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| Pasquier, Virgil; Sansjofre, Pierre; Lebeau, Oanez; Liorzou, Celine; Rabineau, Marina. |
| Rationale Natural stable isotopes ratios (d13Corg and 15N vales) and associated elemental concentrations (i.e. total organic carbon and total nitrogen contents) preserved in marine sediments are frequently used for the determination of paleoenvironmental processes such as the origin of organic matter. Previous studies highlighted biases in the determination of such geochemical proxies due to pre-analysis acid treatment methods. This study is the first systematic comparison of the effect of acid treatment methods on bulk organic matter using a unique sedimentary system, under two contrasting climatic contexts (i.e. glacial vs interglacial). Methods We used the most common method for pre-treatment analysis, which consists of the acidification of bulk... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00407/51830/52429.pdf |
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| Cheize, Marie; Planquette, H.f.; Fitzsimmons, J.n.; Pelleter, Ewan; Sherrell, R.m.; Lambert, Christophe; Bucciarelli, E.; Sarthou, G.; Le Goff, Marion; Liorzou, Celine; Chéron, Sandrine; Viollier, E.; Gayet, Nicolas. |
| A number of trace metals play essential roles in marine ecosystem structure and biological productivity. Until recently, it has been argued that phytoplankton access primarily dissolved iron, while particulate iron was considered a refractory material with little use biologically and limited interaction with the dissolved pool. In order to assess the transfer mechanisms between sediment-sourced particulate trace metals and the dissolved pool, we conducted a 14-month incubation that reacted resuspended sediments with natural seawater, both originating from the Kerguelen area (KEOPS cruises; Southern Ocean), in the dark, and at concentrations replicating natural conditions. Three types of sediments were investigated (named BioSi, BioSi + Ca, and Basalt),... |
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Palavras-chave: Suspended particle dissolution; Sediment; Iron; Manganese; Biogenic silica; Southern Ocean; Kerguelen. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00460/57197/59166.pdf |
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| Van Vliet-lanoe, Brigitte; Schneider, Jean-luc; Gudmundsson, Agust; Guillou, Herve; Nomade, Sebastien; Chazot, Gilles; Liorzou, Celine; Guegan, Solene. |
| Central southern Iceland is one of the main outlets of the Icelandic Ice Sheet where a MIS 5e sedimentary complex, the Ranga Formation, is extensively observed below the last deglaciation terminal moraines. Sedimentary facies demonstrate that the Ranga Formation is mostly tidal, up to 215 m (transgression I) and 168 m (transgression II) in altitude. The first highstand reworks a thick tephra from the Grimsvotn volcano, known in marine cores as 5e low/Bas-IV and positioned at ca. 127 Ka BP, the Eemian thermal optimum. This formation is related to a rapid deglaciation followed by two marine transgressions marked by the development of extended mud flats, which were separated by a complex regression phase, associated with loess deposition, ca. 9 Ka in... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00638/75001/75938.pdf |
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| Callac, Nolwenn; Rommevaux-jestin, Celine; Rouxel, Olivier; Lesongeur, Francoise; Liorzou, Celine; Bollinger, Claire; Ferrant, Anthony; Godfroy, Anne. |
| Oceanic basalts host diverse microbial communities with various metabolisms involved in C, N, S, and Fe biogeochemical cycles which may contribute to mineral and glass alteration processes at, and below the seafloor. In order to study the microbial colonization on basaltic glasses and their potential biotic/abiotic weathering products, two colonization modules called AISICS ("Autonomous in situ Instrumented Colonization System") were deployed in hydrothermal deep-sea sediments at the Guaymas Basin for 8 days and 22 days. Each AISICS module contained 18 colonizers (including sterile controls) filled with basaltic glasses of contrasting composition. Chemical analyses of ambient fluids sampled through the colonizers showed a greater contribution of... |
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Palavras-chave: Colonization module; Basalt alteration; Guaymas basin; Organic-rich sediment; Hydrothermal systems. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00181/29261/27642.pdf |
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| Manrique, Nelida; Samaniego, Pablo; Medard, Etienne; Schiavi, Federica; Marino, Jersy; Liorzou, Celine. |
| Magma recharge into a differentiated reservoir is one of the main triggering mechanisms for explosive eruptions. Here we describe the petrology of the eruptive products of the last explosive eruption of Tutupaca volcano (southern Peru) in order to constrain the pre-eruptive physical conditions (P-T-X-H2O) of the Tutupaca dacitic reservoir. We demonstrate that prior to the paroxysm, magma in the Tutupaca dacitic reservoir was at low temperature and high viscosity (735 +/- 23 degrees C), with a mineral assemblage of plagioclase, low-Al amphibole, biotite, titanite, and Fe-Ti oxides, located at 8.8 +/- 1.6 km depth (233 +/- 43 MPa). The phenocrysts of the Tutupaca dacites show frequent disequilibrium textures such as reverse zonation, resorption zones, and... |
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Palavras-chave: Tutupaca; Magma recharge; Self-mixing; Thermobarometry. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00687/79870/82742.pdf |
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| 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... |
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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 |
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| 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... |
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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 |
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