2 Plate BoundariesWhy do we care about plate boundaries?
3 Plate BoundariesVolcanoes and earthquakes most often occur where tectonic plates come together.At plate boundaries, many other geologic features, such as mountains and rift valleys, can also occur.
4 Plate Boundaries 1. Divergent 2. Convergent There are three basic types of plate boundaries:1. Divergent2. Convergent3. Transform Fault Boundary
5 Divergent BoundaryA divergent boundary occurs where two plates move apart and create a gap between them.
6 Divergent BoundaryHot rock rises from asthenosphere and cools to form new lithospheric rock.Diverging plates then pull newly formed lithosphere away from gap.New lithospheric (oceanic crust) is formed.
7 Divergent BoundaryMid-oceanic ridges are mountain ranges at divergent boundaries in oceanic crust.
8 Divergent Boundary Real Life Example: Mid-Atlantic Ridge Mid-Atlantic Ridge runs through Atlantic Ocean from Arctic Ocean to an area off the southern tip of South America.
9 Convergent BoundaryA convergent boundary occurs where two plates move toward one another.
10 Convergent Boundaries There are two types of convergent boundaries:1. Subduction2. Collision
11 Convergent Boundary - Subduction Subduction is the process by which one lithospheric plate moves beneath another plate.
12 Convergent Boundary - Subduction Ocean – OceanTwo oceanic plates collideGenerates volcanoesGenerates island chainsReal World ExampleJapan
13 Convergent Boundary - Subduction Ocean – ContinentOceanic and continental plate collideA thin, dense oceanic plate collides with a relatively light, thick continental plate, the oceanic plate is forced under the continental plateReal World ExampleAndes Mountains