Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation
Establishing the precise timing for the onset of ice-sheet retreat at the end of the Last Glacial Maximum (LGM) is critical for delineating mechanisms that drive deglaciations. Uncertainties in the timing of ice-margin retreat and global ice-volume change allow a variety of plausible deglaciation tr...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20150002135 2023-05-15T16:40:12+02:00 Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation Legrande, Allegra N. Caffee, Marc Licciardi, Joseph M. Syverson, Kent M. Carlson, Anders E. Moore, Angus K. Ullman, David J. Anslow, Faron S. Unclassified, Unlimited, Publicly available November 14, 2014 application/pdf http://hdl.handle.net/2060/20150002135 unknown Document ID: 20150002135 http://hdl.handle.net/2060/20150002135 Copyright, Distribution as joint owner in the copyright CASI Geophysics Meteorology and Climatology GSFC-E-DAA-TN19598 Geology(ISSN 1943-2682); Volume 43; No. 1; 23-26 2014 ftnasantrs 2016-03-12T23:53:50Z Establishing the precise timing for the onset of ice-sheet retreat at the end of the Last Glacial Maximum (LGM) is critical for delineating mechanisms that drive deglaciations. Uncertainties in the timing of ice-margin retreat and global ice-volume change allow a variety of plausible deglaciation triggers. Using boulder 10Be surface exposure ages, we date initial southern Laurentide ice-sheet (LIS) retreat from LGM moraines in Wisconsin (USA) to 23.0 +/- 0.6 ka, coincident with retreat elsewhere along the southern LIS and synchronous with the initial rise in boreal summer insolation 24-23 ka. We show with climate-surface mass balance simulations that this small increase in boreal summer insolation alone is potentially sufficient to drive enhanced southern LIS surface ablation. We also date increased southern LIS retreat after ca. 20.5 ka likely driven by an acceleration in rising isolation. This near-instantaneous southern LIS response to boreal summer insolation before any rise in atmospheric CO2 supports the Milankovi hypothesis of orbital forcing of deglaciations. Other/Unknown Material Ice Sheet NASA Technical Reports Server (NTRS) |
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Open Polar |
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NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Geophysics Meteorology and Climatology |
spellingShingle |
Geophysics Meteorology and Climatology Legrande, Allegra N. Caffee, Marc Licciardi, Joseph M. Syverson, Kent M. Carlson, Anders E. Moore, Angus K. Ullman, David J. Anslow, Faron S. Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation |
topic_facet |
Geophysics Meteorology and Climatology |
description |
Establishing the precise timing for the onset of ice-sheet retreat at the end of the Last Glacial Maximum (LGM) is critical for delineating mechanisms that drive deglaciations. Uncertainties in the timing of ice-margin retreat and global ice-volume change allow a variety of plausible deglaciation triggers. Using boulder 10Be surface exposure ages, we date initial southern Laurentide ice-sheet (LIS) retreat from LGM moraines in Wisconsin (USA) to 23.0 +/- 0.6 ka, coincident with retreat elsewhere along the southern LIS and synchronous with the initial rise in boreal summer insolation 24-23 ka. We show with climate-surface mass balance simulations that this small increase in boreal summer insolation alone is potentially sufficient to drive enhanced southern LIS surface ablation. We also date increased southern LIS retreat after ca. 20.5 ka likely driven by an acceleration in rising isolation. This near-instantaneous southern LIS response to boreal summer insolation before any rise in atmospheric CO2 supports the Milankovi hypothesis of orbital forcing of deglaciations. |
format |
Other/Unknown Material |
author |
Legrande, Allegra N. Caffee, Marc Licciardi, Joseph M. Syverson, Kent M. Carlson, Anders E. Moore, Angus K. Ullman, David J. Anslow, Faron S. |
author_facet |
Legrande, Allegra N. Caffee, Marc Licciardi, Joseph M. Syverson, Kent M. Carlson, Anders E. Moore, Angus K. Ullman, David J. Anslow, Faron S. |
author_sort |
Legrande, Allegra N. |
title |
Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation |
title_short |
Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation |
title_full |
Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation |
title_fullStr |
Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation |
title_full_unstemmed |
Southern Laurentide Ice-Sheet Retreat Synchronous with Rising Boreal Summer Insolation |
title_sort |
southern laurentide ice-sheet retreat synchronous with rising boreal summer insolation |
publishDate |
2014 |
url |
http://hdl.handle.net/2060/20150002135 |
op_coverage |
Unclassified, Unlimited, Publicly available |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
CASI |
op_relation |
Document ID: 20150002135 http://hdl.handle.net/2060/20150002135 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766030580214923264 |