Mod+2+-+Elena+B

**Plate Tectonics: The Three Types Of Boundaries** **Divergent Boundary**

A divergent boundary occurs when two plates are moving apart from each other. Then molten rock forces up through the cracks it creates, cools, hardens, and forms new rock on the surface. Most of these boundaries are on ocean floors, and have rift valleys. Rift valleys are deep valleys at the center of a mid-ocean ridge. Examples of Divergent Boundaries: **Convergent Boundary**
 * East Africa and Saudi Arabia have been tearing apart from each other, which has formed and continues to add upon the Red Sea. These two plates pushing away from each other forming a third in the middle is called a triple junction.
 * In Ethiopia, researchers have confirmed that a 35 mile rift will eventually become a new ocean. This rift took a matter of days to form.
 * The Krafla Volcano in northeast Iceland is on a divergent boundary. Between 1975-1984, 7 meters of cracks came with the volcano's volcanic activity.

A convergent boundary occurs when two plates move towards each other and either one goes underneath or they come to a point to form mountains. There are two sun types of convergent boundaries, subduction and collision. Subduction happens when either two ocean plates move towards each other or an ocean plate and a continental plate. When sunduction happens, one of the plates dives under the other. The other sub type of covergent boundary is collision, which is when mountians are formed. These boundaries occur only when two continental plates move towards each other. Examples of Convergent Boundaries: **Transform Boundary**
 * [[image:himalaya2.jpg width="350" height="227" caption="The Himalayas"]]India has been colliding with Asia for 50 million years, forming the Himmalays, the largest mountain range in the world. However, most of the growth has happened in the past 10 million years.
 * On June 9, 1994, a magnitude 8.3 earthquake happened around La Paz, Bolivia, within the subduction zone between the Nazca Plate and the South American Plate. It was the deepest and largest earthquake in South America. This subduction was between an ocean and continental plate.
 * In an ocean to ocean subduction, around Marianas Trench, a deep sea trech called The Challenger Deep was formed. It is deeper then Mt. Everest is tall.

A transform boundary occurs when two plates slide past each other. This causes traction between the two plates, and large cracks. Most transform boundaries are found in California. Examples of Transform Boundaries: ** Citations: sharonyau1995,. //Convergent Boundaries //. 2009. //Flickr //. Web. 3 Nov. 2009. <[]>. Sharonyau1995,. //Divergent Boundaries //. 2009. //Flickr //. Web. 3 Nov. 2009. <[]>. elosoenpersona,. //Ghandrava Chuli //. 2007. //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Flickr //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">. Web. 3 Nov. 2009. <[]>. <span style="font-family: arial,helvetica,sans-serif; font-size: 13px;">//<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Transform Boundary //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">. NASA. //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Why isn't the earth perfect //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">. Web. 4 Nov. 2009. <[]>. <span style="font-family: arial,helvetica,sans-serif; font-size: 13px;"><span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Tomes, Ray. //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Tectonic Plates Meet Here //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">. 2008. //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Flickr //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">. Web. 3 Nov. 2009. <[]>. Silva, Jamie. //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Iceland - Krafla mountain //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">. 2008. //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">Flickr //<span style="font-family: Arial,Helvetica,sans-serif; font-size: 14px;">. Web. 3 Nov. 2009. <[]>. <span style="color: #333333; font-family: times,helvetica; font-size: 16px; line-height: 18px;">         ** "Plate Tectonics." //National Geographic//. 2009. Web. 6 Nov. 2009. <http://science.nationalgeographic.com/science/earth/the-dynamic-earth/plate-tectonics-article.html>. "Giant Crack in Africa Will Create a New Ocean." //Yahoo//. 2 Nov. 2009. Web. 6 Nov. 2009. <http://news.yahoo.com/s/livescience/giantcrackinafricawillcreateanewocean>. Jim, Watson. "Understanding Plate Motions." //USGS//. 5 May 1999. Web. 6 Nov. 2009. <http://pubs.usgs.gov/gip/dynamic/understanding.html>.
 * The San Andreas fault zone, where many transform boundaries are active, takes up about two-third the length of California. The Pacific Plate and North American Plate are the two plates in these boundaries.
 * The Pacific Plate has been sliding past the North American Plate for 10 million years. They slide at a rate of about five centimeters per year.[[image:northamericanplate4.jpg width="182" height="250" caption="The North American Plate"]] [[image:pacificplate1.jpg.jpg width="300" height="221" caption="The Pacific Plate"]]
 * There are only a few transform boundaries on the ocean floor. They include the Clarion, Molokai, and Pioneer of the coasts of Mexico and California. All of these have been inactive for years, though.