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Convergent Boundaries

Convergent Boundaries are where plates collide or dive under the other and the crust crumples and rises to form mountain ranges. In ocean-ocean collisions, one plate usually dives beneath the other forming a deep trench. As the plate on top lifts up, it also forms mountain ranges. The diving plate melts and is often spewed out in volcanic eruptions. Divergent Boundaries Divergent Boundaries are where magma from deep in the Earth's mantle rises toward the surface and pushes apart plates. As the plates separate along the boundary the block between the faults cracks and drops down into the soft interior. When the block sinks it forms a central valley called a rift. Magma comes up and fills the cracks which forms new crust along the boundary. Earthquakes occur along the faults, and volcanoes form where the magma reaches the surface. Transform Boundaries Transform Boundaries are where two plates grind past each other along what are called strike-slip faults. Because the plates aren't crunching or tearing each other, they don't cause great features like mountains or volcanoes. However, the grinding motion does trigger large earthquakes.
 * The Farallon plate played a crucial role in the development of the western part of North America. The interaction between it and the North American plate began in the Jurassic period and is still occurring today.
 * The India and Asia plate crashed about fifty-five million years ago and created the Himalaya.
 * The Juan De Fuca and North American plates formed the Mariana Trench in the North Pacific ocean, which is the deepest point on Earth.
 * The Austrailian plate collides with the Philippine plate, pushing the ocean floor up above sea level and creating island chains.
 * The Great Rift Valley in Africa was formed from where the African and Somali plates were tugged apart.
 * The Mid-Atlantic Ridge is a submerged mountain range that was formed from the African plate and the South American plate pulling apart and magma rising up to form new crust.


 * The San Andrea's fault in California, between the Juan De Fuca and Pacific plates, is the cause of many large earthquakes.
 * The Mendicino and Blanco fracture zones are some of many that scar the ocean floor and offset ridges. These are from the African and South American plates.
 * The Clarion and Pioneer fracture zones off the coast of California show evidence of previous transform-fault activity. They are formed from the Juan De Fuca and the Cocos plates.

Citations > //Divergent Boundary //. NASA. //Why isn't the earth perfect //. Web. 4 Nov. 2009. <[]>. > //Transform Boundary //. //Nature Gallery (Earth) //. Web. 4 Nov. 2009. <[]>. > Shaw, Cindy.2005. McGraw Hill Higher Education. //Science-Art //. Web. 4 Nov. 2009. <[]>. 
 * //Cocos Plate//. Web. 12 Nov. 2009. .
 * "Plate Tectonics." //The Earth Floor//. ETE Team, 28 Apr. 2005. Web. 13 Nov. 2009. .
 * [|divergent1.jpg]
 * "Eurasian Plate." //Major Tectonic Plates of the World//. Web. 12 Nov. 2009. .
 * [|transform2.jpg]
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 110%;">[|convergent1.jpg]
 * "Plate Tectonics." //Science and Space//. National Geographic, Web. 12 Nov. 2009. <[]>.
 * Anissimov, Michael. //What is the Mid-Atlantic Ridge?//. Web. 12 Nov. 2009. <http://www.wisegeek.com/what-is-the-mid-atlantic-ridge.htm>.

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