Did North Atlantic overturning halt 17,000 years ago?
MetadataShow full item record
Models indicate that a complete shutdown of deep and intermediate water production is a possible consequence of extreme climate conditions in the northern North Atlantic, and the high ratio of 231Pa to 230Th on Bermuda Rise is evidence that this might have happened ∼17 ka during Heinrich event 1 (H1). However, new radiocarbon data from bivalves that lived at ∼4.6 km on the Bermuda Rise during H1 lead to a different conclusion. The bivalve data do indeed indicate ventilation of the deep western North Atlantic was suppressed during H1 but not as much as it was during the last glacial maximum. We propose that high diatom flux to the Bermuda Rise during H1 is at least in part responsible for increased 231Pa/230Th at that time. Although we cannot say for sure why opal production was so high in a gyre center location at that time, increased leakage of silica rich waters from the Southern Ocean to the North Atlantic is one possibility.
Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 23 (2008): PA1101, doi:10.1029/2007PA001500.
Showing items related by title, author, creator and subject.
Decreased influence of Antarctic intermediate water in the tropical Atlantic during North Atlantic cold events Huang, Kuo-Fang; Oppo, Delia W.; Curry, William B. (Elsevier, 2014-01-15)Antarctic Intermediate Water (AAIW) is a key player in the global ocean circulation, contributing to the upper limb of the Atlantic Meridional Overturning Circulation (AMOC), and influencing interhemispheric heat exchange ...
Hernandez-Guerra, Alonso; Joyce, Terrence M.; Fraile-Nuez, Eugenio; Velez-Belchi, Pedro (2009-08-06)Using a variety of oceanographic data, including direct volume transports in the Florida 19 Strait, and Argo float profiles and drift velocities at 24 and 36N in the North Atlantic, inverse calculations are presented in ...
Johnson, Gregory C.; Purkey, Sarah G.; Toole, John M. (American Geophysical Union, 2008-11-19)We analyze abyssal temperature data in the western North Atlantic Ocean from the 1980s–2000s, showing that reductions in Antarctic Bottom Water (AABW) signatures have reached even that basin. Trans-basin oceanographic ...