Читать книгу VI Settler's Handbook - Mr. Cheyenne Harty - Страница 8

One hundred and fifty million years ago, when reptiles ruled the earth, there was neither a Caribbean Sea nor an Atlantic Ocean. The world’s dry land mass (Pangaea) gradually split and spread to form the continents as we know them today (Continental Drift Theory). Even now the geological spreading continues and, where the great blocks of the earth’s crust meet or diverge, titanic forces construct mountain chains or open deep ocean trenches which lead to rumbling volcanoes or shifting earthquakes. Cuba, Hispaniola, Puerto Rico, St. Thomas, St. John and the British Virgin Islands share a single large submerged bank which is part of the North American Plate. St. Croix, separated from her northern sisters by a two-mile deep ocean trench called the Virgin Islands Trench, is aligned along the northern edge of the Caribbean Plate on a mass called the Aves Ridge. To the south of the Caribbean Plate is the landmass of the South American Plate. The only active area as far as geologists can see is located in the Cayman Trough which runs in a line east-west, north of St. Croix, including Puerto Rico, St. Thomas, and other nearby islands. Other than minor tremors, no major activity has occurred in the area. Geologically, the islands are a conglomeration of ancient undersea lava flows, sedimentary and igneous rock formed under water from volcanic ash and layers of sand, and marine animals laid down by ocean currents. There was a major undersea earthquake along with tidal waves in 1867.Volcanic eruptions such as Montserrat in 1995 and the earthquake that submerged Port Royal, Jamaica three centuries ago, are reminders that the earth is in constant change.

The northern island chain in this part of the Caribbean, running east-west, is called the Greater Antilles. This includes: Hispaniola, Cuba and Puerto Rico. Southeast, including the Virgin Islands and extending in an arc toward the South American continent, are the Lesser Antilles. The island chains are the geophysical dividing line between the Atlantic and the Caribbean.