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Incursions of southern-sourced water into the deep North Atlantic during late Pliocene glacial intensification

Incursions of southern-sourced water into the deep North Atlantic during late Pliocene glacial intensification
Incursions of southern-sourced water into the deep North Atlantic during late Pliocene glacial intensification
The circulation and internal structure of the oceans exert a strong influence on Earth’s climate because they control latitudinal heat transport and the segregation of carbon between the atmosphere and the abyss1. Circulation change, particularly in the Atlantic Ocean, is widely suggested, to have been instrumental in the intensification of Northern Hemisphere glaciation when large ice sheets first developed on North America and Eurasia during the late Pliocene, approximately 2.7 million years ago6. Yet the mechanistic link and cause/effect relationship between ocean circulation and glaciation are debated. Here we present new records of North Atlantic Ocean structure using the carbon and neodymium isotopic composition of marine sediments recording deep water for both the Last Glacial to Holocene (35–5 thousand years ago) and the late Pliocene to earliest Pleistocene (3.3–2.4 million years ago). Our data show no secular change. Instead we document major southern-sourced water incursions into the deep North Atlantic during prominent glacials from 2.7 million years ago. Our results suggest that Atlantic circulation acts as a positive feedback rather than as an underlying cause of late Pliocene Northern Hemisphere glaciation. We propose that, once surface Southern Ocean stratification7 and/or extensive sea-ice cover5 was established, cold-stage expansions of southern-sourced water such as those documented here enhanced carbon dioxide storage in the deep ocean, helping to increase the amplitude of glacial cycles.
1752-0894
375-379
Lang, David C.
a85402ce-148a-41b1-9522-915e8d33eb31
Bailey, Ian
e659068f-e591-4185-afd1-5e19a5794bda
Wilson, Paul A.
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Chalk, Thomas B.
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Foster, Gavin L.
fbaa7255-7267-4443-a55e-e2a791213022
Gutjahr, Marcus
5babbbc4-2a1a-48df-a2e3-d87b2483ea9c
Lang, David C.
a85402ce-148a-41b1-9522-915e8d33eb31
Bailey, Ian
e659068f-e591-4185-afd1-5e19a5794bda
Wilson, Paul A.
f940a9f0-fa5a-4a64-9061-f0794bfbf7c6
Chalk, Thomas B.
0021bbe6-6ab1-4a30-8542-654d0f2d1a0a
Foster, Gavin L.
fbaa7255-7267-4443-a55e-e2a791213022
Gutjahr, Marcus
5babbbc4-2a1a-48df-a2e3-d87b2483ea9c

Lang, David C., Bailey, Ian, Wilson, Paul A., Chalk, Thomas B., Foster, Gavin L. and Gutjahr, Marcus (2016) Incursions of southern-sourced water into the deep North Atlantic during late Pliocene glacial intensification. Nature Geoscience, 9 (5), 375-379. (doi:10.1038/ngeo2688).

Record type: Article

Abstract

The circulation and internal structure of the oceans exert a strong influence on Earth’s climate because they control latitudinal heat transport and the segregation of carbon between the atmosphere and the abyss1. Circulation change, particularly in the Atlantic Ocean, is widely suggested, to have been instrumental in the intensification of Northern Hemisphere glaciation when large ice sheets first developed on North America and Eurasia during the late Pliocene, approximately 2.7 million years ago6. Yet the mechanistic link and cause/effect relationship between ocean circulation and glaciation are debated. Here we present new records of North Atlantic Ocean structure using the carbon and neodymium isotopic composition of marine sediments recording deep water for both the Last Glacial to Holocene (35–5 thousand years ago) and the late Pliocene to earliest Pleistocene (3.3–2.4 million years ago). Our data show no secular change. Instead we document major southern-sourced water incursions into the deep North Atlantic during prominent glacials from 2.7 million years ago. Our results suggest that Atlantic circulation acts as a positive feedback rather than as an underlying cause of late Pliocene Northern Hemisphere glaciation. We propose that, once surface Southern Ocean stratification7 and/or extensive sea-ice cover5 was established, cold-stage expansions of southern-sourced water such as those documented here enhanced carbon dioxide storage in the deep ocean, helping to increase the amplitude of glacial cycles.

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Accepted/In Press date: 1 March 2016
e-pub ahead of print date: 4 April 2016
Published date: 4 April 2016
Organisations: Geochemistry, Paleooceanography & Palaeoclimate

Identifiers

Local EPrints ID: 393696
URI: https://eprints.soton.ac.uk/id/eprint/393696
ISSN: 1752-0894
PURE UUID: f811f4a3-a9f4-49e6-b317-25fe839828d4
ORCID for Thomas B. Chalk: ORCID iD orcid.org/0000-0002-2880-3847
ORCID for Gavin L. Foster: ORCID iD orcid.org/0000-0003-3688-9668

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Date deposited: 29 Apr 2016 13:46
Last modified: 10 Dec 2019 01:40

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Contributors

Author: David C. Lang
Author: Ian Bailey
Author: Paul A. Wilson
Author: Thomas B. Chalk ORCID iD
Author: Gavin L. Foster ORCID iD
Author: Marcus Gutjahr

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