Paleofluvial Mega-Canyon Beneath the Central Greenland Ice Sheet
Ice Lubricant
The Greenland and Antarctic ice sheets both possess hydrological systems that allow water accumulating from the melting of surface ice to be transported to the base of the ice sheet. If that water, when it reaches the ice-bedrock interface, is distributed over large areas, it will lubricate rapid ice sheet flow toward the sea. Bamber et al. (p. 997) report the existence of a large, 750-km-long subglacial canyon in northern Greenland, which may act as a channel for the transport of basal meltwater to the margin of the ice sheet and thus influence overall ice sheet dynamics.
Abstract
Subglacial topography plays an important role in modulating the distribution and flow of basal water. Where topography predates ice sheet inception, it can also reveal insights into former tectonic and geomorphological processes. Although such associations are known in Antarctica, little consideration has been given to them in Greenland, partly because much of the ice sheet bed is thought to be relatively flat and smooth. Here, we present evidence from ice-penetrating radar data for a 750-km-long subglacial canyon in northern Greenland that is likely to have influenced basal water flow from the ice sheet interior to the margin. We suggest that the mega-canyon predates ice sheet inception and will have influenced basal hydrology in Greenland over past glacial cycles.
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Supplementary Material
Summary
Materials and Methods
Figs. S1 to S5
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File (bamber-sm.pdf)
References and Notes
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Information & Authors
Information
Published In
Science
Volume 341 | Issue 6149
30 August 2013
30 August 2013
Copyright
Copyright © 2013, American Association for the Advancement of Science.
Submission history
Received: 29 April 2013
Accepted: 31 July 2013
Published in print: 30 August 2013
Acknowledgments
J.L.B., J.A.G., and G.S. were supported by funding from the ice2sea program from the European Union 7th Framework Programme, grant 226375. This work is ice2sea contribution number 158. J.L.B. and M.J.S. were supported by Natural Environment Research Council grant NE/H021078/1. We acknowledge the use of data products from CReSIS generated with support from NSF grant ANT-0424589, NASA grant NNX10AT68G, and the NASA Operation IceBridge project. J.L.B. wrote the main text with substantial contributions from M.J.S. and input from all authors. J.A.G. carried out the hydraulic potential calculations. G.S. calculated the isostatically adjusted bed, and S.J.M. produced the LGM ice sheet configuration.
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