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| Registros recuperados: 42 | |
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| Tanimizu, Masaharu; Sugiyama, Naoki; Ponzevera, Emmanuel; Bayon, Germain. |
| Isotope ratios of U-236/U-238 were measured at levels below 10(-7) by single collector ICPMS with a tandem quadrupole mass separation mechanism. Peak tailing of the prominent U-238(+) ion beam on the U-236(+) peak was reduced to the level of similar to 10(-10) by use of two quadrupole mass filters. The (UH+)-U-235 interference on U-236(+) was efficiently reduced to a UH+/U+ ratio of 1 x 10(-8) by an ion-molecule reaction between UH+ and O-2 in a collision/reaction cell placed between the two quadrupoles. The resultant detection limit for U-236/U-238 measurement was better than those reported by any other ICPMS study. The U-236/U-238 ratios, measured as (UO+)-U-236-O-16/(UO+)-U-238-O-16, were determined in the range 10(-9) to 10(-7) without correction for... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26358/24440.pdf |
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| Fujii, Toshiyuki; Moynier, Frederic; Agranier, Arnaud; Ponzevera, Emmanuel; Abe, Minori; Uehara, Akihiro; Yamana, Hajimu. |
| Environmental transport of Tl is affected by redox reaction between Tl(I) and Tl(III) and ligand exchange reactions of them. In order to deepen the knowledge of Tl chemistry, we investigated fractionation of Tl stable isotopes (Tl-203 and Tl-205) in a chemical exchange system. Tl isotopes were fractionated in a liquid-liquid extraction system, in which aqueous and organic phases are hydrochloric acid solution and dichloroethane including a crown ether, respectively. After purification by ion-exchange chemistry, the isotope ratio of Tl-205/Tl-203 in equilibrated aqueous phase was measured precisely by multiple-collector-inductively-coupled-plasma-mass-spectrometry. A large isotope fractionation > 1 aEuro degrees was found. Electronic structures of... |
| Tipo: Text |
Palavras-chave: Thallium; Isotope fractionation; Redox; Ligand exchange; Nuclear field shift; Ab initio calculation. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00135/24624/22691.pdf |
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| Grasse, Patricia; Brzezinski, Mark A.; Cardinal, Damien; De Souza, Gregory F.; Andersson, Per; Closset, Ivia; Cao, Zhimian; Dai, Minhan; Ehlert, Claudia; Estrade, Nicolas; Francois, Roger; Frank, Martin; Jiang, Guibin; Jones, Janice L.; Kooijman, Ellen; Liu, Qian; Lu, Dawei; Pahnke, Katharina; Ponzevera, Emmanuel; Schmitt, Melanie; Sun, Xiaole; Sutton, Jill; Thil, Francois; Weis, Dominique; Wetzel, Florian; Zhang, Anyu; Zhang, Jing; Zhang, Zhouling. |
| The first inter-calibration study of the stable silicon isotope composition of dissolved silicic acid in seawater, delta Si-30(OH)(4), is presented as a contribution to the international GEOTRACES program. Eleven laboratories from seven countries analyzed two seawater samples from the North Pacific subtropical gyre (Station ALOHA) collected at 300 m and at 1000 m water depth. Sampling depths were chosen to obtain samples with a relatively low (9 mmol L-1, 300 m) and a relatively high (113 mmol L-1, 1000 m) silicic acid concentration as sample preparation differs for low- and highconcentration samples. Data for the 1000 m water sample were not normally distributed so the median is used to represent the central tendency for the two samples. Median delta... |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00381/49270/49681.pdf |
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| Ponzevera, Emmanuel; Quetel, Christophe R.; Hendrickx, Frans; Fortunato, Giuseppino. |
| This paper describes the preparation of a new type of Pb delta-isotopic Certified Reference Materials (delta-iCRMs), available in liquid form (Pb mass fraction similar to 100 mu g g(-1), 2 mL, 3% HNO3) to prevent the risk of insufficient isotopic homogeneity. These materials are intended for the validation of delta-scale isotope ratio measurements, and come in four pairs. The quantities certified are the relative differences on values of n(Pb-207)/n(Pb-204), n(Pb-207)/n(Pb-206) and n(Pb-207)/n(Pb-208) ratios between the members of each pair. There is a material with similar to natural Pb-isotopic composition (ERM-3800, delta-0 material), common to all pairs, and the same similar to natural Pb progressively enriched in Pb-207 (ERM-3810 series). Pairs I to... |
| Tipo: Text |
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| Ano: 2009 |
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| Quetel, Christophe R.; Ponzevera, Emmanuel; Rodushkin, Ilia; Gerdes, Axel; Williams, Ross; Woodhead, Jon. |
| A blind comparison on Pb-isotope delta-scale measurements by MC-ICPMS of 0.01 parts per thousand to 0.1 parts per thousand level was organised, involving five laboratories. Test samples were obtained from the series of candidate ERM-3810 delta-isotopic Certified Reference Materials (delta-iCRMs), and comprise four pairs of a material with similar to natural Pb-isotopic composition ('delta zero' or 'delta-0') and the same natural Pb progressively enriched in Pb-207 (with delta Pb-207 values certified to similar to 0.1% relative uncertainty, k = 2). Participants were free to apply the measurement strategy of their choice. A result was considered 'acceptable' only when, simultaneously, there was agreement within stated uncertainties with the corresponding... |
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| Ano: 2009 |
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| Bayon, Germain; Schefuss, Enno; Dupont, Lydie; Borges, Alberto V.; Dennielou, Bernard; Lambert, Thibault; Mollenhauer, Gesine; Monin, Laurence; Ponzevera, Emmanuel; Skonieczny, Charlotte; Andre, Luc. |
| There is increasing evidence that abrupt vegetation shifts and large-scale erosive phases occurred in Central Africa during the third millennium before present. Debate exists as to whether these events were caused by climate change and/or intensifying human activities related to the Bantu expansion. In this study, we report on a multi-proxy investigation of a sediment core (KZR-23) recovered from the Congo submarine canyon. Our aim was to reconstruct climate, erosion and vegetation patterns in the Congo Basin for the last 10,000 yrs, with a particular emphasis on the late Holocene period. Samples of modern riverine suspended particulates were also analyzed to characterize sediment source geochemical signatures from across the Congo watershed. We find that... |
| Tipo: Text |
Palavras-chave: Neodymium isotopes; Suspended particulates; Congo Basin; ENSO; Human land-use; Deforestation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00463/57467/59747.pdf |
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| Knoery, Joel; Briant, Nicolas; Chouvelon, Tiphaine; Gonzalez, Jean-louis; Ponzevera, Emmanuel; Brach-papa, Christophe; Brochen, Michelle; Bruzac, Sandrine; Crochet, Sylvette; De Vogue, Benoist; Marco-miralles, Francoise; Ravel, Christophe; Sireau, Teddy; Thomas, Bastien. |
| Ce rapport présente les résultats de l’étude exploratoire SCOTTTI soutenue par l’Agence de l’Eau Rhône Méditerranée Corse. Ce travail vise à étudier les sources de contaminants et leurs transferts au sein des réseaux trophiques des zones littorales par l’utilisation de traceurs et d’outils innovants à partir d’une application au site atelier de la rade de Toulon. Les travaux engagés se décomposent en 3 volets. Le premier (réseaux trophiques, RT) vise à tracer le passage des contaminants métalliques entre les différents compartiments biogéochimiques de la rade de Toulon, et aussi à en caractériser les teneurs spécifiques en utilisant des traceurs et marqueurs du fonctionnement des RT (combinaison de l’utilisation des profils lipidiques... |
| Tipo: Text |
Palavras-chave: Rade de Toulon contaminants (Cu; Pb; Hg) isotopie du cuivre isotopie du mercure transferts trophiques. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00495/60677/64193.pdf |
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| Sutton, Jill N.; Liu, Yi-wei; Ries, Justin B.; Guillermic, Maxence; Ponzevera, Emmanuel; Eagle, Robert A.. |
| The boron isotope composition (δ11B) of marine biogenic carbonates has been predominantly studied as a proxy for monitoring past changes in seawater pH and carbonate chemistry. However, a number of assumptions regarding chemical kinetics and thermodynamic isotope exchange reactions are required to derive seawater pH from δ11B biogenic carbonates. It is also probable that δ11B of biogenic carbonate reflects seawater pH at the organism's site of calcification, which may or may not reflect seawater pH. Here, we report the development of methodology for measuring the δ11B of biogenic carbonate samples at the multi-collector inductively coupled mass spectrometry facility at Ifremer (Plouzané, France) and the evaluation of δ11BCaCO3 in a diverse range of marine... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00430/54152/55481.pdf |
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| Ferreira Araujo, Daniel; Ponzevera, Emmanuel; Briant, Nicolas; Knoery, Joel; Bruzac, Sandrine; Sireau, Teddy; Brach-papa, Christophe. |
| Toulon bay is severely impacted by metal contamination induced by past and recent naval activities. In this work, Cu, Zn and Pb isotope compositions and elemental concentrations of fifty-five surface sediments were determined in order to map the spatial distribution of anthropogenic and natural sources along this land-sea continuum. Two sub-systems of Toulon Bay, the Small and Large bays, showed well-marked patterns on metal contamination levels and isotope signatures for Cu and Pb. The Small bay had the highest metal concentrations, and displayed average Pb and Cu isotope compositions of 1.1664 ± 0.0043 (1s, expressed as 206Pb/207Pb ratios) and −0.17 ± 0.19‰ (1s, expressed as δ65CuNIST values), respectively. It contrasted with the Large bay, with moderate... |
| Tipo: Text |
Palavras-chave: Metal isotopes; Isotope tracers; Geochemical isotopes; Environmental pollution; Coastal pollution; Toulon bay. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00566/67784/67226.pdf |
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| Ruffine, Livio; Germain, Yoan; Polonia, Alina; De Prunele, Alexis; Croguennec, Claire; Donval, Jean-pierre; Pitel-roudaut, Mathilde; Ponzevera, Emmanuel; Caprais, Jean-claude; Brandily, Christophe; Grall, Celine; Bollinger, Claire; Geli, Louis; Gasperini, Luca. |
| Within the Sea of Marmara, the highly active North Anatolian Fault (NAF) is responsible for major earthquakes (Mw>=7), and acts as a pathway for fluid migration from deep sources to the seafloor. This work reports on pore water geochemistry from three sediment cores collected in the Gulfs of Izmit and Gemlik, along the Northern and the Middle strands of the NAF, respectively. The resulting data set shows that anaerobic oxidation of methane (AOM) is the major process responsible for sulfate depletion in the shallow sediment. In the Gulf of Gemlik, depth concentration profiles of both sulfate and alkalinity exhibit a kink-type profile. The Sulfate Methane Transition Zone (SMTZ) is located at moderate depth in the area. In the Gulf of Izmit, the low... |
| Tipo: Text |
Palavras-chave: Anaerobic oxidation of methane; North Anatolian Fault; Pore water geochemistry; Sea of Marmara; Seismic activity. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00272/38339/36570.pdf |
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| Lotfi-kalahroodi, Elaheh; Pierson-wickmann, Anne-catherine; Guénet, Hélène; Rouxel, Olivier; Ponzevera, Emmanuel; Bouhnik-lecoz, Martine; Vantelon, Delphine; Dia, Aliou; Davranche, Mélanie. |
| Colloids have been recognized as key vectors of pollutants in aqueous environment. Amongst them, those formed by iron (Fe) and organic matter (OM) are of major importance due to their ubiquity in the surface environment and strong affinity for metals. In the recent years, Fe stable isotopes have been increasingly used to elucidate the sources and biogeochemical cycling of Fe in Earth's surface environments. In this study, we aim to elucidate (i) the possible Fe isotopic signature resulting from the Fe/OM colloid formation and (ii) the mechanisms involved in the development of such isotopic signature. For this purpose, Fe-OM associations were synthesized through binding and titration experiments. Various pH levels were used in order to study the isotope... |
| Tipo: Text |
Palavras-chave: Filtration; Size fractionation; Isotope fractionation; Colloidal; Dissolved; Fe isotopes. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00480/59174/61811.pdf |
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| Chever, Fanny; Rouxel, Olivier; Croot, Peter L.; Ponzevera, Emmanuel; Wuttig, Kathrin; Auro, Maureen. |
| Vertical distributions of iron (Fe) concentrations and isotopes were determined in the total dissolvable and dissolved pools in the water column at three coastal stations located along the Peruvian margin, in the core of the Oxygen Minimum Zone (OMZ). The shallowest station 121 (161 m total water depth) was characterized by lithogenic input from the continental plateau, yielding concentrations as high as 456 nM in the total dissolvable pool. At the 2 other stations (stations 122 and 123), Fe concentrations of dissolved and total dissolvable pools exhibited maxima in both surface and deep layers. Fe isotopic composition (δ56Fe) showed a fractionation toward lighter values for both physical pools throughout the water column for all stations with minimum... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00266/37715/35733.pdf |
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| Bayon, Germain; Delvigne, C.; Ponzevera, Emmanuel; Borges, A. V.; Darchambeau, F.; De Deckker, P.; Lambert, T.; Monin, L.; Toucanne, Samuel; Andre, L.. |
| The δ30Si stable isotopic composition of silicon in soils and fine-grained sediments can provide insights into weathering processes on continents, with important implications on the Si budget of modern and past oceans. To further constrain the factors controlling the distribution of Si isotopes in sediments, we have analysed a large number (n=50) of separate size-fractions of sediments and suspended particulate materials collected near the mouth of rivers worldwide. This includes some of the world’s largest rivers (e.g. Amazon, Congo, Mackenzie, Mississippi, Murray-Darling, Nile, Yangtze) and rivers from the case study areas of the Congo River Basin and Northern Ireland. Silt-size fractions exhibit a mean Si isotopic composition (δ30Si = -0.21 ± 0.19‰; 2... |
| Tipo: Text |
Palavras-chave: World rivers; Congo basin; Northern Ireland; Si isotopes; Clay minerals; Weathering; Temperature; Precipitation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00434/54609/55991.pdf |
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| Gueguen, Bleuenn; Rouxel, Olivier; Ponzevera, Emmanuel; Bekker, Andrey; Fouquet, Yves. |
| Although initial studies have demonstrated the applicability of Ni isotopes for cosmochemistry and as a potential biosignature, the Ni isotope composition of terrestrial igneous and sedimentary rocks, and ore deposits remains poorly known. Our contribution is fourfold: (a) to detail an analytical procedure for Ni isotope determination, (b) to determine the Ni isotope composition of various geological reference materials, (c) to assess the isotope composition of the Bulk Silicate Earth relative to the Ni isotope reference material NIST SRM 986 and (d) to report the range of mass-dependent Ni isotope fractionations in magmatic rocks and ore deposits. After purification through a two-stage chromatography procedure, Ni isotope ratios were measured by MC-ICP-MS... |
| Tipo: Text |
Palavras-chave: Nickel; Stable isotopes; MC-ICP-MS; Geological reference materials; Bulk Silicate Earth; Abiotic fractionation. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00159/27069/25332.pdf |
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| Ratie, G.; Quantin, C.; Maia De Freitas, A.; Echevarria, G.; Ponzevera, Emmanuel; Garnier, J.. |
| Ultramafic derived soils are characterized by low nutrient soils, a low Ca:Mg ratio, and high metal contents such as Ni, Co and Cr. The vegetation growing on these soils is highly adapted and includes both Ni hyperaccumulator and accumulator species. Today, approximately 530 Ni hyperaccumulator species are listed worldwide and the Ni concentration can be extremely high, e.g. up to 25% in latex from Pycnandra acuminata (Sapotaceae), a tree found in New Caledonia. The aim of this study is to identify the potential role of Ni hyperaccumulator plants in the Ni biogeochemical cycle at the soil surface by using Ni isotopes. A set of Ni hyperaccumulator and Ni accumulator plants as well as topsoils were sampled on the Barro Alto and Niquelândia ultramafic... |
| Tipo: Text |
Palavras-chave: Nickel; Isotope; Ni hyperaccumulator species; Ultramafic environment. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00464/57565/59740.pdf |
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| 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 |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00156/26734/24854.pdf |
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| Registros recuperados: 42 | |
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