On/offshore deep electrical conductivity structure to investigate the Walvis Ridge magmatism and its interaction with the Kaoko Mobile Belt in northern Namibia. (ELCONA)

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We propose an amphibian magnetotelluric (MT) experiment to image the subsurface electrical conductivity structure of the passive continental margin of northern Namibia. The main E-W profile begins off-shore along the Walvis ridge, crosses on-shore all major tectono-stragraphic units of the Kaoko Belt and continues into the Congo Craton. With this proposal, we will for the first time (i) combine on- and offshore MT measurements in a passive margin setting and (ii) be able to integrate electrical conductivity with deep seismic data along the entire length of an amphibian profile. The Kaoko Belt in northern Namibia is characterized by large NNW striking structures generated during late Neoproterozoic continental collision. These old regional structures played an important role in the tectonic evolution of the Kaoko Belt and are intimately related with the evolution of adjacent marginal Walvis basin. Where the Walvis ridge meets the continental crust, gabbroic complexes and basic dykes intersect with the flood volcanics and the Etendeka rocks. With this proposal we intend to determine (i) along-strike variability, homogeneity, and extent of magmatic rocks (ii) the influence of pre-existing structure on the emplacement of magmas (iii) a complete deep electrical conductivity section of a passive continental margin and the adjacent continental lithosphere.