10. Regional Metamorphism
To maintain the sustained unidirectional movement of Pangea northwards followed by the east and westward movements of crustal plates either side of the central part of the African plate, the applied forces have to be both substantial and have a stable permanent origin. It is this requirement that will cause the relative movement of the continental crust, with its variable underside topography, to be forced over the almost mountainous terrains of the oceanic crust. The resistance to motion will result in a plethora of metamorphic processes varying from high- and low-pressure water rejection, to high pressure/high temperature regional metamorphism that would change the crystal structure of the rocks involved. This is in addition to the pushing, tilting, deformation, and uplift of sedimentary sequences from their original horizontal position thus forming the mountain ranges we are now familiar with. The forces associated with the above-mentioned processes would need to be evaluated in conjunction with laboratory simulations and reported field observations to determine the realistic value of the Circumferential Force F and the applied pressure loads at the specific locations. These processes are illustrated in Fig 19.