Osmium concentration and isotopic composition of North Pacific deep-sea sediments
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
1988
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| _version_ | 1867171371422842880 |
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| author | Esser, Bradley K Turekian, Karl K |
| author_facet | Esser, Bradley K Turekian, Karl K |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Pelagic clay and Mn nodules from DOMES sites in the North Pacific and a varved glacial lake deposit from Connecticut were analysed for Os concentration and isotopic composition by isotope-dilution secondary ion mass spectrometry after treatment by NiS fusion or oxalic acid leaching. Bulk pelagic clay from DOMES site C has 187Os/186Os = 6.5 and Os = 0.14 ng/g. Oxalic acid leaches of this same sediment and of Mn nodules from DOMES sites A and C have more radiogenic 187Os/186Os ratios which average 8.3. Bulk glacial Lake Hitchcock sediment has 187Os/186Os = 12.5 and Os = 0.06 ng/g. The total Os flux to North Pacific pelagic clay is 7 to 10 ng Os/cm**2/10**6 y. Lake Hitchcock sediment provides an integrated value for the local crustal 187Os/186Os ratio. The oxalic acid leaches are assumed to attack hydrogenous phases selectively. A simple model in which the only sources of Os to the ocean are continental crust with the isotopic composition of Lake Hitchcock (187Os/186Os = 12.5) and extraterrestrial particles with 187Os/186Os = 1.1 results in a cosmic flux of osmium to the sediment of 4.9 ng Os/cm**2/10**6 y of which 20% is hydrogenous. A model in which the sources of Os to the ocean are continental crust with an 187Os/186Os ratio of 30 (from the model of Palmer and Turekian, 1986), oceanic mantle or crust with 187Os/186Os = 1.04 and extraterrestrial particles with 187Os/186Os = 1.1 results in a cosmic flux of Os to the sediment of 5.7 ng Os/cm**2/10**6 y of which none is hydrogenous. These extraterrestrial Os fluxes correspond to maximum C-1 chondrite accretion rates of between 4.9 × 104 and 5.6 × 104 tonnes/y. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_880007 |
| institution | PANGAEA |
| language | en |
| publishDate | 1988 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Osmium concentration and isotopic composition of North Pacific deep-sea sediments Esser, Bradley K Turekian, Karl K NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS Pelagic clay and Mn nodules from DOMES sites in the North Pacific and a varved glacial lake deposit from Connecticut were analysed for Os concentration and isotopic composition by isotope-dilution secondary ion mass spectrometry after treatment by NiS fusion or oxalic acid leaching. Bulk pelagic clay from DOMES site C has 187Os/186Os = 6.5 and Os = 0.14 ng/g. Oxalic acid leaches of this same sediment and of Mn nodules from DOMES sites A and C have more radiogenic 187Os/186Os ratios which average 8.3. Bulk glacial Lake Hitchcock sediment has 187Os/186Os = 12.5 and Os = 0.06 ng/g. The total Os flux to North Pacific pelagic clay is 7 to 10 ng Os/cm**2/10**6 y. Lake Hitchcock sediment provides an integrated value for the local crustal 187Os/186Os ratio. The oxalic acid leaches are assumed to attack hydrogenous phases selectively. A simple model in which the only sources of Os to the ocean are continental crust with the isotopic composition of Lake Hitchcock (187Os/186Os = 12.5) and extraterrestrial particles with 187Os/186Os = 1.1 results in a cosmic flux of osmium to the sediment of 4.9 ng Os/cm**2/10**6 y of which 20% is hydrogenous. A model in which the sources of Os to the ocean are continental crust with an 187Os/186Os ratio of 30 (from the model of Palmer and Turekian, 1986), oceanic mantle or crust with 187Os/186Os = 1.04 and extraterrestrial particles with 187Os/186Os = 1.1 results in a cosmic flux of Os to the sediment of 5.7 ng Os/cm**2/10**6 y of which none is hydrogenous. These extraterrestrial Os fluxes correspond to maximum C-1 chondrite accretion rates of between 4.9 × 104 and 5.6 × 104 tonnes/y. |
| title | Osmium concentration and isotopic composition of North Pacific deep-sea sediments |
| topic | NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS |
| url | https://doi.org/10.1594/PANGAEA.880007 |