Electrical resistivity image of the South Atlantic continental margin derived from onshore and offshore magnetotelluric data.

Kapinos, G., Weckmann, U., Jegen-Kulcsar, Marion , Meqbel, N., Neska, A., Katjiuongua, T. T., Hölz, Sebastian and Ritter, O. (2016) Electrical resistivity image of the South Atlantic continental margin derived from onshore and offshore magnetotelluric data. Open Access Geophysical Research Letters, 43 (1). pp. 154-160. DOI 10.1002/2015GL066811.

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Abstract

We present a deep electrical resistivity image from the passive continental margin in Namibia. The approximately 700 km long magnetotelluric profile follows the Walvis Ridge offshore, continues onshore across the Kaoko Mobile Belt and reaches onto the Congo Craton. Two-dimensional inversion reveals moderately resistive material offshore, atypically low for oceanic lithosphere, reaching depths of 15–20 km. Such moderate resistivities are consistent with seismic P wave velocity models, which suggest up to 35 km thick crust. The Neoproterozoic rocks of the Kaoko Mobile Belt are resistive, but NNW-striking major shear-zones are imaged as subvertical, conductive structures in the upper and middle crust. Since the geophysical imprint of the shear zones is intact, opening of the South Atlantic in the Cretaceous did not alter the middle crust. The transition into the cratonic region coincides with a deepening of the high-resistive material to depths of more than 60 km.

Document Type: Article
Additional Information: WOS:000369014100019
Keywords: magnetotelluric; electrical conductivity; passive continental margin; mobile belt; Namibia
Research affiliation: HGF-GFZ
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union), Wiley
Date Deposited: 22 Feb 2016 09:36
Last Modified: 01 Feb 2019 15:14
URI: https://oceanrep.geomar.de/id/eprint/31435

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