Clay mineralogy of sediment cores from the South-East Atlantic off Namibia, supplement to: Gingele, Franz; Schmiedl, Gerhard (1999): Comparison of independant proxies on deep water advection in the southeast Atlantic off Namibia. South African Journal of Marine Science, 21, 181-190

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 Atlantic Deep Water (NADW) at approximately 3 000 m depth. Late Quaternary presence of NADW is in...

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Bibliographic Details
Main Authors: Gingele, Franz, Schmiedl, Gerhard
Format: Article in Journal/Newspaper
Language:English
Published: PANGAEA - Data Publisher for Earth & Environmental Science 1999
Subjects:
Gravity corer Kiel type
M20/2
Meteor 1986
Geosciences, University of Bremen GeoB
NADW
North Atlantic Deep Water
North Atlantic
Online Access:https://dx.doi.org/10.1594/pangaea.730462
https://doi.pangaea.de/10.1594/PANGAEA.730462
Description
Summary: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 Atlantic Deep 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 alazanensis assemblage 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 weathering regimes, 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 vary only 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.

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