Earth:List of tectonic plates

From HandWiki
Short description: Overview of different types of tectonic plates
Map of sixteen of Earth's tectonic plates, showing plate boundary types:
Divergent:
  Spreading center
  Extension zone
Convergent: Transform:
  Dextral transform
  Sinistral transform
Plate tectonics map from NASA

This is a list of tectonic plates on 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.

Current plates

Geologists generally agree that the following tectonic plates currently exist on Earth's surface with roughly definable boundaries. Tectonic plates are sometimes subdivided into three fairly arbitrary categories: major (or primary) plates, minor (or secondary) plates, and microplates (or tertiary plates).[1]

Major plates

Map showing Earth's principal tectonic plates and their boundaries in detail

These plates comprise the bulk of the continents and the Pacific Ocean. For purposes of this list, a major plate is any plate with an area greater than 20 million km2.

  • Earth:African Plate – Tectonic plate underlying Africa – 61,300,000 km2
  • Earth:Antarctic Plate – Major tectonic plate containing Antarctica and the surrounding ocean floor – 60,900,000 km2
  • Earth:Eurasian Plate – Tectonic plate which includes most of the continent of Eurasia – 67,800,000 km2
  • Earth:Indo-Australian Plate – A major tectonic plate formed by the fusion of the Indian and the Australian plates (sometimes considered to be two separate tectonic plates) – 58,900,000 km2
    • Earth:Australian Plate – Major tectonic plate separated from Indo-Australian Plate about 3 million years ago – 47,000,000 km2
    • Earth:Indian Plate – Minor plate that separated from Gondwana – 11,900,000 km2
  • Earth:North American Plate – Large tectonic plate including most of North America, Greenland and part of Siberia – 75,900,000 km2
  • Earth:Pacific Plate – Oceanic tectonic plate under the Pacific Ocean – 103,300,000 km2
  • Earth:South American Plate – Major tectonic plate which includes most of South America and a large part of the south Atlantic – 43,600,000 km2

Minor plates

These smaller plates are often not shown on major plate maps, as the majority of them do not comprise significant land area. For purposes of this list, a minor plate is any plate with an area less than 20 million km2 but greater than 1 million km2.

Microplates

These plates are often grouped with an adjacent principal plate on a tectonic plate world map. For purposes of this list, a microplate is any plate with an area less than 1 million km2. Some models identify more minor plates within current orogens (events that lead to a large structural deformation of Earth's lithosphere) like the Apulian, Explorer, Gorda, and Philippine Mobile Belt plates. [2] One study has theorized that microplates may be the basic elements of which the crust is composed. [3]

  • African Plate
    • Earth:Lwandle Plate – Mainly oceanic tectonic microplate off the southeast coast of Africa
    • Earth:Rovuma Plate – One of three tectonic microplates that contribute to the Nubian Plate and the Somali Plate
  • Antarctic Plate
  • Nazca Plate
    • Earth:Coiba Plate – Tectonic plate off the coast south of Panama and northwestern Colombia
    • Earth:Malpelo Plate – A small tectonic plate off the coast west of Ecuador and Colombia
  • South American Plate

Ancient tectonic plates

In the history of Earth, many tectonic plates have come into existence and have over the intervening years either accreted onto other plates to form larger plates, rifted into smaller plates, or have been crushed by or subducted under other plates.

The following is a list of ancient cratons, microplates, plates, and terranes which no longer exist as separate plates. Cratons are the oldest and most stable parts of the continental lithosphere, and shields are exposed parts of them. Terranes are fragments of crustal material formed on one tectonic plate and accreted to crust lying on another plate, which may or may not have originated as independent microplates: a terrane may not contain the full thickness of the lithosphere.

African Plate

  • Earth:Atlantica – Ancient continent formed during the Proterozoic about 2 billion years ago
  • Earth:Congo Craton – Precambrian craton that with four others makes up the modern continent of Africa (Angola, Cameroon, Central African Republic, Democratic Republic of Congo, Gabon, Sudan, and Zambia)
  • Earth:Kalahari Craton – African geological area (South Africa)
  • Earth:Saharan Metacraton – Large area of continental crust in the north-central part of Africa (Algeria)
  • Earth:Tanzania Craton – Old and stable part of the continental lithosphere in central Tanzania (Tanzania)
  • Earth:West African Craton – One of the five cratons of the Precambrian basement rock of Africa that make up the African Plate (Algeria, Benin, Burkina Faso, Côte d'Ivoire, Gambia, Ghana, Guinea, Guinea Bissau, Liberia, Mali, Mauritania, Morocco, Nigeria, Senegal, Sierra Leone, and Togo)
  • Zaire Craton (Congo)

Antarctic Plate

Eurasian Plate

Indo-Australian Plate

Basic geological regions of Australia, by age
Map of chronostratigraphic divisions of India

North American Plate

North American cratons and basement rocks
  • Earth:Avalonia – Microcontinent in the Paleozoic era (Canada, Great Britain, and United States)
  • Earth:Churchill Craton – Northwest section of the Canadian Shield from southern Saskatchewan and Alberta to northern Nunavut (Canada)
  • Earth:Farallon Plate – Ancient oceanic plate that has mostly subducted under the North American Plate (split into the Cocos, Explorer, Juan de Fuca, Gorda Plates, Nazca Plate, and Rivera Plates)
  • Earth:Hearne Craton – Craton in northern Canada (Canada)
  • Laurentian Craton, also known as North American Craton – A large continental craton that forms the ancient geological core of the North American continent (Canada and United States)
  • Earth:Insular Plate – Ancient oceanic plate
  • Earth:Intermontane Plate – Ancient oceanic tectonic plate on the west coast of North America about 195 million years ago
  • Earth:Izanagi Plate – Ancient tectonic plate, which was subducted beneath the Okhotsk Plate
  • Mexican Plate
  • Earth:Nain Province – Part of the North Atlantic Craton in Labrador, Canada (Canada)
  • Newfoundland Plate
  • Nova Scotia Plate
  • Earth:Rae Craton – Archean craton in northern Canada north of the Superior Craton (Canada)
  • Sask Craton (Canada)
  • Earth:Sclavia Craton – Late Archean supercraton (Canada)
  • Earth:Slave Craton – Archaean craton in the north-western Canadian Shield, in Northwest Territories and Nunavut (Canada)
  • Earth:Superior Craton – Large crustal block in North America (Canada)

South American Plate

See also

Notes and references

Notes

  1. 15,600,000 km2 is the original size before the 2017 split of the Coiba and Malpelo plates.

References

  1. Madaan, About Sonia (2020-08-18). "7 Major Tectonic Plates (Pacific, African, Eurasian, Antarctic and more)". How Many Tectonic Plates Are on Earth?. https://eartheclipse.com/geology/tectonic-plates.html#How_Many_Tectonic_Plates_Are_on_Earth. 
  2. Bird, P. (2003). "An updated digital model of plate boundaries". Geochemistry, Geophysics, Geosystems 4 (3): 1027. doi:10.1029/2001GC000252. http://peterbird.name/publications/2003_PB2002/2003_PB2002.htm.
  3. van Dijk, J.P. (2023); The New Global Tectonic Map - Analyses and Implications. Terra Nova, 2023, 27 pp. DOI 10.1111/TER.12662
  4. Niels Henriksen; A.K. Higgins; Feiko Kalsbeek; T. Christopher R. Pulvertaft (2000). "Greenland from Archaean to Quaternary". Greenland Survey Bulletin (185). http://www.geus.dk/publications/bull-gl/nr185/nr185_p12-24.pdf. 

Bibliography

North Andes Plate

External links