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| Titel |
The role of the northward-directed (sub)surface limb of the Atlantic Meridional Overturning Circulation during the 8.2 ka event |
| VerfasserIn |
A. D. Tegzes, E. Jansen, R. J. Telford |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 5 ; Nr. 10, no. 5 (2014-10-24), S.1887-1904 |
| Datensatznummer |
250117062
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| Publikation (Nr.) |
 copernicus.org/cp-10-1887-2014.pdf |
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| Zusammenfassung |
| The so-called "8.2 ka event" is widely regarded as a major Holocene climate
perturbation. It is most readily identifiable in the oxygen-isotope records
from Greenland ice cores as an approximately 160-year-long cold interval
between 8250 and 8090 years BP. The prevailing view has been that the cooling
over Greenland, and potentially over the northern North Atlantic at least,
was triggered by the catastrophic final drainage of the Agassiz–Ojibway
proglacial lake as part of the remnant Laurentide Ice Sheet collapsed over
Hudson Bay at around 8420 ± 80 years BP. The consequent freshening of
surface waters in the northern North Atlantic Ocean and the Nordic Seas
resulted in weaker overturning, and hence reduced northward ocean heat
transport. We have reconstructed variations in the strength of the eastern
branch of the Atlantic Inflow into the Nordic Seas around the time of the
lake outbursts. While the initial freshwater forcing may have been even
larger than originally thought, as the lake outbursts may have been
accompanied by a major iceberg discharge from Hudson Bay, our proxy records
from the mid-Norwegian Margin do not evidence a uniquely large slowdown in
the eastern branch of the Atlantic Inflow at the time. Therefore, its main
role in the 8.2 ka event may have been the (rapid) advection of fresh and
cold waters to high northern latitudes, initiating rapid sea-ice expansion
and an increase in surface albedo. |
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