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149 results on '"Pucéat, Emmanuelle"'

4. Deciphering Paleocene‐Eocene Thermal Maximum Climatic Dynamics: Insights From Oxygen and Hydrogen Isotopes in Clay Minerals of Paleosols From the Southern Pyrenees.

Author

Jaimes‐Gutierrez, Rocio, Adatte, Thierry, Pucéat, Emmanuelle, Vennemann, Torsten, Prieur, Marine, Wild, Amanda L., Khozyem, Hassan, Vaucher, Romain, and Castelltort, Sebastien

Subjects
PRECIPITATION variability, ATMOSPHERIC temperature, OXYGEN isotopes, CLAY minerals, HYDROGEN isotopes
Abstract

This study focuses on the Paleocene‐Eocene Thermal Maximum (PETM), a hyperthermal event characterized by a rapid increase in global temperature (5–8°C) over 20 ka, in the Southern Pyrenean Foreland Basin. Although there is evidence of increased flood discharge and erosion in the Southern Pyrenees, how paleoclimatic conditions and weathering evolved remains to be assessed. This study focuses on the catchment scale climatological changes recorded in the clay minerals of floodplain paleosols, giving insights into how rainfall affected the weathering regime during and after the hyperthermal event. The oxygen (δ18O) and hydrogen (δD) isotope compositions were analyzed in two clay fractions in paleosols of the Esplugafreda continental section. The clay minerals comprise a dominant smectite‐rich assemblage, which indicates a predominantly seasonal, semi‐arid climate throughout the section. Two positive excursions in the δ18O record during the Pre‐Onset Excursion (POE) and the Syn‐PETM support an increase in air near‐surface temperature. Using the δD and δ18O smectite fractionation factors, we estimate a Mean Annual Air Temperature (MAAT) of 24.2 ± 1.0°C for the POE and 27.0 ± 0.8°C for the Syn‐PETM. The δD values show a relatively stable composition during the climatic disturbance, which suggests that this mid‐latitude catchment was overall characterized by low yearly rainfall, with a peak in extreme events during the body of the PETM and a trend toward aridification during the recovery phase of the PETM, supported by the paleosol morphotype. These climatic conditions suggest a kinetically controlled weathering regime, where physical transport of the sediments played a primary role as a denudation mechanism. Plain Language Summary: We investigate the Paleocene‐Eocene Thermal Maximum (PETM), a global warming event occurring 56 million years ago, and its local impact on the Spanish Pyrenees' climate. During the PETM, global temperatures rose by 5–8°C, prompting us to examine its influence on local mean annual temperature and precipitation. To understand how mountain rocks underwent physical and chemical breakdown into smaller, compositionally different minerals (weathering), we aim to unravel the processes of local climatic change during the PETM. Our study presents the hydrogen and oxygen isotopic composition of clay minerals in river floodplains, reflecting the climate in which they formed. A rise in heavy oxygen isotopes is observed before and during the PETM, confirming higher temperatures in the region by ∼3°C. However, hydrogen isotope composition remained unchanged, indicating minimal variations in annual rainfall. Although overall yearly precipitation may have remained steady, the PETM led to infrequent but extreme rainfall events. The precipitation variability implies that erosion played a significant role in the rock‐wasting process, making weathering efficiency the limiting factor in forming secondary clay minerals. Key Points: The δ18O and δD of the clays suggest a Mean Annual Air Temperature of 24.2 ± 1.0°C during the Pre‐Onset Excursion and 27.0 ± 0.8°C during the Syn‐Paleocene‐Eocene Thermal Maximum (PETM)The δ18O and δD suggest a constant Mean Annual Precipitation before and during the PETM [ABSTRACT FROM AUTHOR]

Published
2024
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12. Continental weathering as a driver of Late Cretaceous cooling: new insights from clay mineralogy of Campanian sediments from the southern Tethyan margin to the Boreal realm

Author

Chenot, Elise, Deconinck, Jean-François, Pucéat, Emmanuelle, Pellenard, Pierre, Guiraud, Michel, Jaubert, Maxime, Jarvis, Ian, Thibault, Nicolas, Cocquerez, Théophile, Bruneau, Ludovic, Razmjooei, Mohammad J., Boussaha, Myriam, Richard, James, Sizun, Jean-Pierre, and Stemmerik, Lars

Published
2018
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13. Supplementary material to "Stable oxygen isotopes of crocodilian tooth enamel allow tracking Plio-Pleistocene evolution of freshwater environments and climate in the Shungura Formation (Turkana Depression, Ethiopia)"

Author

Gardin, Axelle, primary, Pucéat, Emmanuelle, additional, Garcia, Géraldine, additional, Boisserie, Jean-Renaud, additional, Euriat, Adélaïde, additional, Joachimski, Michael M., additional, Nutz, Alexis, additional, Schuster, Mathieu, additional, and Otero, Olga, additional

Published
2023
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14. Stable oxygen isotopes of crocodilian tooth enamel allow tracking Plio-Pleistocene evolution of freshwater environments and climate in the Shungura Formation (Turkana Depression, Ethiopia)

Author

Gardin, Axelle, primary, Pucéat, Emmanuelle, additional, Garcia, Géraldine, additional, Boisserie, Jean-Renaud, additional, Euriat, Adélaïde, additional, Joachimski, Michael M., additional, Nutz, Alexis, additional, Schuster, Mathieu, additional, and Otero, Olga, additional

Published
2023
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15. The large-scale evolution of neodymium isotopic composition in the global modern and Holocene ocean revealed from seawater and archive data

Author

Tachikawa, Kazuyo, Arsouze, Thomas, Bayon, Germain, Bory, Aloys, Colin, Christophe, Dutay, Jean-Claude, Frank, Norbert, Giraud, Xavier, Gourlan, Alexandra T., Jeandel, Catherine, Lacan, François, Meynadier, Laure, Montagna, Paolo, Piotrowski, Alexander M., Plancherel, Yves, Pucéat, Emmanuelle, Roy-Barman, Matthieu, and Waelbroeck, Claire

Published
2017
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18. Stable oxygen isotopes of crocodilian tooth enamel allow tracking Plio-Pleistocene evolution of freshwater environments and climate in the Shungura Formation (Turkana Depression, Ethiopia).

Author

Gardin, Axelle, Pucéat, Emmanuelle, Garcia, Géraldine, Boisserie, Jean-Renaud, Euriat, Adélaïde, Joachimski, Michael M., Nutz, Alexis, Schuster, Mathieu, and Otero, Olga

Subjects
OXYGEN isotopes, DENTAL enamel, STABLE isotopes, CROCODILIANS, FOSSIL teeth, OROGENIC belts, GEOCHEMICAL surveys
Abstract

This study adopts a new approach describing palaeohydrology and palaeoclimates based on the interpretation of stable oxygen isotopes (δ18 O p) recorded in fossil crocodilian teeth. They represent an archive of prime interest for tracking freshwater palaeoenvironmental change, applicable to many palaeontological localities in the world: crocodilian teeth are abundant in continental basins and have been widely distributed since their diversification during the Mesozoic; the enamel phosphate is resistant to diagenesis and retains its original isotopic composition over geological timescales; and their δ18 O p mainly relies on that of the crocodilian's home waterbody (δ18 O w), which in turn reflects waterbody types, regional climate, and evaporation conditions. This study presents the first application of this theoretical interpretative model to the Shungura Formation (Lower Omo Valley, Ethiopia), a key witness of the important environmental change in eastern Africa during the Plio-Pleistocene that impacted the evolution of regional faunas, including humans. In this complex and variable environmental context, the δ18 O p of coexisting crocodilians allows for the fingerprinting of the diversity of aquatic environments they had access to at a local scale. This study sheds light on two important results: the δ18 O p of crocodilian teeth (1) indicates stable aquatic environments in the northern Turkana Depression from 2.97 to ca. 2.57 Ma but a decline in local waterbodies diversity after 2.32 Ma, suggesting increasing aridity, and (2) shows, like previous geochemical studies on palaeosols and bivalves in the area, a significant increase in δ18 O w from 2.97 to ca. 1.14 Ma, likely due to the shifting air stream convergence zones between the West African and Indian Summer Monsoons and/or reduced rainfall over the Ethiopian Highlands. [ABSTRACT FROM AUTHOR]

Published
2024
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26. Stable oxygen isotopes of crocodilian tooth enamel allow tracking Plio-Pleistocene evolution of freshwater environments and climate in the Shungura Formation (Turkana Depression, Ethiopia).

Author

Gardin, Axelle, Pucéat, Emmanuelle, Garcia, Géraldine, Boisserie, Jean-Renaud, Euriat, Adélaïde, Joachimski, Michael M., Nutz, Alexis, Schuster, Mathieu, and Otero, Olga

Subjects
OXYGEN isotopes, DENTAL enamel, STABLE isotopes, CROCODILIANS, BODIES of water, PALEOHYDROLOGY
Abstract

This study adopts a new approach describing paleohydrology and paleoclimates based on the interpretation of stable oxygen isotopes (δ18Op) recorded in fossil crocodilian teeth. They represent an archive of prime interest for tracking freshwater paleoenvironmental change, applicable for many paleontological localities in the world: crocodilian teeth are abundant in continental basins and widely distributed since their diversification during the Mesozoic; the enamel phosphate is resistant to diagenesis and retains its original isotopic composition over geological timescales; their δ18Op mainly relies on that of the crocodilian's home water body (δ18Ow), which in turn reflects water body types, regional climate, and evaporation conditions. This study presents the first application of this interpretative model to the Shungura Formation (Lower Omo Valley, Ethiopia), a key witness of the important environmental changes in eastern Africa during the Plio-Pleistocene that impacted the evolution of regional faunas, including humans. In this complex and variable environmental context, the δ18Op of coexisting crocodilians allows for fingerprinting the diversity of aquatic environments they had access to at a local scale. Like previous geochemical studies performed on paleosols and bivalves in this area, our data indicate a marked increase in δ18Ow between 2.97 Ma and ca. 1.14 Ma, probably resulting from the joint effect of the migration of the air streams convergence zones between the West African and Indian Summer Monsoons and of the decrease in rainfall amounts above the Ethiopian Highlands. Contrary to some conclusions based on terrestrial proxies, the δ18Op of crocodilian teeth does highlight any major change affecting aquatic environments, rather pointing to stability of these environments between 2.97 Ma and ca. 2.57 Ma. By contrast, the diversity of aquatic environments accessible to crocodilians seems to be restricted in most analysed stratigraphical units after ca. 2.32 Ma, a feature that may reflect more arid conditions in the Turkana Depression. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Late Cretaceous changes in oceanic currents and sediment sources in the eastern Tethys:insights from Nd isotopes and clay mineralogy

Author

Chenot, Elise, Pucéat, Emmanuelle, Freslon, Nicolas, Deconinck, Jean François, Razmjooei, Mohammad Javad, Thibault, Nicolas, Chenot, Elise, Pucéat, Emmanuelle, Freslon, Nicolas, Deconinck, Jean François, Razmjooei, Mohammad Javad, and Thibault, Nicolas

Abstract

The Late Cretaceous is marked by geodynamical changes including Africa-Eurasia convergence that resulted in the narrowing of the Tethys Ocean and in ophiolite obduction along the southern margin of the various continental blocks in eastern Tethys. Geochemical and mineralogical analyses were performed on the Shahneshin section (Zagros Basin - eastern Tethys), to explore the consequences of this evolution on oceanic circulation, and to estimate the role of ophiolite weathering that can impact climate through atmospheric CO2 drawdown. [Ni] and [Cr] sharply increase in the uppermost Campanian – Maastrichtian interval and are not coeval with an increase in the Nd isotope composition (ɛNd) of the detrital fraction of the sediments. This is interpreted as reflecting weathering of the mantellic, ultramafic part of the ophiolite sequence at that time, implying that ophiolites were exposed on the continents as soon as the Coniacian in the vicinity of the Zagros Basin. Hence their weathering could have contributed to the Late Cretaceous climatic cooling. Clay mineralogy reveals an alternation of kaolinite-rich humid periods (Coniacian/Santonian and late early Campanian to latest Campanian) and kaolinite-depleted arid periods (early Campanian and the latest Campanian to late Maastrichtian). The ɛNd(t) of bathyal waters (carbonate leached fraction) appears quite radiogenic, in the range of -3.4 to -5.2 ɛ-units, about 2 to 4 ɛ-units higher than the detrital fraction. Changes in the ɛNd(t) of detrital material delivered to the Zagros Basin appear to control the ɛNd(t) of the local bottom waters from the Coniacian to the middle Campanian. By contrast, decoupling of detrital ɛNd(t) from that of the local bottom waters from the middle Campanian to the Maastrichtian points to increasing fluxes of westward flowing Pacific radiogenic water masses into the eastern Tethys at that time. These results support an intensific

Published
2021

47. Le climat à découvert

Author

Ablain, Michaël, Allard, Patrick, Anquetin, Sandrine, Balkanski, Yves, Bard, Édouard, Bekki, Slimane, Berthier, Étienne, Blamart, Dominique, Blard, Pierre-Henri, Blay, Michel, Blayo, Éric, Bony, Sandrine, Bopp, Laurent, Braconnot, Pascale, Brenguier, Jean-Louis, Bustarret, Étienne, Cadule, Patricia, Cassou, Christophe, Cazenave, Anny, Céron, Jean-Pierre, Chappellaz, Jérôme, Chauvaud, Laurent, Ciais, Philippe, Codron, Francis, Corrège, Thierry, Cortijo, Elsa, Cottet, Georges-Henri, Criqui, Patrick, Dandin, Philippe, Daux, Valérie, Davin, Édouard, Decharme, Bertrand, Delcroix, Thierry, Delecluse, Pascale, Delire, Christine, Déqué, Michel, de Marsily, Ghislain, de Noblet-Ducoudré, Nathalie, Donnadieu, Yannick, Douville, Hervé, Dubuisson, Philippe, Dudok de Wit, Thierry, Dufresne, Jean-Louis, Durand, Gaël, Féral, Jean-Pierre, Fluteau, Frédéric, France-Lanord, Christian, Friedlingstein, Pierre, Friess, Benjamin, Fuchs, Alain, Gaillardet, Jérôme, Garnier, Emmanuel, Genty, Dominique, Gerbeau, Jean-Frédéric, Goddéris, Yves, Grousset, Francis, Guillemot, Hélène, Guilyardi, Éric, Guimberteau, Matthieu, Guiot, Joël, Hall, Nick, Hourcade, Jean-Charles, Hourdin, Frédéric, Jeandel, Catherine, Joussaume, Sylvie, Jouzel, Jean, Kageyama, Masa, Khodri, Myriam, Klein, Patrice, Krinner, Gerhard, Laj, Paolo, Landais, Amaelle, Laval, Katia, Legras, Bernard, Le Bohec, Céline, Le Hir, Guillaume, Le Maho, Yvon, Le Treut, Hervé, Lilensten, Jean, Llovel, William, Lott, François, Maisonnave, Éric, Marchesiello, Patrick, Mascart, Patrick, Masson-Delmotte, Valérie, Mémery, Laurent, Metzl, Nicolas, Meurdesoif, Yann, Mignot, Juliette, Mosseri, Rémy, Naveau, Philippe, Petit, Jean-Robert, Peyron, Odile, Picon, Laurence, Pironneau, Olivier, Planton, Serge, Polcher, Jan, Pucéat, Emmanuelle, Rabatel, Antoine, Ramonet, Michel, Ramstein, Gilles, Reverdin, Gilles, Ribes, Aurélien, Roche, Didier, Roullet, Guillaume, Roux, Frank, Salas y Mélia, David, Sicre, Marie-Alexandrine, Swingedouw, Didier, Talagrand, Olivier, Tanré, Didier, Tatoni, Thierry, Thouret, Valérie, Thuillier, Gérard, Valcke, Sophie, Verron, Jacques, Vincent, Christian, Viovy, Nicolas, von Ballmoos, Peter, Wagnon, Patrick, Yiou, Pascal, GEOMAR LEGOS, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
effet de serre, climatologie, History & Philosophy Of Science, climat, [SDE.MCG]Environmental Sciences/Global Changes, SCI042000, météorologie, 01 natural sciences, 010305 fluids & plasmas, Outils et méthodes en recherche climatique, RBP, 0103 physical sciences, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 010306 general physics
Abstract

Qu'est ce que l'effet de serre ? Le rôle de l'homme sur le climat est-il détectable et comment ? Comment mesure-t-on la fonte de la banquise, le recul des glaciers de montagne ou bien encore l'élévation du niveau de la mer ? Comment les chercheurs font-ils pour modéliser un système aussi complexe que la planète terre ? Quelles données permettent de décrire et modéliser les climats passés ? Comment s'y prend-on pour prévoir l'évolution à venir du climat ? À l'écart de la polémique médiatique, Catherine Jeandel et Rémy Mosseri ont mobilisé plus d'une centaine de contributeurs qui livrent ici un panorama large des méthodes et outils mis en oeuvre pour étudier notre climat et son avenir. Ils montrent que, pour résoudre cette question extraordinairement complexe, une approche pluridisciplinaire est plus que jamais nécessaire, à la croisée de l'expérimentation, de l'observation, de la simulation et de la théorie. Un livre majeur.

Published
2017

48. 14. Le cycle du carbone à l’échelle des temps géologiques

Author

Goddéris, Yves, Donnadieu, Yannick, Ramstein, Gilles, Pucéat, Emmanuelle, and Le Hir, Guillaume

Abstract

La quantité de CO2 présente dans l’atmosphère a connu des fluctuations importantes au cours des millénaires. Celles-ci sont le reflet des déséquilibres entre sources et puits de carbone actifs à l’échelle géologique. Dans les sources de CO2, on classe le dégazage de la Terre solide (dégazage volcanique, diffus et aux dorsales) et l’oxydation du carbone organique sédimentaire, souvent mis à l’affleurement dans les zones montagneuses. Tandis que du côté des puits de carbone on trouve la consomm...

Published
2017

49. 8. Le climat de la Terre à l’échelle des temps géologiques

Author

Goddéris, Yves, Donnadieu, Yannick, Ramstein, Gilles, Pucéat, Emmanuelle, and Le Hir, Guillaume

Abstract

Depuis le début des années 1980, un intérêt grandissant s’est manifesté pour la reconstruction de l’évolution climatique de la Terre à l’échelle du million d’années. Ces travaux sont motivés par la volonté de comprendre les raisons des fluctuations du climat terrestre, les amplitudes maximales de ces variations et les liens entretenus par le climat avec les processus géologiques : mouvements tectoniques verticaux et horizontaux, évolution de la vie, etc. L’étude des climats passés est un vole...

Published
2017

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

Author

Donnadieu, Yannick, Pucéat, Emmanuelle, Guillocheau, François, Deconinck, Jean-François, Centre européen de recherche et d'enseignement de géosciences de l'environnement ( CEREGE ), Centre National de la Recherche Scientifique ( CNRS ) -Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Collège de France ( CdF ) -Institut National de la Recherche Agronomique ( INRA ) -Institut national des sciences de l'Univers ( INSU - CNRS ), Biogéosciences [Dijon] ( BGS ), AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Géosciences Rennes ( GR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire des Sciences de l'Univers de Rennes ( OSUR ) -Centre National de la Recherche Scientifique ( CNRS ), European Geosciences Union, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Dubigeon, Isabelle, Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[ SDU.STU.OC ] Sciences of the Universe [physics]/Earth Sciences/Oceanography, [SDU.STU.OC] Sciences of the Universe [physics]/Earth Sciences/Oceanography, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; 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 continentalconfiguration 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 revealmajor differences marked by a shift in the southern deep-water production sites from South Pacific at 95Ma toSouth Atlantic and Indian oceans at 70Ma. Our modelling results support an intensification of southern Atlanticdeep-water production as well as a reversal of the deep-water fluxes through the Caribbean Seaway as the maincauses 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 theAtlantic from 95Ma to 70Ma may have driven the disappearance of OAEs after the Late Cretaceous.

Published
2017

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