Gradients in the interpretation of satellite-altitude magnetic data: an example from central Africa

The Euler and the analytic signal methods have been implemented in spherical coordinates to facilitate the interpretation of spherically-registered potential-field anomaly data collected by satellites. Model studies show that the methods are able to delineate the edges of idealized models even from 400 km altitude; the depth resolution is, however, not adequate from this altitude. A very large magnetic anomaly, the Bangui anomaly in central Africa, was studied using these methods. These results, from Magsat data, suggest that impact related remagnetization (Girdler, R.W.,Taylor, P.T., Frawley, J.J., 1992, A possible impact origin for the Bangui magnetic anomaly (Central Africa), Tectonophysics, 212, 45–58) and presence of a highly magnetic source (Ravat, D., Hinze, W.J., von Frese, R.R.B., 1992, Analysis of Magsat magnetic contrasts across Africa and South America. Tectonophysics 212, 59–76) near the center of the impact structure are likely contributors to the anomaly.