Get your minds out of the delicatessen, you sickos. The Sandwich Plate (sometimes called the "South Sandwich Plate") is a tectonic plate under the Scotia Sea near Antarctica. Stop laughing.

As Antarctica broke away from the tip of South America 30 million years ago, the South Sandwich Arc began its march out into the South Atlantic, forming and carrying the South Sandwich Islands along with it, and dragging the Scotia Plate behind. The eastern portion of the Scotia Plate broke away about 10 million years ago in a process called back-arc rifting. The Scotia Plate and the Sandwich Plate spread apart at the East Scotia Ridge; 200 km to the east at the South Sandwich Trench, the South American Plate still subducts beneath this tiny new plate.

   S o u t h   A m e r i c a n   P l a t e
   SGI         |        `-.o  
               |      .     `-.o  <-
     <-       |        .  .     \o
              |     ->           \o     S o u t h
   Scotia    |            *   ->  \o
 <-          '|    Sandwich        \o   <-
      Plate    |            *       |o      A t l a n t i c
               '|      Plate        |o
     <-         |            *      |o      <-
  S c o t i a  |'   S e a           |o   O c e a n
        <-     |      ->    *      /o
               '|          .  ->  /o
     <-         |    ->   *      /o   <-
               |'             .-'
               |          _.-'o

  A n t a r c t i c   P l a t e       ->
    S o u t h e r n   O c e a n
o = subduction
* = island
. - island
-> <- = plate motion

East Scotia Ridge - Back-arc basin of the South Sandwich Subduction zone

Hm. I'll have a whale sandwich with barbecued penguin wings, and a side of fried krill.