A Discussion on global tectonics in Proterozoic times - Pan- African Structures

Abstract

A large proportion of the African Crust yields Pan-African radiometric ages (650-450 Ma). The Pan-African domains form a network of mobile belts surrounding cratons which remained relatively stable, cool and undeformed. The crust in the Pan-African domains had a similar previous history to that in the cratons. There is no process of cratonization and no progressive increase in cratonic dimensions, only a progressive reduction in the area unaffected by successive deformations. Neither tectonic, structural, stratigraphic or palaeomagnetic data suggest large-scale plate motions. No convincing ophiolites or sutures have been recognized within the Pan-African domains. In situ deformation rather than collision orogeny seems probable.