My Blogs (olelog) are mainly based on my daily reading of earth science news.
Here on whatonearth.olehnielsen.dk I try to weave some of the pieces together to a greater whole with added background info.
The Sandwich Plate (sometimes called the "South Sandwich Plate") is a tectonic plate under the Scotia Sea near Antarctica.
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.
CIA map of the South Sandwich Islands.
The South Sandwich Islands consist of a chain of eleven main islands that bend in an arc ~400 km long. The water surrounding the volcanoes has an average depth of about 2.600 m. These volcanic islands are west of the South Sandwich trench. The South Sandwich Islands are a volcanic island arc caused by the subduction of the South American Plate beneath the South Sandwich Plate. The South Sandwich plate is one of the smallest geologic plates and is created at the South Sandwich (back-arc) spreading center. This small plate is less than 8 million years old and moves to the east at about 7 cm per year. The volcanic arc is younger than 5 million years.
The East Scotia Ridge is an active back-arc spreading centre located
to the west of the South Sandwich island arc in the South Atlantic Ocean.
Image from USGS
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