Consulta: creatorFacets:"Cheron, Sandrine"
Registros recuperados: 11
Data/hora: 09/06/2024 03:48:15

A Late Quaternary record of highstand shedding from an isolated carbonate platform (Juan de Nova, southern Indian Ocean)
Provedor de dados: 5
Autores: Counts, John; Jorry, Stephan; Vazquez Riveiros, Natalia; Jouet, Gwenael; Giraudeau, Jacques; Cheron, Sandrine; Boissier, Audrey; Miramontes, Elda.
A 27 m core collected on the seafloor near Juan de Nova island at 1909 m depth in the SW Indian Ocean preserves a high‐resolution record of carbonate sediment export to the deep sea over the past 1 Myr. Core chronology was established using calcareous nannofossil biostratigraphy and benthic foraminiferal δ18O. Throughout the core, preserved highstand intervals (MIS 1, 5, 7, 9, 11, 13, 15, 23 and 25) are marked by an increase in the aragonite content within the sediment. Aragonite is likely sourced from the nearby Juan de Nova carbonate platform ~10 km to the south, and is interpreted to result from flooding of the platform top. Platform inundation allows carbonate muds to be winnowed from their original shallow‐water environment of deposition, suspended in...
Tipo: Text
Palavras-chave: Aragonite; Atoll; MIS 11; Mozambique Channel; Sea-level change.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00474/58553/61108.pdf

Focus on sulfur count rates along marine sediment cores acquired by XRF Core Scanner
Provedor de dados: 5
Autores: Cheron, Sandrine; Etoubleau, Joel; Bayon, Germain; Garziglia, Sebastien; Boissier, Audrey.
The aim of this study is to investigate the information provided by sulfur count rates obtained by X-ray fluorescence core scanner (XRF-CS) along sedimentary records. The analysis of two marine sediment cores from the Niger Delta margin shows that XRF-CS sulfur count rates obtained at the surface of split core sections with XRF-CS correlate with both direct quantitative pyrite concentrations, as inferred from X-ray powder diffraction (XRD) and sulfur determination by wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry, and total dissolved sulfide (TDS) contents in the sediment pore water. These findings demonstrate the potential of XRF-CS for providing continuous profiles of pyrite distribution along split sections of sediment cores. The...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00346/45731/45376.pdf

Ni-Cu-Co-rich hydrothermal manganese mineralization in the Wallis and Futuna back-arc environment (SW Pacific)
Provedor de dados: 5
Autores: Pelleter, Ewan; Fouquet, Yves; Etoubleau, Joel; Cheron, Sandrine; Labanieh, Shasa; Josso, Pierre; Bollinger, Claire; Langlade, Jessica.
The Wallis and Futuna back-arc system is a complex area composed of at least two active oceanic spreading centers (Futuna and Alofi spreading centers) and young volcanic zones characterized by diffuse magmatism locally affected by the Samoan hotspot. This geological setting is favorable to the establishment of hydrothermal systems either high-temperature (HT) hydrothermal venting or low-temperature (LT) diffuse flow. During the 2010 Futuna cruise aboard R/V L'Atalante, three remarkable inactive LT Fe-Si-Mn deposits have been discovered (i.e. Utu Uli, Anakele and Utu Sega). Some of the Mn-rich precipitates exhibit the highest base metals concentrations so far recorded in ferromanganese rocks including the well-documented hydrogenetic crusts and polymetallic...
Tipo: Text
Palavras-chave: Hydrothermal; Diffuse flow; Manganese oxyhydroxides; Metal-rich; Seafloor; Wallis and Futuna Island; South-West Pacific.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00350/46164/45862.pdf

Formation of carbonate chimneys in the Mediterranean Sea linked to deep-water oxygen depletion
Provedor de dados: 5
Autores: Bayon, Germain; Dupre, Stephanie; Ponzevera, Emmanuel; Etoubleau, Joel; Cheron, Sandrine; Pierre, Catherine; Mascle, Jean; Boetius, Antje; De Lange, Gert J.
Marine sediments at ocean margins vent substantial amounts of methane(1,2). Microbial oxidation of the methane released can trigger the precipitation of carbonate within sediments and support a broad diversity of seafloor ecosystems(3,4). The factors controlling microbial activity and carbonate precipitation associated with the seepage of submarine fluid over geological time remain poorly constrained. Here, we characterize the petrology and geochemistry of rocks sampled from metre-size build-ups of methane-derived carbonate chimneys located at the Amon mud volcano on the Nile deep-sea fan. We find that these carbonates comprise porous structures composed of aggregated spherules of aragonite, and closely resemble microbial carbonate reefs forming at present...
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00156/26734/24854.pdf

Linking Danube River Activity to Alpine Ice-Sheet Fluctuations during the Last Glacial (ca. 33-17 ka BP): insights into the continental signature of Heinrich Stadials
Provedor de dados: 5
Autores: Martinez-lamas, Ruth; Toucanne, Samuel; Debret, Maxime; Riboulot, Vincent; Deloffre, Julien; Boissier, Audrey; Cheron, Sandrine; Pitel, Mathilde; Bayon, Germain; Giosan, Liviu; Soulet, Guillaume.
Offshore archives retrieved from marine/lacustrine environments receiving sediment from large river systems are valuable Quaternary continental records. In the present study, we reconstruct the Danube River activity at the end of the last glacial period based on sedimentological, mineralogical and geochemical analyses performed on long-piston cores from the north-west Black Sea margin. Our data suggest that the Danube River produced hyperpycnal floods throughout the ca. 33-17 ka period. Four main periods of enhanced Danube flood frequency, each of 1.5-3 kyr duration, are recorded at ca. 32.5 30.5 ka (equivalent to the first part of Heinrich Stadial HS 3), at ca. 29-27.5 ka (equivalent to Greenland Stadial 4), at ca. 25.3-23.8 ka (equivalent to HS 2) and at...
Tipo: Text
Palavras-chave: Danube river; Floods; Hyperpycnites; Alpine ice sheet; Heinrich stadials; Seasonality; Black sea.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00613/72556/71612.pdf

Geochemical Dynamics of the Natural-Gas Hydrate System in the Sea of Marmara, Offshore Turkey
Provedor de dados: 5
Autores: Ruffine, Livio; Fandino Torres, Olivia; Etoubleau, Joel; Cheron, Sandrine; Donval, Jean-pierre; Germain, Yoan; Ponzevera, Emmanuel; Guyader, Vivien; Dennielou, Bernard; Etiope, Giuseppe; Gasperini, Luca; Bortoluzzi, Giovanni; Henry, Pierre; Grall, Celine; Cagatay, M. Namik; Charlou, Jean-luc; Geli, Louis.
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00139/24982/23065.pdf

Are deep-sea ecosystems surrounding Madagascar threatened by land-use or climate change?
Provedor de dados: 5
Autores: Fontanier, Christophe; Mamo, Briony; Toucanne, Samuel; Bayon, Germain; Schmidt, Sabine; Deflandre, Bruno; Dennielou, Bernard; Jouet, Gwenael; Garnier, Eline; Sakai, Saburo; Lamas, Ruth Martinez; Duros, Pauline; Toyofuku, Takashi; Sale, Aurelien; Belleney, Deborah; Bichon, Sabrina; Boissier, Audrey; Cheron, Sandrine; Pitel, Mathilde; Roubi, Angelique; Rovere, Mickael; Gremare, Antoine; Dupre, Stephanie; Jorry, Stephan.
In this short communication, we present a multidisciplinaty study of sedimentary records collected from a deep-sea interfluve proximal to the mouths of major northwestern Madagascan rivers. For the last 60 years, the seafloor has been repeatedly disturbed by the deposition of organic rich, tropical, terrestrial sediments causing marked reductions in benthic biodiversity. Increased soil erosion due to local land-use, deforestation and intensifying tropical cyclones are potential causes for this sedimentary budget and biodiversity shift. Our marine sedimentary records indicate that until now, these conditions have not occurred within the region for at least 20,000 years.
Tipo: Text
Palavras-chave: Multidisciplinary study; Benthic foraminifera; Land-use; Tropical cyclones.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00413/52488/53276.pdf

Living (stained) deep-sea foraminifera from the Sea of Marmara: a preliminary study
Provedor de dados: 5
Autores: Fontanier, Christophe; Dissard, D.; Ruffine, Livio; Mamo, B.; Ponzevera, Emmanuel; Pelleter, Ewan; Baudin, F.; Roubi, Angelique; Cheron, Sandrine; Boissier, Audrey; Gayet, Nicolas; Bermell-fleury, S.; Pitel, M.; Guyader, Vivien; Lesongeur, Francoise; Savignac, F.
In this preliminary study, we investigate living (stained) foraminifera from the Sea of Marmara. We focus on the faunal composition and geochemical signatures (trace elements, carbon and oxygen stable isotopes) in foraminiferal tests at two deep-sea sites (329 and ~1240 m depth respectively). Documented by ROV observations and sampling, both study areas are heterogeneous (including bacterial mats and carbonate concretions), proximal to cold seeps and consist of dysoxic bottom water (O2&lt;20 µmol/L). The prevailing dysoxia at both study areas restricts foraminiferal diversity to very low values (S&lt;9, H’&lt;0.97). Stress-tolerant species Bolivina vadescens and Globobulimina affinis dominate living faunas at both sites. The highest foraminiferal standing...
Tipo: Text
Palavras-chave: Living (stained) benthic foraminifera; Sea of Marmara; Extreme ecosystems; Trace elements; Stable isotopes.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00416/52774/53646.pdf

A New Discrimination Scheme for Oceanic Ferromanganese Deposits using High Field Strength and Rare Earth Elements
Provedor de dados: 5
Autores: Josso, P.; Pelleter, Ewan; Pourret, O.; Fouquet, Yves; Etoubleau, Joel; Cheron, Sandrine; Bollinger, C.
Ferromanganese (Fe-Mn) deposits constitute a ubiquitous mineral type in oceanic settings, with metal (Cu, Ni, Zn, Co, Pt) and rare earth elements (REE) enrichments of potential economic interest. Routine analysis of trace elements by ICP-MS has advanced our understanding of the impact of hydrogenetic, diagenetic and hydrothermal processes on the mobility and interaction of high field strength elements (HFSE: Zr, Ti) and REE and yttrium (REY) with Fe-Mn oxyhydroxides. Recent discoveries in the French exclusive economic zone (EEZ) of Wallis and Futuna (southwest Pacific Ocean) have brought new insight to the formation of low temperature (LT) hydrothermal Mn deposits and lead us to reconsider the classification and discrimination diagrams for of Fe-Mn...
Tipo: Text
Palavras-chave: Ferromanganese mineralization; Hydrogenetic crusts; Nodules; Hydrothermal deposits; Rare earth elements; High field strength elements; Classification.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00350/46156/45854.pdf

Rare earth elements and neodymium isotopes in world river sediments revisited
Provedor de dados: 5
Autores: Bayon, Germain; Toucanne, Samuel; Skonieczny, Charlotte; Andre, L.; Bermell, Sylvain; Cheron, Sandrine; Dennielou, Bernard; Etoubleau, Joel; Freslon, Nicolas; Gauchery, T.; Germain, Yoan; Jorry, Stephan; Menot, G.; Monin, L.; Ponzevera, Emmanuel; Rouget, M. -l.; Tachikawa, K.; Barrat, Jean-alix.
Over the past decades, rare earth elements (REE) and their radioactive isotopes have received tremendous attention in sedimentary geochemistry, as tracers for the geological history of the continental crust and provenance studies. In this study, we report on elemental concentrations and neodymium (Nd) isotopic compositions for a large number of sediments collected near the mouth of rivers worldwide, including some of the world’s major rivers. Sediments were leached for removal of non-detrital components, and both clay and silt fractions were retained for separate geochemical analyses. Our aim was to re-examine, at the scale of a large systematic survey, whether or not REE and Nd isotopes could be fractionated during Earth surface processes.  Our results...
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00276/38733/37249.pdf

Volcanic and hydrothermal processes in submarine calderas: the Kulo Lasi example (SW Pacific)
Provedor de dados: 5
Autores: Fouquet, Yves; Pelleter, Ewan; Konn, Cecile; Chazot, Gilles; Dupre, Stephanie; Alix, Anne-sophie; Cheron, Sandrine; Donval, Jean-pierre; Guyader, Vivien; Etoubleau, Joel; Charlou, Jean-luc; Labanieh, Shasa; Scalabrin, Carla.
The study area is located at the transition between the northern end of the Tonga Trench and the North Fiji fracture zone, where tectonic movements are reputed to be the fastest in the world. To the southeast of Futuna Island, a broad area of volcanism occurs within a region characterized by a change in the tectonic fabric between a NE-SW oriented volcanic graben and the N-S oriented Alofi ridge. In 2010, the active volcano Kulo Lasi, which represents the most recent volcanic episode in the Futuna area, was discovered in the center of this extensive volcanic zone. Kulo Lasi is a 20 km diameter shield volcano that rises 400 m above the seafloor. It is composed of basaltic to trachy-andesitic lava with no obvious geochemical affinity with the Tonga...
Tipo: Text
Palavras-chave: Subaqueous volcanism; Hydrothermal activity; Kulo Lasi caldera; Sulfides; SW Pacific.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55633/57279.pdf