The South Shetland Trough is an undersea

trough Trough may refer to: In science * Trough (geology), a long depression less steep than a trench * Trough (meteorology), an elongated region of low atmospheric pressure * Trough (physics), the lowest point on a wave * Trough level (medicine), the l ...

located north of the

South Shetland Islands The South Shetland Islands are a group of List of Antarctic and subantarctic islands, Antarctic islands located in the Drake Passage with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the n ...

, which are a group of

Antarctic islands This is a list of Antarctic and sub-Antarctic islands. * Antarctic islands are, in the strict sense, the islands around mainland Antarctica, situated on the Antarctic Plate, and south of the Antarctic Convergence. According to the terms of the ...

. It is the remnant of a

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

zone where the defunct Phoenix Plate, now part of the Antarctic Plate, subducted under the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martin in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica. ...

and the South Shetland Islands.

References

Oceanic basins of the Southern Ocean Subduction zones {{marine-geo-stub