Anomalous geomagnetic variations on the island of South Georgia

Observations of geomagnetic variation fields on South Georgia, in the Scotia Sea, have revealed an unusual polarisation anomaly in the horizontal components, whose characteristics cannot be accounted for by an ocean-edge effect model. In addition, vertical field transfer functions have been calculated in the period range 10-10000 s. Although the data obtained from only one station allows only a limited analysis, it is suggested that the anomalous geomagnetic response on South Georgia can be accounted for by lithospheric conductivity contrasts between the Scotia and South American Plates.