Discovery of till deposition at the grounding line of Whillans Ice Stream

被引:115
作者
Anandakrishnan, Sridhar [1 ]
Catania, Ginny A.
Alley, Richard B.
Horgan, Huw J.
机构
[1] Penn State Univ, Dept Geosci, University Pk, PA 16802 USA
[2] Univ Texas, Inst Geophys, Austin, TX 78758 USA
关键词
D O I
10.1126/science.1138393
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
We report on the discovery of a grounding-line sedimentary wedge ("till delta") deposited by Whillans Ice Stream, West Antarctica. Our observation is that grounding-line deposition serves to thicken the ice and stabilize the position of the grounding line. The ice thickness at the grounding line is greater than that of floating ice in hydrostatic equilibrium. Thus, the grounding line will tend to remain in the same location despite changes in sea level ( until sea level rises enough to overcome the excess thickness that is due to the wedge). Further, our observation demonstrates the occurrence of rapid subglacial erosion, sediment transport by distributed subglacial till deformation, and grounding-line sedimentation, which have important implications for ice dynamics, numerical modeling of ice flow, and interpretation of the sedimentation record.
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页码:1835 / 1838
页数:4
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