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Dynamic Earth

There are three different types of plate boundaries
 * divergent
 * convergent
 * transform

DIvergent Plate Boundaries

Divergent boundaries- where magma rises and pushes plates apart

divergent boundaries occur along spreading centers where plates are moving apart and new crust is created by magma pushing up from the mantle. rift-valleys- deep valleys the center of a mid-ocean ridge
 * the best known divergent boundary is the Mid Atlantic RIdge to make this the two plates involved are the South American Plate and the African Plate
 * another well known divergent boundary is the East Pacific Rise that consists of the Pacific Plate and the Nazca Plate
 * most divergent boundaries are found on the ocean floor and have rift-valleys
 * rift-valleys form the boundary between two diverging plates
 * divergent boundaries may also cause a process called sea floor spreading this is where the magma pushes up out of the earth and becomes lava the lava it quickly cooled to form hard rock to become earth

Convergent Plate Boundaries

Convergent boundaries- when a plate collides with another plate an divides under
 * the two broad classifications of convergent boundaries are subduction and collision boundaries
 * this involves many prosessec like ocean-ocean subdivision, ocean-continent subdivision, and continent-continent collision
 * type 1 ocean-ocean example Island of Indonesia containing the Philippine Plate and the Eurasian Plate
 * type 2 ocean- continent example western coast of South America, the Nazca Plate and the South American Plate
 * type 3 continent-continent example the Himalayas containing the Indian Plate and the Eurasian Plate
 * these also cause deep sea trenches

Transform Plate Boundaries



transform- where two plates grind apart on each other


 * the facture zones that offset the segments of a mid-ocean ridge are transform boundaries
 * the most famous is the San Andreas Fault that contains the Pacific Plate and the North American Plate
 * movement of transform boundaries is not uniform
 * the rate of movement along the San Andreas Fault is about 5 centimeters a year
 * some areas have not moved for a century

Citations
 * http://science.nationalgeogafic.com