Eastern Pacific, East Pacific Rise at 9°46′ N (seawater osmium)
Eastern Pacific, East Pacific Rise (RV Atlantis cruise A3-11, 1997), Océan Pacifique (eaux internationales)
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Vertical osmium profiles 10 km east (104°11′ W) and west (104°22′ W) of the ridge axis, and two hydrothermal plumes near L vent (104°17′ W), November-December 1997. Concentration shows a minimum of about 30 % near 500 m, with the oxygen minimum, then rises with depth; 187Os/188Os stays constant through the water column. Plumes are neither Os-enriched nor less radiogenic than nearby deep water (Woodhouse et al., 1999). Coordinates: midpoint of the two off-axis stations.
187Os/188Os isotope ratio, no unit Values of the same system
Standard : Rapport absolu, sans standard de référence
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 1.072 ± 0.02 | 1.038 / 1.1 | 10 | seawater from 25 to 2778 m, off-axis stations Mean and standard deviation recalculated from 10 analyses, 1.038 to 1.100 (3-8T 1.100; 3-8G 1.038; 3-7T 1.081; 12-7G 1.069; 5-6T 1.046; 5-5T 1.080; 12-6G 1.087; 5-4T 1.055; 3-4T 1.075; 12-4G 1.085). Published mean 1.067 ± 0.011 (2σ), recovered from the 12 N-TIMS analyses other than 3-3T, plumes included. 3-3T (1500 m, 1.051 ± 0.024, 6.47 pg/l) is flagged "suspect" in the table and left out. 12-4G is 30 m above the seafloor. Depths and contents: 3-8T 25 m, 7.19 pg/l; 3-8G 25 m, 7.54 pg/l; 3-7T 44 m, 6.86 pg/l; 12-7G 459 m, 6.75 pg/l; 5-6T 462 m, 6.64 pg/l; 5-5T 1000 m, 7.83 pg/l; 12-6G 1997 m, 9.27 pg/l; 5-4T 1998 m, 9.39 pg/l; 3-4T 2401 m, 9.82 pg/l; 12-4G 2778 m, 8.41 pg/l. | Woodhouse et al. (1999), Osmium in seawater: vertical profiles of concentration and isoto… |
| 1.048 ± 0.006 | 1.043 / 1.052 | 2 | diluted hydrothermal plume (near L vent, 2440 and 2480 m) Mean and standard deviation recalculated from 2 analyses, 1.043 to 1.052 (15-7G 1.043; 22-5UG 1.052). 15-7G 1.4 km from the vent (dilution about 50,000, 9.62 pg/l) and 22-5UG 160 m away (dilution about 7000, 8.74 pg/l): no visible mantle osmium (0.12); the authors rather see scavenging of seawater osmium by plume particles. | Woodhouse et al. (1999), Osmium in seawater: vertical profiles of concentration and isoto… |
Deposits of the same type
- East Pacific Rise hydrothermal fluids at 9° N
- Hydrogenetic Fe-Mn deposit (crust), Pacific (GMAT, 14D)
- East Pacific Rise hydrothermal fluids at 21° N
- Guaymas Basin hydrothermal fluids (Gulf of California)
- Hydrothermal manganese deposit, Galapagos Ridge (Pleiades II, D5-1A)
- Deep-water diagenetic Fe-Mn deposit (nodule), Pacific (USGS, Nod-P-1), USGS reference material
- Hydrogenetic Fe-Mn deposit (crust), Pacific (F7-87-SC, D9-16)
- Santa Barbara Basin
Cite this page
IsoFind Atlas (2026). Eastern Pacific, East Pacific Rise at 9°46′ N (seawater osmium), isotope signatures. https://www.isofind.tech/isotopes/en/sites/pacifique-est-dorsale-est-pacifique-a-9-46-n-osmium-de-l-eau-de-mer/ (accessed 2026-10-20).
@misc{isofind2026easternpacificeastpacificrise,
title = {Eastern Pacific, East Pacific Rise at 9°46′ N (seawater osmium), isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/sites/pacifique-est-dorsale-est-pacifique-a-9-46-n-osmium-de-l-eau-de-mer/},
note = {Accessed 2026-10-20}
}Updated : 2026-10-20