Ice elevation near the West Antarctic Ice Sheet divide during the Last Glaciation

被引:44
作者
Ackert, Robert P., Jr.
Mukhopadhyay, Sujoy
Parizek, Byron R.
Borns, Harold W.
机构
[1] Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA
[2] Coll New Jersey, Dept Phys, Ewing, NJ 08628 USA
[3] Univ Maine, Climate Change Inst, Orono, ME 04469 USA
关键词
D O I
10.1029/2007GL031412
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Interior ice elevations of the West Antarctic Ice Sheet (WAIS) during the last glaciation, which can serve as benchmarks for ice-sheet models, are largely unconstrained. Here we report past ice elevation data from the Ohio Range, located near the WAIS divide and the onset region of the Mercer Ice Stream. Cosmogenic exposure ages of glacial erratics that record a WAIS highstand similar to 125 m above the present surface date to similar to 11.5 ka. The deglacial chronology prohibits an interior WAIS contribution to meltwater pulse 1A. Our observational data of ice elevation changes compare well with predictions of a thermomechanical ice-sheet model that incorporates very low basal shear stress downstream of the present day grounding line. We conclude that ice streams in the Ross Sea Embayment had thin, low-slope profiles during the last glaciation and interior WAIS ice elevations during this period were several hundred meters lower than previous reconstructions.
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页数:6
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