Organic geochemistry of ODP Hole 162-985A sediments
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| Format: | Dataset Open Access |
| Sprache: | en |
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PANGAEA
1999
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| _version_ | 1867169507834855424 |
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| author | Ikehara, Minoru Kawamura, Kimitaka Ohkouchi, Naohiko Taira, Asahiko |
| author_facet | Ikehara, Minoru Kawamura, Kimitaka Ohkouchi, Naohiko Taira, Asahiko |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Dark, organic-rich sediments were recovered from the lower Miocene section (~16.6 Ma) in Hole 985A in the Norway Basin during Ocean Drilling Program Leg 162. Organic carbon and total sulfur contents of the dark sediments showed a maximum concentration of 5.6 and 26.1 wt%, respectively. Sulfur enrichment in the sediments indicates that these dark layers were formed under anoxic conditions in bottom water. Four dark and eight greenish gray sediment samples, ranging in age from early Miocene to Pleistocene, were analyzed for lipid-class compounds (aliphatic hydrocarbons, fatty alcohols, and sterols) using gas chromatography (GC) and GC/mass spectrometry to better understand the formation processes of the organic-rich dark layers and to reconstruct the paleoenvironmental changes. The molecular distributions of n-alkanes and fatty alcohols indicate that terrigenous organic matter largely contributed to both types of sediments. Significant amounts of hopanoid hydrocarbons, such as diploptene and hop-17(21)-ene, however, were detected characteristically in the dark sediments, which suggests that prokaryotes such as methane-oxidizing bacteria or cyanobacteria may have significantly contributed to the formation of these organic-rich, dark sediments. These results indicate that the bottom waters of the Norway Basin had been subjected to anoxic conditions during the early Miocene. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_805163 |
| institution | PANGAEA |
| language | en |
| publishDate | 1999 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Organic geochemistry of ODP Hole 162-985A sediments Ikehara, Minoru Kawamura, Kimitaka Ohkouchi, Naohiko Taira, Asahiko 162-985A; DRILL; Drilling/drill rig; Joides Resolution; Leg162; Norwegian Sea; Ocean Drilling Program; ODP Dark, organic-rich sediments were recovered from the lower Miocene section (~16.6 Ma) in Hole 985A in the Norway Basin during Ocean Drilling Program Leg 162. Organic carbon and total sulfur contents of the dark sediments showed a maximum concentration of 5.6 and 26.1 wt%, respectively. Sulfur enrichment in the sediments indicates that these dark layers were formed under anoxic conditions in bottom water. Four dark and eight greenish gray sediment samples, ranging in age from early Miocene to Pleistocene, were analyzed for lipid-class compounds (aliphatic hydrocarbons, fatty alcohols, and sterols) using gas chromatography (GC) and GC/mass spectrometry to better understand the formation processes of the organic-rich dark layers and to reconstruct the paleoenvironmental changes. The molecular distributions of n-alkanes and fatty alcohols indicate that terrigenous organic matter largely contributed to both types of sediments. Significant amounts of hopanoid hydrocarbons, such as diploptene and hop-17(21)-ene, however, were detected characteristically in the dark sediments, which suggests that prokaryotes such as methane-oxidizing bacteria or cyanobacteria may have significantly contributed to the formation of these organic-rich, dark sediments. These results indicate that the bottom waters of the Norway Basin had been subjected to anoxic conditions during the early Miocene. |
| title | Organic geochemistry of ODP Hole 162-985A sediments |
| topic | 162-985A; DRILL; Drilling/drill rig; Joides Resolution; Leg162; Norwegian Sea; Ocean Drilling Program; ODP |
| url | https://doi.org/10.1594/PANGAEA.805163 |