Magnetic anomalies in the South Atlantic and ocean floor spreading

Magnetic profiles across the South Atlantic Ocean from the Rio Grande rise and Argentine basin to the southwest coast of Africa and between 25° and 50°S are presented. Anomalies have been correlated from profile to profile, and the resulting magnetic pattern is parallel to and symmetric about the axis of the mid-Atlantic ridge. The observed magnetic pattern in the South Atlantic Ocean is very similar to the pattern observed across the East Pacific rise in the Pacific Ocean. The results have been interpreted as supporting ocean floor spreading and the hypothesis of Vine and Matthews for the origin of the anomalous field. Possible fracture zones, the Rio Grande rise, and the Walvis ridge are discussed.