Introduction to Caribbean Tectonics

Summary

The Caribbean, known for its tropical beaches and palm trees, has a fascinating geological history that began 130 million years ago. The Caribbean plate, the 16th largest tectonic plate, is mostly submerged beneath the sea, with tectonic activity occurring along its margins. It is bordered by multiple subduction zones and strike-slip faults. Over time, the Caribbean plate formed through two possible models, one involving the separation of North and South American plates and the other through a mantle plume. This tectonic activity has shaped the region, creating islands, fault lines, and active volcanoes, which continue to evolve the area today.

Takeaways

• 😀 The Caribbean is well-known for its beautiful tropical beaches and palm trees, but it also has a rich geological history dating back 130 million years.
• 😀 The Caribbean plate is the 16th largest tectonic plate, about the size of India, and is mostly submerged beneath the sea except along its edges where most tectonic activity occurs.
• 😀 The Caribbean plate is surrounded by various geological boundaries, including strike-slip faults and subduction zones, primarily to the north, south, east, and west.
• 😀 The Caribbean plate moves eastward relative to North and South America, causing strike-slip faults to behave differently on either side, with the north being mostly sinister and the south dextro.
• 😀 The Caribbean plate is involved in significant subduction at both the west (under Central America) and east (under the Lesser Antilles) edges, creating earthquakes at varying depths known as the Wadati-Benioff zone.
• 😀 The Caribbean plate's geological activity also results in volcanoes, which can be found along its tectonic margins, particularly in Central America and the Lesser Antilles.
• 😀 There are two primary models explaining the formation of the Caribbean plate: the in-situ model, which suggests it formed between the North and South American plates, and the Pacific origin model, which proposes it formed above a mantle plume and migrated eastward.
• 😀 The Greater Antilles arc, which includes islands like Cuba and Hispaniola, formed above a south-dipping subduction zone during the Cretaceous and Paleogene periods.
• 😀 A significant tectonic event occurred around 50 million years ago when the Greater Antilles arc collided with North America, forming part of the northern boundary of the Caribbean plate.
• 😀 The Caribbean plate's geological evolution has been marked by multiple collisions and the accretion of oceanic terrains, especially along the northwestern margin of South America, which has shaped its present structure.

Q & A

What is the Caribbean Plate, and how large is it?

The Caribbean Plate is the 16th largest tectonic plate, about the size of the country of India.

Why is the Caribbean Plate mostly submerged beneath the sea?

The Caribbean Plate is mostly submerged beneath the sea, except along its margins, where tectonic activity occurs and where most people live.

How many political entities are found on the edges of the Caribbean Plate?

There are 13 independent countries and 17 dependencies of the US, the Netherlands, France, and the UK along the edges of the Caribbean Plate.

What is the geological boundary of the Caribbean Plate?

The Caribbean Plate is bounded by strike-slip faults and subduction zones to the north and south, and by the South American Plate and the North American Plate, respectively, to the east and west.

How does the movement of the Caribbean Plate affect its strike-slip faults?

Due to the movement of the Caribbean Plate east relative to North and South America, the strike-slip faults in the north are mostly sinistral, while those in the south are mostly dextral.

What are pull-apart basins, and where can they be found in the Caribbean?

Pull-apart basins are geological formations where tectonic forces cause the Earth's crust to pull apart. These basins, such as the Cayman Trough, Falcon Basin, and Bonneted Basin, can be found in the southern Caribbean.

What is unique about the Cayman Trough?

The Cayman Trough is notable for having the shortest oceanic spreading ridge in the world, which has been creating oceanic crust for about 40 million years.

What is the Wadati-Benioff Zone?

The Wadati-Benioff Zone refers to the earthquake hypocenters occurring at various depths between 0 and 300 kilometers, marking subduction zones beneath the Caribbean Plate.

What are the two models that explain the formation of the Caribbean Plate?

The two models explaining the formation of the Caribbean Plate are the in-situ model, which suggests it was created between the North American and South American Plates, and the Pacific origin model, which suggests it formed above a mantle plume in the Pacific and migrated eastward.

How did the Greater Antilles Arc form?

The Greater Antilles Arc, including Cuba, Hispaniola, and other small islands, formed above a south-dipping subduction zone during the Cretaceous and Paleogene periods and collided with North America about 50 million years ago.