| Title | Comparative geochemistry of four ferromanganese crusts from the Pacific Ocean and significance for the use of Ni isotopes as paleoceanographic tracers |
| Publication Type | Journal Article |
| Year of Publication | 2016 |
| Authors | Gueguen, B, Rouxel, OJ, Rouget, M-L, Bollinger, C, Ponzevera, E, Germain, Y, Fouquet, Y |
| Journal | Geochimica et Cosmochimica Acta |
| Volume | 189 |
| Pagination | 214–235 |
| Keywords | ROV Jason (Remotely Operated Vehicle) |
| Abstract | {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 10Be isotope abundances. The results show that, despite different growth rates, textures and geochemical patterns, Fe-Mn crusts from both North and South Pacific Oceans have fairly homogenous Ni isotope compositions over the last ∼17 Ma, yielding average $δ$60/58Ni values of 1.79 ± 0.21‰ (2sd |
| DOI | 10.1016/j.gca.2016.06.005 |
