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Late Cretaceous changes in continental configuration: toward a better-ventilated ocean?

Abstract : Oceanic anoxic events (OAEs) are large-scale events of oxygen depletion in the deep ocean that happened dur- ing pre-Cenozoic periods of extreme warmth. Last global OAE occurred at the Cenomanian-Turonian boundary (OAE2) prior to the Late Cretaceous long term cooling. Ever since, and despite the occurrence of warming events, Earth no more experienced such large-scale anoxic conditions. Here we explore the role of major continental configuration changes occurring during the Late Cretaceous on oceanic circulation modes through numerical sim- ulations using a General Circulation Model (GCM), that we confront to existing neodymium isotope data ( " Nd). Except from a continuous deep-water production in the North Pacific, the simulations at 95 Ma and 70 Ma reveal major differences marked by a shift in the southern deep-water production sites from South Pacific at 95Ma to South Atlantic and Indian oceans at 70Ma. Our modelling results support an intensification of southern Atlantic deep-water production as well as a reversal of the deep-water fluxes through the Caribbean Seaway as the main causes of the decrease in " Nd values recorded in the Atlantic and Indian deep waters during the Late Cretaceous. We conclude that the change from a sluggish to a much more active circulation depicted by the model in the Atlantic from 95Ma to 70Ma may have driven the disappearance of OAEs after the Late Cretaceous.
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https://hal-insu.archives-ouvertes.fr/insu-01520795
Contributor : Isabelle Dubigeon <>
Submitted on : Thursday, May 11, 2017 - 9:30:01 AM
Last modification on : Wednesday, September 23, 2020 - 4:32:17 AM

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  • HAL Id : insu-01520795, version 1

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Yannick Donnadieu, Emmanuelle Pucéat, François Guillocheau, Jean-François Deconinck. Late Cretaceous changes in continental configuration: toward a better-ventilated ocean?. European Geosciences Union General Assembly 2017, European Geosciences Union, Apr 2017, Vienne, Austria. pp.EGU2017-13996. ⟨insu-01520795⟩

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