|
|
|
|
| |
|
|
| Grenier, Melanie; Garcia-solsona, Ester; Lemaitre, Nolwenn; Trull, Thomas W.; Bouvier, Vincent; Nonnotte, Philippe; Van Beek, Pieter; Souhaut, Marc; Lacan, Francois; Jeandel, Catherine. |
| Distributions of dissolved rare earth element (REE) concentrations and neodymium isotopic compositions (expressed as epsilon(Nd)) of seawater over and off the Kerguelen Plateau in the Southern Ocean are presented. The sampling took place during the austral spring bloom in October-November 2011 (KEOPS2 project, GEOTRACES process study) and aimed to further the investigations of the KEOPS1 austral summer study in terms of sources and transport of lithogenic material, and to investigate the impact of local biogeochemical cycles on the REE distributions. The REE signature of the coastal eastern Kerguelen Islands waters was characterized by negative europium anomalies (Eu/Eu*) and negative epsilon(Nd) in filtered samples. By contrast, the unfiltered sample... |
| Tipo: Text |
Palavras-chave: Southern Ocean; Kerguelen Islands; Rare earth elements; Fractionation; Anomalies; Lithogenic; Biologic; GEOTRACES. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00616/72764/72274.pdf |
| |
|
|
| Ziem A. Bidias, Luc Achille; Chazot, Gilles; Moundi, Amidou; Nonnotte, Philippe. |
| We investigated mafic and felsic volcanic rocks from the Bamoun plateau, a magmatic province located north of Mount Cameroon, in the continental part of the Cameroon Volcanic Line (CVL). Basalts and dacites were probably emplaced more than 40 Ma ago, while basanites represent very young volcanic eruptions. Among the basalts, some of them have suffered crustal contamination during their uprise through the continental crust, and their primary trace element and isotopic compositions have been slightly modified. The formation of the dacites was also accompanied by some crustal contamination. Non-contaminated rocks show that the oldest magmas are transitional basalts formed by relatively high degrees of partial melting of a moderately enriched mantle source,... |
| Tipo: Text |
Palavras-chave: Cameroon Volcanic Line; Geochemistry; Mantle source; Crustal contamination; Basalt. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00638/74996/75730.pdf |
| |
|
|
| Charles, Claire; Pelleter, Ewan; Révillon, Sidonie; Nonnotte, Philippe; Jorry, Stephan; Kluska, Jean-michel. |
| The Mozambique Channel plays a key role in the exchange of water masses between the Indian and Atlantic Oceans, which include the North Atlantic Deep Water (NADW) inflow from the south and the North Indian Deep Water (NIDW), an aged form of the NADW spreading poleward from the northern and equatorial Indian Ocean basin. Several authors assume that the Davie Ridge acts as a topographic barrier to the northward advection of NADW, which would therefore be absent in the Comoros Basin. Other studies suggest that the NADW flows from the south of the Mozambique Channel to the Comoros Basin, indicating that the Davie Ridge may not currently constitute a blocking topographic barrier to deep water mass circulation. To address this question, we studied ferromanganese... |
| Tipo: Text |
Palavras-chave: Ferromanganese crusts; Nd isotopes; Paleoceanography; Mozambique Channel; North Atlantic Deep Water. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00653/76488/77569.pdf |
| |
|
|
| Bonnand, P.; Lalonde, Stefan; Boyet, M.; Heubeck, C.; Homann, M.; Nonnotte, Philippe; Foster, I.; Konhauser, K.o.; Köhler, I.. |
| Precambrian banded iron formations (BIF) are chemical sedimentary deposits whose trace element signatures have been widely used to interrogate the chemical composition and redox state of ancient seawater. Here we investigated trace element signatures in BIF of the 3.22 Ga Moodies Group, Barberton Greenstone Belt (South Africa), which are interbedded with near-shore siliciclastic sedimentary rocks and represent one of the oldest known shallow-water occurrences of BIF. Unusual rare earth element (REE) signatures, notably with pronounced negative Ce anomalies in shale-normalized spectra, have been previously reported for chemical sediments of the Moodies Group, which we confirm here through an expanded dataset for Moodies BIF spanning three different... |
| Tipo: Text |
Palavras-chave: Trace element signatures; Ce anomalies; La-Ce geochronology; Rare earth element mobility. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00641/75328/75861.pdf |
| |
|
|
| Nizou, Jean; Dennielou, Bernard; Révillon, Sidonie; Bassetti, Maria-angela; Jouet, Gwenael; Berné, Serge; Nonnotte, Philippe; Liorzou, Celine. |
| 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... |
| Tipo: Text |
Palavras-chave: Holocene; Marine mud belt; Medieval lead contamination; Roman lead contamination; Sediment source fingerprinting; South of France. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00498/60951/68284.pdf |
| |
|
|
| Chavagnac, Valerie; Ali, Hassan Saleban; Jeandel, Catherine; Leleu, Thomas; Destrigneville, Christine; Castillo, Alain; Cotte, Laura; Waeles, Mathieu; Cathalot, Cecile; Laes, Agathe; Pelleter, Ewan; Nonnotte, Philippe; Sarradin, Pierre-marie; Cannat, Mathilde. |
| While hydrothermal vents are now thought to be a major source of dissolved iron to the oceans, they have always been considered to be a sink for the dissolved rare-earth elements (DREEs). However, true dissolved REE observations in hydrothermal plumes are still lacking. Here we report for the first time the DREE concentrations and neodymium isotopic compositions (DεNd) of buoyant hydrothermal fluids at Lucky Strike (Mid-Atlantic Ridge). We find that 27 to 62% of total hydrothermal DREEs are rapidly scavenged by anhydrite precipitation at the onset of buoyant plume formation. After this initial loss, all DREEs behave quasi-conservatively within the buoyant plume. Dissolved phase εNd (DεNd) in the evolving plume are identical to black smoker DεNd of +9.0 and... |
| Tipo: Text |
Palavras-chave: Black smokers; Rare earth elements; Neodymium isotopes; Hydrothermal; Sulfate minerals; EMSO-Azores. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00456/56733/58511.pdf |
| |
|
| |
|
|
| Van Vliet-lanoë, Brigitte; Knudsen, Oskar; Guðmundsson, Agust; Guillou, Hervé; Chazot, Gilles; Langlade, Jessica; Liorzou, Celine; Nonnotte, Philippe. |
| The Early Holocene (12–8.2 cal ka) deglaciation and pulsed warming was associated in Iceland with two major generations of jökulhlaups around the Vatna ice-cap (Vatnajökull), at ca 11.4–11.2 cal ka and ca 10.4–9.9 cal ka, and major tephra emissions from the Grímsvötn and Bárðarbunga subglacial volcanoes. The earliest flood events were recorded inland during the Middle Younger Dryas and their deposits were overlain by the Early Preboreal Vedde Ash (11.8 cal ka). The first Holocene flood events (ca 11.4–11.2 cal ka) are issued from a glacial advance. The second, and major, set of floods was partly driven by the Erdalen cold events and advances (10.1–9.7 10Be ka) initially issued from the Bárðarbunga (10.4, 10.1–9.9 ka) and Grímsvötn volcanoes (Saksunarvatn... |
| Tipo: Text |
Palavras-chave: Holocene; Deglaciation; Iceland; Geomorphology; Glacial; Flood; Sedimentology; Tephra; Glacio-isostatic rebound; Permafrost; Saksunarvatn event; Askja S. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00613/72489/74845.pdf |
| |
|
|
|
