Middle Jurassic to Lower Cretaceous

By mid-Jurassic times, large complex depocentres had begun to develop along what were later to become the continental margins of southern Africa, and today, mid-Jurassic-Cretaceous sediments are known only from the coastal fringes and under the continental shelf and slope ( Fig.65 ). This radical shift in depocentres from a previous mid-continental location, was accomplished by horst and graben development (taphrogenic tectonics) around the edges of the old cratonic blocks, and ultimately led to the breakup of this part of Gondwanaland. Farther north (in Somalia, Kenya, Tanzania and Madagascar), taphrogenic structures had started to develop in late Permian time, and in Tanzania and Madagascar, up to 9 km of shallow marine Permo-Triassic rocks occur in narrow coastal basins ( Kent 1974 ). Figures 65 and 67 show the distribution of Jurassic-Cretaceous strata around southern Africa.