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|a Deformation, warming and softening of Greenland's ice by refreezing meltwater |h [electronic resource] |y English. |
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|a [S.l.] : |b Macmillan Publishers Limited, |c 2014-06-15. |
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|a Please contact the owning institution for licensing and permissions. It is the user's responsibility to ensure use does not violate any third party rights. |
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|a Meltwater beneath the large ice sheets can influence ice flow
by lubrication at the base or by softening when meltwater refreezes
to form relatively warm ice. Refreezing has produced
large basal ice units in East Antarctica. Bubble-free basal ice
units also outcrop at the edge of the Greenland ice sheet,
but the extent of refreezing and its influence on Greenland’s
ice flow dynamics are unknown. Here we demonstrate that
refreezing of meltwater produces distinct basal ice units
throughout northern Greenland with thicknesses of up to
1,100 m. We compare airborne gravity data with modelled
gravity anomalies to show that these basal units are ice.
Using radar data we determine the extent of the units, which
significantly disrupt the overlying ice sheet stratigraphy. The
units consist of refrozen basal water commonly surrounded
by heavily deformed meteoric ice derived from snowfall. We
map these units along the ice sheet margins where surface
melt is the largest source of water, as well as in the interior
where basal melting is the only source of water. Beneath
Petermann Glacier, basal units coincide with the onset of fast
flow and channels in the floating ice tongue. We suggest
that refreezing of meltwater and the resulting deformation
of the surrounding basal ice warms the Greenland ice sheet,
modifying the temperature structure of the ice column and
influencing ice flow and grounding line melting. |
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|a Electronic reproduction. |c Florida International University, |d 2015. |f (dpSobek) |n Mode of access: World Wide Web. |n System requirements: Internet connectivity; Web browser software. |
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|a dpSobek |c Sea Level Rise |
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|u http://dpanther.fiu.edu/dpService/dpPurlService/purl/FI15062164/00001 |y Click here for full text |
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|a http://dpanther.fiu.edu/sobek/content/FI/15/06/21/64/00001/FI15062164_thm.jpg |