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-Atlantic Ridge.

The easterly edge is a divergent boundary with the African Plate; the southerly edge is a complex boundary with the Antarctic Plate, the Scotia Plate, and the Sandwich Plate; the westerly edge is a convergent boundary with the subducting Nazca Plate; and the northerly edge is a boundary with the Caribbean Plate and the oceanic crust of the North American Plate. At the Chile Triple Junction, near the west coast of the TaitaoTres Montes Peninsula, an oceanic ridge known as the Chile Rise is actively subducting under the South American Plate.

Geological research suggests that the South American Plate is moving westward away from the Mid-Atlantic Ridge: "Parts of the plate boundaries consisting of alternations of relatively short transform fault and spreading ridge segments are represented by a boundary following the general trend."[2] As a result, the eastward-moving and more dense Nazca Plate is subducting under the western edge of the South American Plate, along the continent's Pacific coast, at a rate of 77 mm (3.0 in) per year.[3] The collision of these two plates is responsible for lifting the massive Andes Mountains and for creating the numerous volcanoes which are strewn throughout them.[4][5]

South American Plate
The South American Plate
TypeMajor
Approximate area43,600,000 km2 (16,800,000 sq mi)[1]
Movement1West
Speed127–34 mm (1.1–1.3 in)/year
FeaturesSouth America, Atlantic Ocean
1Relative to the African Plate

See also

References

  1. ^ "Here are the Sizes of Tectonic or Lithospheric Plates". about.com. Retrieved 6 April 2018.
  2. ^ Meijer, P.T.; Wortel, M.J.R. (July 30, 1992). "The Dynamics of Motion of the South American Plate". Journal of Geophysical Research. 97: 11915. Bibcode:1992JGR....9711915M. doi:10.1029/91jb01123.
  3. ^ Pisco, Peru, Earthquake of August 15, 2007: Lifeline Performance. Reston, VA: ASCE, Technical Council on Lifeline Earthquake Engineering. ISBN 9780784410615. Archived from the original on November 14, 2012.
  4. ^ "Convergent Plate Boundaries - Oceanic/Continental: The Andes". The Geological Society. Retrieved 2 July 2018.
  5. ^ Penvenne, Laura Jean (27 January 1996). "South America buckles under the pressure". New Scientist. Retrieved 2 July 2018.
Antarctic Plate

The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau and extending outward under the surrounding oceans. After breakup from Gondwana (the southern part of the supercontinent Pangea), the Antarctic plate began moving the continent of Antarctica south to its present isolated location causing the continent to develop a much colder climate. The Antarctic Plate is bounded almost entirely by extensional mid-ocean ridge systems. The adjoining plates are the Nazca Plate, the South American Plate, the African Plate, the Somali Plate, the Indo-Australian Plate, the Pacific Plate, and, across a transform boundary, the Scotia Plate.

The Antarctic Plate has an area of about 60,900,000 km2 (23,500,000 sq mi). It is the Earth's fifth-largest plate.

The Antarctic Plate's movement is estimated to be at least 1 cm (0.4 in) per year towards the Atlantic Ocean

Caribbean Plate

The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the north coast of South America.

Roughly 3.2 million square kilometers (1.2 million square miles) in area, the Caribbean Plate borders the North American Plate, the South American Plate, the Nazca Plate and the Cocos Plate. These borders are regions of intense seismic activity, including frequent earthquakes, occasional tsunamis, and volcanic eruptions.

Carnegie Ridge

The Carnegie Ridge is an aseismic ridge on the Nazca Plate that is being subducted beneath the South American Plate. The ridge is thought to be a result of the passage of the Nazca Plate over the Galapagos hotspot. It is named for the research vessel Carnegie, which discovered it in 1929.

Chile Rise

The Chile Rise or Chile Ridge is an oceanic ridge, a tectonic divergent plate boundary between the Nazca and Antarctic plates. Its eastern end is the Chile Triple Junction where the Chile Rise is being subducted below the South American Plate in the Peru–Chile Trench. It runs westward to a triple point south of the Juan Fernández Microplate where it intersects the East Pacific Rise.

The Chile Rise subducts near Taitao Peninsula where Taitao ophiolite and other geolical features are associated to the interactions at the triple junction.

Chile Triple Junction

The Chile Triple Junction (or Chile Margin Triple Junction) is a geologic triple junction located on the seafloor of the Pacific Ocean off Taitao and Tres Montes Peninsula on the southern coast of Chile. Here three tectonic plates meet: the South American Plate, the Nazca Plate, and the Antarctic Plate. This triple junction is unusual in that it consists of a mid-oceanic ridge, the Chile Rise, being subducted under the South American Plate at the Peru–Chile Trench.

The Antarctic Plate started to subduct beneath South America 14 million years ago in the Miocene epoch forming the Chile Triple Junction. At first the Antarctic Plate subducted only in the southernmost tip of Patagonia, meaning that the Chile Triple Junction lay near the Strait of Magellan. As the southern part of Nazca Plate and the Chile Rise became consumed by subduction the more northerly regions of the Antarctic Plate begun to subduct beneath Patagonia so that the Chile Triple Junction advanced gradually to its present position in front of Taitao Peninsula at 46°15’.Taitao Peninsula lies near the triple junction and various geological features, such as the Taitao ophiolite, are related to the dynamics of the triple junction.

Geology of Colombia

Geology of Colombia refers to the geological composition of the Republic of Colombia that determines its geography. Most of the emerged territory of Colombia covers vast areas within the South American plate, whereas much submerged territory lies within the Caribbean plate and the Nazca plate.

Leeward Antilles

The Leeward Antilles (Dutch: Benedenwindse Eilanden) are a chain of islands in the Caribbean – specifically, the southerly islands of the Lesser Antilles (and, in turn, the Antilles and the West Indies) along the southeastern fringe of the Caribbean Sea, just north of the Venezuelan coast of the South American mainland. The Leeward Antilles, while among the Lesser Antilles, are not to be confused with the Leeward Islands (also of the Lesser Antilles) to the northeast.

Largely lacking in volcanic activity, the Leeward Antilles island arc occurs along the deformed southern edge of the Caribbean Plate and was formed by the plate's subduction under the South American Plate. Recent studies indicate that the Leeward Antilles are accreting to South America.

Lesser Antilles subduction zone

The Lesser Antilles subduction zone is a convergent plate boundary on the seafloor along the eastern margin of the Lesser Antilles island arc. In this subduction zone, oceanic crust of the South American Plate is being subducted under the Caribbean Plate.

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.

Magallanes-Fagnano Fault

The Magallanes–Fagnano Fault (Spanish: Falla Fagnano–Magallanes) is a continental transform fault. The fault marks a transform boundary between the Scotia Plate and the South American Plate, cutting across continental crust. It runs under the Strait of Magellan's western arm, Almirantazgo Sound and Fagnano Lake.

It has been suggested that the Magallanes-Fagnano Fault is a reactivated suture of pre-Jurassic age separating the basement of two terranes.

Megathrust earthquake

Megathrust earthquakes occur at subduction zones at destructive convergent plate boundaries, where one tectonic plate is forced underneath another, caused by slip along the thrust fault that forms the contact between them. These interplate earthquakes are the planet's most powerful, with moment magnitudes (Mw) that can exceed 9.0. Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes. No other type of known terrestrial source of tectonic activity has produced earthquakes of this scale.

Nazca Plate

The Nazca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru–Chile Trench, of the Nazca Plate under the South American Plate is largely responsible for the Andean orogeny. The Nazca Plate is bounded on the west by the Pacific Plate and to the south by the Antarctic Plate through the East Pacific Rise and the Chile Rise respectively. The movement of the Nazca Plate over several hotspots has created some volcanic islands as well as east-west running seamount chains that subduct under South America. Nazca is a relatively young plate both in terms of the age of its rocks and its existence as an independent plate having been formed from the break-up of the Farallon Plate about 23 million years ago. The oldest rocks of the plate are about 50 million years old.

North Andes Plate

The North Andes Plate is a small tectonic plate located in the northern Andes. It is squeezed between the faster moving South American Plate and the Nazca Plate. Due to the subduction of the Nazca Plate this area is very prone to volcanic and seismic activity.

Oca-Ancón Fault System

The Oca-Ancón Fault System (Spanish: Falla Oca-Ancón) is a complex of geological faults located in the northeastern Colombia and northwestern Venezuela near the Caribbean Sea. The fault system is of right-lateral strike-slip type and extends for an approximate length of 830 km (520 mi). The Oca-Ancón Fault System is part of the diffuse boundary between the Caribbean Plate and the South American Plate. The movement rate of the Oca-Ancón Fault System is estimated at 2 millimetres (0.079 in) each year, more than most Venezuelan faults.

Pampia

Pampia was an ancient microcontinent or terrane that collided with Río de la Plata Craton and Río Apas Craton during the Pampean orogeny of late Proterozoic and early Cambrian. It was one of the first terranes to be amalgamated to the old cratons of the east, and was followed by the suturing of Cuyania and Chilenia terranes into the young South American Plate.

Peru–Chile Trench

The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about 160 kilometres (100 mi) off the coast of Peru and Chile. It reaches a maximum depth of 8,065 meters (26,460 ft) below sea level in Richards Deep (23°10′45″S 71°18′41″W) and is approximately 5,900 kilometres (3,666 mi) long; its mean width is 64 kilometres (40 mi) and it covers an expanse of some 590,000 square kilometres (228,000 mi²).

The trench delineates the boundary between the subducting Nazca Plate and the overriding South American Plate.

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 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.

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Tectonics of South America
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