Atlantic South Current

The South Atlantic occupies the lower section of the Atlantic’s elongated basin, reaching from the equatorial divide toward the southern ocean. Africa lies to the east and South America to the west. Unlike a narrow strait, this is a broad area of open water with room for several deep basins, long ridges and currents whose paths cross much of the hemisphere.

Geologically, the basin formed as West Gondwana broke apart in the Early Cretaceous. Seafloor spreading separated South America and Africa, while the Mid-Atlantic Ridge became the boundary between their plates. The ridge divides the Atlantic lengthwise, but it is not a single unbroken wall: transform faults cross it, and secondary ridges delimit basins on either side. The Walvis Ridge and Rio Grande Rise project across the South Atlantic floor and obstruct currents. These features create deep passages and partial barriers even where the surface seems continuous.

The great subtropical circulation covers this structure with a broad, anti-cyclonic gyre. South Atlantic water turns counter-clockwise under the influence of the Coriolis effect. South Atlantic Central Water belongs to this upper system, while Antarctic Intermediate Water is formed farther south near the Drake Passage and the Falkland Islands. Beneath the thermocline, North Atlantic Deep Water continues southward. The southern basin thus links equatorial waters, southern origin regions and deep return flows within one large oceanic circuit.