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Published Online March 1, 2007
Science DOI: 10.1126/science.1138393

Reports

Submitted on December 4, 2006
Accepted on February 21, 2007

Discovery of Till Deposition at the Grounding Line of Whillans Ice Stream

Sridhar Anandakrishnan 1*, Ginny A. Catania 2, Richard B. Alley 1, Huw J. Horgan 1

1 Department of Geosciences, Pennsylvania State University, University Park, PA, USA.
2 University of Texas at Austin, Austin, TX, USA.

* To whom correspondence should be addressed.
Sridhar Anandakrishnan , E-mail: sak{at}essc.psu.edu

We report on the discovery of a grounding-line sedimentary wedge ("till delta") deposited by Whillans Ice Stream, West Antarctica. Our novel observation is that grounding-line deposition serves to thicken the ice and stabilize the position of the grounding line. The grounding line is well above floatation and will tend to remain in the same location even though sea level changes (until sea level rises high enough to overcome the influence of the wedge). Further, our observation demonstrates the occurrence of rapid subglacial erosion, sediment transport by distributed subglacial till deformation, and grounding-line sedimentation, with important implications for ice dynamics, for numerical modeling of ice flow, and for interpretation of the sedimentation record.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Sea levels: resolution and uncertainty.
R. Edwards (2007)
Progress in Physical Geography 31, 621-632
   PDF »
Effect of Sedimentation on Ice-Sheet Grounding-Line Stability.
R. B. Alley, S. Anandakrishnan, T. K. Dupont, B. R. Parizek, and D. Pollard (2007)
Science 315, 1838-1841
   Abstract »    Full Text »    PDF »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)