Britannica Sources used in this answer

How did the South Atlantic Ocean form?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Permian paleogeography — Pangea Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins near the end of the Permian Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

The South Atlantic Ocean formed as a result of the fragmentation of the supercontinent Pangea during the Mesozoic Era.1

Approximately 140 million years ago, the landmasses of Africa and South America—which were previously joined as part of the larger supercontinent Gondwana—began to separate. This rifting process initiated the formation of new oceanic crust between the two continents, effectively opening the South Atlantic basin.123

This separation is a key stage in the supercontinent cycle, where plate tectonics drive the movement of rigid lithospheric plates. The geological evidence for this historical connection is supported by the striking similarity in the age and composition of Precambrian crystalline massifs found on the opposing coasts of South America and Africa, as well as the impressive fit of their continental margins.234