Abstract

41 airborne magnetic surveys flown between 1962 and 1992 over different areas of Namibia were compiled as part of a German-Namibian technical cooperation project to produce a refined compatible national (countrywide) magnetic data set. Contour maps are available in two scales (1:1 000 000 and 1:250 000) together with digital grids having cell sizes of 2000m, 500m and 200m. The refined magnetic data serve as a new tool suitable to elucidate the crustal evolution and to contribute to the management of renewable and non-renewable natural resources. Namibia can be subdivided into several magnetic domains amongst which the cratonic areas and the Proterozoic fold belts are the most important. Modelling indicates that the magnetic pattern reflects intra-continental rift and collision processes, most clearly on the periphery of the Archean cratons. The mid-Proterozoic, Sinclair Sequence is supposed to be an accreted terrane. Two examples of magnetic data used in the management of natural resources are discussed: Depth values of the top surface of the magnetic basement in the Otavi Mountainland provided by harmonic analysis of the magnetic field and synthesis of magnetization waves have contributed towards the development of a geohydraulic model of one of the most important aquifers of Namibia. In the southern part of the country, structural analysis of the magnetic field yielded intersections and confluences of magnetic lineaments, which are considered sites with future potential for hydrothermal mineralization. They especially cluster in the Proterozoic Sinclair Sequence and Orange River Group. A number of areas with increased mineral potential could be identified.

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