The MAMBA geophysical project aims to explore the ocean-continent transition at the passive continental margin of Namibia, just south of the Walvis Ridge. This continental edge shows typical phenomena of volcanic margin formation, including flood volcanism, intrusions of continental crust by ring complexes, and dike swarms. The continental breakup and related magmatism was probably influenced by pre-existing Pan-African structures. Controversy exists on the nature of the ocean-continent transition in terms of its location, the width of the rifted zone, the degree of thinning of continental crust, and the magmatic impact.
The experiment was designed to provide information on reflectivity, seismic velocity, density and magnetic susceptibility. Near-vertical and wide-angle seismic data as well as magnetic data were collected in cooperation with several German institutions and the Geological Survey of Namibia. Complemented by existing gravity data, these data sets are used to derive crustal sections across the margin.
One of the geophysical traverses was complemented by reflection seismic profiling onshore Namibia (SIMBA'98 project). The two projects are part of the interdisciplinary GFZ Namibia project.

Time Frame

• December 1995

Funding

• BGR - Federal Institute for Geosciences and Natural Resources
• GFZ - Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
• AWI - Alfred Wegener Institute for Polar and Marine Research

Principal Investigators

• Dr. A. Schulze
• Dr. S. Sobolev
• Dr. R. Trumbull
• Dr. K. Bauer

Cooperations

• Dr. S. Neben (BGR Hannover)
• Dr. B. Schreckenberger (BGR Hannover)
• Dr. K. Gohl (AWI Bremerhaven)
• Prof. Dr. K. Weber (Uni Göttingen)
• Dr. B. Baier (Uni Frankfurt)
• Geological Survey of Namibia

Methods & Equipment

• P-velocity modeling using near-vertical and wide-angle data
• CMP-processing and imaging of near-vertical data (BGR)
• CMP-processing and imaging of wide-angle data
• Density modeling using P-velocity information
• Magnetic modeling (BGR)
• Analysis of converted shear-waves

Publications/Results

• Trumbull, R.B., S.V. Sobolev, and K. Bauer, Petrophysical modeling of high seismic velocity crust at the Namibian volcanic margin (2002) In: Menzies, M.A., Klemperer, S.L., Ebinger, C.J., and Baker, J. (Eds.), Volcanic rifted margins, Special Paper - Geological Society of America , 362, 225-234
• Bauer, K., Charakterisierung eines vulkanisch geprägten passiven Kontinentalrandes mit seismischen Verfahren am Beispiel Namibias (2001): Dissertation, Universität Potsdam, 125 pp
• Bauer, K., S. Neben, B. Schreckenberger, R. Emmermann, K. Hinz, N. Fechner, K. Gohl, A. Schulze, R.B. Trumbull, and K. Weber, Deep structure of the Namibia continental margin as derived from integrated geophysical studies.(2000): J. Geophys. Res., 105(B11), 25829-25853