Age model and grain size distribution of the fine fraction of ODP Site 114-704
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
1991
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| _version_ | 1867168556137840640 |
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| author | Mienert, Jürgen Nobes, David C |
| author_facet | Mienert, Jürgen Nobes, David C |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | The physical properties of sediments beneath an upwelling area in the southern part of the Atlantic Ocean (ODP Hole 704A) were investigated. Highly significant correlations characterize the relationship of carbonate content to bulk density (R = 0.85), carbonate content to porosity (R = 0.84), and carbonate content to impedance (R = 0.84). No relationship exists between carbonate content and compressional-wave velocity (R = 0.24), indicating that amplitude variations in impedance are primarily controlled by variations in bulk density, which, in turn, are controlled by climatically driven biogenic opal and carbonate deposition. In general, maxima in impedance correspond to maxima in carbonate content (minima in opal content). The impedance record exhibits its most drastic change at about 2.4 Ma, marking dramatic increases in the average content of biogenic opal and the beginning of large-amplitude fluctuations. Between 0.7 and 0.4 Ma carbonate content, bulk density, and grain density decrease while opal content drastically increases. Similar changes have been observed in sediments beneath an upwelling cell off northwest Africa, indicating an oceanwide enhancement in upwelling or in the calcite corrosiveness of bottom water that appears to be isochronous. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_754910 |
| institution | PANGAEA |
| language | en |
| publishDate | 1991 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Age model and grain size distribution of the fine fraction of ODP Site 114-704 Mienert, Jürgen Nobes, David C 114-704A; 114-704B; DRILL; Drilling/drill rig; Joides Resolution; Leg114; Ocean Drilling Program; ODP; South Atlantic Ocean The physical properties of sediments beneath an upwelling area in the southern part of the Atlantic Ocean (ODP Hole 704A) were investigated. Highly significant correlations characterize the relationship of carbonate content to bulk density (R = 0.85), carbonate content to porosity (R = 0.84), and carbonate content to impedance (R = 0.84). No relationship exists between carbonate content and compressional-wave velocity (R = 0.24), indicating that amplitude variations in impedance are primarily controlled by variations in bulk density, which, in turn, are controlled by climatically driven biogenic opal and carbonate deposition. In general, maxima in impedance correspond to maxima in carbonate content (minima in opal content). The impedance record exhibits its most drastic change at about 2.4 Ma, marking dramatic increases in the average content of biogenic opal and the beginning of large-amplitude fluctuations. Between 0.7 and 0.4 Ma carbonate content, bulk density, and grain density decrease while opal content drastically increases. Similar changes have been observed in sediments beneath an upwelling cell off northwest Africa, indicating an oceanwide enhancement in upwelling or in the calcite corrosiveness of bottom water that appears to be isochronous. |
| title | Age model and grain size distribution of the fine fraction of ODP Site 114-704 |
| topic | 114-704A; 114-704B; DRILL; Drilling/drill rig; Joides Resolution; Leg114; Ocean Drilling Program; ODP; South Atlantic Ocean |
| url | https://doi.org/10.1594/PANGAEA.754910 |