(Appendix A) Geochemistry of Oligocene sediments of ODP Site 177-1090
Fuente:
PANGAEA
Guardado en:
| Autores principales: | , |
|---|---|
| Formato: | Dataset Open Access |
| Lenguaje: | en |
| Publicado: |
PANGAEA
2005
|
| Materias: | |
| Acceso en línea: | |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| _version_ | 1867171830290186240 |
|---|---|
| author | Anderson, Linda Davis Delaney, Margaret Lois |
| author_facet | Anderson, Linda Davis Delaney, Margaret Lois |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Ocean Drilling Program (ODP) Site 1090, on the Agulhas Ridge in the South Atlantic sector of the Southern Ocean, is ideally located to capture changes in Southern Ocean circulation patterns. Using samples taken from cored sediments, we construct multiproxy records of productivity (biogenic barium (Baex), opal, and CaCO3 mass accumulation rates (MARs)), nutrient and organic carbon burial (reactive phosphorus (Pr) MARs), and redox conditions (U and Mn enrichments) to investigate hydrographic conditions associated with climatic shifts from the Oligocene through the early Miocene. Orbitally induced cyclicity in U and Mn enrichments (100 kyr) suggests shifts in deepwater characteristics. However, CaCO3 dissolution coincident with low U and Mn enrichments does not indicate low-oxygen, corrosive waters similar to modern conditions. These observations indicate that a well-developed "modern-type" Antarctic Circumpolar Current (ACC) did not yet exist over the period from 30 to 20 Ma, with two potential consequences: The Southern Ocean was not functioning as a silica trap, permitting a broader distribution of silica that may have facilitated organic carbon burial in the ocean in general, and the lack of a deeply mixing ACC may have facilitated organic carbon burial in the Southern Ocean. Both the relative (high opal MARs coincident with low CaCO3 MARs) and absolute (high Pr MARs) burial of organic carbon suggest a powerful mechanism for pCO2 drawdown. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_838992 |
| institution | PANGAEA |
| language | en |
| publishDate | 2005 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Appendix A) Geochemistry of Oligocene sediments of ODP Site 177-1090 Anderson, Linda Davis Delaney, Margaret Lois 177-1090B; 177-1090D; Accumulation rate, barium, excess; Accumulation rate, calcium carbonate; Accumulation rate, opal; Accumulation rate, phosphorus; Accumulation rate, terrigenous; AGE; Aluminium; Barium; Barium excess; Calcium carbonate; Depth, composite; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Joides Resolution; Leg177; Manganese; Method comment; Ocean Drilling Program; ODP; Opal, biogenic silica; Phosphorus, detrital; Phosphorus, reactive; Phosphorus, total; Sample code/label; South Atlantic Ocean; Titanium; Uranium; Velocity, shear, amplitude Ocean Drilling Program (ODP) Site 1090, on the Agulhas Ridge in the South Atlantic sector of the Southern Ocean, is ideally located to capture changes in Southern Ocean circulation patterns. Using samples taken from cored sediments, we construct multiproxy records of productivity (biogenic barium (Baex), opal, and CaCO3 mass accumulation rates (MARs)), nutrient and organic carbon burial (reactive phosphorus (Pr) MARs), and redox conditions (U and Mn enrichments) to investigate hydrographic conditions associated with climatic shifts from the Oligocene through the early Miocene. Orbitally induced cyclicity in U and Mn enrichments (100 kyr) suggests shifts in deepwater characteristics. However, CaCO3 dissolution coincident with low U and Mn enrichments does not indicate low-oxygen, corrosive waters similar to modern conditions. These observations indicate that a well-developed "modern-type" Antarctic Circumpolar Current (ACC) did not yet exist over the period from 30 to 20 Ma, with two potential consequences: The Southern Ocean was not functioning as a silica trap, permitting a broader distribution of silica that may have facilitated organic carbon burial in the ocean in general, and the lack of a deeply mixing ACC may have facilitated organic carbon burial in the Southern Ocean. Both the relative (high opal MARs coincident with low CaCO3 MARs) and absolute (high Pr MARs) burial of organic carbon suggest a powerful mechanism for pCO2 drawdown. |
| title | (Appendix A) Geochemistry of Oligocene sediments of ODP Site 177-1090 |
| topic | 177-1090B; 177-1090D; Accumulation rate, barium, excess; Accumulation rate, calcium carbonate; Accumulation rate, opal; Accumulation rate, phosphorus; Accumulation rate, terrigenous; AGE; Aluminium; Barium; Barium excess; Calcium carbonate; Depth, composite; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Joides Resolution; Leg177; Manganese; Method comment; Ocean Drilling Program; ODP; Opal, biogenic silica; Phosphorus, detrital; Phosphorus, reactive; Phosphorus, total; Sample code/label; South Atlantic Ocean; Titanium; Uranium; Velocity, shear, amplitude |
| url | https://doi.org/10.1594/PANGAEA.838992 |