Carbon and oxygen isotopic compositions of Cibicidoides spp. and fine fraction separates (<10 µm) from ODP Holes 113-689B, 119-738B, and 120-748B
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| Format: | Dataset Open Access |
| Sprache: | en |
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PANGAEA
2003
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| _version_ | 1867169498724827136 |
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| author | Bohaty, Steven M Zachos, James C |
| author_facet | Bohaty, Steven M Zachos, James C |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | A prominent middle Eocene warming event is identified in Southern Ocean deep-sea cores, indicating that long-term cooling through the middle and late Eocene was not monotonic. At sites on Maud Rise and the Kerguelen Plateau, a distinct negative shift in d18O values (~1.0 per mil) is observed ca. 41.5 Ma. This excursion is interpreted as primarily a temperature signal, with a transient warming of 4°C over 600 k.y. affecting both surface and middle-bathyal deep waters in the Indian-Atlantic region of the Southern Ocean. This isotopic event is designated as the middle Eocene climatic optimum, and is interpreted to represent a significant climatic reversal in the midst of middle to late Eocene deep-sea cooling. The lack of a significant negative carbon isotope excursion, as observed during the Paleocene-Eocene thermal maximum, and the gradual rate of high-latitude warming suggest that this event was not triggered by methane hydrate dissociation. Rather, a transient rise in pCO2 levels is suspected, possibly as a result of metamorphic decarbonation in the Himalayan orogen or increased ridge/arc volcanism during the late middle Eocene. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_713540 |
| institution | PANGAEA |
| language | en |
| publishDate | 2003 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Carbon and oxygen isotopic compositions of Cibicidoides spp. and fine fraction separates (<10 µm) from ODP Holes 113-689B, 119-738B, and 120-748B Bohaty, Steven M Zachos, James C 113-689B; 119-738B; 120-748B; DRILL; Drilling/drill rig; Indian Ocean; Joides Resolution; Leg113; Leg119; Leg120; Ocean Drilling Program; ODP; South Atlantic Ocean; South Indian Ridge, South Indian Ocean A prominent middle Eocene warming event is identified in Southern Ocean deep-sea cores, indicating that long-term cooling through the middle and late Eocene was not monotonic. At sites on Maud Rise and the Kerguelen Plateau, a distinct negative shift in d18O values (~1.0 per mil) is observed ca. 41.5 Ma. This excursion is interpreted as primarily a temperature signal, with a transient warming of 4°C over 600 k.y. affecting both surface and middle-bathyal deep waters in the Indian-Atlantic region of the Southern Ocean. This isotopic event is designated as the middle Eocene climatic optimum, and is interpreted to represent a significant climatic reversal in the midst of middle to late Eocene deep-sea cooling. The lack of a significant negative carbon isotope excursion, as observed during the Paleocene-Eocene thermal maximum, and the gradual rate of high-latitude warming suggest that this event was not triggered by methane hydrate dissociation. Rather, a transient rise in pCO2 levels is suspected, possibly as a result of metamorphic decarbonation in the Himalayan orogen or increased ridge/arc volcanism during the late middle Eocene. |
| title | Carbon and oxygen isotopic compositions of Cibicidoides spp. and fine fraction separates (<10 µm) from ODP Holes 113-689B, 119-738B, and 120-748B |
| topic | 113-689B; 119-738B; 120-748B; DRILL; Drilling/drill rig; Indian Ocean; Joides Resolution; Leg113; Leg119; Leg120; Ocean Drilling Program; ODP; South Atlantic Ocean; South Indian Ridge, South Indian Ocean |
| url | https://doi.org/10.1594/PANGAEA.713540 |