On March 31, 2014, the research vessel Sonne started out on its voyage around the south¬ern tip of Africa. The focus of the work plan is on the Mozambique Ridge to the east of South Africa in the direction of Madagascar. The Mozambique Ridge is a large basalt undersea plateau formed by volcanic activity in the wake of the breakup of supercontinent Gondwana. The Alfred Wegener Institute's Helmholtz Centre for Polar and Marine Research (AWI) is co¬operating with GEOMAR to investigate the questions of when and why the plateau was formed and how its growth has affected the ocean currents over wide areas.

The AWI will primarily be conducting geophysical investigations of the Earth's crust structure and the marine sediments. Among other things, the dimensions of the Mozambique Ridge, which can possibly be linked to the large flood basalt provinces, are to be measured. GEOMAR researchers will be retrieving rocks from the sea floor. For this purpose they use a dredge. This is a rugged, steel-frame, toothed jaw to which a sack made of chains is attached.

The temporal evolution of the Mozambique Ridge can be reconstructed by radiometric age dating of the collected rock samples, thus providing insights into the tectonic development of this region. Geochemical analyses can shed light on whether the plateau was created by the divergence of tectonic plates and the extent to which mantle plumes were involved in its creation.
By means of this multi-disciplinary approach, the researchers of both participating institutes hope to gain a better understanding of the causes and effects of the extensive volcanic activity in this area. The plateau was possibly significant enough to pose an undersea barrier for global ocean currents. With this detailed study, the researchers now wish to find out how strongly and how long this blockade has been intervening in the heat and energy exchange between the hemispheres.

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