Intensification and variability of ocean thermohaline circulation through the last deglaciation

Publication Type  Journal Article
Year of Publication  2004
Authors  Piotrowski, A. M.; Goldstein, S. L.; Hemming, S. R.; Fairbanks, R. G.
Journal Title  Earth and Planetary Science Letters
Volume  225
Issue  1-2
Pages  205-220
Journal Date  Aug 30
ISBN Number  0012-821X
Accession Number  ISI:000223824100016
Key Words  thermohaline circulation; deep water; deglacial; neodymium; younger dryas; last glacial; abrupt climate-change; neodymium isotopic variations; north-atlantic oscillation; deep-water flux; southern-ocean; ice core; glacial maximum; ferromanganese deposits;
Abstract  

Neodymium isotope ratios in the authigenic ferromanganese oxide component in a southeastern Atlantic core reveal a history of the global overturning circulation intensity through the last deglaciation. From a minimum during the Last Glacial Maximum (LGM), North Atlantic Deep Water (NADW) began to strengthen between 18 and 17 kyr cal. BP, approximately 2000-3000 years before the Bolling warming. It exhibits a gradually increasing baseline intensity that plateaus in the early Holocene, tracks increasing Northern Hemisphere insolation and parallels atmospheric CO2 concentration. Millennial-scale fluctuations are superimposed on this baseline NADW increase, corresponding to events in Northern Hemisphere climate records. The millennial excursions show sharp increases associated with the pre-Bolling retreat of continental glaciers and the Bolling warming itself, a decrease with Allerod cooling, and a recovery through the Younger Dryas and early Holocene. The data confirm a close link between deep-ocean circulation and North Atlantic climate changes. There is no clear linkage with meltwater pulses, indicating that rapid meltwater additions did not trigger observable mode changes in NADW production. However, rapid changes in North Atlantic sea ice cover show a strong relationship with the millennial perturbations of NADW flux to the deep Southern Ocean. The data indicate that the baseline intensity of NADW reaching the Cape Basin is paced by Northern Hemisphere insolation and that North Atlantic sea ice coverage acts as a major amplifying link between the oceans and the atmosphere. (C) 2004 Elsevier B.V. All rights reserved.

Notes  

853JRTimes Cited:32Cited References Count:73

URL  <Go to ISI>://000223824100016
DOI  DOI 10.1016/j.epsl.2004.06.002