- The South Sandwich Plate or the Sandwich Plate is a small tectonic plate (microplate) bounded by the subducting South American Plate to the east, the Antarctic Plate to the south, and the Scotia Plate to the west. The plate is separated from the Scotia Plate by the East Scotia Rise, a back-arc spreading ridge formed by the subduction zone on its eastern margin. The South Sandwich Islands are located on this microplate.