The Cayman Trough, is a complex transform fault

Transform fault

A transform fault or transform boundary, also known as conservative plate boundary since these faults neither create nor destroy lithosphere, is a type of fault whose relative motion is predominantly horizontal in either sinistral or dextral direction. Furthermore, transform faults end abruptly...

 zone pull apart basin

Pull Apart Basin

250px|thumb|[[Cami Lake]] in [[Tierra del Fuego]] develops on a [[Patagonian Ice Sheet|glacially]] excavated pull apart basin along the [[Magallanes-Fagnano Fault]], hence its elongated form...

 which contains a small spreading ridge

Divergent boundary

In plate tectonics, a divergent boundary or divergent plate boundary is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent boundaries within continents initially produce rifts which produce rift valleys...

 on the floor of the western Caribbean Sea

Caribbean Sea

The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....

 between Jamaica

Jamaica

Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...

 and the Cayman Islands

Cayman Islands

The Cayman Islands is a British Overseas Territory and overseas territory of the European Union located in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac, and Little Cayman, located south of Cuba and northwest of Jamaica...

. It is the deepest point in the Caribbean Sea and forms part of the tectonic

Tectonics

Tectonics is a field of study within geology concerned generally with the structures within the lithosphere of the Earth and particularly with the forces and movements that have operated in a region to create these structures.Tectonics is concerned with the orogenies and tectonic development of...

 boundary between the North American Plate

North American Plate

The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

 and the Caribbean Plate

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....

. It extends from the Windward Passage

Windward Passage

The Windward Passage is a strait in the Caribbean Sea, between the islands of Cuba and Hispaniola. The strait specifically lies between the easternmost region of Cuba and the northwest of Haiti.80km wide, the Windward Passage has a threshold depth of 1,700m...

, going south of the Sierra Maestra

Sierra Maestra

Sierra Maestra is a mountain range that runs westward across the south of the old Oriente Province from what is now Guantánamo Province to Niquero in southeast Cuba, rising abruptly from the coast. Some view it as a series of connecting ranges , which joins with others extending to the west...

 of Cuba

Cuba

The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

 toward Guatemala

Guatemala

Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...

. The transform continues onshore as the Motagua Fault

Motagua Fault

The Motagua Fault is a major, active left lateral-moving transform fault which cuts across Guatemala. It forms part of the tectonic boundary between the North American Plate and the Caribbean Plate...

, which cuts across Guatemala and extends offshore under the Pacific Ocean, where it intersects the Middle America Trench

Middle America Trench

The Middle America Trench is a major subduction zone, an oceanic trench in the eastern Pacific Ocean off the southwestern coast of Middle America, stretching from central Mexico to Costa Rica...

 subduction zone.

The relatively narrow trough trends east-northeast to west-southwest and has a maximum depth of 7686 metres (25,216.5 ft). Within the trough is a slowly spreading north-south ridge

Mid-ocean ridge

A mid-ocean ridge is a general term for an underwater mountain system that consists of various mountain ranges , typically having a valley known as a rift running along its spine, formed by plate tectonics. This type of oceanic ridge is characteristic of what is known as an oceanic spreading...

 which may be the result of an offset or gap of approximately 420 kilometres (261 mi) along the main fault trace. The Cayman spreading ridge shows a long-term opening rate of The eastern section of the trough has been named the Gonâve Microplate

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...

. The Gonâve plate extends from the spreading ridge east to the island of Hispanola. It is bounded on the north by the Oriente and Septentrional fault zones. On the south the Gonâve is bounded by the Walton fault, the Jamaica

Jamaica

Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...

 restraining bend and the Enriquillo-Plantain Garden fault zone

Enriquillo-Plantain Garden fault zone

The Enriquillo–Plantain Garden fault zone is a system of coaxial left lateral-moving strike slip faults which runs along the southern side of the island of Hispaniola, where the Dominican Republic and Haiti are located...

. The two bounding strike slip fault zones are left lateral. The motion relative to the North American Plate

North American Plate

The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

 is to the east and the motion relative to the Caribbean Plate is .

During the Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 the trough was the site of a subduction zone which formed the volcanic arc

Volcanic arc

A volcanic arc is a chain of volcanoes positioned in an arc shape as seen from above. Offshore volcanoes form islands, resulting in a volcanic island arc. Generally they result from the subduction of an oceanic tectonic plate under another tectonic plate, and often parallel an oceanic trench...

 of the Cayman Ridge and the Sierra Maestra

Sierra Maestra

Sierra Maestra is a mountain range that runs westward across the south of the old Oriente Province from what is now Guantánamo Province to Niquero in southeast Cuba, rising abruptly from the coast. Some view it as a series of connecting ranges , which joins with others extending to the west...

 volcanic terrain

Terrain

Terrain, or land relief, is the vertical and horizontal dimension of land surface. When relief is described underwater, the term bathymetry is used...

 of Cuba to the north, as the northeastward-moving Caribbean Plate

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....

 was subducted beneath the southwest-moving North American Plate

North American Plate

The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

, or as some researchers contend, beneath a plate fragment dubbed the East Cuban Microplate.

In 2010 a UK team from the National Oceanography Centre

National Oceanography Centre

- The National Oceanography Centre :The National Oceanography Centre is a marine science research and technology institution based on two sites in Southampton and Liverpool, United Kingdom...

 in Southampton

Southampton

Southampton is the largest city in the county of Hampshire on the south coast of England, and is situated south-west of London and north-west of Portsmouth. Southampton is a major port and the closest city to the New Forest...

 (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 3.1 miles (5 kilometers), the deepest yet found.