Plate Tectonics

of the

Lesser Antilles

By

Justin Howard

http://www.ngdc.noaa.gov/mgg/image/2minsurface/1350/45N090W.jpg

Lesser AntillesLesser Antilles LocationLocation

• The chain of islands wrapped The chain of islands wrapped around the eastern end of the around the eastern end of the Caribbean Sea on the Caribbean Sea on the boundary with the Atlantic boundary with the Atlantic ocean. ocean.

Islands Islands • The US Virgin Islands, British The US Virgin Islands, British

Virgin Islands, Anguilla, Saint Virgin Islands, Anguilla, Saint Kitts, Nevis, Antigua, Barbuda, Kitts, Nevis, Antigua, Barbuda, Saint Vincent, Barbados, St. Saint Vincent, Barbados, St. Lucia, Dominica, Guadeloupe, Lucia, Dominica, Guadeloupe, Montserrat, Grenadines, Montserrat, Grenadines, Grenada, Trinidad, Tobago, Grenada, Trinidad, Tobago, The Netherlands Antilles, the The Netherlands Antilles, the island off the coast of island off the coast of Venezuela, and Aruba.Venezuela, and Aruba.

http://www.sitesatlas.com/Maps/Maps/309.htm

Tectonic Plates of EarthTectonic Plates of Earth

•Tectonic PlateTectonic Plate

• A piece of the Earth’s lithosphere, or crust.

http://www.sitesatlas.com/Maps/Maps/309.htm

• Plate TectonicsPlate Tectonics• The theory developed to explain the phenomena of continental drift.The theory developed to explain the phenomena of continental drift.• The outermost part of the Earth’s interior is made up of two layers.The outermost part of the Earth’s interior is made up of two layers.

• The AsthenosphereThe Asthenosphere• The region located beneath the lithosphere between 100 and 700 Km The region located beneath the lithosphere between 100 and 700 Km below the surface. below the surface.

The Lithosphere The Lithosphere • The outermost solid shell of Earth between the uppermost layer of The outermost solid shell of Earth between the uppermost layer of mantle and the crust.mantle and the crust.

• Plate BoundariesPlate Boundaries• Transform BoundariesTransform Boundaries

• The grinding of two plates along transform faults, where the rock fracture is The grinding of two plates along transform faults, where the rock fracture is caused by lateral movement of two surfaces. caused by lateral movement of two surfaces.

• Divergent BoundariesDivergent Boundaries• The sliding of plates past each other. The sliding of plates past each other.

• Convergent BoundariesConvergent Boundaries• The sliding of two plates toward each other and one is forced under the other.The sliding of two plates toward each other and one is forced under the other.

Plate BoundariesPlate Boundaries

http://www.wordiq.com/definition/Image:Tectonic_plate_boundaries.png

Plate Tectonics of the Plate Tectonics of the Lesser AntillesLesser Antilles

Consists of Convergent boundaries Consists of Convergent boundaries where the Atlantic and Caribbean where the Atlantic and Caribbean plates meet.plates meet.

The rate of subduction is on average 1 The rate of subduction is on average 1 inch per year.inch per year.

Seventeen volcanoes have been Seventeen volcanoes have been active in the last 10,000 years, the active in the last 10,000 years, the Holocene, in the West Indies.Holocene, in the West Indies.

Active Volcanoes include:Active Volcanoes include: Kick-Em-JennyKick-Em-Jenny Soufriere Hills Soufriere Hills

http://www.mount-pelee.com/arcvolc.htm#

The chain of volcanoes present at the mid-oceanic ridge The chain of volcanoes present at the mid-oceanic ridge is a result of the subducted Cocos Plate beneath the is a result of the subducted Cocos Plate beneath the west edge of the Caribbean Plate.west edge of the Caribbean Plate.

http://volcano.und.nodak.edu/vwdocs/volc_images/north_america/west_indies.html

A Cross-Sectional View of the A Cross-Sectional View of the

Lesser Antilles’ Convergent Lesser Antilles’ Convergent BoundaryBoundary

http://www.mount-pelee.com/arcvolc.htm#

Results of Tectonic Activity Results of Tectonic Activity in the British Virgin in the British Virgin

Islands: Virgin GordaIslands: Virgin Gorda

Justin Howard

70 million years ago, during the Tertiary, magma accumulated on 70 million years ago, during the Tertiary, magma accumulated on the lava layers of the Caribbean seabed forming huge sections of the lava layers of the Caribbean seabed forming huge sections of

granite.granite.

Justin Howard

It wasn’t until It wasn’t until 15-25 million years 15-25 million years ago that the granite ago that the granite created under water created under water was exposed by was exposed by faulting and uplifting.faulting and uplifting. That granite, pictured That granite, pictured here, has since been here, has since been weathered (largely by weathered (largely by acid rain). This acid rain). This explains the rough, explains the rough, flaking surface.flaking surface.

Justin Howard

Justin Howard

BibliographyBibliography Howard, Justin. Personal Photos, Virgin Gorda, BVI. 2004.Howard, Justin. Personal Photos, Virgin Gorda, BVI. 2004.

Press, Frank et al. Press, Frank et al. Understanding the EarthUnderstanding the Earth. Freeman Press, New York, NY. 2004.. Freeman Press, New York, NY. 2004.

http://www.ngdc.noaa.gov/mgg/image/2minsurface/1350/45N090W.jpghttp://www.ngdc.noaa.gov/mgg/image/2minsurface/1350/45N090W.jpg

http://www.mount-pelee.com/arcvolc.htm#http://www.mount-pelee.com/arcvolc.htm#

http://www.sitesatlas.com/Maps/Maps/309.htmhttp://www.sitesatlas.com/Maps/Maps/309.htm

http://www.wordiq.com/definition/Image:Tectonic_plate_boundaries.pnghttp://www.wordiq.com/definition/Image:Tectonic_plate_boundaries.png

http://www.thebathsbvi.com/map.htmhttp://www.thebathsbvi.com/map.htm

http://volcano.und.nodak.edu/vwdocs/volc_images/north_america/west_indies.htmlhttp://volcano.und.nodak.edu/vwdocs/volc_images/north_america/west_indies.html