Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia
Independent proxies were assessed in two Late Quaternary sediment cores from the eastern South Atlantic to compare deep-water changes during the last 400 kyr. Two cores were recovered from beneath North AtlanticDeep Water (NADW) at approximately 3 000 m depth. Late Quaternary presence of NADW is ind...
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ftjafricanj:oai:ojs.ajol.info:article/66497 2023-05-15T17:13:49+02:00 Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia Gingele, FX Schmiedl, G 2011-05-24 application/pdf http://www.ajol.info/index.php/ajms/article/view/66497 eng eng NISC http://www.ajol.info/index.php/ajms/article/view/66497/54228 http://www.ajol.info/index.php/ajms/article/view/66497 Copyright for articles published in this journal is retained by the publisher. African Journal of Marine Science; Vol 21 (1999) 1814-232X info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article 2011 ftjafricanj 2017-03-05T06:42:48Z Independent proxies were assessed in two Late Quaternary sediment cores from the eastern South Atlantic to compare deep-water changes during the last 400 kyr. Two cores were recovered from beneath North AtlanticDeep Water (NADW) at approximately 3 000 m depth. Late Quaternary presence of NADW is indicated by the Cibicidoides wuellerstorfi assemblage on the Walvis Ridge (Core GeoB 1214) and the Bulimina alazanensisassemblage on the Namibian continental slope (Core GeoB 1710). The propagation of NADW is exclusively observed during interglacials, with maximum factor loadings in Stages 1, 5, 7, 9 and 11. These maxima are consistent with peaks in kaolinite/chlorite ratios and maxima of poorly crystalline smectite in the clay-mineral record. Kaolinite and poorly crystalline smectite are products of intense chemical weathering. They are injected into the NADW at low latitudes, north of the study area, and advected south. Chlorite, which is stable under cold weatheringregimes, is a characteristic mineral of water masses of southern origin. During glacial stages, it is advected north with Southern Component Water (SCW). Above the NADW/SCW depths, kaolinite/chlorite ratios varyonly slightly without a significant glacial-interglacial pattern, as measured in a core (GeoB 1712) from 1 000 m deep on the same profile of the Namibian continental slope off Walvis Bay. Article in Journal/Newspaper NADW AJOL - African Journals Online |
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Open Polar |
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AJOL - African Journals Online |
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ftjafricanj |
language |
English |
description |
Independent proxies were assessed in two Late Quaternary sediment cores from the eastern South Atlantic to compare deep-water changes during the last 400 kyr. Two cores were recovered from beneath North AtlanticDeep Water (NADW) at approximately 3 000 m depth. Late Quaternary presence of NADW is indicated by the Cibicidoides wuellerstorfi assemblage on the Walvis Ridge (Core GeoB 1214) and the Bulimina alazanensisassemblage on the Namibian continental slope (Core GeoB 1710). The propagation of NADW is exclusively observed during interglacials, with maximum factor loadings in Stages 1, 5, 7, 9 and 11. These maxima are consistent with peaks in kaolinite/chlorite ratios and maxima of poorly crystalline smectite in the clay-mineral record. Kaolinite and poorly crystalline smectite are products of intense chemical weathering. They are injected into the NADW at low latitudes, north of the study area, and advected south. Chlorite, which is stable under cold weatheringregimes, is a characteristic mineral of water masses of southern origin. During glacial stages, it is advected north with Southern Component Water (SCW). Above the NADW/SCW depths, kaolinite/chlorite ratios varyonly slightly without a significant glacial-interglacial pattern, as measured in a core (GeoB 1712) from 1 000 m deep on the same profile of the Namibian continental slope off Walvis Bay. |
format |
Article in Journal/Newspaper |
author |
Gingele, FX Schmiedl, G |
spellingShingle |
Gingele, FX Schmiedl, G Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia |
author_facet |
Gingele, FX Schmiedl, G |
author_sort |
Gingele, FX |
title |
Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia |
title_short |
Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia |
title_full |
Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia |
title_fullStr |
Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia |
title_full_unstemmed |
Comparison of independent proxies in the reconstruction of deep-water circulation in the south-east Atlantic off Namibia |
title_sort |
comparison of independent proxies in the reconstruction of deep-water circulation in the south-east atlantic off namibia |
publisher |
NISC |
publishDate |
2011 |
url |
http://www.ajol.info/index.php/ajms/article/view/66497 |
genre |
NADW |
genre_facet |
NADW |
op_source |
African Journal of Marine Science; Vol 21 (1999) 1814-232X |
op_relation |
http://www.ajol.info/index.php/ajms/article/view/66497/54228 http://www.ajol.info/index.php/ajms/article/view/66497 |
op_rights |
Copyright for articles published in this journal is retained by the publisher. |
_version_ |
1766071006708891648 |