The South Sandwich plate or the Sandwich plate (not to be confused with a culinary

sandwich A sandwich is a Dish (food), dish typically consisting variously of meat, cheese, sauces, and vegetables used as a filling between slices of bread, or placed atop a slice of bread; or, more generally, any dish in which bread serves as a ''co ...

plate) is a small

tectonic plate Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

( microplate) bounded by the subducting

South American plate The South American plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African plate, with which it forms the southern part of the Mid ...

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. The initiation of the South Sandwich subduction zone, a convergent plate margin, began around 66 million years ago in response to regional convergence of the

Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...

and

South American South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

tectonic plates. Gradual extension of the Scotia Sea and subduction roll back of South American oceanic

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time ...

created the ancestral Scotia plate. The South Sandwich Microplate separated from the Scotia plate around 15 million years ago as a back arc basin formed with development of the East Scotia Rise. There is continued debate over the reason for the separation of the South Sandwich plate from the Scotia plate. Two primary mechanisms have been proposed, subducting slab roll back and absolute motion of the Scotia plate away from the trench. A combination of these two mechanisms could also contribute to the current plate boundary configurations.

References

Citations

* Kurt Stüwe: ''Geodynamics of the Lithosphere: An Introduction'' Springer; 2nd edition (2007) p390

External links

The South Sandwich Microplate
Tectonic plates Geology of the Atlantic Ocean {{Tectonics-stub