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1. Fast Growth May Impair Regeneration Capacity in the Branching Coral Acropora muricata

Author

Andrew C. Baker, Julien Debreuil, Stéphane De Palmas, Vianney Denis, J. Henrich Bruggemann, Roxane K. Boonstra, Madeleine Goutx, Mireille Guillaume, Laboratoire d'Ecologie Marine (ECOMAR), Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Miami University [Ohio] (MU), ANR: CNRS-INSU GDR Marges Project,CNRS-INSU GDR Marges Project, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Laboratoire d'Excellence CORAIL (LabEX CORAIL), Institut de Recherche pour le Développement (IRD)-Université des Antilles et de la Guyane (UAG)-École des hautes études en sciences sociales (EHESS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Réunion (UR)-Université de la Polynésie Française (UPF)-Université de la Nouvelle-Calédonie (UNC)-Institut d'écologie et environnement-Université des Antilles (UA), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables]-University of Miami [Coral Gables], ANR-12-INEG-0001,MARGES,Marges et villes : entre exclusion et intégration. Cas méditerranéens(2012), Université des Antilles (UA)-Institut d'écologie et environnement-Université de la Nouvelle-Calédonie (UNC)-Université de la Polynésie Française (UPF)-Université de La Réunion (UR)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École des hautes études en sciences sociales (EHESS)-Université des Antilles et de la Guyane (UAG)-Institut de Recherche pour le Développement (IRD)

Subjects
0106 biological sciences, Chlorophyll a, [SDE.MCG]Environmental Sciences/Global Changes, Coral, lcsh:Medicine, [SDV.BID]Life Sciences [q-bio]/Biodiversity, Photosynthetic efficiency, Photosynthesis, 010603 evolutionary biology, 01 natural sciences, Neurobiology of disease and regeneration, Calcification, chemistry.chemical_compound, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Calcification, Physiologic, Anthozoa, Botany, Animals, Regeneration, 14. Life underwater, Tissue repair, lcsh:Science, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, geography, Multidisciplinary, geography.geographical_feature_category, biology, Coral Reefs, 010604 marine biology & hydrobiology, Regeneration (biology), [SDV.BA]Life Sciences [q-bio]/Animal biology, lcsh:R, Coral reef, biology.organism_classification, Lipids, [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, Horticulture, chemistry, Zooxanthellae, Corals, lcsh:Q, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Reunion, Research Article
Abstract

International audience; Regeneration of artificially induced lesions was monitored in nubbins of the branching coral Acropora muricata at two reef-flat sites representing contrasting environments at Réunion Island (21u079S, 55u329E). Growth of these injured nubbins was examined in parallel, and compared to controls. Biochemical compositions of the holobiont and the zooxanthellae density were determined at the onset of the experiment, and the photosynthetic efficiency (F v /F m) of zooxanthellae was monitored during the experiment. Acropora muricata rapidly regenerated small lesions, but regeneration rates significantly differed between sites. At the sheltered site characterized by high temperatures, temperature variations, and irradiance levels, regeneration took 192 days on average. At the exposed site, characterized by steadier temperatures and lower irradiation, nubbins demonstrated fast lesion repair (81 days), slower growth, lower zooxanthellae density, chlorophyll a concentration and lipid content than at the former site. A trade-off between growth and regeneration rates was evident here. High growth rates seem to impair regeneration capacity. We show that environmental conditions conducive to high zooxanthellae densities in corals are related to fast skeletal growth but also to reduced lesion regeneration rates. We hypothesize that a lowered regenerative capacity may be related to limited availability of energetic and cellular resources, consequences of coral holobionts operating at high levels of photosynthesis and associated growth.

Published
2013
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2. Three-dimensional architecture of submarine slide surfaces and associated soft-sediment deformation in the Lutetian Sobrarbe deltaic complex (Ainsa, Spanish Pyrenees)

Author

Christophe Basile, Elie-Jean Debroas, Francis Odonne, Agnès Maillard, Damien Dhont, Guilhem Hoareau, Pierre Callot, Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Modélisation et Imagerie en Géosciences - Pau (MIGP), Centre National de la Recherche Scientifique (CNRS)-Université de Pau et des Pays de l'Adour (UPPA)-TotalFinaElf-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Géodynamique des Chaines Alpines (LGCA), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), ANR: CNRS-INSU GDR Marges Project,CNRS-INSU GDR Marges Project, 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 national des sciences de l'Univers (INSU - CNRS)-TotalFinaElf-Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and ANR-12-INEG-0001,MARGES,Marges et villes : entre exclusion et intégration. Cas méditerranéens(2012)

Subjects
slope instabilities, 010504 meteorology & atmospheric sciences, Stratigraphy, Stratification (water), fossil submarine slides, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, sedimentary instabilities, Structural basin, 010502 geochemistry & geophysics, Fault scarp, 01 natural sciences, Unconformity, Tectonic uplift, Ainsa Basin, Geomorphology, Lithification, 0105 earth and related environmental sciences, Sediment, Geology, 3D modelling, tsunamite, seismite, soft-sediment deformation, Sedimentary rock
Abstract

Five successive fossil submarine slides have been mapped and described in the Sobrarbe deltaic complex (Ainsa Basin, Spanish Pyrenees). These slides affect and remove up to 15% of the delta front. The head of the scar surfaces is recognized clearly in the field due to the angular unconformity between the infilling sediments and the underlying layers. Most of the slide scarps trend 55 degrees N with 20 degrees to 40 degrees dips indicating north-westward sliding. Downslope, traces of the sliding surfaces parallel stratification. However, these surfaces can be identified by displaced masses, resedimented sandstones and soft-sediment deformation features such as metre-scale half-grabens, normal faults and tension cracks; all the surfaces indicate a sliding displacement toward the north-west. A three-dimensional model built from topographic data with Earth Vision((R)) software shows the architecture of the slide surfaces and provides an estimation of the volume of each sedimentary body within the limit of the studied area. This study also indicates that: (i) the sediments have been cut and carried away before their lithification; (ii) the sedimentation rate infilling a single slump scar is estimated to be about 8 m per 1000 years, i.e. 10 times higher than in the overall area of the Sobrarbe deltaic complex; (iii) each composite scar progressively develops and infills by retrogressive slumps; (iv) the successive slide surfaces stack vertically in a collapse complex structure and migrate downward to follow the sea-level drop between two successive collapse complex structures; (v) the development of the scars in the Sobrarbe delta is described from a seven-stage conceptual model starting with a regressive event; and (vi) the triggering of the Sobrarbe instabilities is controlled by high values of sedimentation rate, relative sea-level falls mainly controlled by tectonic uplift, and likely seismic activity.

Published
2009
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3. Seismic Atlas of the Messinian Salinity Crisis markers in the Mediterranean Sea - Volume 2

Author

LOFI, Johanna, 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), Projet GDR Marges 'Eclipses', Actions Marges, Total, BRGM, and Commission for the Geological Map of the World

Subjects
Mediterranean sea, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Messinian Salinity Crisis, Seismic
Abstract

Pages 72, 1 CD; International audience; The Messinian Salinity Crisis (MSC) is a huge outstanding succession of events that has eeply modified the Mediterranean area within a short time span at the geological scale and led to the emplacement of one of the youngest and most debated salt giant on Earth.

Published
2018

4. Sediment accumulation rates and turbidite frequency in the eastern Algerian margin. An attempt to examine the triggering mechanisms

Author

Rabah Bracene, Jacques Déverchère, Pierre Giresse, Maria-Angela Bassetti, Henri Pauc, Abdelkarim Yelles, Virginie Gaullier, Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Sonatrach Exploration, Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG), and GDR Marges 'Instabilités' ACI 'Algérie' CMEP-Tassili 041MDU619

Subjects
010504 meteorology & atmospheric sciences, Pleistocene, Lithology, Stratigraphy, Seismicity, Geochemistry, Algerian margin, Sediment, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, Sedimentation, 010502 geochemistry & geophysics, Spatial distribution, 01 natural sciences, Turbidites, Turbidite, 13. Climate action, Sediment accumulation rates, Sedimentary instabilities, Sedimentary rock, 14. Life underwater, Chronostratigraphy, Geomorphology, 0105 earth and related environmental sciences
Abstract

International audience; From the analysis of seven new sediment piston-cores sampled in 2005 (MARADJA-2 French-Algerian cruise), this study aims to identify for the first time possible late Pleistocene to recent sedimentary instabilities controlled by seismicity off or close to the eastern coast of Algeria. The detailed lithologic study allows us to identify the frequency of the gravity events (turbidites, debrites) and to discuss their geographical sources and triggering mechanisms. Based on a chronostratigraphy of 24 14C AMS datings, sediment accumulation rates in zones extending off Bejaia and Annaba and, in particular, semi-quantitative analysis of the microfossils and lithogenic tracers of the origin of gravity flows was discussed. Two sediment cores, here considered as reference cores, enabled the estimation of palaeoenvironmental parameters that controlled sedimentation: (1) in the prodelta of Soummam Oued, after 2215 cal yr BP, floods were less frequent and sediment accumulation rates decreased because of a drier climate; (2) in the middle slope to the NE of Annaba, a location shielded from gravity flows, an increased sedimentation rate coincided with the passage of warmer waters leading to maxima of carbonate biogenic fluxes (particularly pteropods). Off Bejaia, two deep sediment cores show a spectacular increase in sediment accumulation rate between 2200 and 1000 cal yr BP while turbidites become more frequent. According to the eustatic and climatic stability of this interval, an episode of strong slope instability of the slope is suggested. Both sediment cores on the slope of Annaba indicate an increase in gravity flows during the same last thousand years, which is tentatively related to a regional increase of seismicity during this interval. This spatial distribution of gravity events is clearly different to that of the western margin where the sedimentation is less perturbed.

Published
2013
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5. Structure and evolution of the Demerara Plateau, offshore French Guiana : rifting, tectonic inversion and post-rift tilting at transform-divergent margins intersection

Author

Christophe Basile, Martin Patriat, F. Pattier, Lies Loncke, Virginie Gaullier, Walter R. Roest, Agnès Maillard, M. Mercier de Lépinay, Tectonique reliefs et bassins, Institut des Sciences de la Terre (ISTerre), Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), GDR marges, Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-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)-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), Géosciences Marines (GM), and Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
strike-slip, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Equatorial Atlantic, Rift, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Inversion (geology), Transform fault, South America, 010502 geochemistry & geophysics, Strike-slip tectonics, 01 natural sciences, Tectonics, Geophysics, Ridge push, Continental margin, Lithospheric flexure, 14. Life underwater, Seismology, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

International audience; We present the structure and evolution of the eastern part of the Demerara plateau, offshore French Guiana, from the analysis of geophysical data collected during GUYAPLAC cruise. This area is located at the intersection of a transform segment and a divergent segment of a continental margin related to the Early Cretaceous opening of the Equatorial Atlantic. The main structures are NNE-SSW to NNW-SSE trending normal faults on the eastern edge of the plateau, and WNW-ESE to NW-SE trending acoustic basement ridges on its northern edge. When replaced in their Albian position, these structures appear to be parallel to the coeval oceanic accretion axis and transform faults, respectively. The most striking structures are related to a post-rift but syn-transform tectonic inversion, producing E-W to WNW-ESE trending folds, sealed by a regional unconformity. This shortening can not be related to ridge push, but is probably related to a plate kinematic change 105 My ago, that modified the deformation in the vicinity of the transform fault. Late post-rift evolution also includes a significant Tertiary oceanward tilt of the edge of the Demerara plateau. The driving mechanism of this late tilt is unclear, but may be related to a lithospheric flexure resulting from the loading of the abyssal plain by the Orinoco and Amazon deep-sea fans.

Published
2013
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6. Seismic Atlas of the Messinian Salinity Crisis markers in the Mediterranean and Black Seas

Author

Johanna Lofi, Jacques Déverchère, Virginie Gaullier, Hervé Gillet, Christian Gorini, Pol Guennoc, Lies Loncke, Agnès Maillard, Françoise Sage, Isabelle Thinon, Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB), Centre de formation et de recherche sur l'environnement marin (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (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), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut de Modélisation et d'Analyse en Géo-Environnement et Santé (IMAGES), Université de Perpignan Via Domitia (UPVD), Laboratoire des Mécanismes et Transfert en Géologie (LMTG), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 6526), Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Projet GDR Marges 'Eclipses', Actions Marges, Total, BRGM, Commission for the Geological Map of the World, Plateau continental, 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), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), 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), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Black Sea, Mediterranean sea, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Messinian Salinity Crisis, Seismic
Abstract

Pages 72, 1 CD; International audience

Published
2011

7. Distribution of the organic matter in the channel-levees systems of the Congo mud-rich deep-sea fan (West Africa). Implication for deep offshore petroleum source rocks and global carbon cycle

Author

François Baudin, Jean-Robert Disnar, Philippe Martinez, Bernard Dennielou, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), GDR Marges Program, Université de Tours-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-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)-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), and Unité de recherche Géosciences Marines (Ifremer) (GM)

Subjects
South-East Atlantic, 010504 meteorology & atmospheric sciences, Stratigraphy, Geochemistry, 010502 geochemistry & geophysics, Oceanography, Source rocks, 01 natural sciences, Deep sea, Carbon cycle, Paleontology, Organic matter, 14. Life underwater, [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology, Sea level, 0105 earth and related environmental sciences, chemistry.chemical_classification, Total organic carbon, Nitrogen isotopes, Carbon isotopes, Geology, 15. Life on land, Turbidites, Geophysics, chemistry, Source rock, 13. Climate action, Clastic rock, Economic Geology, Sedimentary rock, Biomarkers
Abstract

The quantity and the source of organic matter preserved in the Recent turbiditic channel-levees systems around 4000 m-depth off the Congo River were determined using bulk geochemical approaches (Rock-Eval, elemental and isotopic analyses) as well as molecular and optical analyses on selected samples. These mud-rich sediments contain high amount of organic matter (3% Corg on average), the origin of which is a mixture of terrestrial higher-plant debris and deeply oxidized phytoplanktonic material. Although the relative contribution of continental source versus marine source of the organic matter cannot be precisely quantified, the continental fraction appears significant (at least 70-80%) especially for such depths and distances from the coast. The organic matter distribution appears very homogeneous at different scales, from the single turbiditic event to the entire levee, and changes in accumulation rates have a little impact on the quantity and quality of preserved organic matter. With a petroleum potential around 4.5 kg HC per t rock, the fine-grained turbiditic sediments in the Congo deep-sea system could be regarded as an analog of gas-prone source rocks for the deep offshore of the Atlantic margins. Finally, the Congo deep-sea turbiditic system is a major conveyor of organic carbon to the deep ocean. Further studies are needed to evaluate the efficiency of such systems for the storage of continental organic matter into the deep ocean in relation to sea-level and climatic changes. (C) 2010 Elsevier Ltd. All rights reserved.

Published
2010
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8. Characterization of organic matter in the Oligocene (Chattian) turbiditic fine grained deposits, offshore Angola

Author

François Baudin, Jean-Pierre Houzay, Jean-Robert Disnar, Isabelle Deniau, Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), TOTAL S.A., TOTAL FINA ELF, This project was supported, in part, by financial support from the INSU GDR Marges Program and by a post doctoral grant from TOTAL, and Université de Tours-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Total organic carbon, chemistry.chemical_classification, 010504 meteorology & atmospheric sciences, Soil organic matter, [SDE.MCG]Environmental Sciences/Global Changes, Mineralogy, Sediment, 010502 geochemistry & geophysics, 01 natural sciences, Palynofacies, chemistry.chemical_compound, chemistry, Source rock, 13. Climate action, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Kerogen, Organic matter, 14. Life underwater, Paleogene, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Variations in the abundance and gross composition of the organic matter (OM) content of fine grained turbiditic Chattian sediments off Angola were explored with Rock-Eval pyrolysis of 216 core samples from four wells. The study revealed that the OM in the sediments is immature but is present in sufficient abundance [>1% total organic carbon (TOC)] and with a good enough quality [hydrogen index (HI) around 185 mg hydrocarbon/g TOC on average] to constitute a potential source rock. A deeper insight into the composition of the OM was provided by the extraction and analysis of the kerogen from 15 samples. These samples were submitted to visual inspection and the counting of organic particles under the microscope (palynofacies analysis), elemental analysis and pyrolysis-gas chromatography-mass spectrometry (GC-MS). Although individually the various observations did not provide evidence clearly diagnostic of the origin of the OM, they confirm that it has a mixed marine-terrestrial origin, a notable part of the terrestrial contribution very probably originating from leaves. The good buoyancy of the OM and its richness in lipid components might explain the spreading of terrestrial OM over a large area and its relatively good oil potential.

Published
2010
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9. Slope instabilities from echo-character mapping along the French Guiana transform margin and Demerara abyssal plain

Author

Martin Patriat, Christophe Basile, Lies Loncke, Laurence Droz, Virginie Gaullier, Walter R. Roest, Institut de Modélisation et d'Analyse en Géo-Environnement et Santé (IMAGES), Université de Perpignan Via Domitia (UPVD), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géodynamique des Chaines Alpines (LGCA), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), French Research Program ‘‘GDR Marges', Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut des Sciences de la Terre (ISTerre), and Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)

Subjects
010504 meteorology & atmospheric sciences, Stratigraphy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Paleontology, Bathymetry, Mesozoic, Geomorphology, Slope instabilities, 0105 earth and related environmental sciences, geography, Fluids, geography.geographical_feature_category, Plateau, Continental shelf, Abyssal plain, Geology, Subsidence, Creeping, 15. Life on land, Cretaceous, Geophysics, Economic Geology, Sedimentary rock, Transform margin, Structural heritage
Abstract

International audience; The French Guiana transform margin and Demerara abyssal plain have been recently surveyed in the framework of the EXTRAPLAC French Program of extension of the continental shelf (Guyaplac survey, Ifremer-IFP–SHOM-IPEV). Based on the interpretation of some of the data collected during the Guyaplac survey (Simrad-EM12 multibeam bathymetric data, backscatter imagery, and 3.5 kHz profiles), the area can be divided into three morphostructural domains. (1) The western Guiana margin, including a part of the Demerara plateau, an important bathymetric relief prolonging the continental platform off Guiana and Surinam. This domain is bounded by (1a) the NW– SE trending northern border of the Demerara plateau which appears quite steep and corresponds to a transform segment of the margin, (1b) the N–S eastern border of the Demerara plateau which corresponds to a divergent segment of the margin. The Demerara plateau shows a segmented morphology, lowslope gradients, and a very rough surface (ripples perpendicular to the slope direction). NNW–SSE structural steps seem to correspond to collapses of 100 km long blocs towards the east. Slumps initiate along these directions. The observed rough bathymetry seems to be related to creeping processes. At a greater scale (seismic data), this part of the margin has been totally destabilized (numerous imbricate transparent masses rooted at about 0.5 s.t.w.t.t. belowseafloor). TheNW–SE trending northern border of the Demerara plateau corresponds to a cliff-like continental slope, probably slightly smoother than other transform margins (Ghana/coˆte d'Ivoire margin). The N–S eastern border of Demerara plateau is characterized by numerous small-scale imbricate slumps. Some of these failures seem to be emplaced in the prolongation of the NNW–SSE structural steps identified on the Demerara plateau. (2) The eastern Guiana margin corresponds to a NW–SE oriented gullied transform margin segment. The associated continental slope is very steep and characterized by numerous imbricate slumps and related debris lows. Some undulated masses, probably corresponding to creeping sediments or to older mass-wasting events are still imprinted on bathymetry. This transform margin segment is nearly entirely destabilized and eroded. (3) The Demerara abyssal plain. This domain is characterized eastwards by channels belonging to the Amazon turbidite system and westwards, at the foot of Demerara continental slope, by sediment waves probably created by contour currents. To conclude, it seems that there is a strong relationship between the structure (transform and divergent segments) and the emplacement of recurrent slope instabilities. These are probably related to the steepness of the slopes but also to subsidence histories generating in some cases huge deep-seated collapses of the whole margin. Fluid ascents are common everywhere in the area, probably enhancing slope instability. Their origin is not constrained but the black shales or Cretaceous organic-rich layers could be good candidates.

Published
2009
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10. The chronology of CAMP: relevance for the central Atlantic rifting processes and the Triassic-Jurassic biotic crisis

Author

Nomade, S., B. Knight, K., Beutel, E., R. Renne, P., Vérati, C., Féraud, G., Marzoli, A., Youbi, N., Bertrand, Hervé, Laboratoire de Sciences de la Terre (LST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), GDR Marges, Coopération CNRS-CNRST Maroc, Laboratoire Sciences De La Terre, Umr5570, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Central Atlantic Magmatic Province, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, age compilation, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Triassic-Jurassic, 40Ar-39Ar, Episodic, Migration
Abstract

The Central Atlantic Magmatic Province (CAMP) is among the largest igneous provinces on Earth, emplaced synchronously with or just previous to the Triassic-Jurassic boundary ca. 200 Ma. In great part due to the controversial connection between the occurrence of CAMP and the events of the Triassic-Jurassic boundary, the demand for better constraints on the duration and eruptive chronology of this province has increased. More than 100 new 40Ar/39Ar ages have been published in the last 15 years, with more than half of these in the last 3 years. A careful review and selection of available ages, as well as the publication of 16 new ages from the Carolinas, Newark basin (US), French Guyana and Morocco are presented. Judicious selection yields a total of 61 accepted age determinations for CAMP magmatism, ranging from 202 to 190 Ma covering every part of the CAMP. A clear picture develops with CAMP magmatism commencing as early as 202 Ma, as evidenced by one sill. Extrusive activity commenced abruptly ~200 Ma, reaching peak volume and intensity around 199 Ma on the African margin. The main period of CAMP magmatism is confirmed as brief, but is suggested to consist of at least two phases over ~1 Ma, during which time data suggest a southward migration of the magmatism from the Africa-North American margins towards South America. Two volumetrically minor, but distinctive magmatic peaks centered at 195 and 192 Ma are mirrored in data from all three continents, highlighted by our statistical approach. Despite significant advances in our understanding of the chronology of CAMP, we emphasize that the lack of a well-defined Triassic-Jurassic boundary age, as well as an absence of relevant comparison between U/Pb and 40Ar/39Ar data for this time period remain limiting factors to unambiguously linking CAMP in time with the events of the Triassic-Jurassic boundary.

Published
2006

11. 40Ar/39Ar ages and duration of the Central Atlantic Magmatic Province volcanism in Morocco and Portugal and its relation to the Triassic-Jurassic boundary

Author

Hervé Bertrand, Andrea Marzoli, Gilbert Féraud, Chrystèle Verati, Cédric Rapaille, Nasrrddine Youbi, Laboratoire de Sciences de la Terre (LST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), GDR Marges, Coopération CNRS-CNRST Maroc, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Lava, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, 40Ar/39Ar age, Paleontology, Central Atlantic Magmatic Province, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, Extinction event, Basalt, geography, Plateau, geography.geographical_feature_category, Rift, Portugal, Igneous rock, Morocco, Volcano, 13. Climate action, Magma, Geology, Triassic–Jurassic boundary, Continental volcanism
Abstract

The Central Atlantic Magmatic Province (CAMP) is the world's largest known continental igneous province and is 15 contemporaneous with the Triassic–Jurassic (T–J) boundary that marks one of the five largest biological extinctions in the last 16 600 Ma. Although constraints on the duration of the CAMP volcanism remain yet poorly defined, the assumption that the CAMP 17 may have had a causal relationship with the climatic and biotic crisis was suggested [Marzoli, A., Bertrand, H., Knight, K., Cirilli, 18 S., Buratti, N, Verati, C., Nomade, S., Renne, P.R., Youbi, N., Martini, R., Allenbach, K., Neuwerth, R., Rapaille, C., Zaninetti, L., 19 Bellieni, G., 2004. Synchrony of the Central Atlantic magmatic province and the Triassic–Jurassic boundary climatic and biotic 20 crisis. Geology 32, 973–976.]. In this paper, we present new 40Ar/39Ar ages on basaltic flows from Moroccan (central High Atlas, 21 Oujda and Argana) and Portuguese (Algarve and Santiago do Cacem) basins where CAMP lava flows are interlayered with T–J 22 sedimentary sequences. 23 In the Moroccan basins, where the basalts were erupted across the T–J boundary, well defined 40Ar/39Ar plateau ages (n=12) 24 for more than 90% of the total erupted volume of CAMP basalts range from 197.8±0.7 Ma to 201.7±2.4 Ma and display a main 25 restricted peak at 199.1±1 Ma providing a precise estimate of the 40Ar/39Ar age of the T–J boundary, concordant with the current 26 U–Pb age [199.6±0.3 Ma; Palfy, J., Mortensen, J.K, Carter, E.S., Smith, P.L., Friedman, R.M., Tipper, H.W., 2000. Timing the 27 end-Triassic mass extinction: First on land, then in the sea? Geology 28, 39–42.]. The topmost lava flows (recurrent unit) yield a 28 significantly younger mean age of 196.6±0.6 Ma, highlighting late episodic eruption of CAMP magmas. These late basalts 29 represent a small magma volume (b10% of the total), which was erupted most likely due to asthenospheric upwelling and 30 lithospheric extension within the T–J central High Atlas basins. 31 In the Portuguese basins, stratigraphical and palynological studies of the associated continental sedimentary sequence 32 underlying the volcanic units suggest an age close to the T–J boundary for the CAMP basaltic flows. This is confirmed by new 33 40Ar/39Ar data for the Portuguese basalts, which provide the first accurate radio-isotopic ages for lava flows in the European 34 CAMP, with two plateau ages yielding a mean value of 198.1±0.4 Ma. These plateau ages (plus three concordant mini-plateau 35 ages) suggest synchronous rifting and volcanism both in south-western Europe and Morocco (central High Atlas and Oujda basins).In summary, the eruptive history of the CAMP, with an early extremely widespread and intense peak at 199.1 Ma and a tail of 37 episodic eruption events until 196.6 Ma is consistent with the biotic turnover at the T–J boundary, which was likely caused by 38 devastating effects of extensive volcanic eruptions.

Published
2006
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12. La province magmatique de l'Atlantique central dans le bassin des Ksour

Author

Meddah, Amar, Bertrand, Hervé, Elmi, Serge, Laboratoire de Sciences de la Terre (LST), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), PaleoEnvironnements et PaleobioSphere (PEPS), Université Claude Bernard Lyon 1 (UCBL), GDR Marges, Laboratoire Sciences De La Terre, Umr5570, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Saharian Atlas, tholeiitic basalt, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Algeria, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, CAMP, Triassic-Jurassic boundary, rifting
Abstract

The volcanic succession from the Triassic basin of the Ksour Mountains is formed by three basaltic units, interlayered with silico-clastic to evaporitic sedimentary levels and overlain by Rhaetian-Hettangian limestones. These basalts are low-Ti continental tholeiites which show, from the bottom to the top, the same chemical evolution as the basalts from the Triassic basins in the Moroccan High Atlas. This volcanism represents the easternmost witness of the CAMP province associated with the central Atlantic rifting, at the Triassic- Jurassic boundary.

Published
2006

13. Isotope and trace element evidence for depleted lithosphere in the source of enriched Ko'olau basalts

Author

Vincent J. M. Salters, Afi Sachi-Kocher, Michael Bizimis, Janne Blichert-Toft, Zuzana Fekiacova, Laboratoire de Sciences de la Terre (LST), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), GDR Marges, Coopération CNRS-CNRST Maroc, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)

Subjects
Basalt, Peridotite, 010504 meteorology & atmospheric sciences, Trace element, Geochemistry, Pelagic sediment, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Geophysics, Impact crater, 13. Climate action, Geochemistry and Petrology, Lithosphere, Xenolith, Geology, 0105 earth and related environmental sciences
Abstract

We have measured the Hf and Nd isotopic compositions of 38 basalts from the Ko’olau drill hole, Hawai’i. The basalts show limited variations in both 176Hf/177Hf and 143Nd/144Nd (e Nd varies from +4.2 to +7.3 and e Hf from +8.0 to +12.3). Their correlated variation has an R 2 of 0.86. The data form an array with a slope of 1.2 on an e Hf–e Nd isotope correlation diagram, while the slope of all Hawai’ian basalt data is 0.98. Both slopes are significantly shallower than that of the mantle array of 1.4 defined by ocean island basalts. Previous studies have shown that a shallow slope in Hf–Nd isotope space can be related to ancient pelagic sediments in the mantle source (Blichert-Toft et al. 1999; Salters and White 1998). However, the combined variations in Ko’olau basalts of Hf–Nd–Pb–Os isotopic compositions and trace element ratios, such as La/Nb, Th/La and Sr/Nd, are not consistent with the simple addition of a sediment component to the mantle. We instead propose that the shallow slope on the Hf–Nd isotope correlation diagram for Ko’olau shield stage basalts can be better explained if the enriched endmember contains either an ancient oceanic lithosphere component or the high-176Hf/177Hf component observed in the Salt Lake Crater (SLC) peridotite xenoliths (which also have a depleted lithosphere origin). Since Ko’olau basalts have high 187Os/188Os (0.135–0.160) and the SLC xenoliths have 187Os/188Os up to 0.13 (Lassiter et al. 2000) Os-isotopes are consistent with the latter being a component in the enriched Ko’olau source.

Published
2006
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