South Africa - Inkaba.org

Palaeoceanographic changes identified using seismic and
radiogenic isotope data from the Mozambique Ridge, SW
Indian Ocean
Gabriele Uenzelmann-Neben 1 , Michael K. Watkeys 2 , Warren Kretzinger 2 , Martin Frank 3
and Lasse Heuer 3
1. Alfred-Wegener-Institute for Polar and Marine Research, Am Alten Hafen, 27568 Bremerhaven, Germany,
Gabriele.Uenzelmann-Neben@awi.de
2.School of Geological Sciences, University KwaZulu-Natal, Private Bag X54001, Durban 4000, Republic
of South Africa, Watkeys@ukzn.ac.za, 202521809@uknz.ac.za
3. IfM-Geomar, Leibniz Institute of Marine Sciences at the University of Kiel, Wischhofstr. 1-3, 24148 Kiel,
Germany, mfrank@ifm-geomar.de
ABSTRACT
Seismic reflection data from the southern Mozambique Ridge, SW Indian Ocean, show indications for a
modification in the oceanic circulation system. In the absence of an age-depth model based on a drill site we used
information gathered from the study of radiogenic isotopes of ferromanganese nodules and crusts. Those were
recovered via dredges from the Mozambique Ridge to gain knowledge on the origin of the modifications of the
oceanic circulation system, which is documented in the distinct change in reflection characteristics. This is found to
have occurred at 9 Ma.
KEYWORDS: Mozambique Ridge, seismic data, reorganisation of circulation system, isotopic signatures of water
masses, NADW.
82