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Letter. Episodic fresh surface waters in the Eocene Arctic Ocean

Brinkhuis, Henk, Schouten, Stefan, Collinson, Margaret E., Sluijs, Appy, Sinninghe Damsté, Jaap S., Dickens, Gerald R., Huber, Matthew, Cronin, Thomas M., Onodera, Jonaotaro, Takahashi, Kozo, Bujak, Jonathan P., Stein, Rüdiger, van der Burgh, Johan, Eldrett, James S., Harding, Ian C., Lotter, André F., Sangiorgi, Francesca, van Konijnenburg-van Cittert, Han, de Leeuw, Jan W., Matthiessen, Jens, Backman, Jan, Moran, Kathryn, Clemens, S., Eynaud, F., Gattacceca, J., Jakobsson, M., Jordan, R., Kaminski, M., King, J., Koc, N., Martinez, N. C., McInroy, D., Moore, T. C. Jr., O'Regan, M., Pälike, Heiko, Rea, B., Rio, D., Sakamoto, T., Smith, D. C., StJohn, K. E. K., Suto, I., Suzuki, N., Watanabe, M. and Yamamoto, M. (2006) Letter. Episodic fresh surface waters in the Eocene Arctic Ocean Nature, 441, (7093), pp. 606-609. (doi:10.1038/nature04692).

Record type: Article


It has been suggested, on the basis of modern hydrology and fully coupled palaeoclimate simulations, that the warm greenhouse conditions that characterized the early Palaeogene period (55–45 Myr ago) probably induced an intensified hydrological cycle with precipitation exceeding evaporation at high latitudes. Little field evidence, however, has been available to constrain oceanic conditions in the Arctic during this period. Here we analyse Palaeogene sediments obtained during the Arctic Coring Expedition, showing that large quantities of the free-floating fern Azolla grew and reproduced in the Arctic Ocean by the onset of the middle Eocene epoch (50 Myr ago). The Azolla and accompanying abundant freshwater organic and siliceous microfossils indicate an episodic freshening of Arctic surface waters during an 800,000-year interval. The abundant remains of Azolla that characterize basal middle Eocene marine deposits of all Nordic seas probably represent transported assemblages resulting from freshwater spills from the Arctic Ocean that reached as far south as the North Sea. The termination of the Azolla phase in the Arctic coincides with a local sea surface temperature rise from 10°C to 13°C, pointing to simultaneous increases in salt and heat supply owing to the influx of waters from adjacent oceans. We suggest that onset and termination of the Azolla phase depended on the degree of oceanic exchange between Arctic Ocean and adjacent seas.

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Published date: 2006


Local EPrints ID: 38374
ISSN: 0028-0836
PURE UUID: f39d3d62-3d70-4137-a985-fded8ae3fb88

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Date deposited: 07 Jun 2006
Last modified: 17 Jul 2017 15:39

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Author: Henk Brinkhuis
Author: Stefan Schouten
Author: Margaret E. Collinson
Author: Appy Sluijs
Author: Jaap S. Sinninghe Damsté
Author: Gerald R. Dickens
Author: Matthew Huber
Author: Thomas M. Cronin
Author: Jonaotaro Onodera
Author: Kozo Takahashi
Author: Jonathan P. Bujak
Author: Rüdiger Stein
Author: Johan van der Burgh
Author: James S. Eldrett
Author: Ian C. Harding
Author: André F. Lotter
Author: Francesca Sangiorgi
Author: Han van Konijnenburg-van Cittert
Author: Jan W. de Leeuw
Author: Jens Matthiessen
Author: Jan Backman
Author: Kathryn Moran
Author: S. Clemens
Author: F. Eynaud
Author: J. Gattacceca
Author: M. Jakobsson
Author: R. Jordan
Author: M. Kaminski
Author: J. King
Author: N. Koc
Author: N. C. Martinez
Author: D. McInroy
Author: T. C. Jr. Moore
Author: M. O'Regan
Author: Heiko Pälike
Author: B. Rea
Author: D. Rio
Author: T. Sakamoto
Author: D. C. Smith
Author: K. E. K. StJohn
Author: I. Suto
Author: N. Suzuki
Author: M. Watanabe
Author: M. Yamamoto

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