Topic summary
Scotia plate
The Scotia plate (Spanish: Placa Scotia) is a minortectonic plate on the edge of the South Atlantic and Southern oceans. Thought to have formed during the late Eocene with the opening of the Drake Passage that separates Antarctica and South America, it is a minor plate whose movement is largely controlled by the two major plates that surround it: the Antarctic plate and the South American plate. The Scotia plate takes its name from the steam yachtScotia of the (1902–04), the expedition that made the first bathymetric study of the region.
Roughly rhomboid, extending between 50°S70°W / 50°S 70°W and 63°S20°W / 63°S 20°W, the plate is 800 km (500 mi) wide and 3,000 km (1,900 mi) long. It is moving WSW at 2.2 cm (0.87 in)/year and the South Sandwich plate is moving east at 5.5 cm (2.2 in)/year in an absolute reference frame. Its boundaries are defined by the East Scotia Ridge, the North Scotia Ridge, the South Scotia Ridge, and the Shackleton fracture zone.
The Scotia plate is made of oceanic crust and continentalfragments now distributed around the Scotia Sea. Before the formation of the plate began 40 million years ago (40Ma), these fragments were at least partly exposed above the water, and formed a continuous landmass from Patagonia to the Antarctic Peninsula along an active subduction margin. It served as one end of the Antarctic land bridge, a wider land bridge that connected South America, Antarctica, and Australia. At present, the plate is almost completely submerged, with only the small exceptions of South Georgia on its northeastern edge and the southern tip of South America.