Virgin+Islands

= = = Virgin Islands =

By Tamara Luck and Lauren Baltrus
Welcome to the Virgin Islands!

Introduction: The virgin Islands are located in the Caribbean between the Caribbean Sea and Atlantic Ocean. The US Virgin Islands consist of St. John's, St. Croix and St. Thomas. The British Virgin Islands are made up of Tortola, Virgin Gorda, Jost Van Dyke, and Anegada Islands 10. Each Island has many beautiful secluded beaches with clear blue waters. St. John's has a 7,000 acre national park including subtropical forests, white sand beaches, coral reefs, and over 20 miles of hiking trails, making it a very popular tourist spot easily confused with paradise 8.



The Virgin Islands are part of an oceanic volcanic arc, which starts with Cuba and ends with Trinidad, off the coast of Venezuela. 100 million years ago in the Cretatious period, the Atlantic plate subducted underneath the Caribbean plate, which over time caused the Virgin Islands to form as a volcanically active arc. The Puerto Rican trench just north of the islands is evidence of this convergent boundary. Today, the islands have very few volcanic eruptions, although movement along the Caribbean-Atlantic plate boundary causes frequent earthquakes on the islands. St. Croix, the biggest Virgin Island, was not formed by repeated volcanic eruptions underwater, but instead was formed by collection of erupted volcanic materials from other islands approximately 80 million years ago. There are some places on St. Croix, for example Central Valley, that has noticeably younger bedrock that may have been a result of exposed coral reef from when the island was uplifted 4.
 * Geologic Setting: **

Because most of the islands were formed from oceanic volcanoes, the bedrock of the islands is basaltic igneous rock that is cooled and hardened lava. The bedrock of St. John's can be an example for most of the island's bedrock. The Water Island Formation was the first step in creating St. John. This was formed by layers of cooled and hardened basaltic lava. The next step was the Roisenhoi Formation, which consisted of layers of andesitic cooled lava. The next phase of formation was a time of volcanic peace when eroded sediment from the coral reef washed up onto the slopes of the volcano, compacting together to make the Outer Brass limestone layer, most likely conglomerate limestone. The next layer was created during the Tutu Formation. During this period many underwater earthquakes caused mudslides on the slopes of the volcanoes. After this point, thick rainforest vegetation grew over the new soil 7.

One unique geological feature on St. John's is an igneous intrusion that is visible today because of weathering and erosion. The molten rock shot up through the ground and cooled before reaching the surface. Today, fine grains of diorite are exposed at Threadneedle and Mary's Point 7. The white sand beaches of the Virgin Islands are protected from serious erosion because the islands are surrounded by coral reef. The vast area encloses the islands, which slows down the waves' energy and therefore not causing great amounts of erosion 9.

The Virgin Islands have a subtropical climate with high temperatures that only subtly change each season. Winter temperatures average around low 80's while summer temperatures range from low to mid 90's (temperature measured in fahrenheit). The Virgin Islands are hot and can also be humid. Rainfall occurs mostly from May to November. The weather on the Islands can be influenced and changed by the Easterly Trade Winds 9. The Virgin Islands are located near the equator, making them very hot. Because of the Caribbean- Atlantic plate boundary, the Virgin Islands could be affected by earthquakes, although at this time it is not very likely. Also, due to its location in the ocean, hurricanes are a possible threat 9. The Climate is not changing in the Virgin Islands.
 * Climate and Weather: **

The Virgin Islands are in a tropical forest biome with many species of plants and animals. The Virgin Islands have 740 species of plants. These plants range from moist forrest and flowers to cacti. The Islands also have 140 species of birds, 302 species of fish, 22 species of mammals and 7 species of amphibians 9. One animal native to the Islands are bats. There are 3 different types of bats including the bulldog bat, velvet free-tailed bat and the antillean fruit-eating bat. The bulldog bat is well adapted to the Islands. The bulldog bats have especially long legs and toes with long claws. These long legs and claws allow bats to catch fish swimming near the surface 9.
 * Biome: **



The Virgin Islands also have many different kinds of plants from coconut palms in the topical coastlines to scrub plants in more arid semi-desert areas. There are also plants living in the water near the shore. One example of a plant living in water is seagrass, a flowering plant. Seagrass grows near the surface so that it can get enough light for photosynthesis. The roots of seagrass help stabilize sediment and reduce shoreline erosion 9.

Before the 1700's the Virgin Islands were covered in forest. Around the time when slaves were used for producing crops to sell in the New World, the European slave traders cut most of the forest down, in order to make room for sugarcane and cotton plants. Today, almost all of the vegetation is secondary growth, introduced to the islands from outside sources. Europeans also brought foreign species of animals 2. The constant flow of tourism affects the natural ecosystems by altering the landscape for golf courses, roads, etc. Although, Caribbean organizations are making an effort to conserve the natural beauty in the Virgin Islands 2.
 * Human Impact: **

For more breathtaking pictures and information on the Virgin Islands, watch this video! [|Virgin Island Video]

1. "BBC - Wildlife Finder - Greater Bulldog Bat (video, Facts and News)." //BBC - Homepage//. Web. 09 June 2010. . 2. "Biodiversity Hotspots - Caribbean - Human Impacts." //Biodiversity Hotspots - Home//. Web. 09 June 2010. . 3. "Find a Doctor in the Virgin Islands." //Virgin Islands Information//. Web. 09 June 2010. . 4. "GEOLOGY OF THE VIRGIN ISLANDS." //BCRC Home//. Web. 09 June 2010. . 5. "Noctilio Albiventris." //Digital Morphology at the University of Texas//. Web. 09 June 2010. . 6. "Top Things to Do in the Caribbean." //Top Things to Do in the World//. Web. 09 June 2010. . 7. "Virgin Islands National Park Information Page." //Virgin Islands National Park//. Web. 09 June 2010. . 8. "Virgin Islands National Park." //Shannon Technologies//. Web. 09 June 2010. . 9. "Virgin Islands National Park (U.S. National Park Service)." //U.S. National Park Service - Experience Your America//. Web 09 June 2010. . 10//. Welcome - British Virgin Islands | Caribbean Destination | Tortola | Virgin Gorda | BVI//. Web. 09 June 2010. .
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