Mod+7.8+-+Kaylee+D

 __Convergent Boundaries__
Convergent boundaries occur where a plate of ocean dives in a process called subduction under a land mass. When the overlying plate lifts up it forms mountain ranges.The diving plate melts and is often sweped out in volcanic eruptions. Convergent eruptions also occur when a plate ussaully dives beneath the other forming deep trenches. Those types of collisions can also lead to under water volcanoes that eventually build up into island arcs like japan. One type of convergent boundary is ocean to ocean which is two plates in the ocean floor converging together to make a trench. An example of ocean to ocean convergence is the Mariana Trench. Another type of convergent boundary is ocean Contienental convergence. Contienental conergence is a number of long narrow, curving trenches thousands of killometers long and 8 to 10 killometers deep cutting into the ocean floor. The last boundary is contiental contiental. that is when two contients meet head on, neither is subducted because the contiental rocks are relativly light and like two colliding icebergs resist downward motion. An example of convergent boundary is the himalaya mountains. The himalaya mountains are the tallest mountain range in the world. Another example is the washinton oregon coastline of the united states. The Juan de fuca oceanic plate is subducting beneath the westward moving North American continental plate. The last example is the Andes mountain range of western south america. The nazca plate is subducting beneath the south american plate.

__Divergent Boundaries__
They are locations where plates are moving away from one another. It occurs above rising convention currents. In the oceans, magma from deep in the earths mantle rises toward the surface and pushes apart two or more plates.Mountains and volcanoes rise along the seam. The process renews the ocean floor and widens the giant basins.a single mid ocean ridge system connects the worlds oceans, making them rigde the longest mountain range in the world.There are two divergent plate boundarys. One of the boundarys is oceanic its when the rising current pushes up on the bottom of the lithosphere lifting it and flowing laterally beneath it.Another boundary is Coninental.it is when the thick continental plate is arched upwards from the convection current's lift, then pulled thin by extensional forces and fractured into a rift-shaped structure.  An example of divergent boundary is the Mid-Atlantic Ridge. The Ridge is a high area compared to the surrounding seafloor because of the lift from the convection current below . A Frequent misconception is that the Ridge is a build-up of volcanic materials, however, the magma that fills the fissure does not flood extensively over the ocean floor and stack up to form a topographic high. Instead, it fills the fissure and solidifies. When the next eruption occurs, the fissure most likely develops down the center of the cooling magma plug with half of the newly solidified material being attached to the end of each plate.

Another example is the red sea. The arabian plate and the african plate diverged and made the red sea. The last example is the north american plate and the eurasian plate pulled apart to make the mid atlantic ridge.

Transform boundaries are locations where two plates slide past one another.The fracture zone that forms a transform plate boundary is known as a transform fault.Most transform faults are found in the ocean basin and connect offsets in the mid alantic rigdes. A smaller number connect mid ocean ridges and subduction zones. Two plates grind past each other along what are now called strike slip faults.These boundaries dont produce spectacular features like mountains or oceans, but the halting motion often triggers large earthquakes such as the 1906 one that devastated San Francisco. An example of transform boundary is the San Andreas fault in California.  The San Andreas connects a divergent boundary in the Gulf of California with the Cascadia subduction zone.

 Another example of a transform boundary on land is the Alpine Fault of New Zealand. Both the San Andreas Fault and the Alpine Faultare interactive plate tectonics. The last example is the porto rico trench is formed by the carribean plate and the north american plate.

__Bibliography__
"National Geographic plate tectonics." //national Geographic//. 11 Nov. 2009. Web. 1 Jan. . National Geographic plate tectonics." //national Geographic//. 11 Nov. 2009. Web. 1 Jan. .