Evidence from the high-latitude North Atlantic for variations in Antarctic Intermediate water flow during the last deglaciation.

Rickaby, R. E. M. and Elderfield, H. (2005) Evidence from the high-latitude North Atlantic for variations in Antarctic Intermediate water flow during the last deglaciation. G3 Geochemistry Geophysics Geosystems, 6. Q05001; doi.org/10.1029/2004GC000858. DOI 10.1029/2004GC000858

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Abstract

We present evidence that the characteristic chemical signature (based on coupled benthic foraminiferal Cd/Ca and d13C) of Antarctic Intermediate waters (AAIW) penetrated throughout the intermediate depths of the Atlantic basin to the high-latitude North Atlantic during the abrupt cooling events of the last deglaciation: Heinrich 1 and the Younger Dryas. AAIW may play the dynamic counterpart to the ‘‘bipolar seesaw’’ when near-freezing salty bottom waters from the Antarctic (AABW) sluggishly ventilate the deep ocean. Our data reinforce the concept that interglacial circulation is stabilized by salinity feedbacks between salty northern sourced deep waters (NADW) and fresh southern sourced waters (AABW and AAIW). Further, the glacial ocean may be susceptible to the more finely balanced relative densities of NADW and AAIW, due to either freshwater input or a reversal of the salinity gradient, such that the ocean is poised for NADW collapse via a negative salinity feedback. The unstable climate of the glacial period and its termination may arise from the closer competition for ubiquity at intermediate depths between northern and southern sourced intermediate waters.

Item Type: Article
Uncontrolled Keywords: 2005 AREP 2005 P IA48
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: G3 Geochemistry Geophysics Geosystems
Volume: 6
Page Range: Q05001; doi.org/10.1029/2004GC000858
Identification Number: 10.1029/2004GC000858
Depositing User: Sarah Humbert
Date Deposited: 20 Aug 2010 10:15
Last Modified: 23 Jul 2013 09:59
URI: http://eprints.esc.cam.ac.uk/id/eprint/1796

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