Concept

Plaque Scotia

Résumé
The Scotia Plate (Placa Scotia) is a tectonic plate on the edge of the South Atlantic and Southern oceans. Thought to have formed during the early Eocene with the opening of the Drake Passage that separates South America from Antarctica, it is a minor plate whose movement is largely controlled by the two major plates that surround it: the South American Plate and the Antarctic Plate. The Scotia Plate takes its name from the steam yacht Scotia of the Scottish National Antarctic Expedition (1902–04), the expedition that made the first bathymetric study of the region. Roughly rhomboid, extending between and , the plate is wide and long. It is moving WSW at /year and the South Sandwich Plate is moving east at /year in an absolute reference frame. The Scotia Plate is made of oceanic crust and continental fragments now distributed around the Scotia Sea. Before the formation of the plate began (40Ma), these fragments formed a continuous landmass from Patagonia to the Antarctic Peninsula along an active subduction margin. At present, the plate is almost completely submerged, with only the small exceptions of South Georgia Island on its northeastern edge and the southern tip of South America. Together with the Sandwich Plate, the Scotia Plate joins the southernmost Andes to the Antarctic Peninsula, just like the Caribbean Plate joins the northernmost Andes to North America, and these two plates are comparable in several ways. Both have volcanic arcs at their eastern ends, the South Sandwich Islands on the Sandwich Plate and the Lesser Antilles on the Caribbean Plate, and both plates also had a major impact on global climate when they closed the two major gateways between the Pacific and Atlantic Oceans during the Mesozoic and Cenozoic. The northern edge of the Scotia Plate is bounded by the South American Plate, forming the North Scotia Ridge. The North Scotia ridge is a left-lateral, or sinistral, transform boundary with a transform rate of roughly 7.1 mm/yr. The Magallanes–Fagnano Fault is passing through Tierra del Fuego.
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