The East African Rift is a 6,500-kilometer fracture in the earth’s surface that stretches from Jordan to Mozambique; it is caused by three plates pulling apart from each other—the Nubian plate, the Somalian plate, and the Arabian plate. Beginning around 800 million years ago, tectonic activity in the rift caused ocean water to enter an enclosed basin in the Copper Belt region. Most of the ocean water evaporated, but some of the saline fluids circulated into the sediments within the basin and stripped metals from them, including copper and cobalt.
