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| Marcott, Shaun A.; Clark, Peter U.; Padman, Laurie; Klinkhammer, Gary P.; Springer, Scott R.; Liu, Zhengyu; Otto-bliesner, Bette L.; Carlson, Anders E.; Ungerer, Andy; Padman, June; He, Feng; Cheng, Jun; Schmittner, Andreas. |
| Episodic iceberg-discharge events from the Hudson Strait Ice Stream (HSIS) of the Laurentide Ice Sheet, referred to as Heinrich events, are commonly attributed to internal ice-sheet instabilities, but their systematic occurrence at the culmination of a large reduction in the Atlantic meridional overturning circulation (AMOC) indicates a climate control. We report Mg/Ca data on benthic foraminifera from an intermediate-depth site in the northwest Atlantic and results from a climate-model simulation that reveal basin-wide subsurface warming at the same time as large reductions in the AMOC, with temperature increasing by approximately 2 C over a 1-2 kyr interval prior to a Heinrich event. In simulations with an ocean model coupled to a thermodynamically... |
| Tipo: Text |
Palavras-chave: Paleoceanography; Paleoclimatology; Abrupt climate change. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33819/32479.pdf |
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| Hoffman, Jeremy S.; Carlson, Anders E.; Winsor, Kelsey; Klinkhammer, Gary P.; Legrande, Allegra N.; Andrews, John T.; Strasser, Jeffrey C.. |
| The 8.2 ka event was the last deglacial abrupt climate event. A reduction in the Atlantic meridional overturning circulation (AMOC) attributed to the drainage of glacial Lake Agassiz may have caused the event, but the freshwater signature of Lake Agassiz discharge has yet to be identified in delta O-18 of foraminiferal calcite records from the Labrador Sea, calling into question the connection between freshwater discharge to the North Atlantic and AMOC strength. Using Mg/Ca-paleothermometry, we demonstrate that similar to 3 degrees C of near-surface ocean cooling masked an similar to 1.0 parts per thousand decrease in western Labrador Sea delta O-18 of seawater concurrent with Lake Agassiz drainage. Comparison with North Atlantic delta O-18 of seawater... |
| Tipo: Text |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00496/60740/65179.pdf |
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