المعرفة

قائمة الصفائح التكتونية

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.

Map of Earth's 16 principal tectonic plates, showing plate boundary types:
Divergent:
  Spreading center
  Extension zone
Convergent:
  Subduction zone
  Collision zone
Transform:
  Dextral transform
  Sinistral transform
Plate tectonics map from NASA

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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.

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] The latest studies have shown that microplates are the basic elements of which the crust is composed and that the larger plates are composed of amalgamations of these, and a subdivision of ca. 1200 smaller plates has come forward.[3][4]

 
The new Global Tectonic Map with the subdivision of the Continents, Oceans and Mobile mountain belts in ca. 1200 smaller plates. Legend: Green: Terrane (microplate) boundaries in the Continental Blocks, Cyan: Terranes of the Oceanic Plates, Orange: terranes inside the Mobile Belts, Blue: Oceanic transform faults; Red: Fault zones in the Continental and Mountain belt domain; Purple: Main subduction zones and suture zones; Orange dots: volcanoes.

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

Antarctic Plate

Eurasian Plate

Indo-Australian Plate

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


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North American Plate

 
North American cratons and basement rocks

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)". Earth Eclipse. How Many Tectonic Plates Are on Earth?. Retrieved 2022-05-12.
  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. ^ Hasterok, D., Halpin, J., Collins, A.S., Hand, M., Kreemer, C., Gard, M., and Glorie, S. (2022); New maps of global geological provinces and tectonic plates. Earth Science Reviews, 2022.
  4. ^ van Dijk, J.P. (2023); The New Global Tectonic Map - Analyses and Implications. Terra Nova, 2023, 27 pp. DOI:10.1111/TER.12662
  5. ^ Antarctic Plate Tectonics
  6. ^ Gasperini, L; Ligi, M; Accettella, D; Bosman, A; Cuffaro, M; Lodolo, E; Martorelli, E; Muccini, F; Palmiotto, C; Polonia, A (1 February 2023). "Late Miocene to recent tectonic evolution of the Macquarie Triple Junction". Geology. 51 (2): 146–50. doi:10.1130/G50556.1.
  7. ^ "Introduction - Project Cratera". utl.pt.
  8. ^ Demets, C., Gordon, Richard, & Argus, Donald, «MORVEL: A new estimate for geologically recent plate motions» in AGU Fall Meeting Abstracts.
  9. ^ Niels Henriksen; A.K. Higgins; Feiko Kalsbeek; T. Christopher R. Pulvertaft (2000). "Greenland from Archaean to Quaternary" (PDF). Greenland Survey Bulletin. No. 185. Archived from the original (PDF) on 2008-12-07. Retrieved 2009-10-04.

Bibliography

North Andes Plate

External links

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