The concentration and isotopic composition of osmium in the oceans
Osmium is one of the rarer elements in seawater. Analytical difficulties have previously prevented the direct measurement of the osmium concentration and isotopic composition in seawater. We report a chemical separation procedure that yields quantitative extraction of osmium standard and of osmium t...
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ftcaltechauth:oai:authors.library.caltech.edu:8s6zh-tex12 2024-06-23T07:55:05+00:00 The concentration and isotopic composition of osmium in the oceans Sharma, M. Papanastassiou, D. A. Wasserburg, G. J. 1997-08 https://doi.org/10.1016/S0016-7037(97)00210-X unknown Elsevier oai:authors.library.caltech.edu:8s6zh-tex12 eprintid:42537 https://doi.org/10.1016/S0016-7037(97)00210-X resolverid:CaltechAUTHORS:20131118-150128545 info:eu-repo/semantics/closedAccess Other Geochimica et Cosmochimica Acta, 61(16), 3287-3299, (1997-08) info:eu-repo/semantics/article 1997 ftcaltechauth https://doi.org/10.1016/S0016-7037(97)00210-X 2024-06-12T02:13:56Z Osmium is one of the rarer elements in seawater. Analytical difficulties have previously prevented the direct measurement of the osmium concentration and isotopic composition in seawater. We report a chemical separation procedure that yields quantitative extraction of osmium standard and of osmium tracer by iron hydroxide precipitation from seawater doped with osmium standard, osmium tracer, and FeCI_3. The iron hydroxide precipitate is processed to extract osmium, using techniques developed for iron meteorites. Utilizing this procedure, water samples from the Pacific and Atlantic oceans were analyzed for osmium concentration and isotopic composition. Direct determination of the osmium concentration of seawater gives between 15 and 19 fM kg^(−1). Detailed experiments on different aliquots of one seawater sample from the North Atlantic Ocean, keeping the amounts of reagents constant, yield concentrations from 16 to 19 fM kg^(−1). The variability in concentration is outside the uncertainty introduced because of blanks and indicates a lack of full equilibration between the osmium tracer and seawater osmium. The most reliable osmium concentration of the North Atlantic deep ocean water is 19 fM kg^(−1) with the ^(187)Os^(186)Os ratio being 8.7 ± 0.2 (2σ). Detailed experiments on one seawater sample from the Central Pacific Ocean indicate that the most reliable osmium concentration of the deep ocean water from the Central Pacific is 19 fM kg^(−1) with the ^(187)Os^(186)Os ratio being 8.7 ± 0.3 (2σ). The directly measured osmium isotopic composition of the oceans is in good agreement with that obtained from the analysis of some rapidly accumulating organic rich sediments (Ravizza and Turekian, 1992). A sample of ambient seawater around the Juan de Fuca Ridge gave ^(187)Os^(186)Os= 6.9 ± 0.4. This is distinctly lower than the deep-sea water value and may reflect local hydrothermal activity or some analytical difficulty with this sample. The osmium isotopic composition of the deep oceans indicates that ... Article in Journal/Newspaper North Atlantic Caltech Authors (California Institute of Technology) Pacific Geochimica et Cosmochimica Acta 61 16 3287 3299 |
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Caltech Authors (California Institute of Technology) |
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description |
Osmium is one of the rarer elements in seawater. Analytical difficulties have previously prevented the direct measurement of the osmium concentration and isotopic composition in seawater. We report a chemical separation procedure that yields quantitative extraction of osmium standard and of osmium tracer by iron hydroxide precipitation from seawater doped with osmium standard, osmium tracer, and FeCI_3. The iron hydroxide precipitate is processed to extract osmium, using techniques developed for iron meteorites. Utilizing this procedure, water samples from the Pacific and Atlantic oceans were analyzed for osmium concentration and isotopic composition. Direct determination of the osmium concentration of seawater gives between 15 and 19 fM kg^(−1). Detailed experiments on different aliquots of one seawater sample from the North Atlantic Ocean, keeping the amounts of reagents constant, yield concentrations from 16 to 19 fM kg^(−1). The variability in concentration is outside the uncertainty introduced because of blanks and indicates a lack of full equilibration between the osmium tracer and seawater osmium. The most reliable osmium concentration of the North Atlantic deep ocean water is 19 fM kg^(−1) with the ^(187)Os^(186)Os ratio being 8.7 ± 0.2 (2σ). Detailed experiments on one seawater sample from the Central Pacific Ocean indicate that the most reliable osmium concentration of the deep ocean water from the Central Pacific is 19 fM kg^(−1) with the ^(187)Os^(186)Os ratio being 8.7 ± 0.3 (2σ). The directly measured osmium isotopic composition of the oceans is in good agreement with that obtained from the analysis of some rapidly accumulating organic rich sediments (Ravizza and Turekian, 1992). A sample of ambient seawater around the Juan de Fuca Ridge gave ^(187)Os^(186)Os= 6.9 ± 0.4. This is distinctly lower than the deep-sea water value and may reflect local hydrothermal activity or some analytical difficulty with this sample. The osmium isotopic composition of the deep oceans indicates that ... |
format |
Article in Journal/Newspaper |
author |
Sharma, M. Papanastassiou, D. A. Wasserburg, G. J. |
spellingShingle |
Sharma, M. Papanastassiou, D. A. Wasserburg, G. J. The concentration and isotopic composition of osmium in the oceans |
author_facet |
Sharma, M. Papanastassiou, D. A. Wasserburg, G. J. |
author_sort |
Sharma, M. |
title |
The concentration and isotopic composition of osmium in the oceans |
title_short |
The concentration and isotopic composition of osmium in the oceans |
title_full |
The concentration and isotopic composition of osmium in the oceans |
title_fullStr |
The concentration and isotopic composition of osmium in the oceans |
title_full_unstemmed |
The concentration and isotopic composition of osmium in the oceans |
title_sort |
concentration and isotopic composition of osmium in the oceans |
publisher |
Elsevier |
publishDate |
1997 |
url |
https://doi.org/10.1016/S0016-7037(97)00210-X |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Geochimica et Cosmochimica Acta, 61(16), 3287-3299, (1997-08) |
op_relation |
oai:authors.library.caltech.edu:8s6zh-tex12 eprintid:42537 https://doi.org/10.1016/S0016-7037(97)00210-X resolverid:CaltechAUTHORS:20131118-150128545 |
op_rights |
info:eu-repo/semantics/closedAccess Other |
op_doi |
https://doi.org/10.1016/S0016-7037(97)00210-X |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
61 |
container_issue |
16 |
container_start_page |
3287 |
op_container_end_page |
3299 |
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1802647505531305984 |