Ice-sheet variations as depicted in seismic records of the Amundsen Sea Embayment, West Antarctica


Contact
Estella.Weigelt [ at ] awi.de

Abstract

The dynamics of ice-sheets in response to climate changes becomes increasingly a focus of research. In this regard the glacial history of the Amundsen Sea sector of the West Antarctic Ice-Sheet (WAIS) is of particular interest. A potential deglaciation and collapse of the Thwaites and Pine Island glacier drainage basins alone would result in a global sea level rise of approximately 1.5 m. New multichannel seismic reflection data of high-resolution offer a record of the glacial development and processes in this area. We present a first interpretation of five seismic profiles collected in the western Amundsen Sea Embayment as part of the RV Polarstern cruise ANT-XXIII/4 (2006). The sea-floor morphology of the observed area is highly variable. Close to the present coast, a rough topography includes several troughs with a depth of almost 2000 m which were probably formed by paleo-icestreams cut through the shelf. Here, the seismic lines reveal hardly any sediments. Only a thin sedimentary cover or some sediment pockets (< 80 ms TWT ~ 60 m) on and in between these steep and rugged structures can be identified. On the northern shelf and outside the troughs, the topography is generally smooth and shows only small surface undulations. Northwest-dipping reflectors are striking features in the seismic lines and indicate well pronounced sedimentary sequences of more than 1 s TWT thickness (> 800 m). We suggest for this region a much quieter deposition realm, which was not much affected by melt water streams. These older and dipping layers form an unconformity with the young sedimentary cover running parallel to the seafloor. Only this uppermost cover is interrupted by small scale roughness features of a few meters height. At some locations, shallow and about 10 km wide channel-like structures cut through the upper sedimentary cover. They may be an indication for the activity of recent melt-water streams.



Item Type
Conference (Poster)
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
Internationale Polartagung 2008, 10. - 14. Mar, Münster..
Eprint ID
18484
Cite as
Weigelt, E. , Gohl, K. , Uenzelmann-Neben, G. and Larter, R. (2008): Ice-sheet variations as depicted in seismic records of the Amundsen Sea Embayment, West Antarctica , Internationale Polartagung 2008, 10. - 14. Mar, Münster. .


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