Tectonically restricted deep-ocean circulation at the end of the Cretaceous greenhouse.

Voigt, Silke, Jung, Claudia, Friedrich, Oliver, Frank, Martin, Teschner, Claudia and Hoffmann, Julia (2013) Tectonically restricted deep-ocean circulation at the end of the Cretaceous greenhouse. Earth and Planetary Science Letters, 369-370 . pp. 169-177. DOI 10.1016/j.epsl.2013.03.019.

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Abstract

The evolution of global ocean circulation toward deep-water production in the high southern latitudes is thought to have been closely linked to the transition from extreme mid-Cretaceous warmth to the cooler Cenozoic climate. The relative influences of climate cooling and the opening and closure of oceanic gateways on the mode of deep-ocean circulation are, however, still unresolved. Here we reconstruct intermediate- to deep-water circulation for the latest Cretaceous based on new high-resolution radiogenic neodymium (Nd) isotope data from several sites and for different water depths in the South Atlantic, Southern Ocean, and proto-Indian Ocean. Our data document the presence of markedly different intermediate water Nd-isotopic compositions in the South Atlantic and Southern Ocean. In particular, a water mass with a highly radiogenic Nd isotope signature most likely originating from intense hotspot-related volcanic activity bathed the crest of Walvis Ridge between 71 and 69 Ma, which formed a barrier that prevented deep-water exchange between the Southern Ocean and the North Atlantic basins. We suggest that the Cenozoic mode of global deep-ocean circulation was still suppressed by tectonic barriers in the latest Cretaceous, and that numerous, mostly regionally-formed and sourced intermediate to deep waters supplied the deep ocean prior to 68 million yr ago.

Document Type: Article
Additional Information: WOS:000320684500017
Keywords: cretaceous; ocean circulation; neodymium isotopes; gateways
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.epsl.2013.03.019
ISSN: 0012-821X
Projects: ODP, Transdrift, Laptev Sea System, Future Ocean
Date Deposited: 29 May 2013 08:27
Last Modified: 06 Mar 2017 13:28
URI: http://oceanrep.geomar.de/id/eprint/21336

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