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=**Plate Tectonics**= __3 Types of Boundaries__


 * Convergent Boundary**

A convergent boundary happens when a plate collides with or dives under another. When plates at landmasses collide, the crust crumbles and forms mountain ranges. For example, India and Asia crashed about 55 million years ago, slowly forming the Himalayas. At ocean-ocean convergencies, one plate usually dives under the other and forms trenches like the Mariana Trench in the North Pacific Ocean. This is the deepest point on Earth. When oceanic(ocean) and continental(land) plates collide, the dense oceanic crust is subducted by the continental crust and magma forms from the melting of the crustal material. The Cascade Mountain Range is an example of this process.

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 * Divergent Boundary

A divergent boundary happens when 2 plates move away from eachother and magma is forced up through the cracks that are formed. The magma cools creating new crustal material, this process reapeats forming a series of ridges. The mid-ocean ridges in the atlantic and the East Pacific Rise are a result of this process. The East Africa Linear Lakes are within the rift valley of a developing divergent boundary. The red sea is a narrow sea that is formed where the African and Arabian plates are diverging.


 * Transform Boundary**

A transform boundary occurs when two plates slide past one on another creating a fault. A transform boundary doesn't form mountains or oceans but the haulting motion often triggers large earthquakes. The San Andreas fault in California which was formed in the fracture zone between the Pacific and North American plates. This is one of the few transform faults. The Alpine Fault in the South Island of New Zeland is a strike slip fault between the Australian plate and the Pacific plate. The Mendocino, Murray, and Molokai fracture zones are some of the many fracture zones on the ocean floor.

Plate Tectonics. National Geographic. National Geographic Society. 11/5/09 [] Plate Tectonics Map-Plate Boundary Map. Geology.com. NASA. 11/5/09. [] Understanding Plate Motions. USGS. 5/5/99. 11/6/09. []
 * Citations**