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,[2] and volcanic eruptions.

Caribbean Plate
The Caribbean Plate
TypeMinor
Approximate area3,300,000 km2[1]
Movement1north-west
Speed110-11mm/year
FeaturesCentral America, Cuba, Hispaniola. Caribbean Sea
1Relative to the African Plate
CaribbeanVolcanoMap (cropped)
Volcanoes of the Caribbean.

Boundary types

The northern boundary with the North American plate is a transform or strike-slip boundary which runs from the border area of Belize, Guatemala (Motagua Fault), and Honduras in Central America, eastward through the Cayman trough along the Swan Islands Transform Fault before joining the southern boundary of the Gonâve Microplate. East of the Mid-Cayman Rise this continues as the Walton fault zone and the Enriquillo–Plantain Garden fault zone into eastern Hispaniola. From there it continues into Puerto Rico, and the Virgin Islands. Part of the Puerto Rico Trench, the deepest part of the Atlantic Ocean (roughly 8,400 meters), 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 a subduction zone, the Lesser Antilles subduction zone, where oceanic crust of the South American Plate is being subducted under the Caribbean Plate. Subduction forms the volcanic islands of the Lesser Antilles Volcanic Arc from the Virgin Islands in the north to the islands off the coast of Venezuela in the south. This boundary contains seventeen active volcanoes, most notably Soufriere Hills on Montserrat; Mount Pelée on Martinique; La Grande Soufrière on Guadeloupe; Soufrière Saint Vincent on Saint Vincent; and the submarine volcano Kick 'em Jenny which lies about 10 km north of Grenada. 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 forming Barbados, Trinidad and Tobago (all on the Caribbean Plate), and islands off the coast of Venezuela (including the Leeward Antilles) and Colombia. This boundary is in part the result of transform faulting along with thrust faulting and some subduction. The rich Venezuelan petroleum fields possibly result from this complex plate interaction. The Caribbean plate is moving eastward about 22 millimeters 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 of Boconó, El Pilar and San Sebastián.[5]

The western portion of the plate is occupied by Central America. The Cocos Plate in the Pacific Ocean is subducted beneath the Caribbean Plate, just off the western coast of Central America. This subduction forms the volcanoes of Guatemala, El Salvador, Nicaragua, and Costa Rica, also known as the Central America Volcanic Arc.

Origin

The usual theory as to the origin of the Caribbean Plate was confronted by a contrasting theory in 2002.

The mainstream theory holds that it is the Caribbean large igneous province (CLIP) which formed in the Pacific Ocean tens of millions of years ago. As the Atlantic Ocean widened, North America and South America were pushed westward, separated for a time by oceanic crust.[8] 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 the Isthmus 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 an Atlantic 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 the North American Plate and the South American Plate.[9]

First American land bridge

The Caribbean Plate began its eastward migration 80 million years ago (Ma) during the Late Cretaceous. This migration eventually resulted in a volcanic arc stretching from north-western South America to the Yucatán Peninsula, today represented by the Aves Islands and the Lesser and Greater Antilles. This arc was the subject of constant tectonism and sea-level fluctuations but lasted until the mid-Eocene and intermittently formed a land bridge along the eastern and northern boundaries of the Caribbean Plate.[10] (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 the Late 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, xenarthrans are known from the Itaboraian stage of the South American Land Mammal Age (SALMA) (59–57 Ma), palaeanodonts from the Tiffanian North American Land Mammal Age (NALMA) (57 Ma) and Eurotamandua from the early middle Eocene (50 Ma) of Europe; opossums are known from the Tiupampan/Itaboraian SALMA (64–57 Ma), from the Clarkforkian NALMA (55 Ma); and from the Ypresian in Europe (55 Ma).[10]

Great American Interchange

The Great American Interchange in which land and freshwater fauna 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 three million years (Ma) ago during the Piacenzian age.

See also

References

  1. ^ "Sizes of Tectonic or Lithospheric Plates". About.com Geology.
  2. ^ 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.
  3. ^ Robson, G. R. (1964). "An Earthquake Catalogue for the Eastern Caribbean 1530–1960". Bulletin of the Seismological Society of America. 54 (2): 785–832.
  4. ^ Feuillet, N.; Beauducel, F.; Tapponnier, P. (2011). "Tectonic context of moderate to large historical earthquakes in the Lesser Antilles and mechanical coupling with volcanoes". Journal of Geophysical Research. 116 (B10): B10308. Bibcode:2011JGRB..11610308F. doi:10.1029/2011JB008443.
  5. ^ a b Audemard M., 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. Retrieved 24 November 2015.
  6. ^ 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)
  7. ^ 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)
  8. ^ James, K.H., Lorente, M.A. and Pindfell, J.L. (editors) (2009). The Origin and Evolution of the Caribbean Plate (PDF). London: The Geological Society of London. ISBN 978-1-86239-288-5.CS1 maint: Multiple names: authors list (link) CS1 maint: Extra text: authors list (link)
  9. ^ Meschede, M.; Frisch W. (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. Caribbean Geology: Into the Third Millenium : Transactions of the Fifteenth Caribbean Geological Conference. University of West Indies Press. p. 279. ISBN 978-976-640-100-9.
  10. ^ a b Marshall, 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.

External links

Cayman Trough

The Cayman Trough (also known as the Cayman Trench, Bartlett Deep and Bartlett Trough) is a complex transform fault zone pull-apart basin which contains a small spreading ridge, the Mid-Cayman Rise, on the floor of the western Caribbean Sea between Jamaica and the Cayman Islands. It is the deepest point in the Caribbean Sea and forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It extends from the Windward Passage, going south of the Sierra Maestra of Cuba toward Guatemala. The transform continues onshore as the Motagua Fault, which cuts across Guatemala and extends offshore under the Pacific Ocean, where it intersects the Middle America Trench subduction zone.

The relatively narrow trough trends east-northeast to west-southwest and has a maximum depth of 7,686 metres (25,217 ft). Within the trough is a slowly spreading north-south ridge which may be the result of an offset or gap of approximately 420 kilometres (260 mi) along the main fault trace. The Cayman spreading ridge shows a long-term opening rate of 11–12 mm/yr. The eastern section of the trough has been named the Gonâve Microplate. The Gonâve plate extends from the spreading ridge east to the island of Hispaniola. It is bounded on the north by the Oriente and Septentrional fault zones. On the south the Gonâve is bounded by the Walton fault zone, the Jamaica restraining bend and the Enriquillo-Plantain Garden fault zone. The two bounding strike slip fault zones are left lateral. The motion relative to the North American Plate is 11 mm/yr to the east and the motion relative to the Caribbean Plate is 8 mm/yr. The western section of the trough is bounded to its south by the Swan Islands Transform Fault.During the Eocene the trough was the site of a subduction zone which formed the volcanic arc of the Cayman Ridge and the Sierra Maestra volcanic terrain of Cuba to the north, as the northeastward-moving Caribbean Plate was subducted beneath the southwest-moving North American Plate, or as some researchers contend, beneath a plate fragment dubbed the East Cuban Microplate.In 2010 a UK team from the National Oceanography Centre in Southampton (NOCS), equipped with an autonomously controlled robot submarine, began mapping the full extent of the trench and discovered black smokers on the ocean floor at a depth of 5 km (3.1 mi), the deepest yet found. In January 2012, the researchers announced that water exits the vents at a temperature possibly exceeding 450 °C (842 °F), making them among the hottest known undersea vents. They also announced the discovery of new species, including an eyeless shrimp with a light-sensing organ on its back.

Cocos Plate

The Cocos Plate is a young oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it. The Cocos Plate was created approximately 23 million years ago when the Farallon Plate broke into two pieces, which also created the Nazca Plate. The Cocos Plate also broke into two pieces, creating the small Rivera Plate. The Cocos Plate is bounded by several different plates. To the northeast it is bounded by the North American Plate and the Caribbean Plate. To the west it is bounded by the Pacific Plate and to the south by the Nazca Plate.

Geology of Barbados

The geology of Barbados includes exposures of reef-related carbonate rocks spanning 85 percent of the island's surface. This Coral Rock Formation is 70 meters thick and dates to the Pleistocene. Unlike neighboring islands in the Lesser Antilles volcanic arc, Barbados is unusual because it is not a volcanic island (the only volcanic rocks are some ash beds from eruptions on neighboring islands). Instead, the island of Barbados is the exposed part of the Barbados Ridge Accretionary Prism, left as deep ocean sediments "scraped" to the surface as the Atlantic oceanic crust subducted beneath the Caribbean Plate.

The oldest rocks are in the Scotland Formation and include Eocene age turbidite and radiolarites. This unit is 4.5 kilometers thick from the sea floor to the surface. It is overlain by a syncline basin called the Woodbourne Trough, which includes pelagic sediments. Nappe formations of the Oceanic Formation, from a Miocene forearc basin filled with calcareous pelagic sediments and volcanic ash is thrusted on top of the two older units. Mud, rich in organic molecules intrudes all of these units with diapirs—rising tendrils of mud with behavior similar to salt domes.

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.

Gonâve Microplate

The Gonâve Microplate forms part of the boundary between the North American Plate and the Caribbean Plate. It is bounded to the west by the Cayman spreading center, to the north by the Septentrional-Oriente fault zone and to the south by the Walton fault zone and the Enriquillo-Plantain Garden fault zone. The existence of this microplate was first proposed in 1991. This has been confirmed by GPS measurements, which show that the overall displacement between the two main plates is split almost equally between the transform fault zones that bound the Gonâve microplate. The microplate is expected to eventually become accreted to the North American 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

The Lesser Antilles is a group of islands in the Caribbean Sea. Most form a long, partly volcanic island arc between the Greater Antilles to the north-west and the continent of South America. The islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean. Together, the Lesser Antilles and the Greater Antilles compose the Antilles (or the Caribbean in its narrowest definition). When combined with the Lucayan Archipelago, all three are known as the West Indies.

Lesser Antilles Volcanic Arc

The Lesser Antilles Volcanic Arc is a volcanic arc that forms the eastern boundary of the Caribbean Plate. It is part of a subduction zone, also known as the Lesser Antilles subduction zone, where the oceanic crust of the South American Plate is being subducted under the Caribbean Plate. This subduction process formed a number of volcanic islands, from the Virgin Islands in the north to the islands off the coast of Venezuela in the south. The Lesser Antilles Volcanic Arc includes nineteen 'active' volcanoes., notably Soufriere Hills on Montserrat; Mount Pelée on Martinique; La Grande Soufrière on Guadeloupe; Soufrière Saint Vincent on Saint Vincent; Mount Scenery on Saba; and the submarine volcano Kick 'em Jenny which lies about 10 km north of Grenada.

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 earthquakes in Guatemala

Earthquakes are relatively frequent occurrences in Guatemala. The country lies in a major fault zone known as the Motagua and Chixoy-Polochic fault complex, which cuts across Guatemala and forms the tectonic boundary between the Caribbean plate and the North American plate. In addition, along Guatemala's western coast line, the Cocos plate pushes against the Caribbean plate, forming a subduction zone known as the Middle America Trench located approximately 50 km off Guatemala's Pacific coast. This subduction zone led to the formation of the Central America Volcanic Arc, and is an important source of offshore earthquakes. Both these major tectonic processes have generated deformations within the Caribbean plate and produced secondary fault zones, like the Mixco, Jalpatagua, and Santa Catarina Pinula faults.The most destructive earthquake in recent Guatemalan history was the 1976 quake with a magnitude of 7.5 Mw and a hypocenter depth of just 5 km. This shallow-focus earthquake, originating from the Motagua Fault, caused 23,000 fatalities, leaving 76,000 injured and causing widespread material damage. Surprisingly, the 7.9 Mw earthquake of 1942, though higher in magnitude, was much less destructive, in part because of its substantially deeper hypocenter depth of 60 km.A number of earthquakes with low magnitudes caused major damage in very localized areas, which may in part be explained by their relatively shallow depth. This was the case with the 1985 Uspantán earthquake of 5.0 Mw with a depth of 5 km, which destroyed most buildings in the town of Uspantán, but caused little or no damage in the rest of the country.

Maracaibo Basin

The Maracaibo Basin, also known as Lake Maracaibo natural region, Lake Maracaibo depression or Lake Maracaibo Lowlands, is a foreland basin and one of the eight natural regions of Venezuela, found in the northwestern corner of Venezuela in South America. Covering over 36,657 square km, it is a hydrocarbon-rich region that has produced over 30 billion bbl of oil with an estimated 44 billion bbl yet to be recovered. The basin is characterized by a large shallow tidal estuary, Lake Maracaibo, located near its center. The Maracaibo basin has a complex tectonic history that dates back to the Jurassic period with multiple evolution stages. Despite its complexity, these major tectonic stages are well preserved within its stratigraphy. This makes The Maracaibo basin one of the most valuable basins for reconstructing South America's early tectonic history.

Motagua Fault

The Motagua Fault (also, Motagua Fault Zone) is a major, active left lateral-moving transform fault which cuts across Guatemala, continuing offshore along the southern Pacific coast of Mexico, returning onshore along the southernmost tip of Oaxaca, then continuing offshore until it merges with the Middle America Trench near Acapulco. It forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It is considered the onshore continuation of the Swan Islands Transform Fault which runs under the Caribbean Sea.

The Motagua Fault is regarded by some geologists as part of a system of faults designated the "Motagua-Polochic system" rather than as a discrete single boundary. The Polochic fault (also referred to as the Chixoy-Polochic Fault) lies north and parallel to the Motagua Fault and shares some of the motion between the North American and Caribbean Plates.

The Motagua Fault has been responsible for several major earthquakes in Guatemala's history, including the 7.5 Mw Guatemala 1976 earthquake.

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.

Panama Plate

The Panama Plate is a small tectonic plate sandwiched between the Cocos Plate and Nazca Plate to the south and the Caribbean Plate to the north. Most of its borders are convergent boundaries including a subduction zone to the west. It consists, for the most part, of the nations of Panama and Costa Rica.

Samaná Bay

Samaná Bay is a bay in the eastern Dominican Republic. The Yuna River flows into Samaná Bay, and it is located south of the town and peninsula of Samaná.

Among its features are protected islands that serve as nesting sites for pelicans and frigate birds, caves with pre-Columbian pictographs and petroglyphs, and mangrove-lined river tributaries. In the winter, many whales calve in the bay. It is a significant breeding site for the Humpback whale (McCann, 1994, page 11). Samaná Bay lies along the boundary between the North American Plate and the Caribbean plate. Two named fault lines run the length of Samaná Bay. These fault lines form the western terminal of the nineteen degree fault, that runs north of Puerto Rico and most of Hispaniola to form the northern boundary of the Caribbean plate. Adjoining the bay is Los Haitises National Park, which is popular with national and international ecotourist visitors. Samaná Bay also has 4-star hotels.

Contained within Samana Bay is the island of Cayo Levantado also known as Bacardi Island.The Franklin Pierce administration instructed a special agent to negotiate a treaty permitting the United States to establish a naval base in Samaná Bay, resulting in an agreement in October 1854. However, the British and French envoys convinced the Dominican government to insert a stipulation that Dominican citizens be treated as white people in the United States, which made it a nonstarter because of the prevailing racism which had to be respected by the U.S. government. Again, in the aftermath of the American Civil War, US Secretary of State William H. Seward formed a plan to purchase or lease Samaná Bay for the United States, which was then seeking bases for its navy in the Caribbean. However, the plan failed - partly due to hostility between Congress and President Johnson. making Congress reluctant to allocate funds for the purpose.

Septentrional-Oriente fault zone

The Septentrional-Orient fault zone (SOFZ) is a system of coaxial left lateral-moving strike slip faults that runs along the northern side of the island of Hispaniola where Haiti and the Dominican Republic are located and continues along the south of Cuba along the northern margin of the Cayman Trough. The SOFZ shares approximately half of the relative motion between the North American and Caribbean tectonic plates with the Enriquillo-Plantain Garden fault zone and Walton fault zone which run along the southern side of Hispaniola and aong the southern margin of the Cayman Trough. Both fault zones terminate at the Mid-Cayman Rise to the west. Some researchers believe that the Enriquillo-Plantain Garden fault zone and the SOFZ bound a microplate, dubbed the Gonâve Microplate, a 190,000 km2 (73,000 sq mi) area of the northern Caribbean Plate that is in the process of shearing off the Caribbean Plate and accreting to the North America Plate.A major tremor on this fault destroyed the city of Cap-Haïtien and other cities in the northern part of Haiti and the Dominican Republic on 7 May 1842.

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 Taitao–Tres 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." 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. 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.

Volcán Atitlán

Volcán Atitlán (Spanish pronunciation: [atiˈtlan]) is a large, conical, active stratovolcano adjacent to the caldera of Lake Atitlán in the Guatemalan Highlands of the Sierra Madre de Chiapas range. It is within the Sololá Department, northern Guatemala.

The volcano has been quite active historically, with more than a dozen eruptions recorded between 1469 and 1853, the date of its most recent eruption. Atitlán is part of the Central American Volcanic Arc. The arc is a chain of volcanoes stretching along Central America formed by subduction of the Cocos Plate underneath the Caribbean Plate. These volcanoes are part of the Ring of Fire around the Pacific Ocean.

Volcán Atitlán is few miles south of Volcán Tolimán, which rises from the southern shore of Lake Atitlán. Volcán San Pedro rises above Lake Atitlán northwest of Volcán Atitlán. A long narrow bay separates Volcán Atitlán and Volcán Toliman from Volcán San Pedro.

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