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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2008
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| Online Access: | https://doi.org/10.1594/PANGAEA.706068 |
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| _version_ | 1867170888113192960 |
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| author | Ando, Atsushi Kaiho, Kunio Kawahata, Hodaka Kakegawa, Takeshi |
| author_facet | Ando, Atsushi Kaiho, Kunio Kawahata, Hodaka Kakegawa, Takeshi |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | In order to elucidate early Aptian marine paleotemperature evolution across the period of enhanced organic carbon (Corg)-burial [Oceanic Anoxic Event (OAE) 1a], stable isotope analyses were performed on pelagic limestones at Deep Sea Drilling Project Site 463, central Pacific Ocean. The delta18O data exhibit a distinct anomaly by ~-2 per mil spanning the OAE 1a interval (i.e., a ~6 m-thick, phytoplanktonic Corg-rich unit constrained by magneto-, bio- and delta13C stratigraphy). Elucidation of paleotemperature significance of the delta18O shift is made by taking account of recent Sr/Ca evidence at the same section, which revealed that geochemical signals in carbonate-poor lithologies are relatively unaltered against burial diagenesis. By discriminating delta18O values from carbonate-poor samples (CaCO3 contents=5-30 wt.%), it appears that an abrupt rise in seasurface temperatures (SSTs) by 8 °C (=-1.7 per mil shift in delta18O) occurred immediately before OAE 1a, whereas a cooling mode likely prevailed during the peak Corg-burial. In terms of its stratigraphic relationship as to the Corg-rich interval and to a pronounced negative delta13C excursion, as well as its timescale, the observed SST rise resembles those associated with the Paleocene-Eocene thermal maximum and, more strikingly, Jurassic Toarcian OAE. This observation is consistent with the hypothesis that these paleoenvironmental events were driven by a common causal mechanism, which was likely initiated by the greenhouse effect via massive release of CH4 or CO2 from the isotopically-light carbon reservoir and terminated by a negative productivity feedback. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_706068 |
| institution | PANGAEA |
| language | en |
| publishDate | 2008 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Stable carbon and oxygen isotope ratios of bulk sediment from DSDP Hole 62-463 (Appendix A) Ando, Atsushi Kaiho, Kunio Kawahata, Hodaka Kakegawa, Takeshi 62-463; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Isotope ratio mass spectrometry; Leg62; Lithology/composition/facies; North Pacific/SEAMOUNT; Sample code/label; Sample comment; δ13C, carbonate; δ18O, carbonate In order to elucidate early Aptian marine paleotemperature evolution across the period of enhanced organic carbon (Corg)-burial [Oceanic Anoxic Event (OAE) 1a], stable isotope analyses were performed on pelagic limestones at Deep Sea Drilling Project Site 463, central Pacific Ocean. The delta18O data exhibit a distinct anomaly by ~-2 per mil spanning the OAE 1a interval (i.e., a ~6 m-thick, phytoplanktonic Corg-rich unit constrained by magneto-, bio- and delta13C stratigraphy). Elucidation of paleotemperature significance of the delta18O shift is made by taking account of recent Sr/Ca evidence at the same section, which revealed that geochemical signals in carbonate-poor lithologies are relatively unaltered against burial diagenesis. By discriminating delta18O values from carbonate-poor samples (CaCO3 contents=5-30 wt.%), it appears that an abrupt rise in seasurface temperatures (SSTs) by 8 °C (=-1.7 per mil shift in delta18O) occurred immediately before OAE 1a, whereas a cooling mode likely prevailed during the peak Corg-burial. In terms of its stratigraphic relationship as to the Corg-rich interval and to a pronounced negative delta13C excursion, as well as its timescale, the observed SST rise resembles those associated with the Paleocene-Eocene thermal maximum and, more strikingly, Jurassic Toarcian OAE. This observation is consistent with the hypothesis that these paleoenvironmental events were driven by a common causal mechanism, which was likely initiated by the greenhouse effect via massive release of CH4 or CO2 from the isotopically-light carbon reservoir and terminated by a negative productivity feedback. |
| title | Stable carbon and oxygen isotope ratios of bulk sediment from DSDP Hole 62-463 (Appendix A) |
| topic | 62-463; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Glomar Challenger; Isotope ratio mass spectrometry; Leg62; Lithology/composition/facies; North Pacific/SEAMOUNT; Sample code/label; Sample comment; δ13C, carbonate; δ18O, carbonate |
| url | https://doi.org/10.1594/PANGAEA.706068 |