The African Plate: A history of oceanic crust accretion and subduction since the Jurassic

Abstract

We present a model for the Jurassic to Present evolution of plate boundaries and oceanic crust of the African plate based on updated interpretation of magnetic, gravity and other geological and geophysical data sets. Location of continent ocean boundaries and age and geometry of old oceanic crust (Jurassic and Cretaceous) are updated in the light of new data and models of passive margin formation. A new set of oceanic palaeo-age grid models constitutes the basis for estimating the dynamics of oceanic crust through time and can be used as input for quantifying the plate boundary forces that contributed to the African plate palaeo-stresses and may have influenced the evolution of intracontinental sedimentary basins. As a case study, we compute a simple model of palaeo-stress for the Late Cretaceous time in order to assess how ridge push, slab pull and horizontal mantle drag might have influenced the continental African plate. We note that the changes in length of various plate boundaries (especially trenches) do not correlate well with absolute plate motion, but variations in the mean oceanic crust age seem to be reflected in acceleration or deceleration of the mean absolute plate velocity.