The geomagnetic field pattern in the vicinity of Georg Forster station, Antarctica, is discussed. Induced magnetization is assumed to model the regional minimum in the total field intensity (MAGSAT) located here, and an associated anomalous body at a depth of 50 km is calculated and interpreted. This model is, however, discounted in favour of a cross section derived from a meridional ground magnetic profile recorded over a distance of about 200 km. The most striking features of the profile are positive anomalies over the ice shelf which are explained by dykes of basic rocks emanating from the lower crust and from the mantle. The derived crustal structure reflects a transition from continental crust to transitional type crust.