The significance of paleomagnetic results from Africa

Abstract

Paleomagnetic results from Africa are critically reviewed and polar-wander curves are presented for the early Precambrian and for the interval from the Permian to the present. The data are shown to be consistent with the hypothesis that the dispersion of the geomagnetic field with respect to an axial geocentric dipole field was similar to its present dispersion both in the early Precambrian and in Mesozoic times. Strong evidence is presented that relative movement between Africa and the pole was slight during the Mesozoic. Similar evidence exists for Australia. Mesozoic paleomagnetic poles from the four southern continents are shown to form widely separated groups. Polar wander alone cannot account for both the divergence of the poles and the stability of the Mesozoic paleomagnetic poles relative to Africa and Australia. The results can be reconciled, however, by the supposition that relative movement has occurred between the southern continents since the Mesozoic. A Mesozoic reconstruction of Gondwanaland and also a tentative reconstruction for the Permian are proposed. These are based on the most reliable paleomagnetic results available.