TheCaribbean plate is a mostlyoceanictectonic plate underlyingCentral America and theCaribbean Sea off the northern coast ofSouth America.
| Caribbean plate | |
|---|---|
 | |
| Type | Minor |
| Approximate area | 3,300,000 km2[1] |
| Movement1 | north-west |
| Speed1 | 10-11mm/year |
| Features | Central America,Greater Antilles,Lesser AntillesCaribbean Sea |
| 1Relative to theAfrican plate | |
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Roughly 3.2 million square kilometres (1.2 million square miles) in area, the Caribbean plate borders theNorth American plate, theSouth American plate, theNazca plate and theCocos plate. These borders are regions of intenseseismic activity, including frequentearthquakes, occasionaltsunamis,[2] andvolcanic eruptions.
Boundary types
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The northern boundary with the North American plate is atransform or strike-slip boundary that runs from the border area ofBelize,Guatemala (Motagua Fault), andHonduras in Central America, eastward through theCayman trough along theSwan Islands Transform Fault before joining the southern boundary of theGonâve microplate. East of theMid-Cayman Rise this continues as theWalton fault zone and theEnriquillo–Plantain Garden fault zone into easternHispaniola. From there it continues intoPuerto Rico, and theVirgin Islands. Part of thePuerto Rico Trench, the deepest part of theAtlantic Ocean (roughly 8,400 metres or 27,600 feet), lies along this border. The Puerto Rico Trench is at a complex transition from the subduction boundary to the south and the transform boundary to the west.
The eastern boundary is asubduction zone, theLesser Antilles subduction zone, where oceanic crust of the South American plate is being subducted under the Caribbean plate. Subduction forms the volcanic islands of theLesser Antilles Volcanic Arc from the Virgin Islands in the north to the islands off the coast ofVenezuela in the south. This boundary contains seventeen active volcanoes, most notablySoufriere Hills onMontserrat;Mount Pelée onMartinique;La Grande Soufrière onGuadeloupe;Soufrière Saint Vincent onSaint Vincent; and the submarine volcanoKick 'em Jenny which lies about 10 km north ofGrenada. Large historical earthquakes in 1839 and 1843 in this region are possibly megathrust earthquakes.[3][4]
Along the geologically complex southern boundary,[5] the Caribbean plate interacts with the South American plate formingBarbados,Trinidad andTobago (all on the Caribbean plate), and islands off the coast of Venezuela (including theLeeward Antilles) andColombia. This boundary is in part the result oftransform faulting, along withthrust faulting and some subduction. The rich Venezuelanpetroleum fields possibly result from this complex plate interaction. The Caribbean plate is moving eastward about 22 millimetres (0.87 in) per year in relation to the South American plate.[6][7] In Venezuela, much of the movement between the Caribbean plate and the South American plate occurs along the faults ofBoconó,El Pilar, andSan Sebastián.[5]
The western portion of the plate is occupied by Central America. TheCocos plate in thePacific Ocean is subducted beneath the Caribbean plate, just off the western coast of Central America. This subduction forms the volcanoes ofGuatemala,El Salvador,Nicaragua, andCosta Rica, also known as theCentral America Volcanic Arc.
Origin
editThe usual theory of the origin of the Caribbean plate was confronted by a contrasting theory in 2002.
The mainstream theory holds that it is theCaribbean large igneous province (CLIP) which formed in the Pacific Ocean tens of millions of years ago, perhaps originating at theGalápagos hotspot.[8] As the Atlantic Ocean widened, North America and South America were pushed westward, separated for a time by oceanic crust.[9] The Pacific Ocean floor subducted under this oceanic crust between the continents. The CLIP drifted into the same area, but as it was less dense and thicker than the surrounding oceanic crust, it did not subduct, but rather overrode the ocean floor, continuing to move eastward relative to North America and South America. With the formation of theIsthmus of Panama 3 million years ago, it ultimately lost its connection to the Pacific.
The more recent theory asserts that the Caribbean plate came into being from anAtlantic hotspot which no longer exists. This theory points to evidence of the absolute motion of the Caribbean plate which indicates that it moves westward, not east, and that its apparent eastward motion is only relative to the motions of theNorth American plate and theSouth American plate.[10]
First American land bridge
editThe Caribbean plate began its eastward migration80 million years ago (Ma) during the Late Cretaceous. This migration eventually resulted in avolcanic arc stretching from northwestern South America to theYucatán Peninsula, today represented by theAves Islands and theLesser andGreater Antilles. This arc was the subject of constant tectonism and sea-level fluctuation, but lasted until the mid-Eocene and intermittently formed aland bridge along the eastern and northern boundaries of the Caribbean plate.[11] What would eventually become present-day Central America, part of the western plate boundary, was still isolated in the Pacific.
58.5 to 56.5 Ma, during theLate Paleocene, a local sea-level low-stand assisted by the continental uplift of the western margin of South America, resulted in a fully operative land bridge over which several groups of mammals apparently took part in an interchange. For example, specimens have been assigned toxenarthra,didelphidae, andphorusrhacidae from Eocene North America and Europe (although these have beencriticized),[11][12] andPeradectes from Paleocene South America.[13]
Great American Interchange
editTheGreat American Interchange in which land and freshwaterfauna migrated between North America and South America via the uplifted western margin of the Caribbean plate (Central America) was a later event, which peaked dramatically around 2.6 million years (Ma) ago during thePiacenzian age.
See also
editReferences
edit- ^"Sizes of Tectonic or Lithospheric Plates".About.com Geology. Archived fromthe original on 2007-02-09. Retrieved2015-05-05.
- ^Fernández-Arce, Mario; Alvarado-Delgado, Guillermo (December 2005)."Tsunamis and Tsunami Preparedness in Costa Rica, Central America"(PDF).ISET Journal of Earthquake Technology. Paper No. 466.42 (4):203–212.ISSN 0972-0405.
- ^Robson, G.R. (1964)."An Earthquake Catalogue for the Eastern Caribbean 1530–1960".Bulletin of the Seismological Society of America.54 (2):785–832.Bibcode:1964BuSSA..54..785R.doi:10.1785/BSSA0540020785.
- ^Feuillet, N.; Beauducel, F.; Tapponnier, P. (2011)."Tectonic context of moderate to large historical earthquakes in the Lesser Antilles and mechanical coupling with volcanoes"(PDF).Journal of Geophysical Research.116 (B10): B10308.Bibcode:2011JGRB..11610308F.doi:10.1029/2011JB008443.hdl:10220/8653.
- ^abAudemard, Franck A.; Singer P., André (1996)."Active fault recognition in northwestern Venezuela and its seismogenic characterization: Neotectonic and paleoseismic approach".Geofísica Internacional.35 (3):245–255.doi:10.22201/igeof.00167169p.1996.35.3.460. Retrieved24 November 2015.
- ^Deiros D (2000) [Determination of Displacement Between Caribbean and South American plates in Venezuela using Global Positioning System (GPS) data.] Geological Code of Venezuela.(in Spanish)
- ^Pérez OJ, Bilham R, Bendick R, Hernández N, Hoyer M, Velandia J, Moncayo C y Kozuch M (2001) Relative velocity between the Caribbean and South America plates from observations Within the Global Positioning System (GPS) in northern Venezuela.(in Spanish)
- ^"Crustal structure across the Pacific margin of Nicaragua", Walther, C. H. E. et al,Geophysical Journal, Volume 141, Issue 3, pp. 759-777, (2000).
- ^James, K.H.; Lorente, M.A.; Pindell, J.L., eds. (2009).The Origin and Evolution of the Caribbean Plate(PDF). London: TheGeological Society of London.ISBN 978-1-86239-288-5.
- ^Meschede, Martin; Frisch, Wolfgang (2002)."The Evolution of the Caribbean Plate and its Relation to Global Motion Vectors: Geometric Constraints for an Inter-American Origin". In Jackson, T.A. (ed.).Caribbean Geology: Into the Third Millennium: Transactions of the Fifteenth Caribbean Geological Conference.University of West Indies Press. p. 279.ISBN 978-976-640-100-9.
- ^abMarshall, L.G.; Sempere, T.; Butler, R.F. (1997)."Chronostratigraphy of the Mammal-Bearing Paleocene of South America"(PDF).Journal of South American Earth Sciences.10 (1): 63.Bibcode:1997JSAES..10...49M.doi:10.1016/S0895-9811(97)00005-9.
- ^Angst, Delphine; Buffetaut, Eric; Lécuyer, Christophe; Amiot, Romain (2013-11-27).""Terror Birds" (Phorusrhacidae) from the Eocene of Europe Imply Trans-Tethys Dispersal".PLOS One.8 (11): e80357.doi:10.1371/journal.pone.0080357.ISSN 1932-6203.PMC 3842325.PMID 24312212.
- ^Janis, Christine M.; Gunnell, Gregg F.; Uhen, Mark D., eds. (2008).Evolution of Tertiary Mammals of North America: Volume 2: Small Mammals, Xenarthrans, and Marine Mammals. Vol. 2. Cambridge: Cambridge University Press.ISBN 978-0-521-78117-6.