIS behavior and the potential contribution of the WAIS to global sea-level rise. Large uncertainties exist regarding the chronology, extent, rates, and spatial and temporal variability of past advances and retreats of the WAIS across the continental shelves. These uncertainties mainly result from the fundamental lack of data from drill cores recovered proximal to the WAIS. The continental shelf and rise of the Amundsen Sea are prime targets for drilling, because the records are expected to yield archives of pure WAIS dynamics unaffected by other ice sheets, and the WAIS sector draining into the Amundsen Sea Embayment (ASE) currently experiences the largest ice loss in Antarctica. A series of drill sites are planned for the ASE shelf where seismic data reveal oceanward dipping sedimentary sequences that span the time from the pre-glacial depositional phase to the youngest glacial periods. Our strategy is to drill transects from the oldest sequences close to the bedrock-basin boundary at the middle-inner shelf transition to the youngest sequences on the outer shelf in both the western and the eastern ASE. These transects will provide a detailed history of the glacial cycles in the Amundsen Sea region and allow comparison to the WAIS history known from the Ross Sea sector. In addition, deep-water sites on the continental rise of the Amundsen Sea are selected for recovering continuous records of glacially transported sediments and detailed archives of climatic and oceanographic changes throughout glacial-interglacial cycles. We will apply a broad suite of analytical techniques, including multi-proxy analyses, to address our objectives of reconstructing the onset of glaciation in the greenhouse to icehouse transition and processes of dynamic ice sheet behavior during the Neogene and Quaternary.



Item Type
Conference (Conference paper)
Authors
Divisions
Primary Division
Programs
Primary Topic
Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
SCAR Open Science Conference, 20 Aug 2016 - 30 Aug 2016, Kuala Lumpur, Malaysia.
Eprint ID
40456
Cite as
Gohl, K. , Wellner, J. , Hillenbrand, C. D. , Yoon, H. I. , Anderson, J. B. , Ehrmann, W. , Salzmann, U. , Uenzelmann-Neben, G. , Kuhn, G. , Scherer, R. , Warnock, J. P. , Nitsche, F. O. and Bickert, T. (2016): Drilling in the Amundsen Sea Embayment: development and sensitivity of the West Antarctic Ice Sheet at its heart , SCAR Open Science Conference, Kuala Lumpur, Malaysia, 20 August 2016 - 30 August 2016 .


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