Author: "Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)" - Searchworks@Jio Institute Digital Library Search Results

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405 results on '"Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)"'

1. AN EARLY 3D‐MAP OF A TERRITORY? THE BRONZE AGE CARVED SLAB FROM SAINT‐BÉLEC, LEUHAN (BRITTANY, FRANCE)

Author: Laurent Aubry, Bernard Le Gall, Julie Pierson, Joël Rolet, Yvan Pailler, Pierre Stéphan, Clement Nicolas, Vincent Lacombe, Trajectoires - UMR 8215, Université Paris 1 Panthéon-Sorbonne (UP1)-Centre National de la Recherche Scientifique (CNRS), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire Géosciences Océan (LGO), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Bournemouth University [Poole] (BU), Centre National de la Recherche Scientifique (CNRS), Institut national de recherches archéologiques préventives - Centre de recherches archéologiques de Cesson-Sévigné (Inrap, Cesson-Sévigné), Institut national de recherches archéologiques préventives (Inrap), Université de Bretagne Occidentale - UFR Sciences et Techniques (UBO UFR ST), Université de Brest (UBO), Littoral, Environnement, Télédétection, Géomatique (LETG - Brest), Université de Brest (UBO)-Université de Rennes 2 (UR2)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Nantes Université (Nantes Univ)-Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (Nantes Univ - IGARUN), Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (Nantes Univ - IGARUN), Nantes Université (Nantes Univ), Evaluating, understanding, supporting motor, perceptive and social Trajectories (TRAJECTOIRES), Centre de recherche en neurosciences de Lyon - Lyon Neuroscience Research Center (CRNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), DigiSCAN 3D, UMR 8215 Trajectoires (dir. O. Weller, CNRS)UMR 6554 LETG (dir. F. Gourmelon, CNRS)Collective Research Program ‘Éléments pour une nouvelle approche de l’âge du Bronze en Bretagne’ (dir. S. Blanchet,Inrap/DRAC Bretagne)Bournemouth University, and European Project: 841128,WATCH
Subjects: Bronze Age, 010506 paleontology, Archeology, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, Planimetry, Geography, Planning and Development, Context (language use), 01 natural sciences, Prehistory, Arts and Humanities (miscellaneous), Brittany, Early world maps, Rock art, 0601 history and archaeology, Territorialisation, 0105 earth and related environmental sciences, Carving, 060102 archaeology, Spatial Analyses, SAINT, [SHS.GEO]Humanities and Social Sciences/Geography, 06 humanities and the arts, Archaeology, Geography, Slab, Spatial extent
Abstract: International audience; While early maps are known from all over the world, the key questions always involve: what exactly do they show? And what spatial extent do they cover? In this context, we recently used 3D-modelling to re-examine a carved stone slab datable to the Early Bronze Age (c.2150–1600 BC) that was found at Saint-Bélec in Brittany. We show that the surface of the slab had been shaped in three dimensions to represent the relief of the surrounding landscape in which it was found, while several engraved motifs on it evoke contemporary structures known archaeologically. We argue that the Saint-Bélec slab represents an area of c.545 km2 corresponding to the extent of a prehistoric political entity. The carving and subsequent burying of the slab can be linked to the postulated rise and fall of hierarchical societies and raises many wider questions about socio-economic structures in temperate Europe at that time.
Published: 2021

2. Pervasive detachment faults within the slow spreading oceanic crust at the poorly coupled Antilles subduction zone

Author: Boris Marcaillou, Frauke Klingelhoefer, Muriel Laurencin, Jean-Frédéric Lebrun, Mireille Laigle, Serge Lallemand, Laure Schenini, Aurélien Gay, Milton Boucard, Kingsley Ezenwaka, David Graindorge, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), 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), 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), Université des Antilles (Pôle Guadeloupe), Université des Antilles (UA), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), 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]), 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 Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, QE1-996.5, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Subduction, Fracture zone, Geology, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Environmental sciences, Tectonics, Basement (geology), 13. Climate action, Oceanic crust, Trench, General Earth and Planetary Sciences, GE1-350, Petrology, Oceanic basin, 0105 earth and related environmental sciences, General Environmental Science
Abstract: Oceanic crust formed at slow-spreading ridges is currently subducted in only a few places on Earth and the tectonic and seismogenic imprint of the slow-spreading process is poorly understood. Here we present seismic and bathymetric data from the Northeastern Lesser Antilles Subduction Zone where thick sediments enable seismic imaging to greater depths than in the ocean basins. This dataset highlights a pervasive tectonic fabric characterized by closely spaced sequences of convex-up Ridgeward-Dipping Reflectors, which extend down to about 15 km depth with a 15-to-40° angle. We interpret these reflectors as discrete shear planes formed during the early stages of exhumation of magma-poor mantle rocks at an inside corner of a Mid-Atlantic Ridge fracture zone. Closer to the trench, plate bending could have reactivated this tectonic fabric and enabled deep fluid circulation and serpentinization of the basement rocks. This weak serpentinized basement likely explains the very low interplate seismic activity associated with the Barbuda-Anegada margin segment above.
Published: 2021

3. Tidal Current Energy Resources Assessment in the Patinti Strait, Indonesia

Author: Manoj Methew, Evi Hadrijantie Sudjono, Munawir Bintang Pratama, Franto Novico, Andi Egon, David Menier, Marine Geological Research and Development Center Bandung, Indonesia, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Marine Geological Research and Development Center Bandung, Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Environmental Engineering, Tidal range, 020209 energy, indonesia, lcsh:TJ807-830, lcsh:Renewable energy sources, Energy Engineering and Power Technology, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, [SPI]Engineering Sciences [physics], 0202 electrical engineering, electronic engineering, information engineering, 14. Life underwater, 0105 earth and related environmental sciences, Hydrology, geography, geography.geographical_feature_category, Renewable Energy, Sustainability and the Environment, business.industry, renewable energy, Renewable energy, Current (stream), 13. Climate action, Archipelago, [SDE]Environmental Sciences, Environmental science, Submarine pipeline, resource assessment, Hydrography, business, Energy source, numerical model, Tidal power, tidal current
Abstract: International audience; Indonesia is currently intensively developing its renewable energy resource and targets at least 23% by 2025. As an archipelago country, Indonesia has the potential to benefit from its abundant renewable energy resources from its offshore regions. However, the short tidal range of mixed semi-diurnal and the suitable tidal turbine capacity may hinder marine renewable energy development in Indonesian waters. This paper presents higher-order hydrodynamic numerical models to provide spatial information for tidal current resource assessment of the Patinti Strait. The present study applied the hydrographic and oceanographic method to produce input of the numerical model. Based on the selected simulation analysis, the highest current speed could be identified around Sabatang and Saleh Kecil Island with up to 2.5 m/s in P1 and 1.7 m/s in P4. Besides, the operational hours for the two observation points are 69% and 74.5%, respectively. The results indicate that this location is of prime interest for tidal turbine implementation as an energy source, for medium capacity (300 kW) and high capacity (1 MW).
Published: 2021

4. Occurrence and characterization of tremolite asbestos from the Mid Atlantic Ridge

Author: Di Giuseppe, Dario, Perchiazzi, Natale, Brunelli, Daniele, Giovanardi, Tommaso, Nodari, Luca, Della Ventura, Giancarlo, Malferrari, Daniele, Maia, Marcia, Gualtieri, Alessandro, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Interdisciplinary Graduate School for the Blue planeT, ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), Università degli Studi di Modena e Reggio Emilia (UNIMORE), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Di Giuseppe, D., Perchiazzi, N., Brunelli, D., Giovanardi, T., Nodari, L., Della Ventura, G., Malferrari, D., Maia, M., and Gualtieri, A. F.
Subjects: STRUCTURAL-CHARACTERIZATION, Solid Earth sciences, Science, Mineralogy, Article, SHORT-RANGE ORDER, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Medicine, ROMANCHE FRACTURE-ZONE, Tremolite, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Tremolite is one of the most common amphibole species and, in the fibrous form (i.e., characterized by crystals/particles consisting of fibres with length > 5 µm, width 3), one of the six asbestos minerals. Until now the attention of crystallographers has focused only on samples from continental environment. Here we report the first chemical and structural data of a tremolite asbestos found along the Mid Atlantic Ridge (MAR) at the eastern intersection of the Romanche Transform Fault (Equatorial MAR). Tremolite is associated with chlorite and lizardite and was formed through the green shale facies lower than zeolite in a predominantly fluid system. MAR tremolite asbestos shows very slight deviations from the ideal crystal structure of tremolite. Differences in cation site partitioning were found with respect to tremolite asbestos from ophiolitic complexes, attributed to the different chemical–physical conditions during the mineral formation. In particular, oceanic tremolite asbestos is enriched in Al and Na, forming a trend clearly distinct from the continental tremolites.
Published: 2021

5. Heavy Metals Concentration in Sediments of South Brittany Waters, France: An Ecological Risk Assessment Approach

Author: N.A.M. Shazili, Alexandra Connell, Virginie Dupont, David Menier, Hui-Juan Pan, M. C. Ong, Sidonie Révillon, Malaysia Institute of Oceanography, University of Malaysia, Laboratoire de Biotechnologie et Chimie Marines (LBCM), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), 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), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), and 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)
Subjects: Bay of Quiberon, Range (biology), Sediment, Heavy metals, Gulf of Morbihan, Heavy Metals, 6. Clean water, Current (stream), Sediment Quality Guidelines, 13. Climate action, Threshold effect, Environmental chemistry, [SDE]Environmental Sciences, Environmental science, Mariculture, Ecological risk, 14. Life underwater, Bay
Abstract: International audience; Distribution patterns of selected heavy metals content in sediments from the Bay of Quiberon and Gulf of Morbihan were studied to understand the current heavy metals contamination due to urbanization and mariculture activities in the coastal area. Therefore, a survey was conducted and 196 sediments collected were characterized for heavy metals content using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) after mix acid digestion process. The distribution maps of the concentrations of the heavy metals studied were produced as an isopleth map based on data interpolation by the ArcGIS software application. The association with the adverse effects on aquatic organisms was determined by the classification of the sediment according to the sediment quality guidelines. Therefore, two approaches were employed namely: direct comparison with Sediment Quality Guidelines (SQGs) by USEPA (United States Environmental Protection Agency) and comparison with other numerical SQGs, threshold effect level/probable effect level, and effect range low/effect range medium. In order to estimate the effect of multiple contaminations of heavy metals, the mean-ERM-quotient was calculated at each sampling point.
Published: 2021

6. Occurrence of Omura’s whale, Balaenoptera omurai (Cetacea: Balaenopteridae), in the Equatorial Atlantic Ocean based on Passive Acoustic Monitoring

Author: Alexey Sukhovich, Marcia Maia, Jean-Yves Royer, Sérgio C. Moreira, Renata S. Sousa-Lima, Marcelo Weksler, Milton C C Marcondes, Salvatore Cerchio, Museu Nacional de Historia Natural, <span class='valid'>Universidade Federal do Rio Grande do Norte [Natal] <span class='acronym'>UFRN</span></span> (UFRN), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto Baleia Jubarte (IBJ), Instituto Owaldo Cruz (FIOCRUZ), Maia, Marcia, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, vocalization, Cetacea, 010603 evolutionary biology, 01 natural sciences, biology.animal, Genetics, medicine, song, 14. Life underwater, Atlantic Ocean, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation, geography.geographical_feature_category, Ecology, Balaenoptera, biology, seasonality, Whale, 010604 marine biology & hydrobiology, Balaenopteridae, Balaenoptera omurai, Seasonality, acoustic detection, medicine.disease, biology.organism_classification, Omura's whale, [SDE.BE] Environmental Sciences/Biodiversity and Ecology, Oceanography, Geography, Habitat, Ridge, Archipelago, Animal Science and Zoology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: The current known distribution of Omura’s whale includes the tropical and warm temperate waters of the western Pacific, Indian, and Atlantic Oceans. Evidence of their presence in the Atlantic Ocean is based on beach cast specimens found on the coasts of Mauritania (North Atlantic) and Northeastern Brazil (South Atlantic). The present study characterizes the occurrence of this species in the São Pedro and São Paulo Archipelago (SPSPA), on the mid-Atlantic ridge between South America and Africa, based on autonomous recording systems. Acoustic signals were similar, but not identical, to B. omurai vocalizations recorded off the coast of Madagascar. Although these signals were recorded for only 11 months, there are peaks in vocal activity between May and June in the vicinities of SPSPA, suggesting either a shift in distribution within the Atlantic equatorial waters or seasonality in the species’ vocal behavior in this region. The first acoustic records of Omura’s whales in the Equatorial Atlantic suggest that these animals may also use deep-water habitats, in addition to the shallow-water habitat use observed in other regions., A atual distribuição conhecida da baleia-de-Omura (Balaenoptera omurai) inclui as águas tropicais e temperadas quentes dos oceanos Pacífico ocidental, Índico e Atlântico. A evidência de sua presença no oceano Atlântico baseia-se em espécimes encalhados encontrados em praias da Mauritânia (Atlântico Norte) e do Nordeste do Brasil (Atlântico Sul). O presente estudo caracteriza a ocorrência dessa espécie no Arquipélago de São Pedro e São Paulo (ASPSP), localizado sobre a Dorsal Mesoatlântica entre a América do Sul e a África, com base em sistemas de monitoramento acústico passivo. Os sinais acústicos detectados foram similares, mas não idênticos, às vocalizações de B. omurai gravadas na costa de Madagascar. Embora esses sinais tenham sido registrados por apenas 11 meses, há picos na atividade vocal entre maio e junho nas proximidades do ASPSP, sugerindo uma mudança na distribuição da espécie nas águas equatoriais do Atlântico ou uma sazonalidade no comportamento vocal nessa região. Os primeiros registros acústicos das baleias-de-Omura no Atlântico Equatorial sugerem que esses animais também podem utilizar habitats de águas profundas, além de habitats de águas rasas como observado em outras regiões.
Published: 2020

7. Distribution of modern dinocysts in surface sediments of southern Brittany (NW France) in relation to environmental parameters: Implications for paleoreconstructions

Author: Clément Lambert, Aurélie Penaud, Clément Poirier, Evelyne Goubert, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010506 paleontology, 010504 meteorology & atmospheric sciences, Dinoflagellate cysts, Southern Brittany shelf, Paleontology, 01 natural sciences, Taphonomic issues, 14. Life underwater, Paleoenvironmental reconstructions, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Marine palynology, 0105 earth and related environmental sciences
Abstract: Dinoflagellate cyst assemblages from 15 modern surface sediment samples of the Bay of Quiberon (Southern Brittany shelf) have been examined to assess their potential as marine bio-indicators for paleoenvironmental reconstructions in a shallow coastal environment. Some discrepancies are noted in the distribution of dinocyst taxa in the study area, and particularly regarding dinocyst concentration and diversity (26 different taxa identified in total) as well as heterotrophic taxa percentages. We suggest that the proportion of heterotrophic taxa is, in an embayment of 15 m deep in average, mainly attributed to bottom water oxygenation and sediment granulometry, both acting on species-selective degradation after dinocyst deposition. More precisely, higher heterotrophic abundances are found under lower oxic conditions and in fine grain-size sediment samples, leading to caution about their use as productivity indicators in coastal environments when these parameters are not fully addressed. The comparison of the Bay of Quiberon data with surface sediment samples and top cores from previously published data makes it possible to establish a transect of the modern dinocyst distribution from inshore to offshore areas in the northern Bay of Biscay, allowing to identify different ecological groups according to the hydrological and bathymetric contexts: i) an estuarine assemblage strongly dominated by Lingulodinium machaerophorum, ii) a proximal coastal assemblage dominated by L. machaerophorum and, to a lesser extent, Spiniferites bentorii, iii) a neritic assemblage dominated by L. machaerophorum, Spiniferites ramosus and cysts of Pentapharsodinium dalei, and iv) an oceanic group dominated by Spiniferites mirabilis and Operculodinium centrocarpum.
Published: 2022

8. Enhanced western mediterranean rainfall during past interglacials driven by North Atlantic pressure changes

Author: Yama Dixit, Samuel Toucanne, Christophe Fontanier, Juan M. Lora, Virgil Pasquier, Aradhna Tripati, Gwenael Jouet, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Interdisciplinary Graduate School for the Blue planet, and ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
Subjects: Mediterranean climate, Western mediterranean, 010506 paleontology, Effects of global warming on oceans, Sapropel, Foraminifera, 010502 geochemistry & geophysics, Monsoon, 01 natural sciences, Interglacials, Mg/ca-SST, Mediterranean sea, 14. Life underwater, Holocene, 0105 earth and related environmental sciences, Earth-Surface Processes, geography, geography.geographical_feature_category, Ba/Ca-salinity, Sea surface temperature, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Oceanography, 13. Climate action, Interglacial, Environmental science, Oceanic basin
Abstract: International audience; There is increasing concern with anthropogenic greenhouse gas emissions that ocean warming, in concert with summer and winter precipitation changes, will induce anoxia in multiple ocean basins, such as in the Mediterranean Sea. Although the hydrological changes in the eastern Mediterranean are quite well constrained, quantitative evidence of changes in sea surface temperature (SST) and winter rainfall in the western Mediterranean across the past interglacials is relatively scarce. In this study, we use a combination of trace element (Ba/Ca and Mg/Ca) and stable oxygen isotope composition of planktonic foraminifera from a sediment core located off the Golo River, Corsica (northern Tyrrhenian Sea) to reconstruct variations in SSTs and sea surface salinities (SSS) during the Holocene (MIS 1) and warm periods of the past two interglacials (MIS 5, 7). We also analyse PMIP3 model simulations for the mid-Holocene to investigate the mechanism for moisture transport in the western Mediterranean. Our Mg/Ca-SSTs, Ba/Ca-salinity and derived δ18O-seawater records suggest that the warm periods of the past interglacials were characterized by high river discharge and lower SSS in the northern Tyrrhenian Sea. Since this region is ideally located on the trajectory of wintertime storm tracks across the North Atlantic into the Mediterranean Sea and is also outside the influence of the ITCZ-controlled summer monsoon rains, we suggest enhanced winter rainfall during the past interglacials. Our analysis of PMIP3 model simulations for mid-Holocene also support increased south-westerly moisture transport into the western Mediterranean originating from the North Atlantic. We also find evidence that long-term amplitude of the salinity decrease tightly follows eccentricity. We suggest that these hydrologic changes in the western Mediterranean, and the northern Mediterranean borderlands as a whole, were a contributing factor, together with local cyclogenesis and African summer monsoon rainfall, to basin-wide anoxia in the past. Our findings offer new constraints to the amplitude and cause of winter rainfall changes in the Mediterranean during past warm periods.
Published: 2020

9. Geomorphic Change Detection Using Cost-Effective Structure-from-Motion Photogrammetry: Evaluation of Direct Georeferencing from Consumer-Grade UAS at Orewa Beach (New Zealand)

Author: Patrice Delmas, Benjamin Levy, Stephane Bertin, Trevor Gee, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Department of Computer Science [Auckland], University of Auckland [Auckland], Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Subjects: Photogrammetry, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Georeference, Structure from motion, Computers in Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Geology, Change detection, 0105 earth and related environmental sciences, Remote sensing
Abstract: Unmanned aerial systems (UAS) and structure-from-motion photogrammetry are transforming the way we produce topo- graphic data, with applications covering many disciplines in the geosciences, including coastal studies. To overcome limitations of ground control points (GCPs), we evaluate direct georeferencing (DG) of consumer UAS imagery for the cost-effective measurement of beach topography. Using DG, camera positions determined with on-board instruments provide air control points for photogrammetry, obviating the need for presurveyed GCPs. We validate the approach at Orewa Beach, New Zealand, achieving vertical accuracies similar to light detection and ranging (< 0.2 m) at a higher resolution (< 0.1 m). A low-quality global navigation satellite system onboard a consumer UAS remains the main constraint on measurement quality. We show how independent topo- graphic data sets, which are increasingly available world- wide, can improve measurement quality, and hence change detection capacity. Our understanding of measurement quality achieved in this study is applied to the assessment of morphological and volumetric change at Orewa Beach.
Published: 2020

10. Seismic stratigraphy and depositional architecture of Neogene intraslope basins, offshore western Niger Delta

Author: Christian Gorini, Silvia Gardin, Didier Granjeon, Kelvin Ikenna Chima, Damien Do Couto, Marina Rabineau, Estelle Leroux, Nick Hoggmascall, Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Nigeria, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Muséum national d'Histoire naturelle (MNHN)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Shell Petroleum Development Company, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), IFP Energies nouvelles (IFPEN), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Centre de Recherche en Paléontologie - Paris (CR2P), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Bretagne Sud (UBS)
Subjects: 010504 meteorology & atmospheric sciences, Stratigraphy, Turbidite systems, Seismic sequence stratigraphy, 010502 geochemistry & geophysics, Oceanography, Neogene, 01 natural sciences, Sedimentary depositional environment, Paleontology, Filled ponded basins, Mass-transport deposits, West Africa, Niger Delta, 14. Life underwater, Chronostratigraphy, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Geology, Tectonics, Geophysics, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Meander, Overbank, Economic Geology, Submarine pipeline, Sedimentary rock
Abstract: International audience; Located on a divergent margin dominated by gravity tectonics above overpressured marine shales, the Niger Delta slope has been described as having a stepped profile characterized by ‘filled ponded basins’ that are prone to erosion and sediment bypass. Previous studies based on 3D seismic data have described the depositional architecture of the western Niger Delta's upper slope, but calibration of the seismic facies is lacking and the timing of major changes in sedimentary record remains elusive. In this study, seismic sequence-stratigraphy, 3D geomorphological analyses of high-resolution 3D seismic data, and bio/chronostratigraphic analyses from four boreholes, enabled the identification and characterization of the depositional architecture in Neogene ‘filled ponded basins’. Seven major seismic units were dated as Chattian, Burdigalian, Serravallian, Tortonian, Middle Pliocene and Middle Pleistocene to the present day. Major changes in the sedimentary record occurred in the Plio-Pleistocene, with the onset of erosive channel levee systems (CLSs) and mass-transport deposits (MTDs) generally capped by a hemipelagic drape. Amalgamated CLSs characterize the Tortonian-Late Miocene while erosive MTDs and CLSs characterize the Plio-Pleistocene units. Thick, laterally extensive MTDs are associated with regional slope instability, while active mobile shale triggered local spatially confined MTDs. Submarine channels evolved from moderate to highly sinuous. The degree of channel confinement generally decreases downstream where they are characterized by abandoned meander loops and avulsion resulting from levee breaching. Channel fills and levees/overbank deposits topped by hemipelagic drapes provide effective reservoir/seal (traps) for hydrocarbons. The alternation of channel deposits and hemipelagic layers indicate that eustasy controlled depositional patterns at a regional scale, while the spatio-temporal switches in submarine channel courses show that shale tectonics locally controlled deposition in intraslope basins.
Published: 2019

11. Phosphate remobilization from banded iron formations during metamorphic mineral transformations

Author: Andreas Kappler, Leslie J. Robbins, Manuel Schad, Julian Tejada, Maximilian Halama, Noah J. Planavsky, Muammar Mansor, Stefan V. Lalonde, Kurt O. Konhauser, Tyler J. Warchola, Elizabeth D. Swanner, Rainer Kirchhof, Harald Thorwarth, Natalia Jakus, University of Alberta, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Center for Applied Geoscience [Tübingen] (ZAG), Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen, Yale University [New Haven], and ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
Subjects: Mineral, 010504 meteorology & atmospheric sciences, fungi, Geology, Hematite, 010502 geochemistry & geophysics, Phosphate, 01 natural sciences, chemistry.chemical_compound, Ferrihydrite, Siderite, chemistry, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Environmental chemistry, visual_art, visual_art.visual_art_medium, Vivianite, Banded iron formation, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Magnetite
Abstract: Ratios of phosphorous (P) to iron (Fe) in Precambrian banded iron formations (BIFs) have previously been used to estimate dissolved seawater phosphate concentrations in the ancient oceans. Such studies rely on an assumed composition of the primary iron minerals, the concentrations of the major ions in seawater, and empirical partitioning coefficients for phosphate sorption to Fe(III) (oxyhydr)oxides. There is limited data, however, regarding the post-depositional stability of phosphate associated with presumed primary BIF iron minerals, such as ferrihydrite under low-grade metamorphic temperature and pressure conditions. Here we experimentally formed ferrihydrite in the presence of silica, which was abundant in the Precambrian oceans, and then incubated it at 170 °C and 1.2 kbar in the presence or absence of organic carbon (Corg; either glucose or microbial biomass) as a proxy for ancient planktonic biomass. We found that the post-metamorphic mineral assemblage resulting from thermochemical Fe(III) reduction of Si-doped ferrihydrite depended on Corg reactivity: In the presence of highly reactive glucose, siderite, magnetite, and vivianite were formed, with less than 1.2 mol% of phosphate (0.5 M NaCl extractable) being mobilized. In contrast, the reaction of Si-doped ferrihydrite with less reactive microbial biomass resulted in the formation of hematite and siderite, but not vivianite, and approximately 10 mol% of phosphate was remobilized into the pore fluids. Collectively, our data suggest that the fidelity with which BIFs record ancient oceanic phosphate concentrations depends on the mineralogy and diagenetic history of individual BIFs but should be reliable within 10%.
Published: 2021

12. PCR Au fil du plomb de la Seine. Rapport 2021 (coord. M. Robert)

Author: Robert, Malina, Adrian, Yves-Marie, Bertrand, Isabelle, Baron, Sandrine, Duvernois, Bruno, Fortunato, Juliette, Le Carlier de Veslud, Cécile, Lukas, Dagmar, Marlin, Laurence, Masse, Margot, Mille, Benoit, Monteix, Nicolas, Mouchard, Jimmy, Spiesser, Jérôme, Révillon, Sidonie, Thomann, Aminte, Université de Nantes - Département histoire de l'art et archéologie, Université de Nantes - UFR Histoire, Histoire de l'Art et Archéologie (UFR HHAA), Université de Nantes (UN)-Université de Nantes (UN), Laboratoire de recherche ARchéologie et Architecture (LARA), Université de Nantes (UN)-Centre de Recherche en Archéologie, Archéosciences, Histoire (CReAAH), Le Mans Université (UM)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR Histoire, Histoire de l'Art et Archéologie (UFR HHAA), Université de Nantes (UN)-Université de Nantes (UN)-Ministère de la Culture (MC)-Le Mans Université (UM)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Nantes (UN)-Ministère de la Culture (MC), Centre de Recherche en Archéologie, Archéosciences, Histoire (CReAAH), Institut national de recherches archéologiques préventives (Inrap), Archéologies et Sciences de l'Antiquité (ArScAn), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Archéologie des Sociétés Méditerranéennes (ASM), Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)-Université Paul-Valéry - Montpellier 3 (UPVM), Travaux et recherches archéologiques sur les cultures, les espaces et les sociétés (TRACES), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Musée du Prieuré d'Harfleur, Caux Seine Agglo (CSA), Réunion des Musées Métropolitains Rouen Normandie, Ministère de la Culture (MC), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Groupe de Recherche d'Histoire (GRHis), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche Interdisciplinaire Homme et Société (IRIHS), Normandie Université (NU)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Service archéologique du Loiret, Conseil général du Loiret, SEDISOR, Laboratoire Géosciences Océan UMR CNRS 6538, Université de Bretagne Occidentale et Institut Universitaire Européen de la Mer, Laboratoire Géosciences Océan (LGO), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre Michel de Boüard - Centre de recherches archéologiques et historiques anciennes et médiévales (CRAHAM), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), SRA Normandie, UMR 6566 CReAAH - LARA, Le Mans Université (UM)-Université de Rennes (UR)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR Histoire, Histoire de l'Art et Archéologie (UFR HHAA), Université de Nantes (UN)-Université de Nantes (UN)-Ministère de la Culture (MC)-Le Mans Université (UM)-Université de Rennes (UR)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR Histoire, Histoire de l'Art et Archéologie (UFR HHAA), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Université Paul-Valéry - Montpellier 3 (UPVM)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Université de Lille, Histoire, Archéologie et Littérature des Mondes Anciens - UMR 8164 (HALMA), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), LARA - UMR 6566, Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Institut national de recherches archéologiques préventives (Inrap)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Le Mans Université (UM)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)-Le Mans Université (UM)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Analyses élémentaires, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, Pratiques funéraires, Analyses isotopiques, Métallurgie, Seine, Cercueils, Normandie, [SHS]Humanities and Social Sciences, Gaule, Antiquité tardive, Estuaire de la Seine, Haut-Empire, Plomb, Ossuaires, Artisanat
Abstract: Au cours du XIXe siècle, de nombreux contenants funéraires en plomb d’époque romaine sont découverts dans l’estuaire de la Seine : des vases ossuaires mis au jour à Lillebonne (Seine-Maritime) et ses alentours aux cercueils des environs de Rouen (Seine-Maritime), ils intriguent les érudits locaux et moins locaux, qui relient rapidement la présence de ce métal en grande quantité, dans une région où aucune mine antique n’est connue, à la richesse plombifère de la province proche de Britannia. Trois axes de recherche ont été identifiés les concernant : - Échanges et pratiques commerciales autour du plomb dans l’estuaire. - L'artisanat du plomb estuarien, de la mine au produit fini. - Le plomb dans les pratiques funéraires calètes et véliocasses. À la suite de ces échanges et au regard des premières données rassemblées au cours de l'année probatoire 2020, une réflexion collective a été menée afin de planifier les poursuites de la recherche sur les productions manufacturées en plomb d’époque romaine dans l’estuaire de la Seine. Un programme de recherche triennale a donc débuté en 2021, afin d’étendre la réflexion initiée dans le cadre des axes de recherche du PCR : les différentes enquêtes portant sur la composition et la provenance du métal, tout comme l’étude de la diffusion des contenants en plomb vers et au sein de la région d’étude, ainsi que leur vocation funéraire ne font, en effet, que débuter. Le présent rapport correspond à un bilan des activités de recherches au cours de l’année 2021, première année de la campagne de recherche triennale.
Published: 2021

13. Climate and the Evolution of the Ocean: The Paleoceanographic Data

Author: Natalia Vázquez Riveiros, Jean-Claude Duplessy, Elsa Cortijo, Laurent Labeyrie, Thibaut Caley, 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), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Paléocéanographie (PALEOCEAN), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Ramstein G., Landais A., Bouttes N., Sepulchre P., Govin A. (eds), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Gilles Ramstein, Amaëlle Landais, Nathaelle Bouttes, Pierre Sepulchre, Aline Govin, Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Bretagne Sud (UBS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Water column, Oceanography, 13. Climate action, Sediment, Seawater, 14. Life underwater, Limiting, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Circumnavigation, Geology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; The idea of reconstructing the history of oceans and climates in the past using marine sediment cores arrived quite late after the beginnings of oceanography. It was initiated in the twentieth century, well after the first attempts to measure variations in seawater temperature down the water column, which date back to the eighteenth century with the great circumnavigation expeditions. Land geologists were the first to propose paleoceanographic reconstructions from exposed marine series, limiting the collected information to former coastal waters.
Published: 2021

14. Correlating trace element compositions, petrology, and Raman spectroscopy data in the ∼3.46 Ga Apex chert, Pilbara Craton, Australia

Author: Martin J. Van Kranendonk, Mark A. van Zuilen, Joti Rouillard, Stefan V. Lalonde, Jian Gong, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), School of Biological, Earth and Environmental Sciences [Sydney] (BEES), University of New South Wales [Sydney] (UNSW), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Bretagne Sud (UBS)
Subjects: Micropaleontology, 010504 meteorology & atmospheric sciences, Hydrothermal processes, Maturity (sedimentology), Pilbara Craton, Geochemistry, Trace element, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, Crust, 15. Life on land, 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, Petrography, Geochemistry and Petrology, Rare Earth Elements Geochemistry, Raman spectroscopy, Sedimentary rock, Microbial mat, Archean cherts, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: The Apex chert unit (∼3.46 Ga, Pilbara Craton, Australia) constitutes one of the oldest sedimentary units on Earth in which putative carbonaceous microfossils have been reported. The source of carbonaceous matter (CM) in this unit, however, is hotly debated. Hydrothermal fluids have circulated through the underlying crust and up into the bedded unit; these fluids could have remobilized sedimentary microbial biomass, generated abiological hydrocarbons, or harbored in situ chemolithoautotrophic microbial communities. Are there parts of the unit where microfossils might be best preserved? A potential fossil microbiota – if present – would probably be best preserved in the stratiform portion of the unit where hydrothermal influence seems to have been lowest. In order to shed light on the history of hydrothermal overprinting and the source of carbonaceous fractions in the Apex chert, we correlate here at a high spatial resolution petrographic observations and trace element analyses over a transect from the dyke where putative microfossils were found to the stratiform part where remnants of microbial mats were found. The layered, stratiform part of the unit has positive La anomalies up to 1.7, and Light Rare Earth Element depletions, indicating a seawater source. However, as far as 300 m from the dyke, the stratiform part also shows hydrothermal brecciation, high Eu anomalies (2–12; µ = 4.2) and chondritic Y/Ho ratios (24.3–30.3; µ = 27.0), indicating that hydrothermal fluids have laterally infiltrated over large distances. Overall, the pervasive influence of hydrothermal fluids throughout the entire unit and the presence of carbonaceous matter both in the sedimentary part and the hydrothermal dyke is consistent with a ‘hydrothermal pump’ model that was earlier proposed for the nearby Dresser Formation. In this model, organic matter from surface environments is circulated along with hydrothermal fluids and redistributed in the crust and overlying sediments, therefore complicating paleobiological interpretations. Raman measurements show that most of the CM experienced temperatures of ∼350 °C, while some samples contain CM with a variable, but markedly lower maturity (temperature ranging from 200 to 350 °C). Correlation to texture points out a potential mixing of pre-metamorphic CM with post-metamorphic CM during late hydrothermal events.
Published: 2021

15. Eustatic knickpoint dynamics in an uplifting sequence of coral reef terraces, Sumba Island, Indonesia

Author: Chauveau, Denovan, Authemayou, Christine, Molliex, Stéphane, Godard, Vincent, Benedetti, Lucilla, Pedoja, Kevin, Husson, Laurent, Cahyarini, Sri Yudawati, Team, A.s.t.e.r., Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), 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)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Indonesian Institute of Sciences (LIPI), Centre National de la Recherche Scientifique (CNRS), 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), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Marine Isotopic Stage, coral reef terrace, Eustatic knickpoint, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Digital Elevation Model, 010502 geochemistry & geophysics, 01 natural sciences, 14. Life underwater, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Cosmogenic nuclide, Reef, Geomorphology, Sea level, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes, Canyon, geography, geography.geographical_feature_category, Knickpoint, Coral reef terrace, DEM, Alluvial erosion, Coral reef, MIS, 15. Life on land, Denudation, 13. Climate action, [SDU]Sciences of the Universe [physics], Cosmogenic Nuclide 36Cl Concentration, Erosion, CRT, Cl-36 cosmogenic denudation rates, Geology
Abstract: IF 4.40; Q1); International audience; An emerged coral reef terrace sequence flanks the northern coast of Sumba Island in Indonesia. The sequence was created by the joint effects of uplift and Quaternary sea level oscillations. Since its emergence, it undergoes chemical erosion, which is facilitated by its carbonate lithology. The morphology is dissected by multiple catchments drained by deep canyons, whose stream profiles display several knickpoints. We applied a multi-methods approach using high-resolution topographic data (Pleiades imagery), geomorphological analysis and denudation rates derived from 36Cl cosmogenic nuclide concentrations to characterize the dynamics of these coastal drainages. We specifically investigate (1) the channel response to eustatic forcing, by analyzing knickpoint dynamics along a longitudinal river profile, and (2) the control of internal and external forcing over the catchment-scale erosion. Firstly, knickpoints form at the distal edge of the emergent reef at each regressive stage following a sea level highstand. The knickpoint propagates and rotates upward by regressive erosion. Knickpoint propagation rate decreases sharply over time until it becomes negligible before the next sea-level rise, which implies a marked decline in knickpoint retreat rate before its resorption. We attribute the inability of the river at Cape Laundi to fully propagate eustatic oscillations to its low stream discharge and low sediment supply, related to its small drainage area, to the karstic nature of the coral reef terraces composing the sequence, and to the high frequency of eustatic forcing. Secondly, average denudation rates calculated from 36Cl cosmogenic nuclide concentrations of sands collected at the outlet of five catchments draining the sequence amount to 69 ± 8 mm·ka−1. We emphasize the role of canyon areas in driving the denudation of the major catchments. However, no first-order correlation has been observed between catchment metrics, uplift rates and denudation rates. Finally, our correlations between catchment finite eroded volumes and uplift rates highlight the tendency of catchments to widen with low uplift rate and to lengthen while incising the sequence deeply with higher uplift rates.
Published: 2021

16. Deep‐Sea Electric and Magnetic Surveys Over Active and Inactive Basalt‐Hosted Hydrothermal Sites of the TAG Segment (26°, MAR): An Optimal Combination for Seafloor Massive Sulfide Exploration

Author: Pascal Tarits, Florent Szitkar, Sebastian Hölz, Sven Petersen, Geological Survey of Norway (NGU), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: chemistry.chemical_classification, Basalt, 010504 meteorology & atmospheric sciences, Sulfide, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Geochemistry, 010502 geochemistry & geophysics, 01 natural sciences, Deep sea, Hydrothermal circulation, Seafloor spreading, Geophysics, chemistry, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Optimal combination, 14. Life underwater, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Seafloor mineral exploration started decades ago, however technologies were long limited to surface vessels implementing instruments mounted to their hulls, restricting deep-sea research to low-resolution data. At the beginning of the 1990's, the first deep-sea geophysical measurements were carried out by manned submersible DSV Alvin (Tivey et al., 1993) over the active, high-temperature, basalt-hosted hydrothermal site TAG (26°N, Mid-Atlantic Ridge). This seminal study revealed that the active sulfide mound at TAG is Abstract A GEOMAR (Kiel, Germany) research team has developed a passive electric field acquisition system for Autonomous Underwater Vehicles (AUVs) to optimize seafloor massive sulfides exploration. This sensor was made of two perpendicular and horizontal pairs of electrodes, and was successfully tested over active basalt-hosted hydrothermal site TAG (26°N, Mid-Atlantic Ridge) and several inactive sites in its vicinity. The resulting data underline the efficiency of combining deep-sea electric and magnetic measurements for searching for active and inactive hydrothermal vent fields. With these datasets, it becomes possible to determine the geological nature of the targets and to constrain the characteristics of fluid circulation at depth without involving costly and invasive underwater tools such as Remotely Operated Vehicles or even manned submersibles to collect samples. Data analysis also revealed that AUV attitude variations induce distortions of the electric signal. These distortions start prevailing for dives at altitudes higher than 90 m above the seafloor, as the distance between the AUV becomes too important to guarantee that the signal produced by the geological target still dominates. To improve the acquisition system and reduce the overall noise, we discuss solutions that limit the impact of such attitude variations. These solutions consist of minor adjustments, such as masts at AUVs stern to tow damping electrodes arrays. In such configurations, we believe that deep-sea passive electric measurements combined with high-resolution magnetic measurements can become a highly efficient seafloor exploration tool, including for sulfide deposits associated with inactive hydrothermal systems.
Published: 2021

17. The Cuban staircase sequences of coral reef and marine terraces: A forgotten masterpiece of the Caribbean geodynamical puzzle

Author: Denyse Martin-Izquierdo, Denovan Chauveau, Pedro Davilan, Gino de Gelder, Leandro Peñalver, Arelis Nuñez, Christine Authemayou, Laurent Husson, Kevin Pedoja, Universidad de La Habana [Cuba], Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), 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)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Interdisciplinary Graduate School for the Blue plane, ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), Centre National de la Recherche Scientifique (CNRS), and Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Pleistocene, Glacial cycle, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Paleontology, Geochemistry and Petrology, Marine and coral reef terraces, 14. Life underwater, 010503 geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Caribbean, geography, Caribbean island, geography.geographical_feature_category, Transform fault, Cuba, Geology, Coral reef, Tectonics, Terrace (geology), [SDU]Sciences of the Universe [physics], Interglacial, Archipelago, [SDE]Environmental Sciences
Abstract: (IF 3.62; Q1); International audience; The emerged sequences of coral reef and marine terraces of the Cuban Archipelago have been recognized since the end of the 19th century but with noticeable exceptions, their bio-constructions and/or deposits are not dated. The northern Caribbean islands and associated archipelagos are located in a left-lateral strike-slip tectonic setting, at the boundary between the North America and Caribbean plates. Cuba is the only landmass located on the American Plate directly adjacent to this transform fault zone. Quantifying upper Pleistocene coastal uplift is thus key to elucidate the recent vertical deformation of the Caribbean geodynamic puzzle with regards to the active tectonic segmentation of this area. We compiled bibliographic data and present new measurements concerning the Cuban sequences of coral reef and marine terraces; maximum elevations, minimum number of successive strandlines and elevation of the lowermost terrace. The Cuban Archipelago exhibits five main uplifting coastal stretches separated by subsiding areas, with at least 23 emerged staircase sequences of coastal terraces. At four sites, the lowest coral reef terrace has been previously correlated to the Last Interglacial Maximum (MIS 5e, 122 ± 6 ka). At nine sites, we extended the morpho-stratigraphy to derive Upper Pleistocene apparent and eustasy-corrected uplift rates. Alongshore Cuba, MIS 5e coastal terraces and associated shoreline angles occur at elevations ranging from 7 m to 40 m, yielding eustasy-corrected uplift rates ranging from 0.06 ± 0.01 mm.yr−1 (NW Cuba) to 0.33 ± 0.01 mm.yr−1 (SE Cuba). More than 400 km northward of the transform fault, eustasy-corrected uplift rates (0.13 mm.yr−1) suggest that the whole Cuban Archipelago is affected by the North America/Caribbean plate motion, with a partitioned compressive component resulting in block tectonics with tilting controlled by regional faults.
Published: 2021

18. On the generation and degradation of emerged coral reef terrace sequences: First cosmogenic 36Cl analysis at Cape Laundi, Sumba Island (Indonesia)

Author: Anne-Morwenn Pastier, Gino de Gelder, Kevin Pedoja, Sonny Aribowo, Laurent Husson, Mary Elliot, Sri Yudawati Cahyarini, Vincent Godard, Ann F. Budd, Danny H. Natawidjaja, Denovan Chauveau, Michael Weber, Denis Scholz, Vera Christanti Agusta, Stéphane Molliex, Marion Jaud, Audrey Boissier, Lucilla Benedetti, A.S.T.E.R. Team, Christine Authemayou, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), 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)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Indonesian Institute of Sciences (LIPI), Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), University of Iowa [Iowa City], ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Johannes Gutenberg - Universität Mainz (JGU)
Subjects: Denudation rate, Archeology, 010504 meteorology & atmospheric sciences, Coral, U–Th series, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, Coastal erosion, 01 natural sciences, Quaternary, Paleontology, 36Cl cosmogenic isotope, Deglaciation, 14. Life underwater, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Ecology, Evolution, Behavior and Systematics, Holocene, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Global and Planetary Change, geography, geography.geographical_feature_category, U-Th series, Coral reef terrace, Cl-36 cosmogenic isotope, Geology, Coral reef, Southeastern asia, MIS 5, Terrace (geology), Denudation, [SDU]Sciences of the Universe [physics], Interglacial, Southeastern Asia
Abstract: (IF 4.45: Q1); International audience; The emerged coral reef terrace sequence at Cape Laundi, on the north coast of Sumba Island (Indonesia), with at least 18 successive strandlines, remains poorly dated in spite of numerous previous data. The age discrepancies within these coral reef terraces (CRTs) were previously explained by their polycyclic nature, triggered by marine erosion and reoccupation of old coral colonies by new ones. This study aims at highlighting these processes, as well as the continental denudation that participates in the partial stripping of the thin superficial coral reef layer overlying the pre-existing surface, exhuming older coral colonies. For this purpose, we use a combined analysis of 36Cl cosmogenic concentrations, new 230Th/U ages, and previous dating in order to quantify denudation rates affecting the sequence and to highlight the role of marine erosion in reworking the lowest CRT surface. Our results demonstrate that 1) the lowermost CRT is composite, i.e., formed by different reefal limestone units constructed and eroded during successive highstands of the last interglacial, 2) following the last deglaciation, this CRT has been subjected again to coastal erosion and reoccupation during the Mid Holocene highstand, 3) its distal edge is affected by the current marine erosion and shows denudation rates higher by one to two orders of magnitude (from 279 ± 0.4 to 581 ± 0.4 mm ka−1) than the continental denudation values of higher CRTs (14.7 ± 8.3 mm ka−1 on average), 4) at the scale of a single CRT surface, variations in continental denudation rates are caused by epikarstification roughness, and 5) the distal edges have the highest continental denudation rate due to diffusion and regressive erosion produced by the runoff occurring along the steep downward cliff.
Published: 2021

19. Trace element determinations in Fe–Mn oxides by high resolution ICP-MS after Tm addition

Author: Charles, Claire, Barrat, Jean-Alix, Pelleter, Ewan, Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2021

20. High‐Resolution Isotopic Variability Across EPR Segment 16°N: A Chronological Interpretation of Source Composition and Ridge‐Seamount Interaction

Author: Christophe Hémond, Arnaud Agranier, Pascal Gente, Bérengère Mougel, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, mid-ocean ridge, Seamount, High resolution, 010502 geochemistry & geophysics, 01 natural sciences, Interpretation (model theory), law.invention, Paleontology, Geochemistry and Petrology, law, Hotspot (geology), 14. Life underwater, Electron paramagnetic resonance, isotopes, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Mid-ocean ridge, East Pacific Rise, Geophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Ridge (meteorology), hotspot, mantle heterogeneities, mantle geochemistry, Geology
Abstract: A high-resolution sampling profile constituted of 52 basalt samples from across the East Pacific Rise (EPR) was investigated. These samples provide a unique opportunity to study the coeval recording of isotopic signals derived from sub-marine eruptions at a fast spreading ridge over a time interval of ∼320 kyrs. Additionally, the study area is marked by the presence of a neighboring seamount chain that has recently caused the ridge to jump twice towards it. Combining previous geochemical studies and bathymetry, we established a first-order chronology between analyzed samples, and have reconstructed the evolution of basalt compositions as the ridge and seamounts advance and finally merge. Our data reveal the existence of two distinct types of isotopic variability within the samples. One that has a low amplitude and frequency and is accounted for by the continuous melting of the ambient mantle, indicating a process with a ∼125 kyr periodicity. The other, of higher amplitude, is discontinuous in time, and likely reflects the seamounts source influence on the ridge. Our results support a two-step hotspot-ridge interaction including a first stage (≥ 600 ka) of regional enrichment of the depleted ridge mantle by hotspot material; and a second, more recent (at least 300 ka) even wherein ambient mantle melts mixed with proximal melts from heterogeneous seamounts sourced nearby. We also propose that the ancient gabbroic component previously identified in this region appeared very recently (< hundreds ya) as erupted lavas are exclusively recorded in a cluster proximal to the axial zone of the ridge. Plain Language Summary The Earth’s mantle makes up 80% of the planet’s volume; however, mantle rocks are rare at the surface. At Mid-ocean ridges, the mantle experiences melting and derived melts may reach the Earth's surface as volcanic basalts. These rocks continuously record the geochemical signature of their mantle source region. Very little is known about the evolution of lava composition over time due to the difficulty of sampling off-ridge axis igneous rocks. This study focuses on a specific portion of the East Pacific Rise at ∼16°N, where it interacts with a nearby hotspot. Basaltic rocks were collected with the French submersible Nautile (Ifremer) across the ridge axis during the cruise Parisub (2010, R/V L’Atalante). The sampling profile obtained covers a period of time that allows long term monitoring and assessment of mantle sourced signals and fluctuations in erupted basalts for > 300 kyrs. We have established a relative chronology between these samples, and propose a paleo-reconstruction of the area accounting for both the isotopic variations observed and previously reported geophysical results. Our new results also suggest rapid magma transfers within the crust independent of melting of seamounts and/or ridge sources, including periodic injections of enriched mantle material into the ridge-melting region.
Published: 2021

21. Origin and Evolution of the Fatu Kapa Magmatic System (North-Western Lau Back-arc Basin): Insight on the Genesis of High-Silica Lavas

Author: Yves Fouquet, Shasa Labanieh, Ewan Pelleter, Aurélien Jeanvoine, Gilles Chazot, Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
Subjects: 010504 meteorology & atmospheric sciences, Geochemistry, basalts, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Lau basin, High silica, Geophysics, contamination, 13. Climate action, Geochemistry and Petrology, Back-arc basin, Geology, 0105 earth and related environmental sciences, felsic rocks, geochemistry
Abstract: The South Eastern Futuna Volcanic Zone (SEFVZ; 50 km × 80 km) is located in the NW of the Lau back-arc basin at the northern boundary of the Futuna and YAO microplates. Fatu Kapa is an area (∼15 km × 10 km) of diffuse volcanic activity at the center of the SEFVZ and at the intersection of two volcanic axes with the Futuna fracture zone. At this place, the volcanic, tectonic, and hydrothermal activities are enhanced. The most differentiated volcanic series of the whole Futuna region are found in the Fatu Kapa area. Based on major and trace element data, four groups of volcanic rocks are distinguished in the Fatu Kapa area. The main groups form a well-defined transitional suite from basalts to andesitic and dacitic lavas that display enrichments in Zr, Cl and heavy rare earth elements. The most mafic lavas of this group are extracted from an Indian-type depleted mantle mixed with a component with trace element and isotopic characteristics similar to the nearby Samoa mantle plume. There is no evidence of subduction input. Petrological modelling shows that the mafic melts of the main group (Group 1A) evolve towards trachyandesites through fractional crystallization coupled with assimilation of 10 % of a Cl-rich and Th-poor melt generated by low-degree (≤2 %) partial melting of a hydrothermally altered basaltic crust. Rocks of Groups 1B(a) and 1B(b) were then generated by mixing of a mafic melt from Group 1A with a melt obtained by partial melting of andesitic and hydrothermally altered wallrock in shallow magma chambers. Extremely high Cl concentrations can be explained by assimilation of interstitial K- and Cl-rich brines in the pore water of the hydrothermally altered volcanic rocks before melting of these rocks. This is in good agreement with unusual extension of the Fatu Kapa hydrothermal area and indicates that, in the north of the Lau basin, the microplate boundaries are privileged zones to generate a complex felsic magmatism within areas of widespread hydrothermal alteration. Our study confirms the importance of assimilation and fractional crystallization and mixing processes in generating high-silica lavas in back-arc environments decoupled from subduction.
Published: 2021

22. Morphogenesis of digitate structures in hot spring silica sinters of the El Tatio geothermal field, Chile

Author: Carolina Munoz-Saez, Jian Gong, Martin Homann, Kimberly D. Myers, Gernot Arp, J. R. Skok, Mark A. van Zuilen, Dylan T. Wilmeth, Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Nevada Bureau of Mines & Geology, University of Nevada [Reno], Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Department of Earth Sciences, University College London, University College of London [London] (UCL), Department of Geobiology, Georg-August-University [Göttingen], SETI Institute, Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Bretagne Sud (UBS)
Subjects: Hot spring, 010504 meteorology & atmospheric sciences, Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 15. Life on land, 010502 geochemistry & geophysics, Cyanobacteria, Silicon Dioxide, 01 natural sciences, Arid, Hot Springs, Abiogenic petroleum origin, 13. Climate action, Saltation (geology), Subaerial, Morphogenesis, General Earth and Planetary Sciences, Extremophile, Precipitation, Chile, Geothermal gradient, Ecology, Evolution, Behavior and Systematics, Geology, 0105 earth and related environmental sciences, General Environmental Science
Abstract: International audience; In silica- rich hot spring environments, internally laminated, digitate sinter deposits are often interpreted as bio- mediated structures. The organic components of microbial communities (cell surfaces, sheaths and extracellular polymeric substances) can act as templates for silica precipitation, therefore influencing digitate sinter morphogenesis. In addition to biologic surface- templating effects, various microenvironmental factors (hydrodynamics, local pH and fluctuating wind patterns) can also influence silica precipitation, and therefore the morphology of resulting digitate sinters. Digitate sinter morphology thus depends on the dynamic interplay between microenvironmentally driven silica precipitation and microbial growth, but the relative contributions of both factors are a topic of continuing research. Here we present a detailed study of digitate silica sinters in distal, low- temperature regimes of the El Tatio geothermal field, Chile. This high- altitude geothermal field is extremely arid and windy, and has one of the highest silica precipitation rates found in the world. We find that digitate silica sinters at El Tatio always accrete into the prevailing eastward wind direction and exhibit laminar growth patterns coinciding with day– night cycles of wind- and thermally driven evaporation and rewetting. Subaerial parts of digitate sinters lack preserved organics and sinter textures that would indicate past microbial colonization, while filamentous cyanobacteria with resistant, silicified sheaths only inhabit subaqueous cavities that crosscut the primary laminations. We conclude that, although fragile bio-films of extremophile micro- organisms may have initially been present and templated silica precipitation at the tips of these digitate sinters, the saltation of sand grains and precipitation of silica by recurrent wind- and thermally driven environmental forcing at El Tatio are important, if not dominant factors shaping the morphology of these digitate structures. Our study sheds light on the relative contributions of biogenic and abiogenic factors in sinter formation in geothermal systems, with geobiological implications for the cautious interpretation of stromatolite-like features in ancient silica deposits on Earth and Mars.
Published: 2021

23. Suspended sediment concentration field quantified from a calibrated MultiBeam EchoSounder

Author: Fromant, Guillaume, Le Dantec, Nicolas, Perrot, Yannick, Floc'H, France, Lebourges-Dhaussy, Anne, Delacourt, Christophe, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Informatique Signal et Image de la Côte d'Opale (LISIC), Université du Littoral Côte d'Opale (ULCO), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Eau Mer et Fleuves (Cerema Direction Eau Mer et Fleuves), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), This work was conducted in the framework of the ANR EPURE project (Grant 11 CEPL 005 02). This work was also supported by the Laboratoire d'Excellence LabexMER (ANR-10-LABX-19) and co-funded by a grant from the French government under the program Investissements d'Avenir. Contributions from Romain Cancouet, Christophe Martin, Olivier Blanpain, Susanne Moskalsky, Paul Juby and Marcaurelio Franzetti were key to the success of the field measurements. The authors thank the Direction Generale de l'Armement (DGA), the Centre National de le Recherche Scientifique (CNRS), and l'Universite de Bretagne Occidentale (UBO) for funding G.F.'s doctorate., ANR-11-CEPL-0005,ÉPURE,Éléments trace métalliques Perturbations climatiques Upwelling et REssources(2011), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], MultiBeam, [SDE.IE]Environmental Sciences/Environmental Engineering, Acoustic backscattering, Multifrequency acoustics, EchoSounder, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Suspended sediments concentration, Acoustic inversion, MultiBeam EchoSounder
Abstract: International audience; Acoustic scattering can be used to estimate Suspended Sediment Concentration (SSC) through acoustic inversion methods. Current SSC quantification methods are mostly unable to observe both spatial and temporal variations. Here, we assess the possibility to measure both using a Multibeam Echosounder (MBES). MBES combine a large spatial covering in the water column and the capability to measure ‘on route’, allowing a better representativity of the measurements. Time-series of raw EM3002-MBES data at 300 kHz were acquired during a 5-hours field experiment at a fixed location in the Aulne macrotidal estuary (France) during ebb, ensuring sufficient SSC variations. Concurrently, 4-frequencies Acoustic Backscattering System (ABS) profiles were acquired in the water column, as well as turbidity profiles, further converted into SSC using collected water samples. An original in-situ calibration was performed on the MBES, using a tungsten sphere of known properties, which allowed corrections to be made to the volume backscattered levels over the echosounder fan. Using ABS-derived equivalent radii, the MBES backscattered signal was inverted to retrieve an SSC estimate. Good consistency between MBES time-series observations and turbidity-derived SSC is observed. This experiment demonstrates the potential use of MBES for 3-dimensional turbidity observations in coastal areas, which is of great interest for sediment flux quantification.
Published: 2021

24. Internal solitary waves on the NW African shelf: A heuristic approach to localize diapycnal mixing hotspots

Author: Mathieu Gentil, France Floc'h, Thomas Meunier, Angel Ruiz-Angulo, Gildas Roudaut, Yannick Perrot, Anne Lebourges-Dhaussy, Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-11-CEPL-0005,ÉPURE,Éléments trace métalliques Perturbations climatiques Upwelling et REssources(2011), ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Moroccan shelf, Aquatic Science, Oceanography, 01 natural sciences, Diapycnal mixing, Echo sounding, 14. Life underwater, Dispersion (water waves), Mixing (physics), Internal solitary waves, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], geography, Richardson number, geography.geographical_feature_category, 010505 oceanography, Continental shelf, [SDE.IE]Environmental Sciences/Environmental Engineering, Acoustic backscatter, Geology, Geophysics, Internal wave, Kinetic energy dissipation, 13. Climate action, Upwelling, North african upwelling system, Thermocline
Abstract: International audience; Turbulent mixing on continental shelves plays roles in the structure and dynamics of marine ecosystems, nutrient cycling, primary production and dispersion of pollutants. Describing and understanding internal wave dynamics enables improved mapping of mixing over continental shelves, especially in complex environments where many processes may interact, such as in upwelling systems. This paper describes internal wave propagation and dissipation in the Moroccan upwelling system using a comprehensive set of hydrographic observations made during two in situ surveys. The acoustic backscatter of the echosounder is shown to be a rapid and convenient survey tool for detecting internal solitary waves (ISWs) on large spatial scales, through the high-frequency oscillation of the zooplankton layer during nighttime conditions. Along ISW trains, enhanced diapycnal mixing episodes are observed with increased dissipation coefficients in the thermocline (O(10-7 W kg-1)), associated with overturning up to 6 m. Mixing due to internal wave soliton packets shows large spatial and temporal variability, but contributes to the overall mixing processes and is responsible for large intermittent variations in the thermocline position. The joint use of a multifrequency echosounder and a current profiler ADCP allows mixing to be quantified (via the Richardson number) on large spatial scales. Validation and use of this method in other coastal regions could be useful to determine regional mixing parameterization in numerical models.
Published: 2021

25. In situ carbon and oxygen isotopes measurements in carbonates by fiber coupled laser diode-induced calcination: A step towards field isotopic characterization

Author: O. Musset, Pierre Sansjofre, Christophe Thomazo, Stefan V. Lalonde, Théophile Cocquerez, Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Université de Technologie de Belfort-Montbeliard (UTBM)-Université de Bourgogne (UB)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Supported by the Observatoire des Sciences de l'Univers Terre Homme Environnement Temps Astronomie de Franche-Comte-Bourgogne (OSU THETA), and by the FEDER Bourgogne Franche-Comte., Biogéosciences [UMR 6282] [Dijon] (BGS), 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), Laboratoire Interdisciplinaire Carnot de Bourgogne [Dijon] (LICB), Université de Bourgogne (UB)-Université de Technologie de Belfort-Montbeliard (UTBM)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, δ18O, Carbonate minerals, Analytical chemistry, Carbonates, chemistry.chemical_element, Laser, 010502 geochemistry & geophysics, 01 natural sciences, law.invention, chemistry.chemical_compound, Siderite, Geochemistry and Petrology, law, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Calcination, 0105 earth and related environmental sciences, Carbon isotopes, Geology, Carbon cycle, Calcium carbonate, chemistry, 13. Climate action, Carbon dioxide, Oxygen isotopes, Carbonate, Carbon
Abstract: International audience; Natural stable isotopes ratios (δ13Ccarb and δ18Ocarb) of carbonates archived in the geological record are routinely used to reconstruct local and global paleo temperatures and the secular evolution of the biogeochemical carbon cycle. The state-of-the-art technique, employed since the mid 20th century, to measure these isotopic ratios starts with field sampling followed by several steps of physical and chemical laboratory preparation including: (i) microdrilling and/or sawing and crushing, (ii) CO2 release by wet acid digestion, (iii) gas equilibration, purification and transfer, before (iv) gas phase IRMS measurements. While these steps are time and resource consuming, they provide accurate measurements of δ13Ccarb, δ18Ocarb and carbonate contents. This study presents a new protocol involving a compact and modernized laser calcination system that decreases drastically the analyses time by reducing the number of preparations steps together with offering the possibility of performing spatially resolved analysis at the mm scale. This new method is based on the use of a fiber coupled laser diode device emitting 30 W in the near infrared at 880 nm. The energy provided by the laser source induces the decomposition of calcium carbonate into lime and carbon dioxide. In this work, the CO2 was collected in sample tubes under a controlled atmosphere for offline analysis, however additional developments should permit online analysis in the near future.We analyzed 9 different types of carbonate minerals encompassing a range of isotopic compositions VPDB between +3.3 and − 18.2‰ and between −1.7 and − 14.6‰ for δ13Ccarb and δ18Ocarb, respectively. A comparison of isotopic results was performed for carbonate zones analyzed both by classic methods (micro-drilling followed by acid digestion) and laser calcination. This isotopic cross-calibration exercise shows a direct positive co-variation between both methods with a correlation coefficient of 0.99 and a regression slope of 1 within uncertainties for the δ13Ccarb values. The δ18Ocarb values also compared well with a correlation coefficient of 0.96, suggesting a constant gas-solid phase isotopic equilibrium between carbon dioxide and lime. The reproducibility of our laser calcination method performed on replicate analyses of dolomite, siderite and malachite shows a 1σ standard deviation of 0.31 and 0.77 for δ13Ccarb and δ18Ocarb, respectively. These reproducibilities are within the observed isotopic natural inhomogeneity of samples (up to 1.3 and 0.57‰ for the δ13Ccarb and δ18Ocarb, respectively) as assessed by microdrilling and acid digestion.Based on the suit of samples analyzed in this study, we demonstrate that (i) fiber coupled laser diode calcination enables accurate and reproducible C and O isotopic characterization of natural carbonates, (ii) physical effects during calcination do not introduce any isotopic fractionation for C and is accompanied by a constant isotopic offset for O over a range of isotopic compositions and mineral matrices. These findings pave the way for a new range of possibilities for carbonate δ13C and δ18O measurements directly in the field using rapid, portable, and easy to manipulate laser preparation devices paired with CRDS/IRIS optical-mass spectrometers.
Published: 2021

26. Fossil maerl beds as coastal indicators of late Holocene palaeo-environmental evolution in the Bay of Brest (Western France)

Author: Clément Lambert, Pascal Le Roy, Angélique Roubi, Muriel Vidal, Jacques Grall, Axel Ehrhold, Théo Reixach, Gwenael Jouet, Gwendoline Gregoire, Raffaele Siano, Aurélie Penaud, Jérôme Goslin, Stephan J. Jorry, Laboratoire Géodynamique et enregistrement Sédimentaire - Geosciences Marines (GM-LGS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), UMS 3113, Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LabexMER Marine Excellence Research: a changing ocean, and ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
Subjects: 010504 meteorology & atmospheric sciences, Stratigraphy, Rhodolith, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Brittany, Lithothamnion corallioides, 14. Life underwater, Maerl, Ecology, Evolution, Behavior and Systematics, Holocene, 0105 earth and related environmental sciences, Earth-Surface Processes, Storm impact, geography, geography.geographical_feature_category, biology, Estuarine sedimentation, MESH: Brittany, Rhodoliths, Paleontology, Coralline algae, Estuary, Sedimentation, biology.organism_classification, 13. Climate action, [SDE]Environmental Sciences, Period (geology), Bay, Geology
Abstract: International audience; The Bay of Brest (BB) is a mixed, tide-dominated estuarine system. The shore terraces of this bay are occupied by modern free-living (calcareous) coralline algae locally termed “maerl”, organized in bed-like morphologies (rhodolith deposits). Cores retrieved from around the bay reveal fossilized primitive maerl beds of Holocene age, interbedded in sandy-silt sedimentation. The alternation between biogenic constructions and estuarine sedimentation may provide evidence of varying environmental conditions of the late-Holocene period. This paper mainly focuses on the results of chronostratigraphic and bio-sedimentological interpretations of coring data collected in less than 15 m of water depth in an attempt to decipher the main stages of maerl colonization in the bay. In particular, this study raises several significant points allowing to draw links between centennial to millennial-scale climatic changes in marine estuary sedimentation and episodes within the development of maerl biocenoses. The paleo-bathymetry of the coastal terraces has not changed significantly over the last 5000 years. Yet, the first maerl occurrence only appeared around 2000 cal yr B.P., likely showing that the environmental conditions were not favorable for their emergence prior to that time. Pioneer maerl beds developed on coarse shell deposits inherited from the paleostorms affecting the Atlantic coasts during the colder climatic period of the Iron Age (3100–1950 cal yr B.P.). The accumulations then aggraded at various and discontinuous rates, sometimes reaching up to 2.1 m/kyr. Maerl beds temporarily disappeared in the southern part of the Bay of Brest when sedimentation rates increased throughout the bay during the Dark-Age cold period (1375–1250 cal yr B.P.), suggesting that maerl formations could not keep up with sedimentation rate exceeded a certain threshold. Muddy sedimentation conditions also dramatically changed on two occasions, with the establishment of coarse storm levels, set at the intervals 825–600 cal yr B.P. (MWP) and 113–0 cal yr B.P. But maerl deposits reseed the environment as a result of each new cold period, demonstrating the persistence of such coralline algae against drastic palaeoenvironmental changes in coastal areas.
Published: 2021

27. Morphodynamic modelling of beach cusp formation: The role of wave forcing and sediment composition

Author: Christopher J. Daly, France Floc'h, Luis P.M. Almeida, Rafael Almar, Marion Jaud, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
Subjects: 010504 meteorology & atmospheric sciences, Sorting (sediment), Forcing (mathematics), Beach cusps, 010502 geochemistry & geophysics, 01 natural sciences, Waterline, Physics::Geophysics, symbols.namesake, Wave height, Wave forcing, 14. Life underwater, Geomorphology, 0105 earth and related environmental sciences, Earth-Surface Processes, Cusp (singularity), [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Onshore sediment transport, Sediment, each cusps, [SDE]Environmental Sciences, symbols, Pattern formation, Sediment sorting, Geology, Swash
Abstract: A field of beach cusps formed during a field experiment at Nha Trang Beach, Vietnam, under accretive conditions. The measured data was used to set-up morphodynamic simulations in XBeach, which was able to simulate cusp formation from an initially long-shore uniform beach profile. Several types of simulations were run in order to observe the resulting variation in mean cusp dimensions (length, depth and height), swash flow patterns, and sediment sorting. Both time-constant (JONSWAP) and time-varying (measured) wave forcing conditions were superimposed on the measured tide. In the former, four wave parameters were varied (wave height, period, direction, and spreading), while in the latter, the median sediment size and sediment composition were varied. The wave period was found to primarily influence long-shore length scales, the wave height cross-shore length scales, and obliquely incident waves enhance all these dimensions particularly under narrow-banded conditions. Cusps are not prominent if the wave energy is too low to effect significant onshore transport, if the wave angle of incidence and spreading are too large (effectively smoothing out swash perturbations), or if the sediment is too fine in relation to the wave conditions (dissipative beaches or highly erosive wave conditions). Coarse sediment generally tends to be located on cusp horns above the waterline, but is otherwise variable depending on cross shore location and tide levels. As the XBeach model results show large agreement with well-established norms, it may therefore be used to more rigorously study processes that help to initiate cusps in future work. (c) 2021 Elsevier B.V. All rights reserved.
Published: 2021

28. Evolution of a Holocene banner bank controlled by morphodynamics and structural setting of a macrotidal coast: Saint-Brieuc Bay (NW-Europe)

Author: Kalil Traoré, Romain Le Gall, Paul Bessin, Clément Lambert, David Menier, Kevin Pedoja, Pascal Roy, Anne Duperret, Erwan Gensac, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Holocene climate, Bedform, 010504 meteorology & atmospheric sciences, Fluvial, Context (language use), 010502 geochemistry & geophysics, 01 natural sciences, Sea level rise, Paleontology, Sand banks, Ocean gyre, 14. Life underwater, Sea level, 0105 earth and related environmental sciences, Banner bank, QE1-996.5, geography, geography.geographical_feature_category, Tidal gyre, Shoal, Geology, Geomorphology, 13. Climate action, [SDE]Environmental Sciences, General Earth and Planetary Sciences, Beach morphodynamics, Marine transgression
Abstract: International audience; The morphology and internal structure of the Horaine Bank (Bay of Saint-Brieuc, NW France) are described based on multibeam echosounder and high-resolution seismic datasets coupled with vibro-core data. The Horaine Bank shows large-scale bedforms in the lee of a submerged rocky shoal, which allowed defining it as a Banner Bank. The internal structure of the sandbank reveals four seismic units (U1-U4) on a Cambrian basement (U0). The basal unit U1 is interpreted as reworked lowstand fluvial sediments those infilled micro incised valleys during a rise in sea level. This unit is overlain by paleo-coastal barrier sand-spit (U2) whose development was controlled by swell in the context of a rapid rise in sea level. The successive prograding unit (U3) is interpreted as flooding deposits in continuity with unit U2. The unit U4 is characterized by oblique reflectors oriented in two opposite directions. This last unit, dated post 3500 yr BP, corresponds to migrating dunes superimposed on the bank and observable in the high-resolution bathymetric data. The strong correlation between tidal currents and the apparent clockwise migration of dune crests suggests the presence of a tidal gyre controlling the present-day dynamics of most of the Horaine bank dunes. This study proposes a new model for the construction of banner banks characterized by the gradual transition of a sand spit to a banner bank during marine transgression and ensuing hydrodynamic variability.
Published: 2021

29. The Tutupaca volcanic complex (Southern Peru): Eruptive chronology and successive destabilization of a dacitic dome complex

Author: Jersy Mariño, Olivier Roche, Céline Liorzou, Swann Zerathe, B. van Wyk de Vries, P. Valderrama, Pablo Samaniego, C. Arias, Nélida Manrique, Hervé Guillou, Instituto Geológico Minero y Metalúrgico (INGEMMET), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Pontificia Universidad Católica del Perú (PUCP), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut des Sciences de la Terre (ISTerre), 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)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), ANR-10-LABX-0006,CLERVOLC,Clermont-Ferrand centre for research on volcanism(2010), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Paléocéanographie (PALEOCEAN), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement et la société-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Jean Monnet [Saint-Étienne] (UJM), Centre Chirurgical Emile Gallé [Nancy], Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Bretagne Sud (UBS)
Subjects: 010506 paleontology, Volcanic hazards, Outcrop, Geochemistry, Pyroclastic rock, Central Andes, 010502 geochemistry & geophysics, 01 natural sciences, Dome (geology), Breccia, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, ComputingMilieux_MISCELLANEOUS, Tutupaca, 0105 earth and related environmental sciences, Earth-Surface Processes, geography, geography.geographical_feature_category, Sector collapse, Holocene, Lava dome, Geology, 15. Life on land, Debris, Volcano, [SDE]Environmental Sciences
Abstract: International audience; Several processes have been proposed as triggering mechanisms for the large sector collapses that affect most volcanoes, and which may occur several times in the volcano’s lifetime. Here we present and discuss the case of Tutupaca volcano, located in southern Peru and part of the Central Volcanic Zone of the Andes. Tutupaca is composed of an old, hydrothermally altered and highly eroded Basal edifice, as well as younger twin peakslocated in the northern part of the complex (the Western and Eastern Tutupaca). The youngest Eastern edifice of Tutupaca is composed of at least seven coalescing lava domes and associated deposits, including block-and-ash flow and debris avalanche deposits. We identified two debris avalanche deposits. An older unit (Azufre debris avalanche deposit) was channeled in the valleys located to the E and SE of the basal volcano, reaching up to 3.5 km from its source region. Four cosmogenic nuclide exposure dates (10Be/feldspar) were obtained from boulders of this debris avalanche deposit and ranged between 6.0 ± 0.7 and 7.8 ± 1.5 ka. The younger unit (Paipatja deposit) was associated with the sector collapse of the edifice reconstructed just after the first debris avalanche (domes IV to VIII). The sector collapse produced a debris avalanche deposit that outcrops immediately to the NE of the amphitheater and was associated with a large pyroclastic density current deposit that was previously dated by radiocarbon at 218 ± 14 a BP (Samaniego et al., 2015). Both debris avalanche deposits have two contrasting sub-units: (1) the main subunit, hereafter called hydrothermal-altered debris avalanche deposit, is a whitishyellow volcanic breccia with heterolithic and heterometric blocks, which originated from the Basal edifice, and (2) a dome-rich debris avalanche deposit, composed by non-altered dome blocks from Eastern Tutupaca. Inproximal areas, the dome-rich unit overlaps the hydrothermally-altered unit while in distal areas, these two units are mixed forming a hummocky and/or ridged topography. In addition to the similarity of both debris avalanches, we propose that the triggering mechanism for these debris avalanches was similar. The dacitic dome growth, coupled with a substrate of older, hydrothermally-altered rock, induced the destabilization of the edifice, producing the debris avalanches and the related pyroclastic density currents.
Published: 2021

30. First identification, geochemical characterization, and land-sea correlations of Holocene marine distal tephra from the Ecuadorian arc

Author: François Orange, François Nauret, Silvia Vallejo, Mathilde Bablon, Céline Liorzou, Gueorgui Ratzov, Jean-Noël Proust, Jean-Luc Le Pennec, Jean-Luc Devidal, Marianne Saillard, François Michaud, Pablo Samaniego, Silvana Hidalgo, Patricia Mothes, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut des Sciences de la Terre (ISTerre), 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)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), CCMA - Centre Commun de Microscopie Appliquée, Université Nice Côte D'Azur, Université de Rennes (UNIV-RENNES), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Escuela Politécnica Nacional (EPN), Observatoire de la Côte d'Azur (BQR 2020)Université Côte d'Azur (CSI 2020), ANR-18-CE31-0022,MARACAS,Les terrasses marines comme proxy pour l'appréhension de l'aléa sismique(2018), Bablon, Mathilde, APPEL À PROJETS GÉNÉRIQUE 2018 - Les terrasses marines comme proxy pour l'appréhension de l'aléa sismique - - MARACAS2018 - ANR-18-CE31-0022 - AAPG2018 - VALID, Université Côte d'Azur (UCA), Université de Rennes (UR), and Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Holocene, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Arc (geometry), Paleontology, Geochemistry, Volcanism, 13. Climate action, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU.VO] Sciences of the Universe [physics]/Earth Sciences/Volcanology, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, Tephrochonology, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Identification (biology), Ecuador, Tephra, Geology
Abstract: International audience; Correlations between marine distal ash layers and continental proximal volcanic deposits constitute a strong tool to investigate the eruptive chronology of an active volcanic arc, to constrain the detailed stratigraphy of the marine sediments, as well as help constraining the magnitude of some large explosive eruptions.In the Andean Northern Volcanic Zone (NVZ), Ecuadorian Holocene major explosive eruptions have been widely documented over the past 30 years, and a large geochemical and geochronological database is available. However, the dispersion of distal volcanic products associated with these events is poorly known, and investigation of offshore tephra fallout deposits appears essential to clarify the recurrence, magnitude, and impact of past major explosive eruptions, and thus better define the volcanic hazards.We present for the first time chemical and morphological features of 30 Holocene tephra layers sampled in marine cores off the Ecuadorian coast during the Amadeus and Atacames cruises. Tephra layers are mainly composed of glass shards visible to the naked eye (~50-150 µm) with some calcareous nannofossils, foraminifera and diatoms. We present new geochemical data obtained on these tephra layers and compare different analysis techniques applied on such material. Major and trace element contents were measured on single glass shards by electron microprobe and LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry), respectively, and compared to bulk whole-rock measurements performed by ICP-AES (Atomic Emission Spectrometry). Pb isotopic composition was analyzed by MC-ICP-MS (MultiCollector ICP-MS). Comparison of the chemical and isotopic signature of marine tephra with data acquired on land allows us to correlate some historic events, but also highlights eruptions that do not seem to have been described otherwise.Finally, land-sea correlations of tephra fallout deposits will also provide temporal constraints to marine seismic records, constrain the age of the tectonic structures of the basin, and possibly better define the recurrence of paleoearthquakes in this region where the seismic hazard is particularly high.
Published: 2021

31. High-precision elemental and stable isotope mapping of a Mesoarchean stromatolite: implications for primitive phototrophic metabolism and paleoecology

Author: Munira Afroz, Laureline Patry, Martin Homann, Pierre Sansjofre, Philip Fralick, Tristan Gobert, Stefan V. Lalonde, Lukas Nicol, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lakehead University, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), University College of London [London] (UCL), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Stromatolite, biology, Phototroph, 13. Climate action, Chemistry, Stable isotope ratio, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Paleoecology, Geochemistry, biology.organism_classification, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2021

32. Mantle metasomatism influence on water contents in continental lithosphere: new constraints from garnet pyroxenite xenoliths (France & Cameroon volcanic provinces)

Author: Azevedo-Vannson, Samantha, France, Lydéric, Ingrin, Jannick, Chazot, Gilles, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Unité Matériaux et Transformations - UMR 8207 (UMET), Institut de Chimie du CNRS (INC)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Garnet pyroxenites, Mantle metasomatism, Hydroxyl, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Adamawa Volcanic Plateau, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], [CHIM.MATE]Chemical Sciences/Material chemistry, French Massif Central, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nominally anhydrous minerals
Abstract: International audience; Quantifying water contents of the lithospheric mantle is key for our understanding of global geodynamics, mantle composition and related physical properties. Most of the mantle lithologies contain little water, but some heterogeneities like pyroxenites, likely contain more water, and by their mineralogical assemblage melt at lower temperatures. The quantification of their water content brings new information about water distribution in the mantle. This study focuses on two continental lithospheric domains: the Massif Central (France) and the Adamawa Volcanic Plateau (Cameroon). Garnet pyroxenites in Adamawa Volcanic Plateau are more hydrated ([H2O]Cpx = 386-685 ppm; [H2O]Opx = 124-155 ppm; [H2O]Garnet < 0.5 ppm) than those of French Massif Central ([H2O]Cpx = 112-465 ppm; [H2O]Opx = 61-104 ppm; [H2O]Garnet < 0.5 ppm). These water concentrations are representative of lithospheric water (no water loss during xenolith ascent), however water content of French Massif Central pyroxenites have been modified by metasomatism. Pyroxenites have been dehydrated by a hot carbonatitic fluid, whereas rocks of Adamawa Volcanic Plateau were likely not affected by metasomatic events. In both regions, the metasomatic episodes modified the LREE contents (e.g., Ce). Consequently H2O/Ce ratio, which could be a good source tracer, might not be the most appropriate tool to identify pyroxenites implication in magmas genesis.
Published: 2021

33. Sediment archives reveal irreversible shifts in plankton communities after World War II and agricultural pollution

Author: Nicolas Briant, Véronique Loizeau, Kenneth Neil Mertens, Clément Lambert, Laure Quintric, Cyril Noël, Patrick Durand, Marie Latimier, Raffaele Siano, Sabine Schmidt, Pierre Cuzin, Malwenn Lassudrie, Aurélie Penaud, Axel Ehrhold, Julien Quere, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Environnement Ressources Bretagne Occidentale (LER-BO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Biogéochimie des Contaminants Métalliques (LBCM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre atlantique, Nantes, Biogéochimie des contaminants organiques (LBCO), 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), Unité de recherche Géosciences Marines (Ifremer) (GM), IFREMER-Concarneau, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Laboratoire Environnement Ressource de Bretagne Occidentale (LERBO), LITTORAL (LITTORAL), Biogéochimie et Ecotoxicologie (BE), Laboratoire Biogéochimie des Contaminants Organiques (LBCO), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Géosciences Marines (GM), Laboratoire Environnement Ressource Bretagne Nord (LERBN), and Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, Geologic Sediments, World War II, Agricultural pollution, Biodiversity, Biology, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, 0302 clinical medicine, Humans, Marine ecosystem, Ecosystem, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, Retrospective Studies, Ecology, 15. Life on land, Plankton, 030104 developmental biology, Ancient DNA, 13. Climate action, [SDE]Environmental Sciences, Dinoflagellida, Paleoecology, General Agricultural and Biological Sciences, Bay, 030217 neurology & neurosurgery
Abstract: To evaluate the stability and resilience1 of coastal ecosystem communities to perturbations that occurred during the Anthropocene,2 pre-industrial biodiversity baselines inferred from paleoarchives are needed.3,4 The study of ancient DNA (aDNA) from sediments (sedaDNA)5 has provided valuable information about past dynamics of microbial species6, 7, 8 and communities9, 10, 11, 12, 13, 14, 15, 16, 17, 18 in relation to ecosystem variations. Shifts in planktonic protist communities might significantly affect marine ecosystems through cascading effects,19, 20, 21 and therefore the analysis of this compartment is essential for the assessment of ecosystem variations. Here, sediment cores collected from different sites of the Bay of Brest (northeast Atlantic, France) allowed ca. 1,400 years of retrospective analyses of the effects of human pollution on marine protists. Comparison of sedaDNA extractions and metabarcoding analyses with different barcode regions (V4 and V7 18S rDNA) revealed that protist assemblages in ancient sediments are mainly composed of species known to produce resting stages. Heavy-metal pollution traces in sediments were ascribed to the World War II period and coincided with community shifts within dinoflagellates and stramenopiles. After the war and especially from the 1980s to 1990s, protist genera shifts followed chronic contaminations of agricultural origin. Community composition reconstruction over time showed that there was no recovery to a Middle Ages baseline composition. This demonstrates the irreversibility of the observed shifts after the cumulative effect of war and agricultural pollutions. Developing a paleoecological approach, this study highlights how human contaminations irreversibly affect marine microbial compartments, which contributes to the debate on coastal ecosystem preservation and restoration.
Published: 2021

34. Le gisement paléolithique inférieur de Pen Hat (Crozon, Bretagne) et son contexte stratigraphique régional

Author: Van Vliet-Lanoë, Brigitte, Hérisson, David, Dabrowski, Élie, Authemayou, Christine, Frechen, Manfred, Hallégouët, Bernard, Paris, Florentin, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Archéologies et Sciences de l'Antiquité (ArScAn), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Anthropologie des techniques, des espaces et des territoires au Pliocène et au Pléistocène (AnTET), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Université Paris Nanterre (UPN), Leibniz Institute for Applied Geophysics (LIAG), Leibniz Association, Département de Géographie, Université de Bretagne Occidentale, 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), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), 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), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Institut national de recherches archéologiques préventives (Inrap)-Centre National de la Recherche Scientifique (CNRS), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Institut national de recherches archéologiques préventives (Inrap)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Ministère de la Culture et de la Communication (MCC)-Institut national de recherches archéologiques préventives (Inrap)-Centre National de la Recherche Scientifique (CNRS), 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), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-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), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: marine high stand, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, palaeoenvironments, stratigraphie, banquise, datation, paléoenvironnements, stratigraphy, lithic technology, technologie lithique, dating, sea ice, haut niveau marin
Abstract: International audience; The two exceptional sites of Pen Hat and Trez Rouz (Crozon Peninsula, Brittany), and that of Trégana (North of the Brest Harbour, Brittany) are rare owing to the preservation of Pleistocene formations dated by infrared stimulated luminescence, electron spin resonance and radiocarbon. They highlight the regional occurrence of periglacial cover sands from the MIS 6, and of a high marine level attributed to the MIS 9a. These three sites in Western Finistere are key-sites to determine the conditions of occupation of archaeological sites during the Middle Pleistocene. During late MIS 11, the men settled south-east of the relief of the Toulinguet point, in an area sheltered from the prevailing west and north winds on the shore of a lagoon, between two pebble spits, an outcrop for small flint pebbles. Human occupations are mainly observed at the end of the interglacial periods thanks to the preservation of sediments of high marine stands or of early marine regressions with some fast ice, allowing hunting’ possibilities on the just cleared sandy plains. Small and poorly prepared flakes with a single raw cutting-edge characterise this lithic series. Pen Hat toolkit appears atypical in the landscape of the Briton Lower Palaeolithic, especially known for its Large Cutting Tools of grained rocks (pebble tools and handaxes). Comparisons with the contemporaneous units of the Menez-Dregan reference site (layers 9 to 7) reveal some similarities. Nevertheless, it remains insufficient for a better inside the variability of the Lower Palaeolithic in Armorican lands. This suggests to explore another Middle Pleistocene sedimentary sequences with interesting archaeological potential, such as Pen Hat, Trez-Rouz and Trégana. If Pen Hat –Toulinguet represents clearly a key site and, for the moment, an atypical assemblage at a regional scale, its technology is seemingly coherent with the variability of the assemblages of the Lower European Palaeolithic.; Les deux sites exceptionnels de Pen Hat et de Trez Rouz (presqu’île de Crozon, Bretagne), et celui de Trégana (bordure nord de la rade de Brest, Bretagne), sont rares de par la préservation de formations du Pléistocène moyen datées par les méthodes de luminescence stimulée par infra-rouge, résonance de spin électronique et radiocarbone. La mise en évidence régionale de sables de couvertures périglaciaires du MIS 6 et d'un haut niveau marin attribué au MIS 9a sont d'une grande importance stratigraphique à l'échelle régionale. Ces trois sites permettent en outre de reconstituer les conditions d'occupation de sites archéologiques du Pleistocène moyen en Finistère ouest. A la fin du MIS 11, les hommes se sont implantés au sud-est du relief de la pointe du Toulinguet, dans un secteur abrité des vents d'ouest et de nord dominants en bordure d'une lagune, barrée par deux flèches en galets, une source d'approvisionnement en petits galets de silex. Les occupations par l'Homme sont surtout observées en fin d'interglaciaire pour raison de préservation de corps sédimentaires de haut niveau marin et de début de régression associés avec une banquise littorale, et avec une possibilité de chasse sur les plaines sableuses ainsi dégagées. L'industrie lithique se caractérise par la production faiblement prédéterminée de petits éclats de silex possédant un tranchant brut. L'industrie de Pen Hat apparaît atypique dans le paysage du Paléolithique inférieur breton, surtout connu pour ces pièces massives en roches grenues (galets aménagés et bifaces). Une comparaison avec les niveaux pénécontemporains du gisement-référence de Menez-Dregan (couches 9 à 7) révèle un certain nombre de similitudes mais reste cependant insuffisant pour mieux cerner la variabilité du Paléolithique inférieur en terres armoricaines. Cela invite à explorer d'autres séquences du Pléistocène moyen à potentiel archéologique intéressant, à l'instar de Pen Hat, Trez-Rouz et Trégana qui ont également livré des artéfacts. Si Pen Hat se présente comme un gisement clé et par certains aspects atypiques à l'échelle régionale, il s'inscrit à notre avis pleinement dans la variabilité des assemblages du Paléolithique inférieur européen.
Published: 2021

35. CO - UNE INFRASTRUCTURE DE RECHERCHE FRANÇAISE POUR L'OBSERVATION DES OCÉANS ET DES LITTORAUX CÔTIERS

Author: Cocquempot, Lucie, Burden, Joanne, Delacourt, Christophe, Paillet, Jérôme, Raimbault, Patrick, Charria, Guillaume, Schmitt, François, Planes, Serge, Bertin, Xavier, Bertin, Stéphane, Coppola, Laurent, Testor, Pierre, Lemoine, Maud, Claquin, Pascal, Hocdé, Régis, Aucan, Jérôme, Sylvie, Fiat, Savoye, Nicolas, Conan, Pascal, Testut, Laurent, Gravelle, Médéric, WOPPELMANN, Guy, Bouchet, Vincent, Desroy, Nicolas, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), 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)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie des Substances Naturelles (LCSN), Université de Limoges (UNILIM)-Génomique, Environnement, Immunité, Santé, Thérapeutique (GEIST FR CNRS 3503), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-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), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Variabilité de l'Océan et de la Glace de mer (VOG), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Biologie des mollusques marins et des écosystèmes associés (BioMEA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Laboratoire d'Océanographie Microbienne (LOMIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), 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]), Shom, Ifremer, EuroGOOS AISBL, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut de Recherche pour le Développement (IRD), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), and 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)
Subjects: multidisciplinary observation, [SDE]Environmental Sciences, coastal ocean and seashore, French national research infrastructure
Abstract: International audience; ILICO, a French Research Infrastructure (RI) for Coastal Ocean and Nearshore Observations is a notable example of national and pan-institutional efforts to expand knowledge of the complex processes at work within the critical coastal zone in line with the European Ocean Observing System perspective. Providing a forum for its community to work together on priority issues is a challenge, and ILICO’s organizational structure and governance are designed accordingly. Future challenges for this RI include the question of whether France’s original model of combining both land and nearshore in its study of the coastal domain is transferable to the pan-European context and how far we can go in integrating overseas and ultramarine issues.; ILICO, une infrastructure de recherche (IR) française pour l'observation de l'océan côtier et du littoral, est un exemple remarquable des efforts nationaux et pan-institutionnels visant à étendre la connaissance des processus complexes à l'œuvre dans la zone côtière critique, conformément à la perspective du système européen d'observation de l'océan. Offrir à sa communauté un forum pour travailler ensemble sur les questions prioritaires est un défi, et la structure organisationnelle et la gouvernance d'ILICO sont conçues en conséquence. Les défis à venir pour ce IR incluent la question de savoir si le modèle original de la France, qui combine à la fois la terre et le littoral dans son étude du domaine côtier, est transférable au contexte paneuropéen et jusqu'où nous pouvons aller dans l'intégration des questions ultramarines.
Published: 2021

36. DYNALIT: a research and observation service monitoring coastal morphodynamics in metropolitan and overseas France

Author: Bertin, Stéphane, Bertin, Xavier, Institut Universitaire Européen de la Mer (IUEM), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Shom, Ifremer, EuroGOOS AISBL, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: remote sensing, long-term coastal evolutions, topography, [SDE]Environmental Sciences, Coastal monitoring, morphodynamics
Abstract: International audience; DYNALIT is a research-based observatory on coastal morphodynamics. Created in 2014 from existing and new monitoring programs, recognised 'Service National d'Observation' by CNRS-INSU and member of Research Infrastructure ILICO, the observatory integrates over 30 sites in metropolitan and overseas France.
Published: 2021

37. Relict hydrocarbon seeps in the Oligocene–Miocene Subis carbonate platform, Malaysia: Implications on hydrocarbon generation and migration pathways and potential sealing by shale gouging

Author: M. Santosh, Manoj Joseph Mathew, Benjamin Sautter, Ramasamy Nagarajan, Numair Ahmed Siddiqui, David Menier, Muthuvairavasamy Ramkumar, Bing B. Saw, Michael Poppelreiter, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: chemistry.chemical_classification, Total organic carbon, 010504 meteorology & atmospheric sciences, Carbonate platform, Geochemistry, Geology, 010502 geochemistry & geophysics, 01 natural sciences, Hydrocarbon, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], 14. Life underwater, Oil shale, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience
Published: 2021

38. Detecting, classifying, and counting blue whale calls with Siamese neural networks

Author: Maelle Torterotot, Jean-Yves Royer, Ming Zhong, Kathleen M. Stafford, Trevor A. Branch, Juan Lavista Ferres, Rahul Dodhia, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Interdisciplinary Graduate School for the Blue plane, ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), AI for Good Research Lab, Microsoft, School of Aquatic and Fisheries Sciences University of Washington (SAFS), University of Washington [Seattle], Applied Physics Laboratory [Seattle] (APL-UW), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Acoustics and Ultrasonics, Computer science, Feature vector, Population, 01 natural sciences, Convolutional neural network, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Arts and Humanities (miscellaneous), biology.animal, 0103 physical sciences, Animals, 14. Life underwater, education, Indian Ocean, 010301 acoustics, Categorical variable, ComputingMilieux_MISCELLANEOUS, education.field_of_study, biology, Artificial neural network, Whale, business.industry, 010604 marine biology & hydrobiology, Deep learning, Pattern recognition, Acoustics, [SDE]Environmental Sciences, Balaenoptera, Spectrogram, Neural Networks, Computer, Artificial intelligence, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Vocalization, Animal, business
Abstract: International audience; The goal of this project is to use acoustic signatures to detect, classify, and count the calls of four acoustic populations of blue whales so that, ultimately, the conservation status of each population can be better assessed. We used manual annotations from 350 h of audio recordings from the underwater hydrophones in the Indian Ocean to build a deep learning model to detect, classify, and count the calls from four acoustic song types. The method we used was Siamese neural networks (SNN), a class of neural network architectures that are used to find the similarity of the inputs by comparing their feature vectors, finding that they outperformed the more widely used convolutional neural networks (CNN). Specifically, the SNN outperform a CNN with 2% accuracy improvement in population classification and 1.7%-6.4% accuracy improvement in call count estimation for each blue whale population. In addition, even though we treat the call count estimation problem as a classification task and encode the number of calls in each spectrogram as a categorical variable, SNN surprisingly learned the ordinal relationship among them. SNN are robust and are shown here to be an effective way to automatically mine large acoustic datasets for blue whale calls.
Published: 2021

39. Semibrittle seismic deformation in high-temperature mantle mylonite shear zone along the Romanche transform fault

Author: Emma P. M. Gregory, Marcia Maia, Zhikai Wang, Zhiteng Yu, Daniele Brunelli, Satish C. Singh, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Dipartimento di Scienzedella Terra, Università di Modena e Reggio Emilia largo, Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, mantle mylonite shear, Induced seismicity, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Lithosphere, Romanche transform fault, Research Articles, 0105 earth and related environmental sciences, Multidisciplinary, Semibrittle, Supershear earthquake, Transform fault, SciAdv r-articles, Geology, seismic deformation, Plate tectonics, Geophysics, 13. Climate action, [SDU]Sciences of the Universe [physics], Shear zone, Seismology, Mylonite, Research Article
Abstract: Deep microseismicity occurs in high-temperature ductile mantle mylonite shear zones resulting from semibrittle fracturing., Oceanic transform faults, a key element of plate tectonics, represent the first-order discontinuities along mid-ocean ridges, host large earthquakes, and induce extreme thermal gradients in lithosphere. However, the thermal structure along transform faults and its effects on earthquake generation are poorly understood. Here we report the presence of a 10- to 15-kilometer-thick in-depth band of microseismicity in 10 to 34 kilometer depth range associated with a high-temperature (700° to 900°C) mantle below the brittle lithosphere along the Romanche mega transform fault in the equatorial Atlantic Ocean. The occurrence of the shallow 2016 moment magnitude 7.1 supershear rupture earthquake and these deep microearthquakes indicate that although large earthquakes occur in the upper brittle lithosphere, a substantial amount of deformation is accommodated in the semibrittle mylonitic mantle that resides at depths below the 600°C isotherm. We also observe a rapid westward deepening of this band of seismicity indicating a strong lateral heterogeneity.
Published: 2021

40. Morphodynamique des plages sableuses et quantification du transport sédimentaire

Author: Floc'H, France, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Occidentale, Serge Suanez, Floc'h, France, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: nearshore, littoral, transport sédimentaire, submersion, érosion, erosion, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, sediment transport
Published: 2021

41. Multiple pygmy blue whale acoustic populations in the Indian Ocean: whale song identifies a possible new population

Author: Tracey L. Rogers, Ben Maslen, Jean-Yves Royer, Abigail Alling, Emmanuelle C. Leroy, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Sound Spectrography, Science, Population, Endangered species, 010603 evolutionary biology, 01 natural sciences, Article, Species Specificity, biology.animal, 0103 physical sciences, Animals, Whaling, 14. Life underwater, education, 010301 acoustics, Southern Hemisphere, Indian Ocean, Marine biology, education.field_of_study, Multidisciplinary, Extinction, geography.geographical_feature_category, biology, Whale, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Fishery, Indian ocean, Geography, Biogeography, [SDU]Sciences of the Universe [physics], Marine mammals, Archipelago, Medicine, Balaenoptera, Animal Migration, Seasons, Vocalization, Animal
Abstract: Blue whales were brought to the edge of extinction by commercial whaling in the twentieth century and their recovery rate in the Southern Hemisphere has been slow; they remain endangered. Blue whales, although the largest animals on Earth, are difficult to study in the Southern Hemisphere, thus their population structure, distribution and migration remain poorly known. Fortunately, blue whales produce powerful and stereotyped songs, which prove an effective clue for monitoring their different ‘acoustic populations.’ The DGD-Chagos song has been previously reported in the central Indian Ocean. A comparison of this song with the pygmy blue and Omura’s whale songs shows that the Chagos song are likely produced by a distinct previously unknown pygmy blue whale population. These songs are a large part of the underwater soundscape in the tropical Indian Ocean and have been so for nearly two decades. Seasonal differences in song detections among our six recording sites suggest that the Chagos whales migrate from the eastern to western central Indian Ocean, around the Chagos Archipelago, then further east, up to the north of Western Australia, and possibly further north, as far as Sri Lanka. The Indian Ocean holds a greater diversity of blue whale populations than thought previously.
Published: 2021

42. Three-dimensional (3D) reconstructions of the coastal cliff face in Normandy (France) based on oblique Pléiades imagery: assessment of Ames Stereo Pipeline® (ASP®) and MicMac® processing chains

Author: Roza Taouki, Olivier Maquaire, Christophe Delacourt, Stéphane Costa, Pauline Letortu, Marion Jaud, Littoral, Environnement, Télédétection, Géomatique (LETG - Brest), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-Université de Nantes (UN)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Caen Normandie (UNICAEN), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Littoral, Environnement, Télédétection, Géomatique (LETG - Caen), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Interdisciplinary Graduate School for the Blue planet, ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École pratique des hautes études (EPHE), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Subjects: 010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, Pl&#233, 02 engineering and technology, 01 natural sciences, Pléiades satellites, coastal cliff erosion, Cliff, Proxy (statistics), [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, oblique images, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, coastal erosion, geography, geography.geographical_feature_category, 3D restitution, Oblique case, [SHS.GEO]Humanities and Social Sciences/Geography, Viewing angle, Pipeline (software), Coastal erosion, Face (geometry), General Earth and Planetary Sciences, iades satellites, Pleiades, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, Geology, cliff face
Abstract: Images from agile (viewing angle over 40 degrees) and very high spatial resolution satellites (inferior to 1 m) can be useful for monitoring cliff faces, which is the best proxy to better understand coastal cliff dynamics. However, these images with a specific configuration are rarely used, partly because it is cumbersome to process them. Based on Pleiades images of the coastal cliff face along the coast of Normandy, with a high angle of incidence (up to 40 degrees) and taken on multiple dates, the paper aims to identify i) the best open-source processing chain to reconstitute three-dimensional (3D) cliff faces by stereo restitution ii) the reasons behind its best performance and iii) the key parameters to change depending on the image datasets or processing chains so as to facilitate transposition. The Ames Stereo Pipeline (R) (ASP (R)) and MicMac (R) software programmes were tested using different parameters (matching algorithm, size of correlation window, etc.) for the 3D reconstructions. MicMac (R) provides the best performance using GeomImage (1-2 pixel matching) with a size of correlation window of 3 x 3 or 7 x 7 associated with a regularization parameter of 0.10. With these parameters, the point clouds of the cliff face have an average point density of 1.70 point m(-2), a mean distance from Unmanned Aerial Vehicle (UAV) ground truth data of 0.04 m and a standard deviation of 1.72 m. With these characteristics, the threshold of rockfall detection using a multi-source comparison is assessed at 100 m(3), which involves that the large majority of rockfalls (69%) around the study area could be detected by a diachronic approach. Considering the daily Pleiades revisiting time, this method offers a great opportunity to monitor erosion and to better understand coastal cliff dynamics.
Published: 2021

43. Nonseismic Signals in the Ocean: Indicators of Deep Sea and Seafloor Processes on Ocean‐Bottom Seismometer Data

Author: Jing Yi Lin, Clément Monteil, Gaye Bayrakci, David Dellong, Emmy T. Y. Chang, Eve Tsang-Hin-Sun, Louis Géli, Frauke Klingelhoefer, Evangelia Batsi, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Southampton, National Chiao Tung University (NCTU), National Central University [Taiwan] (NCU), European Commission, EC: 116Y371, ANR‐16‐CE03‐0010‐02Seventh Framework Programme, FP7, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Seismometer, Sea of Marmara, 010504 meteorology & atmospheric sciences, Submarine, marine seismology, 010502 geochemistry & geophysics, 01 natural sciences, Deep sea, Seafloor spreading, Cold seep, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Geophysics, Water column, Geochemistry and Petrology, Seawater, 14. Life underwater, Chilean subduction, gas and fluid migration, Geology, Seismology, 0105 earth and related environmental sciences, Hydrothermal vent
Abstract: Ocean bottom seismometers (OBS) commonly record short duration events (SDEs), that could be described by all of these characteristics: (i) duration < 1 s, (ii) one single‐wave train with no identified P‐ nor S‐wave arrivals and (iii) a dominant frequency usually between 4 Hz and 30 Hz. In many areas, SDEs have been associated with gas or fluid‐related processes near cold seeps or hydrothermal vents, although fish bumps, instrumental or current‐generated noise have been proposed as possible sources. In order to address some remaining issues, this study presents results from in situ and laboratory experiments combined with observations from 2 contrasting areas, the Sea of Marmara (Turkey) and the Chilean subduction zone. The in situ experiment was conducted at the EMSO‐Molène submarine observatory (near Brest, France) and consisted in continuously monitoring two OBSs with a camera. The images revealed that no fish regularly bumped into the instruments. Laboratory experiments aimed at reproducing SDEs’ waveforms by injecting air or water in a tank filled by sand and sea‐water and monitored with an OBS. Injecting air in the sediments produced waveforms very similar to the observed SDEs, while injecting air in the water column did not, constraining the source of SDEs in the seafloor sediments. Finally, the systematic analysis of two real data sets revealed that it is possible to discriminate gas‐related SDEs from biological or sea‐state related noise from simple source parameters, such as the temporal mode of occurrence, the back azimuth and the dominant frequency. Key Points Short duration high amplitude events routinely recorded on marine seismometers are not created by fish bumping into the geophone. In laboratory experiments, the waveforms of these events are well reproduced by fluid migration in the sediments. We propose 3 simple source parameters to discriminate gas‐related short duration events in ocean bottom seismometer data.
Published: 2019

44. Records of Holocene climatic fluctuations and anthropogenic lead input in elemental distribution and radiogenic isotopes (Nd and Pb) in sediments of the Gulf of Lions (Southern France)

Author: Céline Liorzou, Sidonie Révillon, Bernard Dennielou, Jean Nizou, Philippe Nonnotte, Maria-Angela Bassetti, Gwenael Jouet, Serge Berné, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité de recherche Géosciences Marines (Ifremer) (GM), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Environnements Sédimentaires - Géosciences Marines (GM/LES), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Archeology, Global and Planetary Change, Holocene, 010504 meteorology & atmospheric sciences, Ecology, Lead (sea ice), Geochemistry, Paleontology, 010502 geochemistry & geophysics, 01 natural sciences, medieval lead contamination, marine mud belt, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, 13. Climate action, Elemental distribution, Roman lead contamination, sediment source fingerprinting, Radiogenic Isotopes, 14. Life underwater, south of France, ComputingMilieux_MISCELLANEOUS, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: Marine mud belts represent potential continuous high-resolution climatic, environmental and anthropogenic archives. In this study, a geochemical record of the Gulf of Lions mud belt, which receives sediments from the Rhône watershed and to a lesser extent from the Languedoc region, is reported from Core KSGC-31. The effects of natural climatic changes and possible anthropogenic disturbances on Holocene sedimentation were ascertained by analysing sedimentation rates, chemical weathering (Al2O3/K2O) and sediment-source shifts (neodymium isotopic ratios; εNd). Measurements of elemental and isotopic lead were used to trace the source and determine the potential vectors of anthropogenic contaminations over the Holocene. High εNd values, recorded from 9000 to 3000 calibrated annum before present (cal. a BP) and around 1500 and 600 cal. a BP, are interpreted as an increase in sediment transport from the Alpine crystalline massifs to the sea induced by enhanced hydro-sedimentary conditions upstream. During the early and middle Holocene, low and stable weathering conditions were persistent, while the late Holocene was characterized by higher and more fluctuating weathering conditions. Sudden changes in the 206Pb/207Pb ratio observed during the Roman and Medieval periods suggest clear shifts in lead source from a natural Holocene background to late Holocene anthropogenic contaminations. Even though those shifts are coeval with atmospheric lead contaminations from Spain and Germany recorded in several sediment and ice archives, the local origin (the Cévennes) and the fluvial contamination is more likely in these cases. Those findings are contemporaneous with historical mining records in the Cévennes and point to an intensification of the merchant shipping.
Published: 2019

45. Simulating sediment supply from the Congo watershed over the last 155 ka

Author: Laurence Droz, Dimitri Laurent, Marina Rabineau, Guy Dieudonne Moukandi N’Kaya, Albert J. Kettner, Stéphane Molliex, Alain Laraque, Tania Marsset, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), GeoRessources, Institut national des sciences de l'Univers (INSU - CNRS)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-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), 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), 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), University of Colorado [Boulder], Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), 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), Université Marien Ngouabi, ISBlue - Interdisciplinary Graduate School for the Blue planet (2017), ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), 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), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Institut national des sciences de l'Univers (INSU - CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and 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)
Subjects: Sediment supply modeling, HydroTrend, 010506 paleontology, Archeology, 010504 meteorology & atmospheric sciences, Floodplain, Weathering, Equatorial Africa, Drainage basin, Fluvial, Land cover, 01 natural sciences, Vegetation dynamics, Hydrology (agriculture), Glacial/interglacial, Glacialinterglacial, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, 14. Life underwater, Glacial period, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Hydrology, Global and Planetary Change, geography, geography.geographical_feature_category, Congo watershed, Sediment, Geology, 15. Life on land, 13. Climate action, Interglacial, Environmental science, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
Abstract: The Congo River is the world's second largest river in terms of drainage area and water discharge. Monitored for decades, a large dataset is available, onshore for both the hydrology and sediment load, and offshore by many paleo-environmental proxies compiled at the Late-Quaternary time-scale. These numerous data allow for accurate calibration of numerical modeling. In this study, we aim to numerically quantify the evolution of sediment supply leaving the tropical Congo watershed during the last 155 ka and to decipher the forcing parameters that control this sediment supply over glacial/interglacial stages. For this, a modified version of the model HydroTrend, that besides morphologic, climatic, hydrologic, lithologic, land cover and anthropogenic factors now also considers sediment deposition on the floodplain, is used. In addition, a method to quantify the impact of natural vegetation changes is developed. Simulations match well the present-day observed data. They indicate that a significant portion of suspended sediments is trapped on the floodplain. Long-term simulations indicate that environmental changes between glacial and interglacial stages account for a 30% maximum variation of sediment supply. Climatic changes - precipitation and temperature, account for a maximum decrease in sediment supply of 20% during cold periods while conversely, induced land cover changes (loss of forest during colder and dryer stages) lead to enhanced sediment supply up to 30%. Over a longer period, the average sediment supply remained almost constant during glacial and interglacial periods, while peaks may have occurred during a warming period, just before forests had time to recover the catchment, i.e. during post-glacial periods. These moderate changes in sediment export, despite major changes in climate and vegetation cover, can be explained by the efficiency of sediment trapping of large tropical catchments that buffer fluvial fluxes towards the ocean.
Published: 2019

46. Broad-scale study of the seasonal and geographic occurrence of blue and fin whales in the Southern Indian Ocean

Author: Flore Samaran, Jean-Yves Royer, Kathleen M. Stafford, Julien Bonnel, Emmanuelle C. Leroy, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Lab-STICC_ENSTAB_CID_TOMS, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)
Subjects: 0106 biological sciences, Sympatry, Scale (anatomy), Pygmy blue whales, Endangered species, Passive acoustic monitoring, 01 natural sciences, lcsh:Botany, lcsh:Zoology, 0103 physical sciences, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, medicine, Whaling, lcsh:QL1-991, 14. Life underwater, Antarctic blue whales, 010301 acoustics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Nature and Landscape Conservation, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Ecology, 010604 marine biology & hydrobiology, Fin whales, Seasonality, medicine.disease, lcsh:QK1-989, Fin Whales, Geography, Oceanography, Habitat, Spatial variability, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, Southern Indian Ocean
Abstract: International audience; The southern Indian Ocean is believed to be a natural territory for blue and fin whales. However, decades after commercial and illegal whaling decimated these populations, little is known about their current status, seasonal habitat or movements. Recent passive acoustic studies have described the presence of 4 acoustic populations of blue whales (Antarctic and 3 ‘pygmy’ types), but are generally limited temporally and geographically. Here, we examine up to 7 yr of continuous acoustic recordings (2010-2016) from a hydrophone network of 6 widely spaced sites in the southern Indian Ocean, looking for the presence of Antarctic and pygmy blue and fin whales. Power spectral density analyses of characteristic and distinct frequency bands of these species show seasonal and geographic differences among the different populations, and the overall patterns for each display interannual consistencies in timing and occurrence. Antarctic blue and fin whales are recorded across the hydrophone network, mainly from austral autumn to spring, with peak intensity in winter. Pygmy blue whales show spatial variation: Madagascan pygmy blue whales are mainly present in the west of the network, while the Australian call type is heard at the eastern sites. Both populations share a common seasonality, with a presence from January to June. Finally, the Sri Lankan call type is recorded only on a single site in the northeast. These results confirm the importance of the southern Indian Ocean for several populations of endangered large whales and present the first long-term assessment of fin whales in the southern Indian Ocean.
Published: 2018

47. Dinoflagellate fossils: Geological and biological applications

Author: Mélanie Wary, William Hardy, Kenneth Neil Mertens, Thomas Servais, Edwige Masure, Fabienne Marret, Aurélie Penaud, Raffaele Siano, Clément Lambert, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Department of Geography, University of Liverpool, Paléobiodiversité et paléoenvironnements, Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de paléontologie et paleogéographie du paleozoique (LPPP), Université de Lille, Sciences et Technologies-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), 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), IFREMER-Concarneau, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-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), Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Évolution, Écologie et Paléontologie (Evo-Eco-Paleo) - UMR 8198 (Evo-Eco-Paléo), Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut d'écologie et environnement-Observatoire des Sciences de l'Univers-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: 010506 paleontology, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Biostratigraphy, 01 natural sciences, Paleontology, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Dinocyst, Uniformitarianism, 14. Life underwater, Modern dinocyst distribution, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Cyst-motile stage relationship, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Dinoflagellate, Ancient DNA, biology, Plankton, Future climate, biology.organism_classification, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU]Sciences of the Universe [physics], 13. Climate action, [SDE]Environmental Sciences, Paleoecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, Quaternary, Geology
Abstract: Dinoflagellates are part of the marine plankton and about 200 species produce a cyst (dinocyst) during their life cycle, these organic-walled sexually-produced cysts being fossilizable in sediments for hundreds of millions of years. Over the past 40–50 years, dinocysts have led to major advances on Mesozoic-Cenozoic research, in terms of biostratigraphy and paleogeogeography. Dinocyst taxonomy has then been continuously revised, with the tabulation being the main morphological link between living dinoflagellates and fossilized cysts. Over the Quaternary, and based on the principle of uniformitarianism (i.e. species ecology did not change through time), relationships between modern assemblages and present-day environmental factors controlling their distribution also allow for dinocyst-based quantitative reconstructions derived from transfer function calculations. This paper presents a non-exhaustive review of the dinocyst literature allowing the reader to get a perspective about how they were discovered and defined, but also how they are applied in (paleo)ecological studies according to the timescale considered allowing then to provide useful insights into the future climate change and its associated ecological repercussions.
Published: 2018

48. Carbonate stable and clumped isotopic evidence for late Eocene moderate to high elevation of the east-central Tibetan Plateau and its geodynamic implications

Author: Bryce A. Mitsunaga, Devon A. Orme, Aradhna Tripati, Majie Fan, Lin Li, Nathaniel Davila, Greg Jesmok, University of Texas at Arlington [Arlington], Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), American Chemical Society Petroleum Research FundAmerican Chemical Society [PRF-54673-DNI8], National Science Foundation CAREER awardNational Science Foundation (NSF) [EAR-1325054], 'Laboratoire d'Excellence' LabexMER [ANR-10-LABX-19], French government under the program 'Investissements d'Avenir'French National Research Agency (ANR), and ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
Subjects: geography, Plateau, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Geochemistry, Geology, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, chemistry, 13. Climate action, High elevation, Carbonate, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: International audience; The topographic history of mountain belts reflects changes in lithospheric structure and rheology and exerts an influence on climate. Although substantial progress has been made to constrain the growth history of the southern Tibetan Plateau, the timing and geodynamic drivers for surface uplift of the central plateau remain poorly constrained. Here, we used both carbonate clumped isotope geothermometry and modified stable isotope-based paleoaltimetry that considers proportional mixing of two major moisture sources to infer late Eocene paleoelevations of the Nangqian Basin in the east-central Tibetan Plateau. The mean clumped isotope temperature, T(Delta(47)), of minimally altered late Eocene lacustrine carbonates is 30.0 degrees C, and the reconstructed least-evaporated paleowater delta O-18(mw) value is -9.8 parts per thousand. These two independent approaches indicate that during late Eocene time, the Nangqian Basin floor was 2.7 (+0.6/-0.4) km above sea level, and the hypsometric mean elevation of surrounding mountains was 3.0 +/- 1.1 km above sea level. These estimates are 1.1-1.2 km lower than their modern counterparts. The moderate to high late Eocene paleoelevation of the Nangqian Basin suggests that Eocene upper-crustal shortening and thickening can explain most, but not all, of the surface uplift of the east-central Tibetan Plateau. The additional 1.1-1.2 km (at most) of post-late Eocene elevation increase to the present height may have been a result of either lower-crustal flow or slab detachment.
Published: 2018

49. The Red Beds series in the Erta Ale segment, North Afar. Evidence for a 6 Ma-old post-rift basin prior to continental rupturing

Author: S. Leleu, Gilles Chazot, Gezahegn Yirgu, B. Le Gall, Raphaël Pik, Christophe Cloquet, F. Chauvet, Dereje Ayalew, Fred Jourdan, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre de géochimie de la surface (CGS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Western Australian Argon Isotope Facility, Department of Applied Geology & JdL-CMS, Curtin University [Perth], Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC), School of Earth Sciences [Addis Ababa], and Addis Ababa University (AAU)
Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Basalt, geography, Red beds, geography.geographical_feature_category, Rift, 010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, Volcanic rock, Paleontology, Tectonics, Geophysics, Basement (geology), Sill, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Alluvium, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: The Erta Ale rift segment, North Afar, is regarded as the most mature rift part within the entire Afar rift system. Very little is known about its deformation history because of limited exposures of geological records in its inner floor, except volcanics of the Erta Ale chain, and the poorly-known Red Beds series along the flanks of the depression. An integrated study, combining sedimentological, geochemical, 40Ar-39Ar radiometric and tectonic approaches, has been devoted to Red Beds series flanking the depression to the SW. Our new results allow to argue that (1) the >300 m-thick Red Beds exposed section comprises alluvial deposits that enclose (2) basaltic lavas and related sill intrusions that both yield ~6 Ma 40Ar-39Ar ages and display similar geochemical affinities, (3) the Red Beds series locally overlap unconformably basement bounding terrains, and (4) are involved in a limited number of low-displacement normal faults that recorded a modest amount of extension (
Published: 2018

50. Discovery of buried historical structures in the Kaveri-Kollidam interfluve, southern India

Author: K. Balasubramani, E. Manikandan, S. Abdul Rahaman, Mu. Ramkumar, A. Balasundareshwaran, David Menier, G. Prithiviraj, C. Ramachandran, Ramasamy Nagarajan, U. Kumara Ganesh, Numair Ahmed Siddiqui, R. Ayyanthurai, Manoj Joseph Mathew, M. Santosh, K. Kumaraswamy, R. Jegankumar, M. Sathyaseelan, P. Sivakumar, Periyar University, Bharathidasan University [Tiruchirappalli, India], Department of Geography, Central University of Tamil Nadu, Faculty of Science - Japan, Curtin University, Sarawak Malaysia, Universiti Teknologi PETRONAS (UTP), Faculty of Geosciences and petroleum Engineering, Universiti Tecknologi Petronas, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical Engineering, Vickram College of Engineering, ISBlue - Interdisciplinary Graduate School for the Blue planet (2017), ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017), and Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Subjects: geophysical explorationg, Archeology, History, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, 010504 meteorology & atmospheric sciences, Exploration geophysics, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Geoarchaeology, ground‐penetrating radar, India, 15. Life on land, catastrophic floods, 010502 geochemistry & geophysics, 01 natural sciences, Paleontology, Kaveri River, Ground-penetrating radar, buried sites, geoarchaeology, Geology, 0105 earth and related environmental sciences
Abstract: International audience; The Srirangam interfluve, formed between the Kaveri and Kollidam Rivers in southern India, has been a religious and cultural human settlement for over 2000 years of recorded history. It contains thousands of ancient, yet in use, man‐made structures. Owing to its geographic location, and episodic catastrophic floods from the Kaveri and Kollidam Rivers, the region has been inundated frequently leading to the burial of many smaller structures. Thematic maps of geomorphology, vegetation index, land use, digital elevation model, slope, etc., have been generated through multi‐temporal remote sensing satellite images. A compilation of historic (stone inscriptions, temple documents) and literature data followed by detailed survey of the region using vertical electrical sounding (VES) and ground‐penetrating radar (GPR) through 200 and 400 MHz shielded antennas has led to the discovery of several buried manmade structures at various depths ranging from 0.54 to 3.55 m below ground level (b.g.l.) that were known only in the literature, hearsay and folklore. The VES, GPR and field surveys delineated four major soil/sediment horizons below the ground surface. Sedimentological characteristics of a massive river sand bed found overlying a weathered zone suggest deposition during a major catastrophic flood. The occurrence of flood deposits burying historic structures especially adjoining the regional tectonic structure indicate episodically active climatic and tectonic processes that played a significant role in the burial of ancient‐historic land surface and manmade structures that were under desolation after invasion and desecration by war‐lords of yore. This study demonstrates the potential of combining traditional knowledge and modern technologies to gain insights to locate historic/archaeological sites and discover buried structures.
Published: 2018

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