PALEOPROTEROZOIC NEOPROTEROZOIC NORTH-AMERICA AUSTRALIA LINK - NEW EVIDENCE FROM PALEOMAGNETISM

Comparison of a new approximately 1700-1600 Ma segment of the Proteroz oic apparent polar wander path (APWP) for Australia with the time-equi valent segment of the North American APWP that has been rotated clockw ise by 117-degrees about the Euler pole, long 100-degrees-E, lat 38-de grees-N, superposes the North American APWP onto the Australian APWP a nd shows the segments to be similar. The same rotation makes the Pacif ic margins of the North American and Australian cratons adjacent, as p redicted by the Southwest U.S.-East Antarctic (SWEAT) hypothesis, but North America is located farther north relative to Australia than orig inally suggested. However, the reconstruction is consistent with the i dentification of western sediment sources for the Belt-Purcell basin i n western North America, with matching of basement provinces, and with correlation of major lineaments of the two continents. The rotation g ives only very broad agreement between the younger Proterozoic pole se ts. This is probably partly due to the sparseness of poles on the Aust ralian APWP whereby prominent features that are found on the North Ame rican APWP, such as the Grenville loop, are eliminated on the Australi an path by smoothing. Nevertheless, some discrepancies between the you nger Proterozoic poles cannot be accounted for without revision of the APWPs.