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1. Late Miocene onset of the modern Antarctic Circumpolar Current

Author

Evangelinos, Dimitris, Etourneau, Johan, van de Flierdt, Tina, Crosta, Xavier, Jeandel, Catherine, Flores, José-Abel, Harwood, David M., Valero, Luis, Ducassou, Emmanuelle, Sauermilch, Isabel, Klocker, Andreas, Cacho, Isabel, Pena, Leopoldo D., Kreissig, Katharina, Benoit, Mathieu, Belhadj, Moustafa, Paredes, Eduardo, Garcia-Solsona, Ester, López-Quirós, Adrián, Salabarnada, Ariadna, and Escutia, Carlota

Published
2024
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5. Late Miocene onset of the modern Antarctic Circumpolar Current

Author

Australian Research Council, Ministère de l'Europe et des Affaires étrangères (France), Generalitat de Catalunya, International Ocean Discovery Program, Ministerio de Economía, Industria y Competitividad (España), UK Research and Innovation, Evangelinos, Dimitris, Etourneau, Johan, van de Flierdt, Tina, Crosta, Xavier, Jeandel, Catherine, Flores, José Abel, Harwood, David M., Valero, Luis, Ducassou, Emmanuelle, Sauermilch, Isabel, Klocker, Andreas, Cacho, Isabel, Pena, Leopoldo D., Kreissig, Katharina, Benoit, Mathie, Paredes, Eduardo, García-Solsona, Ester, López-Quirós, Adrián, Escutia, Carlota, Australian Research Council, Ministère de l'Europe et des Affaires étrangères (France), Generalitat de Catalunya, International Ocean Discovery Program, Ministerio de Economía, Industria y Competitividad (España), UK Research and Innovation, Evangelinos, Dimitris, Etourneau, Johan, van de Flierdt, Tina, Crosta, Xavier, Jeandel, Catherine, Flores, José Abel, Harwood, David M., Valero, Luis, Ducassou, Emmanuelle, Sauermilch, Isabel, Klocker, Andreas, Cacho, Isabel, Pena, Leopoldo D., Kreissig, Katharina, Benoit, Mathie, Paredes, Eduardo, García-Solsona, Ester, López-Quirós, Adrián, and Escutia, Carlota

Abstract

The Antarctic Circumpolar Current plays a pivotal role in global climate through its strong influence on the global overturning circulation, ocean heat and CO uptake. However, when and how the Antarctic Circumpolar Current reached its modern-like characteristics remains disputed. Here we present neodymium isotope and sortable silt records from sediment cores in the Southwest Pacific and South Indian oceans spanning the past 31 million years. Our data indicate that a circumpolar current like that of today did not exist before the late Miocene cooling. These findings suggest that the emergence of a homogeneous and deep-reaching strong Antarctic Circumpolar Current was not linked solely to the opening and deepening of Southern Ocean Gateways triggering continental-scale Antarctic Ice Sheet expansion during the Eocene–Oligocene Transition (∼34 Ma). Instead, we find that besides tectonic pre-conditioning, the expansion of the Antarctic Ice Sheet and sea ice since the middle Miocene Climate Transition (∼14 Ma) played a crucial role. This led to stronger density contrast and intensified Southern Westerly Winds across the Southern Ocean, establishing a vigorous deep-reaching circumpolar flow and an enhanced global overturning circulation, which amplified the late Cenozoic global cooling.

Published
2024

9. International Ocean Discovery Program Expedition 401 Preliminary Report: Mediterranean–Atlantic Gateway Exchange.

Author

Flecker, Rachel, Ducassou, Emmanuelle, and Williams, Trevor

Subjects
OCEAN circulation, MIOCENE Epoch, SALINITY, PLUMES (Fluid dynamics), OCEANOGRAPHY
Abstract

Marine gateways play a critical role in the exchange of water, heat, salt, and nutrients between oceans and seas. Changes in gateway geometry can significantly alter both the pattern of global ocean circulation and climate. Today, the volume of dense water supplied by Atlantic– Mediterranean exchange through the Gibraltar Strait is among the largest in the global ocean. For the past 5 My, this overflow has generated a saline plume at intermediate depths in the Atlantic that deposits distinctive contouritic sediments and contributes to the formation of North Atlantic Deep Water. This single gateway configuration only developed in the Early Pliocene. During the Miocene, two narrow corridors linked the Mediterranean and Atlantic: one in northern Morocco and the other in southern Spain. Formation of these corridors followed by progressive restriction and closure resulted in extreme salinity fluctuations in the Mediterranean, leading to the precipitation of the Messinian Salinity Crisis salt giant. International Ocean Discovery Program (IODP) Expedition 401 is the offshore drilling component of a Land-2-Sea drilling proposal, Investigating Miocene Mediterranean–Atlantic Gateway Exchange (IMMAGE). Its aim is to recover a complete record of Atlantic–Mediterranean exchange from its Late Miocene inception to its current configuration by targeting Miocene offshore sediments on either side of the Gibraltar Strait. Miocene cores from the two precursor connections now exposed on land will be obtained by future International Continental Scientific Drilling Program (ICDP) campaigns. [ABSTRACT FROM AUTHOR]

Published
2024

15. Middle Miocene development of the modern-like Antarctic Circumpolar Current

Author

Evangelinos, Dimitris, Escutia, Carlota, Etourneau, Johan, van de Flierdt, Tina, Crosta, Xavier, Ducassou, Emmanuelle, Jeandel, Catherine, Flores, José Abel, Harwood, David, Valero Montesa, Luis, Sauermilch, Isabel, Klocker, Andreas, Kreissig, Katharina, Benoit, M., Belhadji, Moustafa, López Quirós, Adrián, Salabarnada, Ariadna, Evangelinos, Dimitris, Escutia, Carlota, Etourneau, Johan, van de Flierdt, Tina, Crosta, Xavier, Ducassou, Emmanuelle, Jeandel, Catherine, Flores, José Abel, Harwood, David, Valero Montesa, Luis, Sauermilch, Isabel, Klocker, Andreas, Kreissig, Katharina, Benoit, M., Belhadji, Moustafa, López Quirós, Adrián, and Salabarnada, Ariadna

Abstract

The Antarctic Circumpolar Current (ACC) is a key component of Earth¿s climate system due to its strong influence on the global overturning circulation, ocean heat and CO2 uptake and storage. The timing and mechanisms of the development of a homogeneous and deep circumpolar flow remain disputed, despite the critical significance of the ACC for Earth¿s climate. Here we present neodymium isotope and sortable silt records from two pelagic sedimentary archives in the Southwest Pacific and South Indian Ocean (DSDP 278 and ODP 744, respectively) spanning the last 31 million years (Ma). Our data demonstrate that a modern-like deep-reaching circumpolar current did not exist before the Middle Miocene. This contrasts the long-held convictions that the development of a strong, deep ACC was solely controlled by the opening and deepening of Southern Ocean gateways, and resulted in significant glaciation across the Eocene-Oligocene Transition (34 Ma). We suggest that besides tectonic pre-conditioning, the expansion of the Antarctic ice sheet and sea ice during the Middle Miocene Climate Transition played a vital role in driving intensification of Southern Westerly Winds and establishment of a deep-reaching circumpolar flow.

Published
2023

17. Quaternary chronostratigraphic framework and sedimentary processes for the Gulf of Cadiz and Portuguese Contourite Depositional Systems derived from Natural Gamma Ray records

Author

Lofi, Johanna, Voelker, Antje Helga Luise, Ducassou, Emmanuelle, Hernández-Molina, F. Javier, Sierro, Francisco J., Bahr, André, Galvani, Aurélie, Lourens, Lucas J., Pardo-Igúzquiza, Eulogio, Pezard, Philippe, Rodríguez-Tovar, Francisco Javier, and Williams, Trevor

Published
2016
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18. Fluid Seepage in Relation to Seabed Deformation on the Central Nile Deep-Sea Fan, Part 1: Evidence from Sidescan Sonar Data

Author

Dano, Alexandre, Praeg, Daniel, Migeon, Sébastien, Augustin, Jean-Marie, Ceramicola, Silvia, Ketzer, João Marcelo, Augustin, Adolpho Herbert, Ducassou, Emmanuelle, Mascle, Jean, Krastel, Sebastian, editor, Behrmann, Jan-Hinrich, editor, Völker, David, editor, Stipp, Michael, editor, Berndt, Christian, editor, Urgeles, Roger, editor, Chaytor, Jason, editor, Huhn, Katrin, editor, Strasser, Michael, editor, and Harbitz, Carl Bonnevie, editor

Published
2014
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19. Fluid Seepage in Relation to Seabed Deformation on the Central Nile Deep-Sea Fan, Part 2: Evidence from Multibeam and Sidescan Imagery

Author

Praeg, Daniel, Ketzer, João Marcelo, Augustin, Adolpho Herbert, Migeon, Sébastien, Ceramicola, Silvia, Dano, Alexandre, Ducassou, Emmanuelle, Dupré, Stéphanie, Mascle, Jean, Rodrigues, Luiz Frederico, Krastel, Sebastian, editor, Behrmann, Jan-Hinrich, editor, Völker, David, editor, Stipp, Michael, editor, Berndt, Christian, editor, Urgeles, Roger, editor, Chaytor, Jason, editor, Huhn, Katrin, editor, Strasser, Michael, editor, and Harbitz, Carl Bonnevie, editor

Published
2014
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20. Post-failure Processes on the Continental Slope of the Central Nile Deep-Sea Fan: Interactions Between Fluid Seepage, Sediment Deformation and Sediment-Wave Construction

Author

Migeon, Sébastien, Ceramicola, Silvia, Praeg, Daniel, Ducassou, Emmanuelle, Dano, Alexandre, Ketzer, João Marcelo, Mary, Flore, Mascle, Jean, Krastel, Sebastian, editor, Behrmann, Jan-Hinrich, editor, Völker, David, editor, Stipp, Michael, editor, Berndt, Christian, editor, Urgeles, Roger, editor, Chaytor, Jason, editor, Huhn, Katrin, editor, Strasser, Michael, editor, and Harbitz, Carl Bonnevie, editor

Published
2014
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24. A reference time scale for Site U1385 (Shackleton Site) on the SW Iberian Margin

Author

Abrantes, Fatima, Acton, Gary D., Alvarez Zarikian, Carlos A., Bahr, André, Balestra, Barbara, Barranco, Estefanìa Llave, Carrara, Gabriela, Ducassou, Emmanuelle, Flood, Roger D., Flores, José-Abel, Furota, Satoshi, Grimalt, Joan, Grunert, Patrick, Hernández-Molina, Javier, Kim, Jin Kyoung, Krissek, Lawrence A., Kuroda, Junichiro, Li, Baohua, Lofi, Johanna, Margari, Vasiliki, Martrat, Belen, Miller, Madeline D., Nanayama, Futoshi, Nishida, Naohisa, Richter, Carl, Rodrigues, Teresa, Rodríguez-Tovar, Francisco J., Roque, Ana Cristina Freixo, Sanchez Goñi, Maria F., Sierro Sánchez, Francisco J., Singh, Arun D., Sloss, Craig R., Stow, Dorrik A.V., Takashimizu, Yasuhiro, Tzanova, Alexandrina, Voelker, Antje, Xuan, Chuang, Williams, Trevor, Hodell, D., Lourens, L., Crowhurst, S., Konijnendijk, T., Tjallingii, R., Jiménez-Espejo, F., Skinner, L., and Tzedakis, P.C.

Published
2015
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25. Onset of Mediterranean outflow into the North Atlantic

Author

Hernández-Molina, F. Javier, Stow, Dorrik A. V., Alvarez-Zarikian, Carlos A., Acton, Gary, Bahr, André, Balestra, Barbara, Ducassou, Emmanuelle, Flood, Roger, Flores, José-Abel, Furota, Satoshi, Grunert, Patrick, Hodell, David, Jimenez-Espejo, Francisco, Kim, Jin Kyoung, Krissek, Lawrence, Kuroda, Junichiro, Li, Baohua, Llave, Estefania, Lofi, Johanna, Lourens, Lucas, Miller, Madeline, Nanayama, Futoshi, Nishida, Naohisa, Richter, Carl, Roque, Cristina, Pereira, Hélder, Goñi, Maria Fernanda Sanchez, Sierro, Francisco J., Singh, Arun Deo, Sloss, Craig, Takashimizu, Yasuhiro, Tzanova, Alexandrina, Voelker, Antje, Williams, Trevor, and Xuan, Chuang

Published
2014

30. High-resolution analysis of submarine lobes deposits: Seismic-scale outcrops of the Lauzanier area (SE Alps, France)

Author

Mulder, Thierry, Callec, Yannick, Parize, Olivier, Joseph, Philippe, Schneider, Jean-Luc, Robin, Cécile, Dujoncquoy, Emmanuel, Salles, Tristan, Allard, Jonathan, Bonnel, Cédric, Ducassou, Emmanuelle, Etienne, Samuel, Ferger, Brice, Gaudin, Mathieu, Hanquiez, Vincent, Linares, Fabien, Marchès, Elodie, Toucanne, Samuel, and Zaragosi, Sébastien

Published
2010
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31. Post-depositional evolution over a time scale of 1 million years of eastern Mediterranean organic-rich and organic-poor sediments: new insights on the debromination and layer-silicate markers

Author

Murat Anne, Beaufort Daniel, Hébert Benoît, Baudin François, Bernasconi Stefano Michele, Ducassou Emmanuelle, Lelièvre Céline, Poizot Emmanuel, Mathian Maximilien, and Grauby Olivier

Subjects
organic matter, clay minerals, bromine, eogenesis, sapropel, mediterranean sea, Geology, QE1-996.5
Abstract

Organic matter degradation is the engine behind the biogeochemical evolution of sediments during burial. Previous research has shown that eogenesis is the seat of a complex interplay between organic matter, microbes and the most reactive part of inorganic compounds, such as clay minerals. To explore the variability and stability of bromine and clay minerals as geochemical and mineral tracers, we selected an eastern Mediterranean core that has a high degree of stability in the quality and quantity of organic matter through time at a one-million-year scale and great variability in organic matter content at a 10 ky scale. According to the very low maximal burial depth reached by these sediments (the core length is only 36.5 m), physical parameters, such as temperature and pressure, did not significantly influence the evolution of the studied parameters during the burial history. The bulk clay mineralogy of organic-rich and organic-poor sediments is similar all along the investigated core material; smectite predominates over kaolinite. The only identified authigenic minerals are biogenetic framboidal pyrite and manganese oxides. The X-ray data and the chemical compositions of the smectite are characteristic of a montmorillonite which is representative of a detrital Nile source. At a one-million-year scale, the organic matter content has no significant influence on clay eogenesis, and detrital smectite and kaolinite remain unchanged. Bromine is present in marine organic matter as organobromine compounds. During eogenesis, bromine is released from organic matter as bromide ion, resulting in an increase in the bromide concentration in the pore water with depth. Dissolved bromide can be used as a conservative tracer of the debromination of sedimentary organic matter. For the first time, we established that solid-phase BrOrg is a reliable tracer of debromination rates in marine sediments. The rate of debromination depends on the organic matter content. The rate increases from less than 2.3 × 10−4 μmolBrOrg mol.C−1.y−1 to 6.3 × 10−4 μmolBrOrg mol.C−1.y−1 when TOC varies from 0.17 to 3%. This increase is related to the development of the bacterial population and provides the basis for further investigation of other oceanic basins. For TOC values >4%, the rate of debromination decreases. We propose that the bioavailability of organic matter is another factor of variability in the debromination rate.

Published
2017
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37. Le canyon le plus profond du monde sur une pente carbonatée

Author

Mulder, Thierry, Wilks, Stanislas, Hanquiez, Vincent, Ducassou, Emmanuelle, Droxler, André, Faubert, Léa, and Sciencesconf.org, CCSD

Subjects
[SDU] Sciences of the Universe [physics], chenal, Canyon, carbonates, bahamas, levée, turbidites
Published
2021

38. Changes in the intermediate water masses of the Mediterranean Sea during the last climatic cycle ‐ New constraints from neodymium isotopes in foraminifera

Author

Colin, Christophe, Duhamel, Maxence, Siani, Giuseppe, Dubois‐dauphin, Quentin, Ducassou, Emmanuelle, Liu, Zhifei, Wu, Jiawang, Revel, Marie, Dapoigny, Arnaud, Douville, Eric, Taviani, Marco, Montagna, Paolo, Colin, Christophe, Duhamel, Maxence, Siani, Giuseppe, Dubois‐dauphin, Quentin, Ducassou, Emmanuelle, Liu, Zhifei, Wu, Jiawang, Revel, Marie, Dapoigny, Arnaud, Douville, Eric, Taviani, Marco, and Montagna, Paolo

Abstract

Variations in Mediterranean thermohaline circulation of the Quaternary are still not well constrained whereas they have been considered to have an influence on the Atlantic Meridional Overturning Circulation and on the oxygenation of waters in the deep basins of the Mediterranean Sea. εNd analyses have been carried out on planktonic foraminifera of cores collected in the central Mediterranean Sea to constrain water mass exchange between the Eastern and Western Mediterranean Sea (EMS and WMS) during the last climatic cycle. εNd records from the WMS and EMS display similar higher values during warm substages of interglacial Marine Isotopic Stage (MIS) 1 and 5. This suggests an efficient connection between the two Mediterranean sub‐basins and the transfer of radiogenic waters to the Tyrrhenian Sea via the Levantine Intermediate Water (LIW). Conversely, during glacial MIS, εNd of the intermediate depth of the Tyrrhenian Sea are less radiogenic than the EMS, implying limited hydrological connection between sub‐basins during low sea‐level stands. Superimposed on these glacial‐interglacial variations, increased εNd occurred during Heinrich Stadial events. This suggests a reduction in the formation of unradiogenic WIW in the Gulf of Lions due to the input of relatively fresh surface Atlantic water to the WMS and/or the inflow of radiogenic glacial LIW and upper EMDW to the Tyrrhenian Sea as a result of an active EMS convection related to saltier and colder conditions. Such potential millennial‐scale pulses of LIW intrusion into the Tyrrhenian Sea may have lead to an enhanced Mediterranean Outflow Water intensity in the Gibraltar Strait.

Published
2021
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41. PALEOCEANOGRAPHY: Onset of Mediterranean outflow into the North Atlantic

Author

Hernández-Molina, Javier F., Stow, Dorrik A. V., Alvarez-Zarikian, Carlos A., Acton, Gary, Bahr, André, Balestra, Barbara, Ducassou, Emmanuelle, Flood, Roger, Flores, José-Abel, Furota, Satoshi, Grunert, Patrick, Hodell, David, Jimenez-Espejo, Francisco, Kim, Jin Kyoung, Krissek, Lawrence, Kuroda, Junichiro, Li, Baohua, Llave, Estefania, Lofi, Johanna, Lourens, Lucas, Miller, Madeline, Nanayama, Futoshi, Nishida, Naohisa, Richter, Carl, Roque, Cristina, Pereira, Hélder, Goñi, Maria Fernanda Sanchez, Sierro, Francisco J., Singh, Arun Deo, Sloss, Craig, Takashimizu, Yasuhiro, Tzanova, Alexandrina, Voelker, Antje, Williams, Trevor, and Xuan, Chuang

Published
2014
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42. Changes in the Intermediate Water Masses of the Mediterranean Sea During the Last Climatic Cycle—New Constraints From Neodymium Isotopes in Foraminifera

Author

Colin, Christophe, primary, Duhamel, Maxence, additional, Siani, Giuseppe, additional, Dubois‐Dauphin, Quentin, additional, Ducassou, Emmanuelle, additional, Liu, Zhifei, additional, Wu, Jiawang, additional, Revel, Marie, additional, Dapoigny, Arnaud, additional, Douville, Eric, additional, Taviani, Marco, additional, and Montagna, Paolo, additional

Published
2021
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43. Establishment of the modern Antarctic Circumpolar Current

Author

Evangelinos, Dimitris, Escutia, Carlota, van de Flierdt, Tina, Etourneau, Johan, Flores, José-Abel, Ducassou, Emmanuelle, Harwood, David, Kreissig, Katharina, Perelló, Marie-Claire, López-Quirós, Adrián, and Salabarnada, Ariadna

Published
2020

47. Fluid Seepage in Relation to Seabed Deformation on the Central Nile Deep-Sea Fan, Part 2: Evidence from Multibeam and Sidescan Imagery

Author

Praeg, Daniel, primary, Ketzer, João Marcelo, additional, Augustin, Adolpho Herbert, additional, Migeon, Sébastien, additional, Ceramicola, Silvia, additional, Dano, Alexandre, additional, Ducassou, Emmanuelle, additional, Dupré, Stéphanie, additional, Mascle, Jean, additional, and Rodrigues, Luiz Frederico, additional

Published
2013
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49. Mediterranean Outflow Water and contourite depositional systems in the Gulf of Cadiz

Author

Ducassou, Emmanuelle, Moal-Darrigade, Paul, Lofi, Johanna, Bout-Roumazeilles, Viviane, Bahr, Andre, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Heidelberg University, SGF, Environnements et Paléoenvironnements OCéaniques (EPOC), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), and Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord])

Subjects
[PHYS]Physics [physics], [SDU]Sciences of the Universe [physics], [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences
Abstract

International audience; The Contourite Depositional Systems (CDS) in the Gulf of Cadiz are unique archives of the Mediterranean Outflow Water (MOW) variability since the Gibraltar gateway opening. These CDS have been generated by the upper and lower paths of the MOW, MUW and MLW respectively. These CDS have been drilled during the IODP Expedition 339 (2011-2012), offering a new data set over a longer period, allowing comparisons between recent and older climatic cycles, in sites both under the MUW and MLW cores. This work provides results of a detailed sedimentological and facies analysis of different CDS in the Gulf of Cadiz, using mainly grain size, grain sources (petrography of sands and clay assemblages), natural gamma ray data, and XRF results from specific intervals. Downhole and core gamma ray data coupled to grain-size results provided a regional scale chronostratigraphic framework for the CDS contourite deposits and hiatuses at the regional scale. These long sedimentary records provide an overview of the behavior and circulation regime of the MOW over the large changes in climate and sea-level cyclicities and especially over two periods: the last climatic cycle MIS1-MIS2 and at the mid-Brunhes Event (MIS10-12) which is an analog of the last cycle. One of the defining characteristics of contourite systems is the marked cyclicity in grain-size and related sediment properties. Drilling in the Gulf of Cadiz during IODP 339 recovered over 4.5 km of contourites with over 600 distinct contourite sequences. These show irregular cyclicity, much variation in thickness (0.5-4.0 m) and estimated duration (4-10 ky). Approximately 60% are bi-gradational sequences, whereas the rest are partial sequences. Three principal controls have been considered as likely causes for the sequences: (a) long-term variation in bottom-current velocity; (b) episodic lateral influx of clastic material; and (c) variation in vertical supply of biogenic material. The bi-gradational sequence, particularly for the muddy drift sites, validate the primary control exerted by long-term variation in bottom-current velocity. The high degree of cycle correlation between adjacent sites further supports this contention. A secondary control of lateral clastic supply is more evident for the proximal sandy contourite sites, and for partial base-cut sequences. Work is in progress on cycle duration and sediment sources.

Published
2019

50. Mediterranean Outflow Water and contourites over two analog climate cycles in the Gulf of Cadiz

Author

Moal-Darrigade, Paul, Ducassou, Emmanuelle, Giraudeau, Jacques, Bout-Roumazeilles, Viviane, Flood, Roger, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Institute for Terrestrial and Planetary Atmospheres [Stony Brook] (ITPA), School of Marine and Atmospheric Sciences [Stony Brook] (SoMAS), Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY)-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), Environnements et Paléoenvironnements OCéaniques (EPOC), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), and Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord])

Subjects
[PHYS]Physics [physics], [SDU]Sciences of the Universe [physics], [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences
Abstract

International audience; The Contourite Depositional Systems (CDSs) in the Gulf of Cadiz are unique archives of the Mediterranean Outflow Water (MOW) variability since the opening of the Gibraltar gateway at the end of the Miocene (5.33 Ma). The construction of these systems involves the upper (MUW) and lower (MLW) branches of the MOW. Drilling of these CDSs during IODP Expedition 339 (2011-2012) enables to investigate the MOW dynamics over an extended time period of the late Cenozoic. This study is centered on the sedimentological and facies characteristics of contourite beds over two periods with similar astronomic configurations (MIS1-2 and MIS 11-12) in order to compare the behavior and circulation regime of the MOW over two contrasted climatic cycles and their associated deglaciation. Sedimentological and facies analysis of different CDSs in the Gulf of Cadiz are based on an extensive set of data including grain size, petrographic (?) analyses of sandy components and clay assemblages, thin sections of contourite sequences, XRF core-scanner data, natural gamma ray data and biostratigraphy based on planktonic foraminifers. The results show a different behavior of the MOW between MIS 1/2 and MIS 11/12. For instance, in the Faro Drift (upper MOW), MIS 11 is characterized by the presence of several fine grained contourites (silt/ fine sand) while they are rare during MIS 1. During MIS 2 and MIS 12, only one contourite bed is recorded. These time periods are also characterized by different types of contourite beds in terms of grain size and composition: some are carbonate-rich whereas others are enriched in siliciclastic/terrigenous or/and authigenic particles. Different patterns of component evolution are also observed showing both changes in MOW velocity and availability of different sources of sediment involved.

Published
2019

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