Caribbean Plate
From Wikipedia, the free encyclopedia
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, and the Cocos Plate. These borders are regions of intense seismic activity, including frequent earthquakes, occasional tsunamis, and volcanic eruptions.
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[edit] 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, and Honduras in Central America, eastward through the Cayman trough on south of the southeast coast of Cuba, and just north of Hispaniola, 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, but since the boundary between the North and South American Plates in the Atlantic is as yet undefined, it is unclear which one, or possibly both, is descending under the Caribbean Plate. Subduction forms the volcanic islands of the Lesser Antilles island 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.
Along the geologically complex southern boundary the Caribbean Plate interacts with the South American Plate forming Barbados, Trinidad (on the South American Plate) and Tobago (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 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.
[edit] Origin
The Caribbean Plate is thought to be a large igneous province that formed in the Pacific Ocean tens of millions of years ago. As the Atlantic ocean widened, North America and South America were pushed westward, and the Pacific Ocean floor began to subduct under the western edges of the American continents. The Caribbean Plate is thicker and lay higher than the rest of the Pacific Ocean floor, and instead overrode the Atlantic Ocean floor, moving eastward relative to North America and South America, and, with the formation of the Isthmus of Panama 2–3 million years ago, ultimately losing its connection to the Pacific.
There is some speculation that the westward motion of the South American Plate may have forced the Caribbean and Scotia Plates at its northern and southern ends respectively to squeeze around it. Both share a similar shape and are being subducted along their eastern boundary.[1]
