Synchronous Deglacial Overturning and Water Mass Source Changes

Understanding changes in ocean circulation during the last deglaciation is crucial to unraveling the dynamics of glacial-interglacial and millennial climate shifts. We used neodymium isotope measurements on postdepositional iron-manganese oxide coatings precipitated on planktonic foraminifera to rec...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2010, Vol.327 (5961), p.75-78
Main Authors: Roberts, Natalie L, Piotrowski, Alexander M, McManus, Jerry F, Keigwin, Lloyd D
Format: Article
Language:English
Subjects:
Climate
Climate change
Coatings
Deep water
Deglaciation
Earth sciences
Earth, ocean, space
Exact sciences and technology
Glaciers
Heinrich events
Isotopes
Marine and continental quaternary
Neodymium isotopes
Ocean bottom
Ocean circulation
Oceans
Oxide coatings
Oxides
Paleoclimatology
Sea water
Sediments
Surface water
Surficial geology
Synchronous
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Summary:Understanding changes in ocean circulation during the last deglaciation is crucial to unraveling the dynamics of glacial-interglacial and millennial climate shifts. We used neodymium isotope measurements on postdepositional iron-manganese oxide coatings precipitated on planktonic foraminifera to reconstruct changes in the bottom water source of the deep western North Atlantic at the Bermuda Rise. Comparison of our deep water source record with overturning strength proxies shows that both the deep water mass source and the overturning rate shifted rapidly and synchronously during the last deglacial transition. In contrast, any freshwater perturbation caused by Heinrich event 1 could have only affected shallow overturning. These findings show how changes in upper-ocean overturning associated with millennial-scale events differ from those associated with whole-ocean deglacial climate events.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1178068