|
|
|
|
|
| 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 |
| |
|
|
| Radford Knoery, Joel; German, C; Charlou, Jean-luc; Donval, Jean-pierre; Fouquet, Yves. |
| Through the deep ocean, hydrothermal plumes disperse high concentrations of key chemical tracers including He-3, CH4, Mn, Fe, H2S, etc. This paper focuses on the distribution and behavior of total dissolved sulfide (sulfide hereafter) in hydrothermal plumes to show that its plume concentration decreases to subnanomolar a few kilometers from the vents. We also report on sulfide removal rates determined at in situ conditions; we observe that they are two orders of magnitude greater than for open ocean seawater, consistent with sulfide being detected only in the vicinity of hydrothermal vents. From our observations, we infer that the sole presence of sulfide in hydrothermal plumes locates active venting at the kilometer scale. |
| Tipo: Text |
Palavras-chave: Chemical oceanography; Mid ocean ridges; Metals; Helium isotopes; Methane; Tracers; Hydrogen sulphide; Plumes; Hydrothermal activity. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/2001/publication-688.pdf |
| |
|
| |
|
|
|
