South Sandwich Plate

The South Sandwich Plate or Sandwich Plate is a minor tectonic plate bounded by the subducting South American Plate 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 small plate.

South Sandwich Plate
The Sandwich Plate
TypeMinor
Approximate area170,000 km2[1]
Movement1east
Speed147mm/year
FeaturesSouth Sandwich Islands, Southern Ocean
1Relative to the African Plate
East Scotia Ridge vents map
Map of South Sandwich Plate (SAN) shows its position between the Scotia Plate (SCO), South American Plate (SAM) and the Antarctic Plate (ANT). There are also visible The East Scotia Ridge (ESR), South Sandwich Islands (SSI) and the South Sandwich Trench (SST).

References

  1. ^ "Sizes of Tectonic or Lithospheric Plates". 2014-03-05. Retrieved 2016-05-15.
Gigantopelta chessoia

Gigantopelta chessoia is a species of deep sea snail from hydrothermal vents, a marine gastropod mollusk in the family Peltospiridae.

Hoff crab

The "Hoff crab" (Kiwa tyleri) is a species of deep-sea squat lobster in the family Kiwaidae, which lives on hydrothermal vents near Antarctica. The crustacean was given its English nickname in 2010 by UK deep-sea scientists aboard the RRS James Cook, owing to resemblance between its dense covering of setae on the ventral surface of the exoskeleton and the hairy chest of the actor David Hasselhoff. The 2010 expedition to explore hydrothermal vents on the East Scotia Ridge was the second of three expeditions to the Southern Ocean by the UK led research consortium, ChEsSo (Chemosynthetic Ecosystems of the Southern Ocean).

Lepetodrilus sp. East Scotia Ridge

Lepetodrilus sp. East Scotia Ridge (nomen nudum) is an as yet undescribed species of small, deep-sea sea snail, a hydrothermal vent limpet, a marine gastropod mollusk in the family Lepetodrilidae.

The first information about this species, under the name "Lepetodrilus n. sp.", was published on 3 January 2012.

List of tectonic plate interactions

Tectonic plate interactions are of three different basic types:

Divergent boundaries are areas where plates move away from each other, forming either mid-oceanic ridges or rift valleys. These are also known as constructive boundaries.

Convergent boundaries are areas where plates move toward each other and collide. These are also known as compressional or destructive boundaries.

Subduction zones occur where an oceanic plate meets a continental plate and is pushed underneath it. Subduction zones are marked by oceanic trenches. The descending end of the oceanic plate melts and creates pressure in the mantle, causing volcanoes to form.

Obduction occurs when the continental plate is pushed under the oceanic plate, but this is unusual as the relative densities of the tectonic plates favours subduction of the oceanic plate. This causes the oceanic plate to buckle and usually results in a new mid ocean ridge forming and turning the obduction into subduction

Orogenic belts occur where two continental plates collide and push upwards to form large mountain ranges. These are also known as collision boundaries.

Transform boundaries occur when two plates grind past each other with only limited convergent or divergent activity.

List of tectonic plates

This is a list of tectonic plates on the Earth's surface. Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). The composition of the two types of crust differs markedly, with mafic basaltic rocks dominating oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks.

Scotia Plate

The Scotia Plate (Spanish: Placa Scotia) is a tectonic plate on the edge of the South Atlantic and Southern Ocean. Thought to have formed during the early Eocene with the opening of the Drake Passage that separates South America from Antarctica, it is a minor plate whose movement is largely controlled by the two major plates that surround it: the South American Plate and Antarctic Plate.Roughly rhomboid, extending between 50°S 70°W and 63°S 20°W, the plate is 800 km (500 mi) wide and 3,000 km (1,900 mi) long. It is moving WSW at 2.2 cm (0.87 in)/year and the South Sandwich Plate is moving east at 5.5 cm (2.2 in)/year in an absolute reference frame. It takes its name from the steam yacht Scotia of the Scottish National Antarctic Expedition (1902–04), the expedition that made the first bathymetric study of the region.The Scotia Plate is made of oceanic crust and continental fragments now distributed around the Scotia Sea. Before the formation of the plate began 40 million years ago (40Ma), these fragments formed a continuous landmass from Patagonia to the Antarctic Peninsula along an active subduction margin. At present the plate is almost completely submerged, with only the small exceptions of the South Georgia Islands on its northeastern edge and the southern tip of South America.

South American–Antarctic Ridge

The South American–Antarctic Ridge (SAAR or AAR) is the tectonic spreading center between the South American Plate and the Antarctic Plate. It runs along the sea-floor from the Bouvet Triple Junction in the South Atlantic Ocean south-westward to a major transform fault boundary east of the South Sandwich Islands. Near the Bouvet Triple Junction the spreading half rate is 9 mm/a (0.35 in/year), which is slow, and the SAAR has the rough topography characteristic of slow-spreading ridges.

South Sandwich Trench

The South Sandwich Trench is a deep arcuate trench in the South Atlantic Ocean lying 100 kilometres (62 mi) to the east of the South Sandwich Islands. The trench is produced by the subduction of the southernmost portion of the South American Plate beneath the small South Sandwich Plate. The South Sandwich Islands constitute a volcanic island arc which results from this active subduction. Mount Belinda on Montagu Island is an active volcano.

It is the deepest trench of the Southern Atlantic Ocean, and the second deepest of the Atlantic Ocean after the Puerto Rico Trench.

The trench is 965 kilometres (600 mi) long and has a maximum depth of 8,266 metres (27,119 ft) below sea level at 55°13.47′S 26°10.23′W, as measured by a Kongsberg EM124 multibeam sonar from February 2–7, 2019 during the Five Deeps Expedition. This measurement was made during the first complete sonar mapping of the trench which covered its entire length, with a measurement error of +/- 11 metres (36 ft). It is noteworthy that the deepest point of the South Sandwich Trench is only 110 metres (361 ft) shallower than the deepest point in the Puerto Rico Trench, which hosts the deepest point in the Atlantic at the Brownson Deep.

The deepest point in the entire trench is the Meteor Deep, whose location prior to February 2019 was identified as 55°25.12′S 026°24.28′W at a depth of 8,202 metres (26,909 ft). This deepest point was originally named after HMS Meteor, which first surveyed the area in 1926.

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