GEOPHYSICAL PROFILE OF THE ROTER-KAMM IMPACT CRATER, NAMIBIA

New gravity and magnetic data were obtained along ground profiles acro ss the Roter Kamm impact crater in the southern Namib desert of Namibi a. As the traverses of previous studies did not extend sufficiently be yond the crater rim, it had not been possible to adequately determine the regional background values. The gravity results of this study are similar to those obtained by Fudali in 1973, in that a negative, near- symmetrical anomaly was obtained over the crater center. This anomaly conforms to the results expected for a sediment and impact breccia-fil led, simple bowl-shaped crater. The magnetic results of this study, ho wever, are different to those previously reported, which is most proba bly as a result of the longer profiles used in this new study. A Sligh t positive magnetic anomaly was obtained over the crater interior. Sho rt-wavelength, high-amplitude anomalies observed in the vicinity of th e crater rim reflect magnetization contrasts that are probably related to brecciation and block rotation. Modelling of the positive magnetic anomaly indicates the possibility of a small magnetic body or lining at the crater floor-breccia interface in the interior of the crater. A lso presented is a 10 m contour digital elevation model of the crater and its environs.