Evolution of rifting in Africa

Abstract

WHILE not disagreeing with Girdler et al.'s basic premise of thinning and breaking up of the African plate, I cannot see how the increase in age of rift faulting and vulcanicity of the East African rift valleys away from the rift can be compared with the increase in age of islands on the oceanic floor away from mid-oceanic ridges. The latter phenomena can be explained by crustal movement away from the mid-oceanic ridge, which remains the centre of seismic activity, whereas in East Africa there is certainly no corresponding increase in age of rocks away from the rift valleys. Could not the apparent increase in age of seismic activity away from the centres of the rift valleys be explained more simply ? © 1970 Nature Publishing Group.