Composition of hydrothermal manganese oxide deposits from Galapagos mounds, DSDP Leg 70, Hole 509B
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| Format: | Dataset Open Access |
| Sprache: | en |
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PANGAEA
1983
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| _version_ | 1867167660152717312 |
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| author | Lalou, Claude Brichet, Evelyne Jehanno, Celestine Perez-Leclaire, Heloise |
| author_facet | Lalou, Claude Brichet, Evelyne Jehanno, Celestine Perez-Leclaire, Heloise |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | During DSDP Leg 70, a 1.60 m thick manganese oxide layer was sampled in hole 509B. This deposit is formed of alternating layers of hard plates of pure todorokite, about 2 mm thick, and of a more powdery material deeply impregnated with manganese oxide, about 3 mm thick. A SEM study of the plates and the associated powder shows that the powdery material is a transformation of a pre-existing sediment, while the plates are a direct precipitation from a hydrothermal solution. The uranium series disequilibrium method was used to determine the ages of the plates. They are found to be in good chronological sequence and in accordance with the sedimentation rate of the area (4.9 cm/10^3 years) which implies that they have been formed at the sediment-seawater interface during a pulsed injection of hydrothermal solution. The powder presents systematically an “older age” which is explained by a slowing down of the injection while the normal sediment settles; the older age is due to the 230Th excess of the sediment. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_698981 |
| institution | PANGAEA |
| language | en |
| publishDate | 1983 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Composition of hydrothermal manganese oxide deposits from Galapagos mounds, DSDP Leg 70, Hole 509B Lalou, Claude Brichet, Evelyne Jehanno, Celestine Perez-Leclaire, Heloise 70-509B; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg70; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; North Pacific/MOUND During DSDP Leg 70, a 1.60 m thick manganese oxide layer was sampled in hole 509B. This deposit is formed of alternating layers of hard plates of pure todorokite, about 2 mm thick, and of a more powdery material deeply impregnated with manganese oxide, about 3 mm thick. A SEM study of the plates and the associated powder shows that the powdery material is a transformation of a pre-existing sediment, while the plates are a direct precipitation from a hydrothermal solution. The uranium series disequilibrium method was used to determine the ages of the plates. They are found to be in good chronological sequence and in accordance with the sedimentation rate of the area (4.9 cm/10^3 years) which implies that they have been formed at the sediment-seawater interface during a pulsed injection of hydrothermal solution. The powder presents systematically an “older age” which is explained by a slowing down of the injection while the normal sediment settles; the older age is due to the 230Th excess of the sediment. |
| title | Composition of hydrothermal manganese oxide deposits from Galapagos mounds, DSDP Leg 70, Hole 509B |
| topic | 70-509B; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg70; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; North Pacific/MOUND |
| url | https://doi.org/10.1594/PANGAEA.698981 |