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|a Modelling West Antarctic ice sheet growth and collapse through the past five million years |h [electronic resource] |y English. |
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|a [S.l.] : |b Macmillan Publishers Limited, |c 2009. |
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|a Nature Magazine Volume 458. |
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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 The West Antarctic ice sheet (WAIS), with ice volume equivalent to
5m of sea level1, has long been considered capable of past and
future catastrophic collapse. Today, the ice sheet is fringed by
vulnerable floating ice shelves that buttress the fast flow of inland
ice streams. Grounding lines are several hundred metres below sea
level and the bed deepens upstream, raising the prospect of runaway
retreat. Projections of future WAIS behaviour have been
hampered by limited understanding of past variations and their
underlying forcing mechanisms6,7. Its variation since the Last
Glacial Maximum is best known, with grounding lines advancing
to the continental-shelf edges around 15 kyr ago before retreating
to near-modern locations by 3 kyr ago. Prior collapses during
the warmth of the early Pliocene epoch and some Pleistocene
interglacials have been suggested indirectly fromrecords of sea level
and deep-sea-core isotopes, and by the discovery of open-ocean
diatoms in subglacial sediments.Until now, however, little direct
evidence of such behaviour has been available. Here we use a
combined ice sheet/ice shelf model capable of high-resolution
nesting with a new treatment of grounding-line dynamics and iceshelf
buttressing to simulate Antarctic ice sheet variations over the
past five million years. Modelled WAIS variations range from full
glacial extents with grounding lines near the continental shelf break,
intermediate states similar to modern, and brief but dramatic
retreats, leaving only small, isolated ice caps on West Antarctic
islands. Transitions between glacial, intermediate and collapsed
states are relatively rapid, taking one to several thousand years.
Our simulation is in good agreement with a new sediment record
(ANDRILL AND-1B) recovered from the western Ross Sea, indicating
a long-term trend from more frequently collapsed to more
glaciated states, dominant 40-kyr cyclicity in the Pliocene, and
major retreats atmarine isotope stage 31 ( 1.07Myr ago) and other
super-interglacials. |
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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/FI15062096/00001 |y Click here for full text |
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|a http://dpanther.fiu.edu/sobek/content/FI/15/06/20/96/00001/FI15062096_thm.jpg |
