a major tectonic division of the earth's crust, comprising the African continent as well as adjacent ocean basins (the Canary, Cape Verde, Angola, Cape Agulhas, Somali, Madagascar, and Natal Basins), and bounded on the north by the Eurasian and Arabian Plates, on the east by mid-ocean ridges (the Southwest Indian, Mid-Indian, and Carlsberg Ridges), on the south by the Antarctic Plate, and on the west by the Mid-Atlantic Ridge