Caribbean Plate
Categories: Caribbean | Plate tectonics
The Caribbean Plate is an oceanic tectonic plate that encompasses roughly 3.2x106 km² and underlies Central America and the Caribbean Sea off the north coast of South America. The Caribbean Plate borders the North American Plate, the South American Plate, and the Cocos Plate. These borders are hotspots for seismic activity, including frequent earthquakes and tremors, occasional tsunamis, and volcanic eruptions.
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 8400 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 formed as the westward moving North American Plate plunges 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, Soufriere Guadeloupe, Soufriere 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 Trinidad (on the South American Plate) and Tobago (on the Caribbean Plate), the southern islands of the Netherlands Antilles, and other islands off the coast of Venezuela 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 subducting the Caribbean Plate under and just off the western coast of Central America. This subduction forms the volcanoes of Guatemala, El Salvador, Nicaragua, and Costa Rica.
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.