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| Gueguen, Bleuenn; Rouxel, Olivier; Rouget, Marie-laure; Bollinger, Claire; Ponzevera, Emmanuel; Germain, Yoan; Fouquet, Yves. |
| Ferromanganese (Fe-Mn) crusts are potential archive of the Ni isotope composition of seawater through time. In this study we aim at (1) understanding Ni isotope fractionation mechanisms and metal enrichment processes in Fe-Mn deposits, (2) addressing global vs. local control of Ni isotope composition of these deposits. Two Fe-Mn crusts from the North Pacific Ocean (Apuupuu Seamount, Hawaii) and two Fe-Mn crusts from the South Pacific Ocean (near Rurutu Island, Austral archipelago of French Polynesia) were characterized for their elemental geochemistry and Ni isotope composition. Geochemical analyses were performed at millimeter intervals in order to provide time-resolved record of Ni isotopes. Chronology and growth rates were determined using cosmogenic... |
| Tipo: Text |
Palavras-chave: Ferromanganese crusts; Nickel isotopes; Paleoceanography; Pacific Ocean; Biogeochemical cycling. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00341/45255/44696.pdf |
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| Chu, N; Johnson, C; Beard, B; German, C; Nesbitt, R; Frank, M; Bohn, Marcel; Kubik, P; Usui, A; Graham, I. |
| Temporal variations in Fe isotope compositions at three locations in the Pacific Ocean over the last 10 Ma are inferred from high-resolution analyses of three hydrogenetic ferromanganese crusts. Iron pathways to the central deep Pacific Ocean appear to have remained constant over the past 10 Ma, reflected by a remarkably constant Fe isotope composition, despite large changes in the Fe delivery rates to the surface ocean via dust. These results suggest that the Fe cycle in the deep ocean is decoupled from that in surface waters. By contrast, one ferromanganese crust from the Izu-Bonin (IB) back-arc/marginal basin of the W. Pacific exhibits large delta Fe-56 variations. In that crust, decreases in delta Fe-56 values correlate with increases in Mn, Mg, Ni,... |
| Tipo: Text |
Palavras-chave: Pacific Ocean; Izu Bonin; Hydrothen nal; Ferromanganese crusts; Fe isotopes. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3700.pdf |
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| 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 |
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