Embedded Files
Now that we understand the composition of the Planet Earth, let's begin by breaking down plate boundaries. There are two types of plates at the crust, the oceanic and continental plates. Please remember that the continental plates are denser than the oceanic plates. These plates interact at plate boundaries and move in different ways because they float on the mantle. There are three plate boundaries and they are:
Convergent Plate Boundary
Divergent Plate Boundary
Transform Plate Boundary
There are several plates around the world and they all move in various ways. Those of us living on the islands in the Caribbean Archipelago exist on the Caribbean Plate.
Diagram showing the movement of Plates globally.
Covergent Plate Boundary
Covergent Plate Boundary
Convergent Plate boundaries can be broken down into two types of convergent boundaries. The first is the regular convergent boundary where an oceanic plate and continental plate collide. The other, is known as a collision margin, where two continental plates collide.
Diagram of a Convergent Plate Boundary
As you can see in the diagram above and below, when an oceanic plate and a continental plate collide, the oceanic plate is forced downward because it is less dense than the continental plate. When this happens the continental plate rises above the oceanic plate. As the oceanic plate breaks down in the mantle, that forces pressure to build and rise. This rising pressure escapes through volcanic eruptions.
2D Diagram of Convergent Plate Boundary
It should be noted that where the oceanic plate begins to subdue and is called the subduction zone. This zone is where Oceanic trenches form as seen in the image above. Volcanoes form overtime as the oceanic plate continues to subdue and more pressure escapes. The escaping magma cools and form the volcano.
Collision Margin
Collision Margin
Diagram of a Collision Margin
Unlike the regular Convergent Plate Boundary, the Collision Margin is a plate boundary where two continental plates collide and instead of one subduing, both end up buckling. This buckling causes an upthrust which creates Fold Mountain. A famous example of Fold Mountains would be the Himalayas.
Click the videos above and use them as supplemental resources for this lesson on Convergent Plate Boundaries.
Divergent Plate Boundary
Divergent Plate Boundary
Divergent Plate Boundaries are a bit different from the other plate boundaries. At divergent plate boundaries, two plates either continental or oceanic are moving away from each other causing a rift to appear in the space left behind.
Look at the picture of Iceland and see an example of a divergent plate boundary. Here, gentle volcanoes form.
At a Divergent Plate Boundary, some of the natural features you would see formed are:
Rift Valleys - are lowland regions formed where Earth’s tectonic plates move apart, or rift. They can be found on land and at the bottom of the ocean, where they are created by the process of seafloor spreading.
Midocean Ridges - Formed as two plates separate, causing molten rock to rise from the seafloor, producing enormous volcanic eruptions of basalt. The speed of spreading affects the shape of a ridge – slower spreading rates result in steep, irregular topography while faster spreading rates produce much wider profiles and more gentle slopes.
Diagram of a Divergent Plate Boundary
Click the videos above and use them as supplemental resources for this lesson on Divergent Plate Boundaries.
Transform plate boundary
Transform plate boundary
Third plate boundary you will learn about today is the Transform Plate boundary. At the transform plate boundary, plates side past each other going in opposite directions. See the diagram below for more.
Just look at this image and you'll see an example of the Transform Plate Boundary where the North American Plate and Pacific Plate slide by each other.
Diagram of Transform Plate Boundary
At the Transform Plate Boundary, as plates slide past each other, the space between the two creates a fault. As the plates slide past each other they cause friction to occur. This friction then produces earthquakes.
Currently, the most famous Transform Plate Boundary is the San Andreas Fault, California.
Click the videos above and use them as supplemental resources for this lesson on Transform Plate Boundaries.
Page updated
Google Sites
Report abuse