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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
1991
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| Online Access: | https://doi.org/10.1594/PANGAEA.757151 |
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| _version_ | 1867170911939985408 |
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| author | Pedersen, Thomas F Shimmield, Graham |
| author_facet | Pedersen, Thomas F Shimmield, Graham |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Interstitial water analyses made at 12 sites during Leg 117 are used to define the nature of diagenetic reactions in organic-rich sediments on the Owen Ridge and Oman Margin. Minor variations in chloride concentration profiles are ascribed to past changes in bottom water salinity at two mid-depth margin sites and to upward migration of low salinity water at another. There is no evidence for subsurface brine movement, unlike the case on the Peru Margin. Dolomitization is widespread and accounts for the depletions of magnesium observed in pore waters at variable depths at nearly all sites. The mineral occurs both as disseminated euhedral limpid crystals and, in at least one location, in massive stringers. Formation of the latter is suggested to reflect precipitation during sea level transgressions when the sedimentation rate was low, but when productivity was high. Authigenic carbonate fluorapatite is also widespread, the phosphorus being derived from the breakdown of organic matter. Sulfate is quantitatively depleted at depth at most locations but the rate of depletion is markedly less than that observed on the Peru Margin where sedimentation is also similarly influenced by high rates of upwelling. The reason for this contrast is not clear and merits further investigation. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_757151 |
| institution | PANGAEA |
| language | en |
| publishDate | 1991 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Chemistry of interstitial waters of ODP Leg 117 samples (Table 1) Pedersen, Thomas F Shimmield, Graham 117-720A; 117-721; 117-722; 117-723; 117-724; 117-725A; 117-725B; 117-725C; 117-726A; 117-727A; 117-728; 117-729A; 117-730A; 117-731A; 117-731B; 117-731C; Alkalinity, total; Ammonium; Arabian Sea; Calcium; Carbon, organic, dissolved; Chloride; COMPCORE; Composite Core; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Joides Resolution; Leg117; Magnesium; Magnesium/Calcium ratio; Ocean Drilling Program; ODP; pH; Phosphate; Salinity; Sample code/label; Silicon dioxide; Sulfate Interstitial water analyses made at 12 sites during Leg 117 are used to define the nature of diagenetic reactions in organic-rich sediments on the Owen Ridge and Oman Margin. Minor variations in chloride concentration profiles are ascribed to past changes in bottom water salinity at two mid-depth margin sites and to upward migration of low salinity water at another. There is no evidence for subsurface brine movement, unlike the case on the Peru Margin. Dolomitization is widespread and accounts for the depletions of magnesium observed in pore waters at variable depths at nearly all sites. The mineral occurs both as disseminated euhedral limpid crystals and, in at least one location, in massive stringers. Formation of the latter is suggested to reflect precipitation during sea level transgressions when the sedimentation rate was low, but when productivity was high. Authigenic carbonate fluorapatite is also widespread, the phosphorus being derived from the breakdown of organic matter. Sulfate is quantitatively depleted at depth at most locations but the rate of depletion is markedly less than that observed on the Peru Margin where sedimentation is also similarly influenced by high rates of upwelling. The reason for this contrast is not clear and merits further investigation. |
| title | Chemistry of interstitial waters of ODP Leg 117 samples (Table 1) |
| topic | 117-720A; 117-721; 117-722; 117-723; 117-724; 117-725A; 117-725B; 117-725C; 117-726A; 117-727A; 117-728; 117-729A; 117-730A; 117-731A; 117-731B; 117-731C; Alkalinity, total; Ammonium; Arabian Sea; Calcium; Carbon, organic, dissolved; Chloride; COMPCORE; Composite Core; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Joides Resolution; Leg117; Magnesium; Magnesium/Calcium ratio; Ocean Drilling Program; ODP; pH; Phosphate; Salinity; Sample code/label; Silicon dioxide; Sulfate |
| url | https://doi.org/10.1594/PANGAEA.757151 |