Significant Relative Motion Research Articles

Summary Samples collected from three Jurassic igneous formations in South Morocco carry a stable component of magnetic remanence, giving a mean palaeomagnetic pole-position at 61° S, 71° E, A95= 14°. Two of the formations were situated in the stable Saharan Shield region, and one within the Central High Atlas fold-belt. There is no systematic difference between the pole-positions derived from these two regions of contrasting tectonic history, and furthermore, no significant difference between the mean Jurassic pole-position for Morocco and that for South-east Africa. It is concluded that no significant post-Jurassic relative motion has occurred between NW and SE Africa. Two of the formations studied were previously thought to be Upper Palaeozoic, but radiometric age determinations presented in this paper give consistent values of between 181 and 187 My. These results indicate the occurrence of a widespread episode of Jurassic igneous activity, producing structures which frequently parallel the coastline, and are possibly related to the break-up and dispersal of the fragments of Pangaea during the Mesozoic.

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