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| Yu, Ef; Liang, Ch; Chen, Mt. |
| Anomalously high uranium contents and U-238/Th-232 activity ratios deposited during the oxygen isotope stages 2 to 4 are observed in the MD962085 core from the Benguela Current upwelling area. In conjunction,vith the activity ratio of U-234/U-238, the high uranium contents found in this core cannot be considered as detrital; instead, they must be of authigenic origin. The high biological productivity in the overlying seawater may have induced a high flux of organic matter resulting, directly or indirectly, in a reducing environment, and may have led to the addition of authigenic uranium to the sediments during the last glacial period. The correspondence between the variations in authigenic U content, %TOC, and Th-230(ex)-normalized TOC flux supports this... |
| Tipo: Text |
Palavras-chave: Authigenic uranium; Last glacial stage; Benguela Current upwelling. |
| Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35071/34562.pdf |
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| Chang, Yp; Chang, Cc; Wang, Lw; Chen, Mt; Wang, Ch; Yu, Ef. |
| A high-resolution (similar to 4 - 5cm/kyr) giant piston core record (MD962085) retrieved during an IMAGES II - NAUSICAA cruise from the continental slope of the southeast Atlantic Ocean reveal striking variations in planktonic foraminifer faunal abundances and sea-surface temperatures (SST) during the past 400,000 years. The location and high-quality sedimentary record of the core provide a good opportunity to assess changes in the intensity and position of the Benguela Current System and the Subtropical Convergence, two key features of the ocean-climate system in the south Atlantic. This record can be also used to evaluate the possible influence of Agulhas Current from the throughflow of the Indian Ocean into the South Atlantic. The planktonic foraminifer... |
| Tipo: Text |
Palavras-chave: Paleoceanography; Late Quaternary; Micropaleontology; South Atlantic. |
| Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35070/34563.pdf |
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