The 8200 year B.P. event in the slope water system, western subpolar North Atlantic

View/ Open
Date
2005-04-15Author
Keigwin, Lloyd D.
Concept link
Sachs, Julian P.
Concept link
Rosenthal, Yair
Concept link
Boyle, Edward A.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/3434As published
https://doi.org/10.1029/2004PA001074DOI
10.1029/2004PA001074Keyword
Lake Agassiz; 8200 year event; Meltwater pulseAbstract
Stable isotope, trace metal, alkenone paleothermometry, and radiocarbon methods have been applied to sediment cores in the western subpolar North Atlantic between Hudson Strait and Cape Hatteras to reveal the history of climate in that region over the past ∼11 kyr. We focus on cores from the Laurentian Fan, which is known to have rapid and continuous accumulation of hemipelagic sediment. Although results among our various proxy data are not always in agreement, the weight of the evidence (alkenone sea surface temperature (SST), δ18O and abundance of Globigerinoides ruber) indicates a continual cooling of surface waters over Laurentian Fan, from about 18°C in the early Holocene to about 8°C today. Alternatively, Mg/Ca data on planktonic foraminifera indicate no systematic change in Holocene SST. The inferred long-term decrease in SST was probably driven by decreasing seasonality of Northern Hemisphere insolation. Two series of proxy data show the gradual cooling was interrupted by a two-step cold pulse that began 8500 years ago, and lasted about 700 years. Although this event is associated with the final deglaciation of Hudson Bay, there is no δ18O minimum anywhere in the Labrador Sea, yet there is some evidence for it as far south as Cape Hatteras. Finally, although the 8200 year B.P. event has been implicated in decreasing North Atlantic ventilation, and hence widespread temperature depression on land and at sea, we find inconsistent evidence for a change at that time in deep ocean nutrient content at ∼4 km water depth.
Description
Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 20 (2005): PA2003, doi:10.1029/2004PA001074.
Collections
Suggested Citation
Paleoceanography 20 (2005): PA2003Related items
Showing items related by title, author, creator and subject.
-
Species-specific control of external superoxide levels by the coral holobiont during a natural bleaching event
Diaz, Julia M.; Hansel, Colleen M.; Apprill, Amy; Brighi, Caterina; Zhang, Tong; Weber, Laura; McNally, Sean; Xun, Liping (Nature Publishing Group, 2016-12-07)The reactive oxygen species superoxide (O2·−) is both beneficial and detrimental to life. Within corals, superoxide may contribute to pathogen resistance but also bleaching, the loss of essential algal symbionts. Yet, the ... -
The Jason II virtual control van system, data acquisition system, web-based event logger, and SeaNet
Lerner, Steven A.; Maffei, Andrew R. (Woods Hole Oceanographic Institution, 2002-12)Scientific underwater remotely operated vehicles (ROVs) collect data from multiple video cameras and scientific instruments. This integrated information is often only available in an ROV control-van during operations. ... -
Winter mixed layer development in the central Irminger Sea : the effect of strong, intermittent wind events
Våge, Kjetil; Pickart, Robert S. (American Meteorological Society, 2008-03)The impact of the Greenland tip jet on the wintertime mixed layer of the southwest Irminger Sea is investigated using in situ moored profiler data and a variety of atmospheric datasets. The mixed layer was observed to reach ...