The north and south boundaries of the plate are transform fault boundaries. At the eastern margin the Scotia has a spreading boundary between it and the small South Sandwich Plate. The South American Plate is subducting under east side of the South Sandwich Plate, which is thought to have brought about its separation from the Scotia Plate, starting as backarc spreading. The western boundary with the Antarctic plate is a complex and rather ill-defined boundary.
There is some speculation that the westward motion of the South American Plate may have forced the Caribbean and Scotia Plates at its northern and southern ends respectively to squeeze around it. Both share a similar shape and are bounded along their eastern side by a subducting part of the South American Plate .[1]
